El periodo de transición en la vaca lechera y la eficiencia reproductiva

Noticias de Reproducción Bovina

AGOSTO 2009

AÑO 2, NÚMERO 24, AGOSTO DE 2009

El periodo de transición en la vaca lechera y la eficiencia reproductiva El periodo de transición en la vaca lechera comprende las tres semanas antes y las tres después del parto (también conocido como periparto). En los últimos años, este tema ha merecido mucha investigación, pues lo que se haga bien o mal durante el mismo repercutirá en la eficiencia reproductiva y en la producción de leche de las vacas. Durante el periodo de transición la glándula mamaria se prepara para la lactogénesis, el feto crece exponencialmente, se suprime la respuesta inmune y el consumo de materia seca decrece; además, el rumen debe adaptarse a la dieta que reciben las vacas frescas, dieta caracterizada por el alto contenido de energía en forma de grano. Muchos trastornos que se presentan en las primeras dos semanas posparto (hipocalcemia clínica y subclínica, cetosis, retención placentaria, prolapso uterino, metritis, mastitis, desplazamiento de abomaso), como aquellos que se presentan tiempo después (laminitis, quistes ováricos, endometritis y anestro) tienen el mismo origen que consiste en los errores cometidos durante el periodo de transición. En gran parte los problemas están relacionados con la disminución del consumo de materia seca durante el periodo de transición; de manera que, el consumo decrece alrededor de 30% durante las últimas tres semanas de gestación pero la mayor parte de la reducción ocurre 5 a 7 días antes del parto. Como se aprecia, el consumo disminuye cuando las necesidades son mayores, esto queda subsanado por la movilización de grasa que a su vez genera acumulación de ácidos grasos en el hígado y cetosis preparto. El manejo moderno del periodo de transición ha estado orientado a mantener la normocalcemia, fortalecer el sistema inmune, adaptar el rumen a una dieta alta en energía e incrementar el consumo de materia seca. Finalmente, algunas recomendaciones generales de manejo durante el periodo de transición son: separar a las vaquillas de las vacas, tener para todos los animales suficiente espacio de comedero, estos deben contar con las mismas características que tienen los comederos de las vacas frescas y la dieta debe estar disponible las 24 horas del día. Sin duda, un buen manejo durante el periodo de transición garantiza una mayor producción de leche y además los veterinarios sufriremos menos, tratando vacas con problemas reproductivos.

Dr. Joel Hernández Cerón Compilador

Departamento de Reproducción

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Noticias de Reproducción Bovina

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MANEJO REPRODUCTIVO Reproduction in Domestic Animals Volume 44 Issue 4, Pages 663 – 671

Effect of Prepartum Energetic Supplementation on Productive and Reproductive Characteristics, and Metabolic and Hormonal Profiles in Dairy Cows under Grazing Conditions

D Cavestany 1,2 , M Kulcsár 3 , D Crespi 1 , Y Chilliard 4 , A La Manna 1 , O Balogh 3 , M Keresztes 3 , C Delavaud 4 , G Huszenicza 3 and A Meikle 2 1 National Agricultural Research Institute (INIA La Estanzuela), Colonia, Uruguay ; 2 Faculty of Veterinary Sciences, Montevideo, Uruguay ; 3 Szent Isván University, Faculty of Veterinary Science, Budapest, Hungary ; 4 Unité de Recherche sur les Herbivores, INRA-Theix, Saint-Genès-Champanelle, France Author's address (for correspondence): D Cavestany, National Institute of Agricultural Research (INIA) La Estanzuela, C. Correos 39173, 70000 Colonia, Uruguay. E-mail: daniel.cavestany@gmail.com

The effect of cracked corn grain supplementation (3.5 kg/day) during 3 weeks before the expected calving date on milk production and composition, body condition score (BCS), metabolic and hormonal profiles and length of postpartum anoestrus was evaluated in multiparous Holstein dairy cows under grazing conditions (Energy supplemented group, n = 10; Control group, n = 10). Body condition score was weekly recorded during the peripartum period, from days −21 to +35 (parturition = day 0). Non-esterified fatty acids, β-hydroxybutyrate, cholesterol, urea, insulin, insulin-like growth factor I (IGF-I), leptin, thyroxine (T4) and 3,3''5-triiodothyroinine (T3) were weekly determined in plasma from days −21 to +35. The reinitiation of ovarian cyclicity was twice weekly determined by ovarian ultrasonography and confirmed by plasma progesterone concentrations. Cows fed energy concentrate prepartum had higher BCS during the prepartum and postpartum and produced more milk.

Non-esterified fatty acids plasma concentrations were significantly higher in the energy group, while cholesterol was higher in the control group. Treated cows had higher levels of plasma insulin, IGF-I and leptin pre-calving. IGF-I, leptin and T4 were diminished during the early postpartum period in both groups. Insulin levels were also diminished in the control group, but levels remained high in the energy-supplemented

group. Treated cows ovulated sooner after parturition than controls. We conclude that Energetic supplementation prepartum in cows under grazing conditions increased milk production and reduced the reinitiation of ovarian activity, consistent with a better EB (BCS), higher prepartum levels of IGF-I, leptin and insulin, and higher insulin levels during early postpartum.

Correspondence: daniel.cavestany@gmail.com

Reproduction in Domestic Animals Volume 44 Issue 4, Pages 643 – 646

Incidence of Error in Oestrus Detection Based on Secondary Oestrus Signs in a 24-h Tie-Stalled Dairy Herd with Low Fertility

RMSBK Ranasinghe 1 , T Nakao 1 and A Kobayashi 2 Laboratory of Theriogenology, Department of Veterinary Medicine, Faculty of Agriculture, Yamaguchi University, Yoshida, Yamaguchi, Japan ; 2 Kitami Farm Animal Medical Center, Kitami, Hokkaido, Japan Author's address (for correspondence): T. Nakao, Laboratory of Theriogenology, Department of Veterinary Medicine, Faculty of Agriculture, Yamaguchi University, Yoshida 1677-1, Yamaguchi, 7538515, Japan. E-mail: tnakao@yamaguch-u.ac.jp 1

Oestrus detection error and conception rates after AI based only on secondary oestrus signs were evaluated in a high yielding, 24-h tie-stalled dairy herd with low fertility, using milk progesterone profiles. Oestrus detection was based on the secondary oestrus signs such as restlessness, swelling, congestion of vulva and clear mucus discharge. Sixty eight AI conducted after observing the secondary oestrus signs in 44 animals were included in the study. Of the 68 AI, 53 (77.9%) were conducted in the follicular phase, and 13 (19.1%) and 2 (2.9%) were carried out in the luteal phase and during pregnancy, respectively. The overall error in oestrus detection based on milk progesterone profiles was 22.1%.

The oestrus detection error did not differ significantly among different secondary oestrus signs. None of the AI conducted in the luteal phase resulted in conception, whereas 20.8% of AI conducted in the follicular phase resulted in conception. No significant difference in the

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Noticias de Reproducción Bovina conception rates among the groups of cows with different secondary oestrus signs was shown. The high incidence of oestrus detection error in this study might have been caused by the detection of cows in oestrus based only on secondary oestrus signs due to the confinement of animals. In conclusion, there was a high incidence of heat detection error in the 24-h tie-stalled dairy herd and oestrus detection based only on secondary oestrus signs resulted in low conception rate.

Correspondence: tnakao@yamaguch-u.ac.jp

Theriogenology 72 (2009) 408–416

Effect of growth and development during the rearing period on the subsequent fertility of nulliparous Holstein-Friesian heifers

J.S. Brickell *, N. Bourne, M.M. McGowan 1, D.C. Wathes Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Herts, AL9 7TA, United Kingdom

This study investigated the effect of growth parameters and metabolic indices during the rearing period on the fertility of nulliparous Holstein-Friesian heifers managed on 17 UK dairy farms. Growth parameters (body weight [BW], heart girth, height, and crown-rump length) and metabolic indices (insulin-like growth factor-I [IGF-I], insulin, glucose, and urea) were measured at approximately 30, 180, and 450 d of age. Fertility data collected included age at first breeding (AFB), number of services per conception, pregnancy rate to first artificial insemination (AI), and age at first calving (AFC).

Of the heifers initially bred (n = 428), 4% failed to conceive. The mean pregnancy rate to first AI for heifers that conceived and calved without suffering reproductive loss (n = 392) was 67%, and 6% required >2 inseminations. The mean AFB and AFC was 473 5 d (range, 357 to 936 d) and 791 6 d (range, 636 to 1529 d), respectively. Increased BW, girth, and IGF-I concentration (at 30, 180, and 450 d) and increased skeletal growth (at 180 and 450 d) was associated with a reduced AFB and AFC (P < 0.05 to 0.001). Heifers calving at <775 d had a mean BW gain of 0.82 0.01 kg from 30 to 180 d.

Increased glucose concentration at 180 d was associated with a reduced AFB (P < 0.01), but no

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associations were found between insulin and urea concentrations and any of the fertility traits recorded (P > 0.1). Suboptimal growth associated with an increased AFC could be alleviated by improved monitoring of replacement heifers during the rearing period.

Correspondence: jbrickell@rvc.ac.uk

Animal Reproduction Science 114 (2009) 1–13

Effect of prepartum diet on postpartum ovarian activity in Holstein cows in a pasture-based dairy system , C. Viñolesa, M.A. Crowec, A. La Mannaa, A. Mendozab a National Agricultural Research Institute, INIA La Estanzuela, C. Correos 39173, 70000 Colonia, Uruguay b Faculty of Veterinary, University of Uruguay, Lasplaces 1620, 11600 Montevideo, Uruguay c School of Agriculture, Food Science and Veterinary Medicine and Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland D. Cavestany

a,b,*

The hypothesis was that supplementation during the late prepartum period will differentially affect reproductive and productive variables according to parity. Primiparous (n = 22) and multiparous (n = 22) pregnant autumn calving Holstein cows were stratified in two groups according to parity (primiparous or multiparous) and within each group were randomly assigned to two treatments: (a) low supplemented (LS) or (b) high supplemented (HS) prepartum diet. The LS group was offered 5.2 kg/cow/day (DM basis) of wheat silage, and the HS group 4.7 kg cow/day (DM basis)/of corn silage and 3.6 kg (DM basis) of wheat bran + 12 g of urea. Both groups grazed on natural pastures. After calving, all cows received the same diet. The experimental period was from 3 weeks before calving to 7 weeks postpartum (PP); body condition score (BCS) and blood samples for hormonal analyses were obtained weekly and ovarian ultrasonography was conducted three times per week. The loss in BCS around calving was less pronounced in HS cows, but only multiparous supplemented cows maintained BCS throughout the study. Nonesterified fatty acids (NEFA) increased during the prepartum period in the LS but not in the HS cows, with peak values occurring on day 14 PP in all groups. During the remainder of the experiment NEFAwas greater in LS than in HS

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Noticias de Reproducción Bovina cows. Prepartum treatment did not affect the proportion of cows that had ovulations from the first dominant follicle postpartum, but decreased the interval to first ovulation in multiparous cows (22.9 compared with 38.2 days; P < 0.05). This was associated with greater plasma IGF-I concentrations at the time the dominant follicle of the first follicular wave reached its maximum diameter (8.0 compared with 3.6 nmol/L; P < 0.05). However, prepartum treatment had no effect on onset of ovarian activity in primiparous cows. Supplementation had no effect on milk production or milk protein percentage but increased milk fat percentage.We conclude that feeding a high-supplemented prepartum diet to multiparous cows allowed them to maintain BCS around calving, and thiswas associated with greater concentrations of IGF-I and an earlier onset of estrous cycles after calving.

Correspondence: daniel.cavestany@gmail.com

Animal Reproduction Science 114 (2009) 109–114

Effect of selenium and vitamin E supplementation during the late pregnancy on reproductive indices and milk production in heifers M.M. Moeini*, H. Karami, E. Mikaeili Razi University, College of Agriculture, Kermanshah, Iran

A trial was performed to determine the effects of supplementation of selenium (Se) and vitamin E (VE) on reproductive indices and milk production in Holstein heifers. Sixty heifers at the late stage of gestation were randomly assigned into three groups. Heifers were balanced for age, weight and time of calving. Four and 2 weeks before expected calving the heifers were injected 0ml (C), 20 ml (T1), and 40 ml (T2) Se and VE supplements. Each ml contained 0.5mg Se and 50 IU of d, l-alpha-tocopheryl acetate. Blood samples were collected from heifers 4weeks before expected calving and at calving day. Se concentrations in serum and colostrums were measured. The reproductive parameterswere recorded. The effects of Se and VE supplements on somatic cell count (SCC) and milk yield also were measured. Supplementation of Se increased the level of Se in serum of treated heifers at

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calving day (P < 0.05). Se concentration of colostrums were affected by the treatments (P < 0.05). Concerning reproductive performance of treated heifers; gestation length was similar among groups but in comparison with controls, T1 and T2 had no incidence of retained fetal membrane (i.e., beyond 12 h.). In addition, open dayswere fewer in T1 and T2 heifers and the number of services per conception was fewer in T2 compared with controls (P > 0.05). Daily milk production at 8 weeks lactation was significantly increased in T2 compared with controls (P < 0.05). Likewise, the milk SCC decreased in treated heifers compared with controls (P < 0.05). *Correspondence. mmoeini2008@yahoo.com

Livestock Science 123 (2009) 276–282

Influence of management and genetic merit for milk yield on the oxidative status of plasma in heifers

N. Wullepit a,b,*, K. Raes a,1, B. Beerda c, R.F. Veerkamp c, D. Fremaut b, S. De Smet a a Laboratory for Animal Nutrition and Animal Product Quality, Department of Animal Production, Ghent University, Proefhoevestraat 10, 9090 Melle, Belgium b Faculty of Biosciences and Landscape Architecture, University College Ghent, Voskenslaan 270, 9000 Ghent, Belgium c Animal Breeding and Genomics Centre, Wageningen University and Research Centre, Po Box 65, 8200 AB Lelystad, The Netherlands

This study was part of a larger study that addressed whether milk production levels affect health risks in dairy cows as influenced by genetic merit for milk yield and management factors.

Plasma samples were collected from 80 Holstein Friesian heifers at 2 weeks pre-partum and at 4 and 8 weeks post-partum in a 2×2×2 factorial arrangement design with the factors breeding value for milk production (high or low), milking frequency (2 or 3 times a day) and feed energy density (high or low). The following parameters indicative of the oxidative status were measured in plasma: ferric reducing ability of plasma (FRAP), α-tocopherol level, glutathione peroxidase activity (GSH-Px), superoxide dismutase activity (SOD), thiobarbituric acid reactive substances (TBARS) concentration and paraoxonase activity (PON). There was a significant effect of time for FRAP, α-tocopherol, GSH-Px and SOD, indicating changes in the plasma oxidative status around parturition. A high merit for milk yield, three-

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Noticias de Reproducción Bovina times-daily milking and especially feeding the high energy feed all stimulated milk production level.

However, the influence on oxidative status parameters was minimal. Only the FRAP value was significantly lower in the high compared to the low energy group. Cows seem to undergo some oxidative stress around parturition, which can make them more susceptible to disorders.

However, there were no clear indications that breeding value, milk frequency or feed energy level jeopardizes heifers in a way oxidative stress became critical.

Correspondence: Nicolas.Wullepit@hogent.be (N. Wullepit), Stefaan.DeSmet@UGent.be (S. De Smet).

Animal Reproduction Science 114 (2009) 54–61

Influence of the breed of bull (Bos taurus indicus vs. Bos taurus taurus) and the breed of cow (Bos taurus indicus, Bos taurus taurus and crossbred) on the resistance of bovine embryos to heat

Bruno G. Eberhardta, Rafael A. Satrapaa, Cláudia R.L. Capinzaikib, Luzia A. Trincab, Ciro M. Barros a,* a Department of Pharmacology, Institute of Bioscience, University of Sao Paulo State (UNESP), 18618-000 Botucatu, Sao Paulo, Brazil b Department of Biostatistics, Institute of Bioscience, University of Sao Paulo State (UNESP), 18618-000 Botucatu, Sao Paulo, Brazil

In vitro studies have shown that Bos taurus indicus (B. t. indicus) embryos submitted to heat shock at early stages of development are better able to survive as compared to Bos taurus taurus embryos. Embryo genotype influences resistance to heat shock thus leading to the question as to whether embryos sired by thermo-tolerant breeds exhibit the same resistance to heat shock. In the present study the influence of both oocyte and semen, on the resistance to heat shock (HS) at early stages of in vitro development, was assessed in B. t. indicus [Nelore (N) breed], B. t. taurus [Holstein (H) and Angus (A) breeds] and crossbreds. In Experiment 1, Nelore and crossbred oocytes were collected from slaughterhouse ovaries and fertilized with spermatozoa from Nelore and Angus bulls.

Presumptive embryoswere collected and randomly assigned to control (39 ◦C) or HS at 12, 48 or 96 h post insemination (hpi; 41 ◦C for 12 h)

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treatments. The cleavage rates and proportion of embryos developing to the blastocyst and hatched blastocyst stages were recorded on Days 2, 8 and 10, respectively. Heat shock treatment decreased development of both Nelore and crossbred embryos. There was a significant interaction between time (12, 48 or 96 hpi) and temperature for blastocyst rates, i.e., the embryos became more thermotolerant as development proceeded.

In Experiment 2, oocytes from Nelore and Holstein cows were fertilized with semen from bulls of either Nelore or Angus breeds, and subjected to 12 h HS at 96 hpi. Heat shock at 96 hpi, decreased embryo development. Additionally, cow×treatment and bull×treatment interactions were significant for blastocyst rates, i.e., both breed of cow and breed of bull affected the decline in blastocyst rate caused by heat shock treatment. In conclusion, the present results indicate that Nelore embryos (indicus) are more resistant to heat shock than Holstein (taurus) at early stages of in vitro development, and that embryos become more thermo-tolerant as development proceeds.

Additionally, the resistance to heat shockwas a result of the genetic contribution from both oocyte and spermatozoa.

Correspondence: cmbarros@ibb.unesp.br

Animal Reproduction Science 114 (2009) 301–305

Maternal plasma oestrone sulphate concentration prior to parturition in relation to birth weight of the calf in primiparous, 2-year-old, Angus heifers

R.E. Hickson*, P.R. Kenyon, N. Lopez-Villalobos, S.T. Morris Institute of Veterinary, Animal and Biomedical Sciences, College of Sciences, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand

Dystocia and assisted calving in primiparous heifers are persistent problems in beef herds, and incidence increases with increasing birth weight of calves. Plasma samples taken from 33 primiparous, 2-year-old, Angus heifers 2 days prior to parturition were analysed for oestrone sulphate concentration. Additional samples taken at 4, 6, 8 and 10 days prior to parturition were analysed for 17 of these heifers. At parturition, birth weight of the calf, post-partum live weight of

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Noticias de Reproducción Bovina the heifer, assistance at calving (n = 6) and status of the calf (stillborn (n = 4) vs. alive)were recorded. Maternal plasma oestrone sulphate concentration was stable from 10 to 4 days prior to parturition and increased between 4 and 2 days prior to parturition for non-assisted heifers.

Maternal plasma oestrone sulphate concentration did not affect the probability of assistance at calving or stillbirth.

Correspondence: r.hickson@massey.ac.nz

Animal Reproduction Science 114 (2009) 81–88

Pre-freeze bull sperm head morphometry related to post-thaw fertility

C.G. Gravance, M.E. Casey*, P.J. Casey One Helix Trust, Research Centre for Reproductive Medicine, The University of Auckland, Private Bag 92016, Auckland, New Zealand

Artificial insemination using cryopreserved semen is a common management tool of the contemporary livestock producer. The ability to determine post-thaw fertility from pre-freeze sperm function parameters would be of major benefit to producers. In this study computer-aided sperm head morphometry was used to determine whether there is any association between prefreeze bull sperm head measurements and post-thaw non-return to oestrus rates. Sixteen commercial artificial insemination bulls were used for this study. Of the 16 bulls, eight had ≥69% nonreturn to oestrus rates while the remaining eight bulls had <69% non-return to oestrus rates, based on artificial insemination of cryopreserved semen from a minimum of 748 inseminations per bull. Microscope slides of extended or cryopreserved and thawed semen were prepared and stained by the MGZIN procedure. The morphometric dimensions for length, width, width/length, area and perimeter for a minimum of 200 sperm heads were analyzed from each slide by ASMA and the mean measurements and intra-analysis coefficients of variation (CV) recorded. The post-thaw non-return to oestrus rates for all bulls were correlated with pre-freeze measurements of width (r = 0.53, P < 0.05), and the change in width/length after cryopreservation (r = 0.61, P < 0.05). There were no significant differences in the mean prefreeze or post-thaw

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sperm head measurements between the two groups. However, the mean post-thaw change in width/length was significantly (P = 0.003) different between the groups. The mean postthaw intra-analysis variability for width was significantly lower (P = 0.03) in bulls with nonreturn to oestrus rates (NRR)≥69%. Overall, the data suggests that pre-freeze and postthaw bull sperm head morphometry measurements of individual bulls may have minimal predictive value of post-thaw fertility as determined by non-return to oestrus rates between groups of bulls with limited variance in non-return to oestrus rates.

The clinical relationship ofspermheadmorphometry and fertility in bulls with a greater, clinically significant range of non-return to oestrus, remains to be studied.

Correspondence: mecasey@xtra.co.nz

Theriogenology 72 (2009) 378–385

Progesterone concentrations, exogenous equine chorionic gonadotropin, and timing of prostaglandin F2a treatment affect fertility in postpuberal Nelore heifers

C.C. Dias a, F.S. Wechsler a, M.L. Day b, J.L.M. Vasconcelos a,* a Departamento de Produςão Animal, Faculdade de Medicina Veterinária e Zootecnia, FMVZ-UNESP, CEP 18618-000, Botucatu, SP, Brazil, b Department of Animal Sciences, The Ohio State University, Columbus, OH 43210, USA

Two experiments were performed to test the hypothesis that elevated progesterone concentrations impair pregnancy rate to timed artificial insemination (TAI) in postpuberal Nelore heifers. In Experiment 1, postpuberal Nelore heifers (n = 398) received 2 mg estradiol benzoate (EB) and either a new progesteronereleasing intravaginal device containing 1.9 g of progesterone (CIDR) (first use) or a CIDR previously used for 9 d (second use) or for 18 d (third use) on Day 0, 12.5 mg prostaglandin F2a (PGF2a) on Day 7, 0.5 mg estradiol cypionate (ECP) and CIDR withdrawal on Day 9, and TAI on Day 11. Largest ovarian follicle diameter was determined on Day 11. The third-use CIDR treatment increased largest ovarian follicle diameter and pregnancy rate. Conception to TAI was reduced in heifers with smaller follicles in the

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Noticias de Reproducción Bovina first- and second-use CIDR treatments, but not in the third-use CIDR treatment. In Experiment 2, postpuberal Nelore heifers received the synchronization treatment described in Experiment 1 or received 12.5 mg PGF2a on Day 9 rather than Day 7. In addition, 50% of heifers received 300 IU equine chorionic gonadotropina (eCG) on Day 9. Heifers were either TAI (Experiment 2a; n = 199) or AI after detection of estrus (Experiment 2b; n = 125 of 202). In Experiment 2a, treatment with eCG increased pregnancy rate to TAI in heifers that received PGF2a on Day 9 but not on Day 7 and in heifers that received a first-use CIDR but not in heifers that received a third-use CIDR. Treatments did not influence reproductive performance in Experiment 2b. In summary, pregnancy rate to TAI in postpuberal Nelore heifers was optimized when lower concentrations of exogenous progesterone were administered, and eCG treatment was beneficial in heifers expected to have greater progesterone concentrations.

Correspondence: vasconcelos@fca.unesp.br

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luteum were examined using Bmode sonography.

Blood flow was measured by determining blood flow volume (BFV) and pulsatility index (PI) of the uterine arteries. Clinical uterine involutionwas complete on day 28 as demonstrated by transrectal palpation and B-mode sonography.

BFV declined (P < 0.05) steeply between days 1 and 7 from 4312 ml/min to 1443 ml/min and moderately (P < 0.05) to 230 ml/min on day 28.

From this time on there were no significant changes (P > 0.05) of BFV until the end of the study. The pulsatility index rose from 1.54 on day 1 reaching a peak value of 5.56 on day 28 and decreased (P < 0.05) linearly to 3.13 on day 86.

The results showthat transrectal colour Doppler sonography is an additional tool for examining uterine changes during the first 12 weeks after parturition in cows. While uterine blood flow changes were only demonstrated during the first 4 weeks of the puerperium, the pulsatility index was also suitable to investigate alterations in uterine perfusion during the next 8 weeks after parturition.

Correspondence: lars.krueger@tiho-hannover.de

Animal Reproduction Science 114 (2009) 23–31

Transrectal Doppler sonography of uterine blood flow during the first 12 weeks after parturition in healthy dairy cows Lars Kruegera,*, Juliane Koertea, Georgios Tsousisa, Kathrin Herzoga, Gerhard Flachowskyb, Heinrich Bollweina a Clinic for Cattle, University of Veterinary Medicine Hannover, Foundation, Bischofsholer Damm 15, 30173 Hannover, Germany b Institute of Animal Nutrition, Federal Agricultural Research Centre (FAL), Braunschweig, Germany

The aim of this studywas to determine if transrectal colour Doppler sonography of uterine arteries is a useful method to quantify uterine changes during the first 12 weeks after parturition in cows. Examinations were carried out on days 1, 7, 14, 28, 56 and 86 after parturition (day 0) in 42 Holstein–Friesian multiparous dairy cows (mean lactation number: 2.63±0.73). Findings obtained by transrectal manual palpation were quantified using scores for uterine size (SUS) graded from 1 to 6. The mean diameter of intrauterine fluid accumulation within the uterine body and the presence of a dominant follicle and/or a corpus

Livestock Science 123 (2009) 175–179

Validation of body condition score as a predictor of subcutaneous fat in Nelore (Bos indicus) cows

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Henderson Ayres a,*, Roberta Machado Ferreira a, José Ribamar de Souza Torres-Júnior a,b, Clarice Garcia Borges Demétrio c, César Gonçalves de Lima d, Pietro Sampaio Baruselli a Departamento de Reprodução Animal, FMVZ/USP, São Paulo - SP – Brazil b Universidade Federal Rural da Amazônia, UDP-UFRA, Parauapebas - PA – Brazil, c Departamento de Ciências Exatas, ESALQ, USP, Piracicaba - SP – Brazil, d Departamento de Ciências Básicas, FZEA/USP, Pirassununga - SP - Brazil

The aim of the present study was to determine the relationship among body weight (BW), body condition score (BCS) and rump fat thickness (RFAT) measured by ultrasonography, and validate the relationship between BCS and RFAT over the time. Two hundred sixty and six Nelore cows had their BW, BCS and RFAT evaluated at five different moments during the production cycle: M1) weaning; M2) parturition, M3) 42 days post-partum; M4) 82 days postpartum and M5) 112 days post-partum. A BCS valuewas attributed for each cow following a 1 to 5 points scale.

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Noticias de Reproducción Bovina Ultrasonographic images for RFAT measurement were obtained using a 3.5 MHz linear transducer.

Images were immediately analyzed as soon as they were formed and frozen. Body condition scores and ultrasound measurements were collected on the same day by a single trained technician. The relationship between BCS and RFAT values was investigated by regression models. The analysis of similarity among the five obtained models was performed using the proc MIXED from SAS and the correlations among variables were analyzed with proc CORR from

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SAS. The BCS was able to predict RFAT in Nelore cows in all different moments evaluated. Also, it was shown that BCS presented high correlation (r=0.82 to 0.93) and relationship (R2=0.73 to 0.92) with RFAT. However, both BCS and RFAT showed low correlation (r=0.37 to 0.50) and relationship (R2=0.13 to 0.25) with BW. The BCS classification by visual method using a 1 to 5 point scale, was able to predict the RFAT in Nelore cows over the time.

Correspondence: hayres65@yahoo.com.br

ARTÍCULOS DE REVISIÓN Reproduction (2009) 138 195–209

Comparative aspects of implantation

Fuller W Bazer1, Thomas E Spencer1, Greg A Johnson2, Robert C Burghardt2 and Guoyao Wu1 Departments of 1Animal Science and 2Veterinary Integrative Biosciences, Texas A&M University, 2471 TAMU, College Station, Texas 77843-2471, USA Correspondence should be addressed to F W Bazer; Email: fbazer@cvm.tamu.edu

Uterine receptivity to implantation of blastocysts in mammals includes hatching from zona pellucida, precontact with uterine luminal (LE) and superficial glandular (sGE) epithelia and orientation of blastocyst, apposition between trophectoderm and uterine LE and sGE, adhesion of trophectoderm to uterine LE/sGE, and, in some species, limited or extensive invasion into the endometrial stroma and induction of decidualization of stromal cells. These periimplantation events are prerequisites for pregnancy recognition signaling, implantation, and placentation required for fetal–placental growth and development through the remainder of pregnancy. Although there is a range of strategies for implantation in mammals, a common feature is the requirement for progesterone (P4) to downregulate expression of its receptors in uterine epithelia and P4 prior to implantation events. P4 then mediates its effects via growth factors expressed by stromal cells in most species; however, uterine luminal epithelium may express a growth factor in response to P4 and/or estrogens in species with a true epitheliochorial

placenta. There is also compelling evidence that uterine receptivity to implantation involves temporal and cell-specific expression of interferon (IFN)-stimulated genes that may be induced directly by an IFN or induced by P4 and stimulated by an IFN. These genes have many roles including nutrient transport, cellular remodeling, angiogenesis and relaxation of vascular tissues, cell proliferation and migration, establishment of an antiviral state, and protection of conceptus tissues from challenges by the maternal immune cells.

Correspondence: fbazer@cvm.tamu.edu

Physiol Rev 89: 921–956, 2009

From Pheromones to Behavior

ROBERTO TIRINDELLI, MICHELE DIBATTISTA, SIMONE PIFFERI, AND ANNA MENINI Department of Neuroscience, University of Parma, Parma; and International School for Advanced Studies, Scuola Internazionale Superiore di Studi Avanzati (SISSA) and Italian Institute of Technology, SISSA Unit, Trieste, Italy

In recent years, considerable progress has been achieved in the comprehension of the profound effects of pheromones on reproductive physiology and behavior. Pheromones have been classified as molecules released by individuals and responsible for the elicitation of specific behavioral expressions in members of the same species.

These signaling molecules, often chemically

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Noticias de Reproducción Bovina unrelated, are contained in body fluids like urine, sweat, specialized exocrine glands, and mucous secretions of genitals. The standard view of pheromone sensing was based on the assumption that most mammals have two separated olfactory systems with different functional roles: the main olfactory system for recognizing conventional odorant molecules and the vomeronasal system specifically dedicated to the detection of pheromones. However, recent studies have reexamined this traditional interpretation showing that both the main olfactory and the vomeronasal systems are actively involved in pheromonal communication. The current knowledge on the behavioral, physiological, and molecular aspects of pheromone detection in mammals is discussed in this review.

Correspondence: fbazer@cvm.tamu.edu

J. Dairy Sci. 2009. 92:3545-3565.

Invited review: Use of meta-analysis in animal health and reproduction: Methods and applications

J. Lean*,+,1, A. R. Rabiee*,+, T. F. Duffield+ and I. R. Dohoo§ * SBScibus, PO 660, Camden, New South Wales, Australia + University of Sydney, Camden, New South Wales, Australia + Department of Population Medicine, University of Guelph, Guelph, Ontario, N1G 2W1 Canada §Centre for Veterinary Epidemiological Research, Atlantic Veterinary College, 550 University Avenue, Charlottetown, Prince Edward Island, Canada 1 Corresponding author: ianl@dairydocs.com.au

The objectives of this paper are to provide an introduction to meta-analysis and systematic review and to discuss the rationale for this type of research and other general considerations. We highlight methods used to produce a rigorous meta-analysis and discuss some aspects of interpretation of meta-analysis drawing on examples from the animal and veterinary science literature. Meta-analysis is a rapidly expanding area of research that has been relatively underutilized in animal and veterinary science. It is a quantitative, formal, epidemiological study design used to systematically assess previous research studies to derive conclusions about that body of research. Outcomes from a meta-analysis may include a more precise estimate of the effect of treatment or risk factor for disease, or other outcomes, than any individual study contributing

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to the pooled analysis. The examination of variability or heterogeneity in study results is also a critical outcome. The benefits of meta-analysis include a consolidated and quantitative review of a large, and often complex, sometimes apparently conflicting, body of literature. Meta-analytic methods place less emphasis on dichotomous outcomes from null hypothesis significance testing and greater emphasis on determining the magnitude and the precision of an effect of interest. A substantial benefit of meta-analysis is the potential to investigate new hypotheses using existing data, both through the development of a priori hypotheses and by examination of the heterogeneity in study responses.

The specification of the outcome and hypotheses that are tested is critical to the conduct of metaanalyses, as is a sensitive literature search. A failure to identify the majority of existing studies can lead to erroneous conclusions; however, there are methods of examining data to identify the potential for studies to be missing; for example, by the use of funnel plots. Many of the statistical methods to conduct meta-analysis are widely used. Bayesian methods are well suited to metaanalysis. The post-hoc methods used to evaluate heterogeneity and publication bias, which include the I 2 statistic, L’Abbé plots, Galbraith plots, Rosenthal’s N, and influential study analysis are exclusively used in meta-analysis. Examples where meta-analyses have been repeated in animal science or veterinary medicine show good consistency in estimates of effect. Findings of studies to date have provided new understandings of rumen modifiers, milk fever, parasite control, mastitis, somatotropin, and reproductive manipulations. Rigorously conducted metaanalyses are useful tools to improve animal wellbeing and productivity. The need to integrate findings from many studies ensures that metaanalytic research is desirable and the large body of research now generated makes the conduct of this research feasible.

Correspondence: ianl@dairydocs.com.au

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Noticias de Reproducción Bovina Reproduction (2009) 138 187–194

Recent developments in testis tissue xenografting

Jose R Rodriguez-Sosa and Ina Dobrinski School of Veterinary Medicine, Center for Animal Transgenesis and Germ Cell Research, New Bolton Center, University of Pennsylvania, Kennett Square, Pennsylvania 19348, USA Correspondence should be addressed to I Dobrinski who is now at Department of Comparative Biology and Experimental Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, Canada AB T2N 4N1; Email: idobrins@ucalgary.ca

Development of the mammalian testis and spermatogenesis involve complex processes of cell migration, proliferation, differentiation, and cell– cell interactions. Although our knowledge of these processes has increased in the last few decades, many aspects still remain unclear. The lack of suitable systems that allow to recapitulate and manipulate both testis development and spermatogenesis ex situ has limited our ability to

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study these processes. In the last few years, two observations suggested novel strategies that will improve our ability to study and manipulate mammalian spermatogenesis: i) testis tissue from immature animals transplanted ectopically into immunodeficient mice is able to respond to mouse gonadotropins and to initiate and complete differentiation to the level where fertilizationcompetent sperm are obtained, and ii) isolated testis cells are able to organize and rearrange into seminiferous cords that subsequently undergo complete development, including production of viable sperm. The current paper reviews recent advances that have been obtained with both techniques that represent novel opportunities to explore testis development and spermatogenesis in diverse mammalian species.

Correspondence: idobrins@ucalgary.ca

FISIOLOGÍA REPRODUCTIVA Reproduction in Domestic Animals Volume 44 Issue 4, Pages 647 - 652

Effect of GnRH Dose on Occurrence of Short Oestrous Cycles and LH Response in Cyclic Dairy Heifers

MH Rantala, OAT Peltoniemi, T Katila and J Taponen Department of Production Animal Medicine, University of Helsinki, Mäntsälä, Finland Author's address (for correspondence): DVM Mari Rantala, Saari Unit, Pohjoinen pikatie 800, 04920 Saarentaus, Finland. E-mail: mari.h.rantala@helsinki.fi

Prostaglandin F2α (PGF2α) and GnRH treatments given 24 h apart have been shown to result in short oestrous cycles (8–12 days) in some cows and heifers. The differences in responses may depend on the dose of GnRH. Therefore, the effect of the dose of GnRH on occurrence of short cycles and LH response was studied here. Oestrus was induced with dexcloprostenol (0.15 mg) in two groups of Ayrshire heifers. A second luteolysis was induced similarly on day 7 after ovulation; 24 h after PGF2α treatment, the heifers were administered either a high (0.5 mg, n = 15, group T500) or low (0.1 mg, n = 10, group T100) dose

of gonadorelin. Blood samples for progesterone analyses were collected daily from the second PGF2α administration to the second ovulation after the PGF2α injection. Beginning 24 h after the GnRH treatment, ovaries were examined by transrectal ultrasonography every 6 h until ovulation, and daily between day 4 and the next ovulation. Five heifers from both groups were sampled for LH analyses via a jugular catheter every 30 min from 1 h before to 6 h after the GnRH administration. Short oestrous cycles were detected in 7 of 10 cases in group T100 and in 12 of 15 cases in group T500. No significant differences in LH responses were detected between the groups. In group T500, the rise in LH concentration tended to be somewhat slower than in group T100. The dose of GnRH (0.1 vs 0.5 mg) did not affect the occurrence of short oestrous cycles and LH response.

Correspondence: mari.h.rantala@helsinki.fi

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Noticias de Reproducción Bovina Reproduction in Domestic Animals Volume 44 Issue 4, Pages 600 - 605

Factors Affecting Plasma Pregnancyassociated Glycoprotein 1 Concentrations Throughout Gestation in High-producing Dairy Cows

B Serrano 1, F López-Gatius 2, P Santolaria 3, S Almería 4, I García-Ispierto 4, G Bech-Sabat 2, J Sulon 5, NM de Sousa 5, JF Beckers 5 and JL Yániz 3 1 Department of Animal Production, CITA, Zaragoza, Spain; 2 Department of Animal Production, University of Lleida, Lleida, Spain; 3 Department of Animal Production, University of Zaragoza, Huesca, Spain; 4 Department of Animal Health and Anatomy, Autonomous University of Barcelona, Barcelona, Spain; 5 Physiology of Reproduction, Faculty of Veterinary Medicine, University of Liège, Liège, Belgium Author's address (for correspondence): B Serrano, bserranop@aragon.es

This study was designed to establish the factors, if any, which could affect plasma pregnancyassociated glycoprotein-1 (PAG-1) expression in a study population of 87 pregnant, high-producing dairy cows. The factors examined were: semen providing breed (Holstein-Friesian vs Limousin), outcome of gestation (male vs female newborn, and singleton vs twin pregnancies), lactation number, milk production at pregnancy diagnosis, plasma progesterone concentration, season of gestation (warm period, March–November vs cool period, December–February), and day of gestation (40, 90, 120, 150, 180 and 210).

Pregnancy was diagnosed by transrectal ultrasound on day 40 post-insemination and by palpation per rectum on days 90, 120, 150, 180 and 210. Blood samples were collected from each animal immediately before each pregnancy diagnosis. The relative contributions of the different factors on PAG-1 concentrations were evaluated by GLM repeated measures analysis of variance. No significant effects of the herd, foetal sex, milk production, lactation number and plasma progesterone concentrations were observed. In contrast, twin pregnancy, the use of Limousin semen and conception during the cool period were correlated with significantly increased plasma PAG-1 concentrations throughout gestation. Our data indicate that both cow wellbeing during early placental development, determined in our conditions by reduced heat stress when conception occurred in the cool season, and crossbreed pregnancies lead to

improved PAG-1 gestation period.

production

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throughout

the

Correspondence: bserranop@aragon.es

Reproduction in Domestic Animals Volume 44 Issue 4, Pages 672 - 676

Anomalous Pregnancies during Late Embryonic/Early Foetal Period in High Producing Dairy Cows

B Serrano 1 , F López-Gatius 2 , RHF Hunter 3 , P Santolaria 4 , I García-Ispierto 5 , G Bech-Sabat 2 , NM de Sousa 6 , JF Beckers 6 and JL Yániz 4 1 Department of Animal Production, CITA, Zaragoza, Spain; 2 Department of Animal Production, University of Lleida, Lleida, Spain; 3 Reproduction of Clinics, University of Veterinarian Medicine, Hannover, Germany ; 4 Department of Animal Production, University of Zaragoza, Huesca, Spain; 5 Department of Animal Health and Anatomy, Autonomous University of Barcelona, Barcelona, Spain ; 6 Physiology of Reproduction, Faculty of Veterinary Medicine, University of Liège, Liège, Belgium Author's address (for correspondence): B Serrano, Departamento de Producción Animal, CITA/DGA, Avda. Montañana 930, 50059 Zaragoza, Spain. E-mail: bserranop@aragon.es

This study analyses anomalous cases of gestation ending in pregnancy loss during the early foetal period and their effect on progesterone and plasma pregnancy-associated glycoprotein-1 (PAG-1) concentrations. Data derived from a large-scale ultrasound pregnancy diagnosis programme in high producing dairy cows. Over a 3-year period (2004–2007), a very low incidence (0.5%: 15 of 3094) of anomalous pregnancies was recorded. The results revealed that the following anomalies were detected on days 35–41 of gestation in cows carrying singletons with one single corpus luteum: embryo death in eight cows (0.3%); and embryo in the uterine horn contralateral to the corpus luteum in seven cows (0.2%). All these animals suffered pregnancy loss during the early foetal period. In cows carrying dead embryos, no signs of conceptus degeneration were observed on pregnancy diagnosis. Amnion size (approximately 25 mm diameter) and uterine horn fluid contents were estimated to be similar to those of the normal pregnant cows in this period. In the contralateral gestations, live embryos were observed in all ultrasound checks before pregnancy loss. Uterine fluid contents increased in the two cows in which gestation continued for more than a week. In the cases of embryo death but not in those of contralateral gestation, a drop in PAG-1 levels was

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Noticias de ReproducciĂłn Bovina noted prior to pregnancy loss. Two cows carrying dead embryos increased with time allantoic fluid contents. The PAG-1 values increased with time in one cow bearing a dead embryo (from 2.31 to 6.79 ng/ml) and in two of the contralateral gestations (from 1.66 to 2.33 ng/ml and from 0.39 to 6.79 ng/ml, respectively). Results of this study indicate that the foetal membranes continue to undergo some activity following embryo death, and that contralateral pregnancy may determine failure of the gestation process.

Correspondence: bserranop@aragon.es

J. Dairy Sci. 2009. 92: 3659-3666.

Identification, susceptibility, and detection of integron-gene cassettes of Arcanobacterium pyogenes in bovine endometritis

M.-C. Liu*,, C.-M. Wu*, Y.-C. Liu, J.-C. Zhao, Y.-L. Yang and J.-Z. Shen*,1 * Department of Pharmacology and Toxicology, College of Veterinary Medicine, China Agricultural University, Beijing 100193, P. R. China College of Animal Husbandry and Veterinary Medicine, Shenyang Agricultural University, Shenyang 110161, P. R. China 1 Corresponding author: sjz@cau.edu.cn

The present study aimed to identify, determine the susceptibility, and detect gene cassettes of Arcanobacterium (Actinomyces) pyogenes isolates from cows with endometritis. Arcanobacterium pyogenes isolates were identified first by using the API Coryne Vit system test, and further through PCR. Minimum inhibitory concentrations of 23 antimicrobial agents against A. pyogenes were tested using standard broth microdilution assays according to the protocols of the Clinical and Laboratory Standards Institute. The genes of integrons I and II were amplified by PCR using specific primers. Thirty-two A. pyogenes isolates were isolated from 136 endometritic cows in the Hohhot region. Antibiotic susceptibility tests revealed that all isolates were highly sensitive to fluoroquinolones (100%), macrolides (~81.2 to 100%) and florfenicol (90.6%), aminoglycosides (~15.6 to 81.2%), and tetracyclines (~43.7 to 68.7%). However, 53.1% were resistant to clindamycin, ~50 to 65.6% were resistant to penicillins, and ~37.5 to 71.9% were resistant to cephalosporins. One hundred percent were resistant to sulfonamides and bacitracin zinc. The

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integrons were further confirmed by sequencing.

No class II integrons were detected, whereas 50% (n = 16) of the A. pyogenes isolates were positive for the presence of the intI I gene, but only 13 contained gene cassettes. Sequence analysis of gene cassettes revealed 6 gene cassettes, 4 of which encode resistant determinants of aminoglycosides (aadA1, aadA5, aadA24, and aadB) and 1 of which encodes the resistance gene of chloramphenicol (cmlA6). The function of the sixth identified cassette, designated ORF1, is unknown. The gene cassette arrays aadA24-ORF1, aadA5, and aadA1-addBcmlA6 were found in 46.13% (6/13), 38.46% (5/13), and 38.46% (5/13) of the isolates, respectively.

These cassettes segregated according to a consistent pattern, with aadA5 always alone, ORF1 always with aadA24, and aadA1-aadB and cmlA6 always together. Most of the positive integrons existed in the multiresistant isolates (n = ~3 to 7), indicating that the integrons played an important role in the dissemination and spread of antimicrobial resistance. This is the first report of A. pyogenes infections in dairy cows in China and of detection of gene cassettes and integrons in A. pyogenes.

Correspondence: sjz@cau.edu.cn

Reproduction (2009) 138 371â&#x20AC;&#x201C;382

Quantitative characterization of prostaglandins in the uterus of early pregnant cattle

S E Ulbrich, K Schulke, A E Groebner, H D Reichenbach1, C Angioni2, G Geisslinger2 and H H D Meyer Physiology-Weihenstephan, Technische Universitaet Muenchen,Weihenstephaner Berg 3, 85354 Freising, Germany, 1 Institute of Animal Breeding, Bavarian State Institute for Agriculture, Prof.-Duerrwaechter-Platz 1, D-85586 Grub, Germany and 2Institute of Clinical Pharmacology/ZAFES, Johann Wolfgang Goethe-University Frankfurt, Theodor Stern Kai 7, 60590 Frankfurt am Main, Germany Correspondence should be addressed to S E Ulbrich; Email: ulbrich@wzw.tum.de

Prostaglandins (PGs) are important regulators of reproductive processes including early embryonic development.We analyzed the most relevant PG in bovine uteri at different preimplantation pregnancy stages when compared with nonpregnant controls. Additionally, endometrium and

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Noticias de Reproducción Bovina trophoblast tissues were examined regarding specific enzymes and receptors involved in PG generation and function. Simmental heifers were artificially inseminated or received seminal plasma only. At days 12, 15, or 18, post-estrus uteri were flushed for PG determination by liquid chromatography–tandem mass spectrometry.

Endometrium and trophoblast tissues were sampled for RNA extraction and quantitative realtime PCR analysis. At all days and points of time examined, the concentration of 6-keto PGF1a (stable metabolite of PGI2) was predominant followed by PGF2aOPGE2OPGD2zTXB2 (stable metabolite of TXA2). At days 15 and 18, PG increased from overall low levels at day 12, with a much more pronounced increase during pregnancy. The PGF2a/PGE2 ratio was not influenced by status.

The highest PG concentration was measured at day 15 with 6keto PGF1a (6.4 ng/ml) followed by PGF2a (1.1 ng/ml) and PGE2 (0.3 ng/ml). Minor changes in endometrial PG biosynthesis enzymes occurred due to pregnancy. Trophoblasts revealed high transcript abundance of general and specific PG synthases contributing to uterine PG. As PGI2 and PGF2a receptors were abundantly expressed by the trophoblast, abundant amounts of PGI2 and PGF2a in the uterine lumen point towards an essential role of PG for the developing embryo.

High amounts of PG other than PGE2 in the preimplantation uterus may be essential rather than detrimental for successful reproduction.

Correspondence ulbrich@wzw.tum.de

Animal Reproduction Science 114 (2009) 89–98

Early apoptosis is associated with improved developmental potential in bovine oocytes H.J. Li, D.J. Liu*, M. Cang, L.M.Wang, M.Z. Jin, Y.Z. Ma, B. Shorgan Key Laboratory of China Education Ministry for Research of Mammal Reproductive Biology and Biotechnology, Inner Mongolia University, Hohhot 010021, PR China

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regulated by apoptosis in vivo. The aim of this studywas to investigate the levels of apoptosis in bovine immature oocytes with different developmental potentials and to determine whether early apoptosis in bovine oocytes is correlated with their subsequent development.

Cumulus–oocyte complexes (COCs) were selected and classified into four groups according to oocyte cytoplasm and cumulus status. Early and late stages of apoptosiswere detected by Annexin-V and TUNEL staining, respectively. Developmental competence was evaluated by nuclear maturation (MII) after in vitro maturation and development rates in different stages following in vitro fertilization. Meanwhile, the transcripts of Bcl-2 and Bax genes were carried out in immature oocytes by realtime RT-PCR. Results indicated that Annexin-V-positive oocytes were detected in various groups at different percentages, and Group III showed the highest positive ratio. No TUNEL-positive oocytes were found in any immature COCs. Group III oocytes demonstrated the highest nuclear maturation, cleavage, blastocyst, and hatching blastocyst rates.

Meanwhile, Group III oocytes exhibited the highest Bax (initiating apoptosis) transcriptional level and the lowest Bcl-2 (preventing apoptosis) transcriptional level. Taken together, Annexin-V and quantitative PCR results indicated that early apoptosis was beneficial for developmental competence, while TUNEL staining showed that none of the immature oocytes were undergoing late-stage apoptosis. This is the first time that Bax and Bcl-2 transcripts were characterized in the immature bovine oocyte, and results indicated that the genes are good markers of early apoptosis and embryo development. This research overthrows the traditional view that oocytes undergoing apoptosis have poor developmental competence, and the findings will facilitate oocyte selection and improvement of in vitro embryo production.

Correspondence: nmliudongjun@sina.com

The poor quality of oocytes may be the main reason for the lowefficiency of the current in vitro embryo production. However, efforts are required to understand the mechanisms of oocyte development, which is believed to be largely

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Noticias de Reproducción Bovina Animal Reproduction Science 114 (2009) 62–71

Elevated progesterone concentrations enhance prostaglandin F2 synthesis in dairy cows

Ricarda Maria dos Santosa, Marcelo Demarchi Goissisb, David Augusto Fantinib, Claudia Maria Bertanc, José Luiz Moraes Vasconcelosd, Mario Binelli b,∗ a Escola Agrotécnica Federal, Uberlândia, MG, Brazil b Department of Animal Reproduction, College of Veterinary Medicine and Animal Sciences, University of São Paulo, Pirassununga, SP, Brazil c College of Animal Sciences, São Paulo State University “Julio de Mesquita Filho”, Campus Dracena, Dracena, SP, Brazil d Department of Animal Production, College of Veterinary Medicine and Animal Science, São Paulo State University “Julio de Mesquita Filho”, Botucatu, SP, Brazil

The objective was to evaluate the influence of varying plasma progesterone (P4) concentrations throughout the luteal phase in dairy cows on PGF2 production (assessed as plasma concentrations of 13,14-dihydro-15-keto-PGF2 ; PGFM) following treatment with estradiol-17 (E2) or oxytocin (OT). In all experiments, time of ovulations was synchronized with the OvSynch protocol and Day 0 corresponded to day of second GnRH injection. In Experiment 1, non-lactating dairy cows on Day 6 remained non-treated (n = 9), received 20mg LH (n = 7), or had ovarian follicles larger than 6mm aspirated (n = 8). In Experiment 2, cows on Day 6 were untreated (n = 9) or received 5000 IU hCG (n = 10). In Experiments 1 and 2, all cows received 3mg E2 on Day 17, and blood samples were collected every 30 min from 2 h before to 10 h after E2.

Experiment 3 was conducted in two periods, each from Days 0 to 17 of the estrous cycle. At the end of Period 1, animals switched treatments in a crossover arrangement. Animals in Group 2/8 (n = 4) received 2 kg/d of concentrate in the first period and 8 kg/d in the second period. Animals in Group 8/2 (n = 7) received the alternate sequence. Blood was collected daily for measurement of P4 4 h after concentrate feeding.

On Day 17, blood was collected from 1 h before to 1 h after a 100 IU OT injection. In Experiment 1, both plasma P4 and release of PGF2 were similar between LH-treated and control cows (P > 0.10). In Experiment 2, plasma P4 was elevated to a greater extent on Day 17 in cows treated with hCG (P < 0.05) and plasma PGFM was also greater in hCG-treated animals (treatment×time interaction; P < 0.05). In Experiment 3, therewas

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a group×period interaction (P < 0.01) for plasma P4, indicating that less concentrate feeding was associated with greater plasma P4. Release of PGF2 in response to OT was greater for cows receiving less concentrate (group×period interaction; P < 0.05). In conclusion, dairy cows with more elevated blood P4 concentrations released more PGF2 in response to E2 or OT. Correspondence: binelli@usp.br

Animal Reproduction Science 114 (2009) 99–108

Expression of IGF receptors and its ligands in bovine oocytes and preimplantation embryos

L.M.Wanga, H.L. Fenga,b, Y.Zh. Maa, M. Canga, H.J. Li a, Zh. Yana, P. Zhoua, J.X.Wena, Shorgan Boua, D.J. Liua,∗ a Key Laboratory of Ministry of Education of China for Mammal Reproduction Biology and Biotechnology of Inner Mongolia University, Huhhot 010021, PR China b Department of Obstetrics and Gynecology, Center for Human Reproduction, North Shore University Hospital, New York University School of Medicine, Manhasset, NY 11030, USA

The objectives of this studywere to assess themRNAexpression and protein location of IGF receptors and its ligands in bovine oocytes and different stages of preimplantation embryos, and then evaluate the effect of different concentrations of IGF-II when added to either the maturation or culturemedium on in vitro embryo development. For the assessment of mRNA expression by RT-PCR three replicates each of 100 oocytes, and 60 embryos at each of the 2- cell, 8cell, morula and blastocyst stages of developmentwere used. Immunocytochemical techniqueswere used to study the location of IGFs and their receptors for COC, oocytes, and embryos at the same stages of development (n = 25).

The effect of supplementing maturationmedium with IGF-IIwas examined using groups of 20 oocytes exposed to 0 (control), 10, 20, 50 or 100 ng IGF-II/ml medium. Each treatment was replicated five times. To study the effect of IGF-II added to culture medium, groups of 10 zygotes were cultured in the presence of 0 (control), 50, 100 or 150 ng IGF-II/ml medium and the treatments replicated four times. The results showed that IGF-I mRNA could not be detected but IGF-II, IGF-IR and IGF-IIR mRNA existed in bovine preimplantation embryos.

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Noticias de ReproducciĂłn Bovina Proteins for IGFII, IGF-IR and IGF-IIR were detected on the cell plasma membrane of cumulus cells of COC, immature and mature oocytes, and 2-cell stage embryos. They were observed in blastomere cytoplasm of 8- cell and morula stage embryos. In blastocysts, the IGF proteinswere distributed in the trophectoderm but not in the inner cell mass. Adding 20 ng/ml IGF-II to maturation medium resulted in higher rates of post-fertilization development than control at 8cell (58.2% versus 44.5%; p < 0.05) and blastocyst (37.0% versus 25.0%; p < 0.05) stages of development; and thenumber of viable cells per blastocyst were significantly higher

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(126Âą6 versus 103Âą5; p < 0.05). When IGF-II was added to the culture medium, no significant treatment differences were observed at 8-cell embryo stage but the development rate of zygotes cultured in the presence of 100 ng IGFII/ml medium to blastocysts was significantly higher than that of control (30.0% versus 19.2%; p < 0.05). It was concluded that supplementation of in vitro maturation or culture media with IGF-II affects the development of bovine embryos and could be used to improve in vitro embryo production.

Correspondence: nmliudongjun@sina.com

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Noticias de Reproducción Bovina

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PRÓXIMOS EVENTOS

Día Internacional del Ganadero Lechero 2009 Delicias, Chihuahua 3,4 y 5 de septiembre de 2009 http://www.digal.com.mx

Noveno Congreso Internacional de Médicos Veterinarios Especialistas en Bovinos, 2009.

Torreón, Coahuila 5, 6 y 7 de noviembre de 2009 http://www.amveblaguna.com/

5tas Jornadas Bovinas FMVZ-UNAM, CD. Universitaria, D.F. 7 y 8 de Septiembre de 2009 decvet@servidor.unam.mx http://www.fmvz.unam.mx

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SITIOS DE INTERÉS 

Agrociencia http://www.colpos.mx/agrocien/agrociencia.htm



Animal



Animal Reproduction http://www.cbra.org.br/publicacoes/animalreproduction/issues.do



Animal Reproduction Science http://www.sciencedirect.com/science/journal/03784320



Ciencia



Journal of Animal Science http://jas.fass.org/



Journal of Dairy Science http://jds.fass.org



Journal of Reproduction and Development http://www.jstage.jst.go.jp/browse/jrd



Livestock Science http://www.sciencedirect.com/science/journal/18711413



Manejo lechero http://www.manejolechero.com/



Nature



Physiological . Reviews http://physrev.physiology.org/



Proceedings of the National Academy of Sciences of the United States of America http://www.pnas.org/



Reproduction http://www.reproduction-online.org/



Reproduction in Domestic Animals http://www.wiley.com/bw/journal.asp?ref=0936-6768



Reproduction, Fertility and Development http://www.publish.csiro.au/nid/44.htm

http://www.animal-journal.eu/

http://www.revistaciencia.amc.edu.mx/

http://www.nature.com/nature/index.html

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Science http://www.sciencemag.org/



Técnica Pecuaria en México http://www.tecnicapecuaria.org.mx/index2.php



The American Association of Bovine Practitioners http://www.aabp.org/



The Dairy Cattle Reproduction Council (DCRC) http://www.dcrcouncil.org/index.html



The Veterinary Record http://veterinaryrecord.bvapublications.com/



Theriogenology http://www.sciencedirect.com/science/journal/0093691X



Veterinary Clinics of North America: Food Animal Practice http://www.vetfood.theclinics.com/



Veterinaria México http://www.fmvz.unam.mx/fmvz/revvetmex/revvetmex.htm

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Antonio 19