Agronomy and Crop Improvement
Utilisation and management of white clover (Trifolium repens) for dairy cows in pastures
Introduction The utilisation of pastures for grazing largely depends on careful monitoring of conditions and their effect on crops and livestock, and the flexibility in management to optimise production. The main constraints on dairy pasture productivity are (i) the unpredictable varying seasonal conditions (rainfall, temperature fluctuations) (Campbell and Bryants, 1978), (ii) vegetation sensitivity to abiotic stress, competition (Sanderson et al., 2003), diseases, pests, trampling (Drewry et al., 2008), (iii) soil composition (Greenwood and McKenzie, 2001) and (iv) correct application of fertilisers (Andrews et al., 2007). The introduction of white clover (WC, Trifolium repens, Fabaceae) into pasture-based dairy production systems as fresh feed or silage, has the potential to (1) increase milk yield and (2) decrease nitrogen (N) fertiliser application (Lane et al., 2000; Lane et al., 1997; Caradus et al., 1996; Chestnutt and Lowe, 1970). Milk yield per dairy cow between 2001-2002 and 2011-2012 has increased by 18% on average but the number of dairy cow numbers declined by 19% (DairyCo, 2012) in the UK. Overall, the total milk production on dairy farms has decreased by 4% (Andrews et al., 2007). Therefore, improving dairy pastures in a cost-effective and sustainable way is crucial to sustain milk production in the UK. For example, in New Zealand, the financial contribution of white clover to the economy reaches the total of $3.1 billion (Caradus et al., 1996) through nitrogen fixation, forage yield, seed production and honey production. The major biotic constraints of WC is to maintain an optimal clover content within a pasture (Harris et al., 1997) while it has numerous competitors such as grasses, weeds, pests, diseases in the field while sustain its growth under trampling pressures by the cows. This essay reviews the major benefits of WC introduction in dairy pastures, requirements for its establishment, and effects of different management practices and briefly discusses appropriate crop protection and breeding strategies. Main benefits of WC compared to grass monoculture dairy pastures One of the major benefits of WC is its ability to fix nitrogen with Rhizobium trifolii. It is estimated that 200-300 kg N per annum can be fixed by WC inclusion which varies on the WC content within the pasture and it can save ÂŁ125-160 ha-1 annum-1 on a field (Andrews et al., 2007). Numerous studies have investigated the effect of N fertiliser and have shown that 400 kg N/ha application negatively effects clover growth and morphology (Harris et al., 1996), while 150 kg N/ha application has shown to increase clover content, but 250 kg N/ha and 200 kg N/ha had no significant effect under low (3.2 cows/ha) and high (4.5 cows/ha) stocking rates (Clark and Harris, 1996; Egan et al., 2018). McDonagh et al. (2017) found that WC on a mixed pasture with 100 kg N/ha under 21 grazing days yielded 1009 kg dry matter (DM)/ha more than on 250 kg N/ha pure perennial grass pasture with 30 grazing days throughout the whole year. Therefore, WC reduces the cost of N fertilisation by its N fixing ability and produces higher yields than ryegrass pastures with high amounts of fertilisers.
Agronomy and Crop Improvement
Milk yields have also been shown to increase by 3kg d-1 on average on pure WC swards compared to perennial ryegrass swards (PRG) (Wilkins and Munro, 1998). This depends on clover content - 50% of total DM of WC content increased milk yields by 22% (13.4 l/cow/day) and 75% content increased milk yields by 33% (13.8 l/cow/day) for both ad libatum and restricted herbage allowances (Harris et al., 1997). This could be explained by better nutritive values in terms of crude protein content, low structural fibre and better organic matter (OM) digestibility (Thomson et al., 1985; Harris et al., 1998), the increase in yield is mainly caused by higher voluntary intake (Bertilsson and Murphy, 2003, Ribeiro Filho et al., 2005).
Requirements for white clover establishment Sowing WC in spring has been shown to be more effective with the possibility of resowing in the autumn (Elgersma and Schlepers, 2003). The ideal soil conditions for WC establishment requires a soil pH around 6.0, and applying phosphorus (between 16-140 kg P/ha-1 annum-1) (Andrews et al., 2007; Singh et al., 1999), potassium and little or no N to ensure optimal soil fertility (Elgersma and Schlepers, 2003). Significant differences have been shown in a three year study between an 8 kg/ha and 3 kg/ha sowing rates (Kelly et al., 2006) on their establishment and survival long-term. Lower, 2 kg/ha sowing rates with suboptimal emergence (30-40%) rate could lead to only a 30% survival (Brock and Kane, 2003). Increased row spacing (36 cm from 18 cm) also increased clover DM yield by 42% (Annicchiarico and Tomasoni, 2010) while another study by Muto and Martin (2000) showed that sowing by specialised Hunter seeder increased clover content and establishment compared to conventional Vredo seeder at 20 cm row spacing. Due to the smallness of the seeds, it requires shallow (1-2-3 mm) seeding (Brock and Kane, 2003) and should be pre-inoculated with Rhizobium (type B) (Hayman and Mosse, 1979). The aim of clover establishment is 150 WC plants per m2 after three months of sowing (Haggar et al., 1985). It is crucial to take clover development and morphology into account in terms of management and supporting its growth (Figure 1).
Figure 1. White clover goes through quiescence during the winter, enters primary growth in the spring, during grazing and cutting of the summer months, it is in a regrowth phase (Brock et al., 2000). After flowering in July, it enters vegetative growth phase in the autumn. The morphology of the plants significantly changes in between season as well as in between seedling, tap-rooted and clonal phases.
Agronomy and Crop Improvement
Key issues with optimum utilization and grazing management As there are no conclusive studies about dairy cow foraging behaviour for WC (Ribeiro Filho and Peyrand, 2005; Cosgrove et al., 1996), maintaining high content (Rutter et al., 2004; Harris et al., 1997) and sward height (Rutter et al., 2002; Rook et al., 1994) within a pasture is the most important objective in order to benefit from the potential increase in milk yields as well reducing the risk of bloating (Rutter et al., 2004). By combining different grazing management strategies (Table 1) in between seasons, the WC content can be manipulated according to plant development and nutritional values. Deferred grazing (Harris et al., 1999) and lower ryegrass tiller density (Brock and Hay, 1996) at the beginning of the establishment could significantly promote WC establishment. Ayres et al. (1998) found that post-flowering, OM digestibility decreased 0.0016 d-1 until ripe seed stage and it is crucial to promote daughter tiller formation (Matthew et al., 1991) by decreasing the number of competitive grasses (Thomas, 1984) and weeds (Seefeldt et al., 2005). The damaging effect of trampling on WC development also increases with stocking rates, especially combined with suboptimal soil conditions (Tuohy et al., 2015; Menneer et al., 2005), soil moisture stress (Lucero et al., 1999; Turner, 1991) and low earthworm populations (Hay et al., 1987).
Table 1. Overview of different grazing management strategies, their finding and particular advantages. Management
Findings
Advantages
Reference
Set stocking
Comparing WC content in 56,000 tillers/m2 and 11-15,000 tiller/m2 ryegrass densities Deferring summer grazing by 25, 50, 75, 100
Continual removal of flower heads enables daughter tiller formation and growth
Brock and Hay, 1996
60% higher survival for WC stolons for 50100 day deferral
Harris et al., 1999
Cutting
Comparing rotational grazing with cutting with N fertiliser addition
Schils et al., 1999
Zero grazing
Giving 200, 500, 800 g of WC/kg of total DM
Average annual DM yields were 13.4 t ha-1 with rotations and 12.82 t ha-1 with cutting and a second silage cut increased WC cover by 8% Daily intake, milk yield, solids and fat increased at 500 g but not at 800 g
PRG, WC and Red clover silages
WC was superior to RC and PRG, modifying the milk fatty acid profile
Van Dorland et al. 2008
Strip grazing
Pure grass and mixed sward grazing, recording sward heights
Enriquez-Hidalgo et al., 2014
Rotational
Comparing WC content in 56,000 tillers/m2 and 11-15,000 tiller/m2 ryegrass densities Plots containing 25% and 75% WC by ground area and pure PRG
Diurnal feeding pattern, during the autumn ruminating time decreased, rumen pH was higher for mixed swards, and foraging behaviour was significant at 18% clover content At 5,000 tillers/m2, there is little competition between WC and ryegrass During the day, WC was partially preferred (63.2%) on the 25% content pastures but showed a clear diurnal feeding behaviour
Rutter et al., 2004
Deferred grazing
Facilitating diurnal feeding
Harris et al., 1998
Brock and Hay, 1996
Agronomy and Crop Improvement
Pasture protection and WC breeding Some varieties are better at competing with weeds than others (e.g. Giga) (Annicchiarico and Proietti, 2010b). Herbicides such as carbetamide, paraquat and propyzamide have significantly increased WC content (89% with 1-2 kg/ha propyzamide) in the spring and led to 70% reduction is grass growth (Haggar and Bastian, 1980). Over 250 cultivars have been developed dating back to the 16th century (Lane et al., 2000) and a 6%/decade of genetic improvement, 1%/year genetic gain for yield and 2.3-7.3% /cycle for nematode resistance has been accomplished (Jahufer et al., 2002) in WC breeding. There are numerous WC plant pathogens risking pasture health which has been in the frontline of fungicide improvement and breeding programmes (Figure 2) (Woodfield et al., 1996; Pederson and Pratt, 1995; Skipp and Watson, 1987). Disease resistance in WC varieties can greatly vary (Voisey et al., 2001; Burdon, 1980). Other patterns (e.g. leaflet width, mean stolon number, plant height, root density) (Lane et al., 2000; Woodfield and Caradus, 1994; Rhodes et al., 1994; Caradus et al., 1989; Thomson, 1865), production (DM yield, seed production) (Woodfield and Caradus, 1994) and chemical compositions (water soluble carbohydrates, tannins, cyanogenesis) (Higgs et al., 2009; Caradus et al., 1995; Thomson et al., 1985) are traits to evaluate within breeding strategies. The future of WC breeding is suggested to focus on winter hardiness (Frankow-Lindberg, 2001; Dalmannsdรณttir et al., 2001), ozone stress (Hofmann et al., 2001; Heagle et al., 1991), and water stress (Annicchiarico, 2004; Marshall et al., 2001; Brock and Kim, 1994).
Table 1. White clover diseases in the UK, New Zealand (NZ) and Australia. a) Black/sooty blotch (Cymadothea trifolii, Lewis and Thomas, 1991), b) White clover mosaic virus (WClMV), c) Clover rust (Uromyces nerviphilus) pustules, d) Pepper spot (Leptosphaerulina trifolii), e) Ascochyta leaf spot (Ascochyta sp.) f) Clover root weevil (Sitona lepidus), g) Argentine stem weevil larvae (Listronotus bonariensis), and h) Rust.
Agronomy and Crop Improvement
Total word count: 1,206 words (Essay) + 323 words (Advisory Note) = 1529 words References Andrews, M., Scholefield, D., Abberton, M.T., McKenzie, B.A., Hodge, S. and Raven, J.A., 2007. Use of white clover as an alternative to nitrogen fertiliser for dairy pastures in nitrate vulnerable zones in the UK: productivity, environmental impact and economic considerations. Annals of Applied Biology, 151(1), pp.11-23. Annicchiarico P, Piano E. 2004. Indirect selection for root development of white clover and implications for drought tolerance. Journal of Agronomy and Crop Science, 190(1), pp.28-34. Annicchiarico, P. and Proietti, S., 2010b. White clover selected for enhanced competitive ability widens the compatibility with grasses and favours the optimization of legume content and forage yield in mown clover� grass mixtures. Grass and Forage Science, 65(3), pp.318-324. Annicchiarico, P. and Tomasoni, C., 2010. Optimizing legume content and forage yield of mown white clover– Italian ryegrass mixtures through nitrogen fertilization and grass row spacing. Grass and Forage Science, 65(2), pp.220-226. Ayres, J.F., Nandra, K.S. and Turner, A.D., 1998. A study of the nutritive value of white clover (Trifolium repens L.) in relation to different stages of phenological maturity in the primary growth phase in spring. Grass and Forage Science, 53(3), pp.250-259. Bertilsson, J. and Murphy, M., 2003. Effects of feeding clover silages on feed intake, milk production and digestion in dairy cows. Grass and Forage Science, 58(3), pp.309-322. Brock, J.L. and Hay, M.J.M., 1996. A review of the role of grazing management on the growth and performance of white clover cultivars in lowland New Zealand pastures. Special Publication -Agronomy Society of New Zealand, pp.65-70. Brock, J.L. and Kane, G.J., 2003. Variability in establishing white clover in pastures on farms. Proceedings of the New Zealand Grassland Association, 65, pp. 223-228. Brock, J.L. and Kim, M.C., 1994. Influence of the stolon/soil surface interface and plant morphology on the survival of white clover during severe drought. In Proceedings of the New Zealand Grassland Association, 56, pp. 187-191. Brock, J.L., Albrecht, K.A., Tilbrook, J.C. and Hay, M.J.M., 2000. Morphology of white clover during development from seed to clonal populations in grazed pastures. The Journal of Agricultural Science, 135(2), pp.103-111. Burdon, J.J., 1980. Variation in disease-resistance within a population of Trifolium repens. The Journal of Ecology, pp.737-744. Campbell, A.G. and Bryant, A.M., 1978. Pasture constraints on dairy production. In Proceedings of the Agronomy Society of New Zealand, 8, pp.115-118. Caradus, J.R., MacKay, A.C., Woodfield, D.R., Van den Bosch, J. and Wewala, S., 1989. Classification of a world collection of white clover cultivars. Euphytica, 42(1-2), pp.183-196. Caradus, J.R., McNabb, W., Woodfield, D.R., Waghom, G.C. and Keogh, R., 1995. Improving quality characteristics of white clover. Proceedings Agronomy Society of New Zealand, 25, pp.7. Caradus, J.R., Woodfield, D.R. and Stewart, A.V., 1996. Overview and vision for white clover. Special Publication-Agronomy Society of New Zealand, 11(6), pp.1-6. Chestnutt, D.M.B. and Lowe, J., 1970. White clover/grass relationships: agronomy of white clover/grass swards: a review. Occasional Symposium 6 of the British Grassland Society, pp.191-213.
Clark, D.A. and Harris, S.L., 1996. White clover or nitrogen fertiliser for dairying?. Special Publication Agronomy Society of New Zealand, pp.107-114. Cosgrove, G.P., Anderson, C.B. and Fletcher, R.H., 1996. Do cattle exhibit a preference for white clover? Special Publication - Agronomy Society of New Zealand, 11(6) pp.83-86. Dalmannsdóttir, S., Helgadóttir, Á. and Gudleifsson, B.E., 2001. Fatty acid and sugar content in white clover in relation to frost tolerance and ice-encasement tolerance. Annals of Botany, 88(suppl_1), pp.753-759. Drewry, J.J., Cameron, K.C. and Buchan, G.D., 2008. Pasture yield and soil physical property responses to soil compaction from treading and grazing—a review. Soil Research, 46(3), pp.237-256. Egan, M., Galvin, N. and Hennessy, D., 2018. Incorporating white clover (Trifolium repens L.) into perennial ryegrass (Lolium perenne L.) swards receiving varying levels of nitrogen fertilizer: Effects on milk and herbage production. Journal of Dairy Science, 101(4), pp.1-16. Elgersma, A. and Schlepers, H., 2003. Effects of white clover cultivar and companion grass on winter survival of seedlings in autumn‐sown swards. Grass and Forage Science, 58(2), pp.215-219. Enriquez-Hidalgo, D., Hennessy, D., Gilliland, T., Egan, M., Mee, J.F. and Lewis, E., 2014. Effect of rotationally grazing perennial ryegrass white clover or perennial ryegrass only swards on dairy cow feeding behaviour, rumen characteristics and sward depletion patterns. Livestock Science, 169, pp.48-62. Frankow-Lindberg, B.E., 2001. Adaptation to winter stress in nine white clover populations: changes in nonstructural carbohydrates during exposure to simulated winter conditions and ‘spring’regrowth potential. Annals of Botany, 88(suppl_1), pp.745-751. Greenwood, K.L. and McKenzie, B.M., 2001. Grazing effects on soil physical properties and the consequences for pastures: a review. Australian Journal of Experimental Agriculture, 41(8), pp.1231-1250. Haggar, R.J. and Bastian, C.J., 1980. Regulating the content of white clover in mixed swards using grass‐ suppressing herbicides. Grass and Forage Science, 35(2), pp.129-137. Haggar, R.J., Standell, C.J. and Birnie, J.E., 1985. Occurrence, impact and control of weeds in newly sown leys. Weeds, Pests and Diseases of Grassland and Herbage Legumes Occasional Symposium, 18, pp.11-19. Harris, S., Clark, D.A., Auldist, M.J., Waugh, C.D. and Laboyrie, P.G., 1997. Optimum white clover content for dairy pastures. Proceedings of the Conference – New Zealand Grassland Association, 59, pp.29-34. Harris, S.L. and Clark, D.A., 1996. Effect of high rates of nitrogen fertiliser on white clover growth, morphology, and nitrogen fixation activity in grazed dairy pasture in northern New Zealand. New Zealand Journal of Agricultural Research, 39(1), pp.149-158. Harris, S.L., Auldist, M.J., Clark, D.A. and Jansen, E.B., 1998. Effects of white clover content in the diet on herbage intake, milk production and milk composition of New Zealand dairy cows housed indoors. Journal of Dairy Research, 65(3), pp.389-400. Harris, S.L., Waugh, C.D., McCabe, R.J. and Van Vught, V.T., 1999. Effect of deferred grazing during summer on white clover content of Waikato dairy pastures, New Zealand. New Zealand Journal of Agricultural Research, 42(1), pp.1-7. Hay, M.J.M., Chapman, D.F., Hay, R.J.M., Pennell, C.G.L., Woods, P.W. and Fletcher, R.H., 1987. Seasonal variation in the vertical distribution of white clover stolons in grazed swards. New Zealand Journal of Agricultural Research, 30(1), pp.1-8. Hayman, D.S. and Mosse, B., 1979. Improved growth of white clover in hill grasslands by mycorrhizal inoculation. Annals of Applied Biology, 93(2), pp.141-148. Heagle, A.S., McLughlin, M.R., Miller, J.E., Joyner, R.L. and Spruill, S.E., 1991. Adaptation of a white clover population to ozone stress. New Phytologist, 119(1), pp.61-68.
Higgs, R.J., Cosgrove, G.P., Burke, J.L., Lane, G.A., Pacheco, D., Fraser, K., Death, A.F. and Ford, J.L., 2009. Effect of white clover containing either high or low concentrations of water-soluble carbohydrate on metabolic indicators of protein degradation in the rumen of dairy cows. In Proceedings of the New Zealand Society of Animal Production, 70, pp.23-28. Hofmann, R.W., Campbell, B.D., Fountain, D.W., Jordan, B.R., Greer, D.H., Hunt, D.Y. and Hunt, C.L., 2001. Multivariate analysis of intraspecific responses to UV‐B radiation in white clover (Trifolium repens L.). Plant, Cell and Environment, 24(9), pp.917-927. Jahufer, M.Z.Z., Cooper, M., Ayres, J.F. and Bray, R.A., 2002. Identification of research to improve the efficiency of breeding strategies for white clover in Australia-a review. Australian Journal of Agricultural Research, 53(3), pp.239-257. Kelly, K.B., Stockdale, C.R. and Mason, W.K., 2006. Effects of initial sowing rate and subsequent grazing management on the growth and clover content of irrigated white clover–perennial ryegrass swards in northern Victoria. Australian Journal of Experimental Agriculture, 45(12), pp.1595-1602. Lane, L.A., Ayres, J.F. and Lovett, J.V., 1997. A review of the introduction and use of white clover (Trifolium repens L.) in Australia—significance for breeding objectives. Australian Journal of Experimental Agriculture, 37(7), pp.831-839. Lane, L.A., Ayres, J.F. and Lovett, J.V., 2000. The pastoral significance, adaptive characteristics, and grazing value of white clover (Trifolium repens L.) in dryland environments in Australia: a review. Australian Journal of Experimental Agriculture, 40(7), pp.1033-1046. Lucero, D.W., Grieu, P. and Guckert, A., 1999. Effects of water deficit and plant interaction on morphological growth parameters and yield of white clover (Trifolium repens L.) and ryegrass (Lolium perenne L.) mixtures. European Journal of Agronomy, 11(3-4), pp.167-177. Marshall, A.H., Rascle, C., Abberton, M.T., Michaelson‐Yeates, T.P.T. and Rhodes, I., 2001. Introgression as a route to improved drought tolerance in white clover (Trifolium repens L.). Journal of Agronomy and Crop Science, 187(1), pp.11-18. Matthew, C., Chu, A.C.P., Hodgson, J. and Mackay, A.D., 1991. Early summer pasture control: what suits the plant. Proceedings of the New Zealand Grassland Association, 53, pp.73-77. McDonagh, J., Gilliland, T.J., McEvoy, M., Delaby, L. and O'Donovan, M., 2017. Nitrogen and white clover impacts on the management of perennial ryegrass–clover swards for grazing cattle. The Journal of Agricultural Science, 155(9), pp.1381-1393. Menneer, J.C., Ledgard, S.F., McLay, C.D.A. and Silvester, W.B., 2005. The effects of treading by dairy cows during wet soil conditions on white clover productivity, growth and morphology in a white clover–perennial ryegrass pasture. Grass and Forage Science, 60(1), pp.46-58. Muto, P.J. and Martin, R.C., 2000. Effects of pre-treatment, renovation procedure and cultivar on the growth of white clover sown into a permanent pasture under both grazing and mowing regimes. Grass and Forage Science, 55(1), pp.59-68. Pederson, G.A. and Pratt, R.G., 1995. Differential Summer Suvival of White Clover Stolons: Germplasm and Fungicide Effects. Crop Science, 35(5), pp.1282-1287. Rhodes, I., Collins, R.P. and Evans, D.R., 1994. Breeding white clover for tolerance to low temperature and grazing stress. Euphytica, 77(3), pp.239-242. Ribeiro Filho, H.M.N., Delagarde, R. and Peyraud, J.L., 2003. Inclusion of white clover in strip-grazed perennial ryegrass swards: herbage intake and milk yield of dairy cows at different ages of sward regrowth. Animal Science, 77(3), pp.499-510.
Ribeiro Filho, H.M.N., Delagarde, R. and Peyraud, J.L., 2005. Herbage intake and milk yield of dairy cows grazing perennial ryegrass swards or white clover/perennial ryegrass swards at low-and medium-herbage allowances. Animal Feed Science and Technology, 119(1-2), pp.13-27. Rook, A.J., Huckle, C.A. and Wilkins, R.J., 1994. The effects of sward height and concentrate supplementation on the performance of spring calving dairy cows grazing perennial ryegrass-white clover swards. Animal Science, 58(2), pp.167-172. Rutter, S.M., Orr, R.J., Penning, P.D., Yarrow, N.H. and Champion, R.A., 2002. Ingestive behaviour of heifers grazing monocultures of ryegrass or white clover. Applied Animal Behaviour Science, 76(1), pp.1-9. Rutter, S.M., Orr, R.J., Yarrow, N.H. and Champion, R.A., 2004. Dietary preference of dairy heifers grazing ryegrass and white clover, with and without an anti-bloat treatment. Applied Animal Behaviour Science, 85(1), pp.1-10. Sanderson, M.A., Byers, R.A., Skinner, R.H. and Elwinger, G.F., 2003. Growth and complexity of white clover stolons in response to biotic and abiotic stress. Crop Science, 43(6), pp.2197-2205. Schils, R.L.M., Vellinga, T.V. and Kraak, T., 1999. Dry-matter yield and herbage quality of a perennial ryegrass/white clover sward in a rotational grazing and cutting system. Grass and Forage Science, 54(1), pp.1929. Seefeldt, S.S., Stephens, J.M., Verkaaik, M.L. and Rahman, A., 2005. Quantifying the impact of a weed in a perennial ryegrass–white clover pasture. Weed Science, 53(1), pp.113-120. Singh, D.K., Gourley, C.J.P., Sale, P.W.G. and Hasthorpe, C., 1999. High phosphorus supply increases persistence and growth of white clover in grazed dairy pastures during dry summer conditions. Australian Journal of Experimental Agriculture, 39(5), pp.579-585. Skipp, R.A. and Watson, R.N., 1987. Pot experiments with pasture soils to detect soilborne pathogens of white clover and lucerne, and effects of field application of fungicides. New Zealand journal of agricultural research, 30(1), pp.85-93. Thomas, H., 1984. Effects of drought on growth and competitive ability of perennial ryegrass and white clover. Journal of Applied Ecology, 21(2), pp.591-602. Thomson, D.J., Beever, D.E., Haines, M.J., Cammell, S.B., Evans, R.T., Dhanoa, M.S. and Austin, A.R., 1985. Yield and composition of milk from Friesian cows grazing either perennial ryegrass or white clover in early lactation. Journal of Dairy Research, 52(1), pp.17-31. Tuohy, P., Fenton, O., Holden, N.M. and Humphreys, J., 2015. The effects of treading by two breeds of dairy cow with different live weights on soil physical properties, poaching damage and herbage production on a poorly drained clay-loam soil. The Journal of Agricultural Science, 153(8), pp.1424-1436. Turner, L.B., 1991. The Effect of Water Stress on the Vegetative Growth of White Clover (Trifolium repens L): Comparison of Long-term Water Deficit and a Short-term Developing Water Stress. Journal of Experimental Botany, 42(3), pp.311-316. Van Dorland, H.A., Kreuzer, M., Leuenberger, H. and Wettstein, H.R., 2008. Comparative potential of white and red clover to modify the milk fatty acid profile of cows fed ryegrass‐based diets from zero‐grazing and silage systems. Journal of the Science of Food and Agriculture, 88(1), pp.77-85. Voisey, C.R., Dudas, B., Biggs, R., Burgess, E.P.J., Wigley, P.J., McGregor, P.G., Lough, T.J., Beck, D.L., Forster, R.L.S. and White, D.W.R., 2001. Transgenic pest and disease resistant white clover plants. In Molecular Breeding of Forage Crops, Springer, Dordrecht, pp. 239-250. Wilkins, R., Munro, H., 1988. The prospects for livestock production from white clover. In ‘Science and change in agriculture’. (Ed. Hardcastle), Agriculture and Food Research Council: London, pp. 12–13.
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Utilisation of White Clover (Trifolium repens) in dairy systems
Major benefits The introduction of white clover (WC,Trifolium repens) into pasture-based dairy production systems as fresh feed or silage, has the potential to (1) increase milk yield and (2) decrease nitrogen (N) fertiliser application.
Milk yields have also been shown to increase by 3kg day -1 on average on pure WC swards compared to perennial ryegrass swards (PRG).
More benefits
How to sow it?
?Soil structuring? by taproots can overcome problems of soil compaction
- Treat the soil with N, P, K and adjust soil pH to 6.0 - Sow in spring or autumn - Drill with 30-40 cm row spacing, with 3-5 kg/ha with shallow seeding (1-2 mm) - Target: 150 plants per m2 after three months of sowing
Cows consume 20 ? 30% more white clover than grass hence the milk yield production
Nutritional values and varieties - Choose a productive and persistent white clover variety - large-leaved, ladino varieties for silage and low stocking, medium to most dairy pastures (small ones are mostly for sheep) - Annual clover yield 30% greater from IBERS-bred varieties - Increased digestibility of clover leads to higher voluntary intake and hence increased milk yields
Utilisation of White Clover (Trifolium repens) in dairy systems Clover content - Maintain at least 30 - 40% of clover content within the pasture - 40 - 50% clover content will reduce risk of bloating - Keep sward height at > 4 cm - To reduce clover diseases, keep sward height < 6 cm - Keep ryegrass tiller density at 5 - 6,000 tillers/m2
Grazing management - Graze frequently ? approx. every 3 weeks at covers of no more than 1400 kg DM/ha - Rotational grazing: 5 - 21 grazing days - Set stocking/ continous grazing: during flowering time - Zero-grazing: silage cut in vegetative growth - Facilitate diurnal feeding (clover in the morning, ryegrass in the evening)
Monitoring morphology, growth and content - The main structural of a clover is the stolon which consists of nodes and internodes. - Each node produces one trifoliate leaf, a lateral bud and two nodal root buds. - Promote stolon production by reducing trampling and overshadowing by ryegrasses and weeds.