SESSION 6: Rocio Crespo

Brooding Turkey Poults Rocio Crespo

Dr. Rocio Crespo, DVM, MS, PhD, DACPV College of Veterinary Medicine, North Carolina State University

Bio

Dr. Rocio Crespo is a professor at the NC State College of Veterinary Medicine. Her research focuses on exploring ‘non- invasive or minimally invasive procedures’ to monitor poultry health, with emphasis on parasites and clinical pathology. Dr. Crespo is the current president of the American Association of Avian Pathologists and past president of the American College of Poultry Veterinarians.

Effect of Environmental Manipulations on Blood Chemistry and Performance in Turkeys

Rocio Crespo and Jesse Grimes

The purpose of climate control in poultry production is to produce a healthy bird, which enables it to grow more efficiently and live in the most desirable and least stressful environment available. A good in-house climate results in lower mortality and reduced disease risk. As a rule of thumb, when the temperature of the house is above 80 °F (26.5 °C), the addition of the temperature (measured in °F) and relative humidity numbers should be less than 160, to avoid heat stress in the birds. Interestingly, poult brooder guidelines are centered on temperature only.

In mammals and humans, blood chemistry profile is essential for medical assessment. Furthermore, it is known that some analytes change to external stressors and health challenges even before obvious behavioral or clinical signs are observed. We hypothesize that analysis of selected blood parameters could aid objective assessment of the effect of environmental manipulation and performance in young growing turkeys.

The purpose of this study was to evaluate how changes in the environmental temperature and humidity affects the blood parameters and its association with the incidence of mortality, dilated cardiomyopathy, and overall turkey poult performance up to 5 weeks of age.

Methodology: A total of 2,240 poults from a commercial hatchery were assigned to one of the following treatments:

Treatment Temperature Relative humidity 1 29 C (85 F) 60-70 % 2 32 C (90 F) 60-70 % 3 35 C (95 F) 60-70 % 4 38 C (95 F) 75-85 %

Ambient temperature and relative humidity were closely monitored and recorded every 30 minutes. Temperatures were lowered 5 degrees Fahrenheit each week. Blood from 12 birds, from each room, was collected on days 1, 3, 5, 7, 10, 14, 21, 28, 35. Whole heparinized blood was analyzed using an iSTAT 1 analyzer using the CG8+ cartridge. Additionally, the Freestyle Optium Neo Blood Glucose & Ketones Monitoring System to measure ketone. Statistics for all variables were performed by age by treatment.

Results: A total of 32 birds died or were culled. Most of the mortality (20 birds or 63%) died due to bacterial infection in the 2 first weeks. Interestingly 11 of them were from treatment 1. By 3 days of age, only 1 bird (treatment 3) showed signs of flip over. Other performance parameters observed in the first 2 weeks were cold and piling of birds from treatment 1; numerous poults had “angel wings” by 5 days of age (15% and 20% from treatments 3 and 4 respectively). Pendulous crop was observed at 14 days of age, in 5% and 10% of the turkeys from treatment 3 and 4 respectively

At 25 days of age, ultrasound of the heart was performed in 3 randomly selected turkeys from each room (12 birds per treatment). The hearts of 90% of the birds from treatments 3 and 4 showed severe abnormal contractility. Surprisingly, no significant gross changes were observed in any of these turkey hearts. Between 21-35 days of age, 9 turkeys were culled due to severe pecking (1, 4, 2, and 2 turkeys from treatments 1-4 respectively). Treatment affected blood pH, partial CO2, bicarbonate (HCO3), potassium (K), ionized calcium (iCa), and glucose. Turkeys kept at the highest temperature had the higher blood pH and glucose. On the other hand, these two groups had the lower blood pCO2 and HCO3. High pH and lower pCO2 probably is due to respiratory alkalosis associated with panting. In chickens, the addition of 0.5% NaHCO3 in the diet of birds subjected to chronic heat stress enhanced body weight gain. Considerations of diet supplementation, such addition of NaHCO3 in turkeys exposed to chronic heat exposure, may help overcome some of the negative effects of heat stress. The birds exposed to higher temperature not only had higher blood glucose but also increased incidence of pendulous crop. Increased blood glucose is a common finding in heat stressed mammals due to dehydration and inability to metabolize sugar. Animals exposed to excessive heat drink more water to overcome dehydration. The increased incidence of pendulous crop in may be associated with higher water consumption.

Summary: Turkeys brooded at 90F performed better overall. Birds brooded at 80F appeared cold and succumbed more easily to bacterial infection early in life. Turkeys brooded at 95F had higher pH and glucose, and lower blood pCO2 and HCO3. Additionally, these birds had a higher incidence of angel wings, pendulous crop and functionally abnormal hearts. Analysis of troponin, a heart specific protein, is pending.