| To maximize the subsequent reproductive efficiency of the mares and allow for the marketing or specialized feeding of the foals, the artificial weaning is universally applied in horse production. Artificial weaning is a painful experience to mares and foals. Weaning process is associated with potential psychological, physical and nutritional stressors that affect foal welfare. The purpose of the research was to decrease the stress-related behavioral response, find the optimal weaning age and take the scientific management measures. Thoroughbred horses in Xinjiang Yili Zhaosu stud were chosen. The mare-foal pairs were separated by using abrupt and group weaning method, their weaning behaviour were observed and their blood serum indexes and hormone were measured on pre-weaning day, weaning day and post-weaning day. Meantime this research focuses on the main temperament candidate genes (such as BDNF, COMT, DBH, SLC6A4 and MAOB) and weaning behavioural of Thoroughbred horses by using PCR-SSCP and PCR-RFLP. We hope that this research can provide a scientific basis on Thoroughbred foals and mare’s healthy growth and welfare level, and horse industry in Xinjiang development of animal behaviour science and animal welfare science in China.1. Effect of different age on stress-related weaning behaviour in foals (Equus caballus) by abrupt group weaning methodThe purpose of the research was to examine the stress-related behavioural response of foals and find the optimal weaning age by using abrupt and group weaning method. A total of 15 Thoroughbred mare-foal pairs were divided into three groups A (6-month foals), B (7-month foals) and C (8-month foals) according to the weaning age. These foals were observed for 3 days before weaning, weaning day and 9 days after separation, and 15 behavioural patterns were compiled and collected. All statistical analysis was performed by R2.14.2. Comparing to pre-weaning, frequency of drinking, urination, fast-moving, aggression behaviors increased and the frequency of standing, lying and individual rolling behaviors decreased after separation for three groups. On the weaning day, frequency of urination, defecation and kidding behaviors were more significantly higher than its on pre-weaning and post-weaning day (P<0.05).While the drinking behavior was obviously higher than its on pre-weaning day. The 6-month foals showed less stress-related behavior categories compare to 7-month and 8-month. We conclude that the 6-month foals are the optimal age when we use abrupt and group weaning method in China.2. Study on the changes of weaning behaviour on different age mareTo confirm the effect of weaning on mare’s behaviour, A total of 15 Thoroughbred mare-foal pairs were selected and weaned by using abrupt and group weaning method.7 behavioural patterns of these mares were observed for 3 days before weaning, weaning day and 9 days after separation,. According to the weaned foal and mare’s age, the data of behavior measurement were analyzed by R2.14.2.The results showed that the frequency of standing and walking behaviors on weaning day were highest than these on pre-weaning and post-weaning day(P<0.05).The frequency of drinking on weaning day and post-weaning day significantly less than these on pre-weaning day. For 6-month and 7-month foal’s mares, the frequency of eating and drinking on weaning day and post-weaning day significantly less than these on pre-weaning day. Urination behavior of 6-month foal’s mares and 10-13 years old mare were significantly higher than those on pre-weaning and post-weaning day(P<0.05).Except for the standing and walking behavior, the other 5 behaviors had no difference between pre-weaning and post-weaning day for 8-month foal’s mares and 6-9 years old mare. In conclusion,6-month foal’s mares and 10-13 years old mares show more stress weaning when their foals were weaned.3. Effects of Weaning Stress on Blood Serum Indices and Body Growth at Different Ages FoalsIn this study, the effects of weaning stress on blood serum index and body growth at different ages foals were investigated to get the best weaned time. A total of 15 Thoroughbred mare-foal pairs were divided into three groups (each group, n=5) according to the weaning age. Foals and mares were separated by using the abrupt-weaned method, the changes of 10 blood serum biochemical indices and body weight of foals were measured on pre-weaning day, weaning day and post-weaning day. The results showed as follows:The concentrations of GLU in all foals on weaning day more significantly increased than those on pre-weaning day and post-weaning day (P<0.05). For 7-month and 8-month foals, the concentration of FFA on weaning day more significantly increased than these on pre-weaning day and post-weaning day (P <0.05).While the concentration of FFA had no difference between pre-weaning and post-weaning day for 6-month foals.The daily weight gain of 6-month foals was the highest (0.78±0.05 kg) and that of 8-month foals was the least (0.13±0.52 kg) from weaning day to post-weaning day. Results of the present study indicated that 6-month foals had less weaning stress and rapid weight gain compared with 7-month and 8-month foals by using the abrupt-weaned method.4. Effects of Weaning Stress on Blood Serum Indexes and Hormone of MaresTo study the effects of weaning stress on blood serum indexes and hormone of mares, a total of 15 Thoroughbred weaned foal’s mare were investigated. The 10 serum biochemical indexes of mares were measured on pre-weaning, weaning and post-weaning day. According to the weaned foal and mare’s age, the data of measurement were analyzed by R2.14.2. The results showed that the concentrations of GLU in all mares on weaning day more significantly increased than these on pre-weaning day (P<0.05). For 7-month and 8-month foal’s mare, the concentration of FFA on weaning day more significantly decreased than these on pre-weaning day (P<0.05).While the concentration of FFA had no difference between pre-weaning and post-weaning day for 6-month foal’s mare. For 6-9 years old mares, ALB content was the highest, FFA and COR contents were the least On weaning day, which FFA content had strong difference with its on pre-weaning and COR content and ALB content had obvious significance with its on post-weaning day(P<0.05). Whilst the contents of ALB, FFA and COR had no difference between pre-weaning and post-weaning day for 10-13 years old mares. In conclusion,6-month foal’s mares and 10-13 years old mares should be pay more attention when their foals were weaned.5. Study on weaning temperament candidate genes of Thoroughbred horsesThe purpose of this study is to reduce weaning stress, studies of candidate genes can provide the foundation for reasonable clustering before weaning on different character of the pony. The blood DNA of thoroughbred were extracted and the polymorphism of BDNF, COMT, DBH-1, DBH-2, SLC6A4-1, SLC6A4-3, SLC6A4-2, and MAOB temperament genes, were analysed by PCRPCR-SSCP and PCR-RFLP. The result showed that there had 5 temperament genes in Thoroughbred horses,3 genes (SLC6A4-1 SLC6A4-2、SLC6A4-3) showed high polymorphism. So the SLC6A4-1 gene and SLC6A4-3 gene related weaning behavior exist polymorphism in Thoroughbred horse, the study has certain guiding significance to raise a horse production practice stress prevention and control.In conclusion, compared to 7-month and 8-month Thoroughbred foals, the 6-month foals showed lower weaning stress behaviour and blood serum indexes when the foals were weaned by abrupt and group weaning method. Thus 6-month is a fit weaning time to Thoroughbred foals,which will contribute to the Thoroughbred foals’ growth,welfare and feeding benefits. In the actual production of the foals were weaned, we should focus on 6-month foal’s mares and 10～13 years old mares to avoid and reduce the effect of weaning on the mare and improve the health benefits of the mare. |
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