Investigation On Aetiology And Prevention Of Anoestrus Cow In Intensive Dairy Farm

In this study, There are three experiment which were included:The investigation and research on performance trait and breeding performance of dairy cow;The relation metabolism and endocrine index in blood plasma on estrus and anoestrus of dairy cow on postpartum;The prevention and cure high energy diet and reproductive hormone on anoestrus of dairy cow on postpartum.Through the investig -ations of performance trait, breeding performance, nutrition level and rules of plasma biochemical and endocrine parameters, the objective were to illuminate the aetiology of anoestrus disease in high milk yield cows, and provided scientific basis for the prevention and treatment of this disease.Experiment one, the nutritional level(Energy,Protein,Water,Crude fat,Crude fiber and Calcium,Phosphours)were measured and dairy breeding performance(conception rate,anoestrus rate,Breeding index,Interval of calving),The study indicated that diet energy and protein are lower than that NRC (2001) standard of in cattle farmⅠ. The energy, protein and fat contents of diet are lower than NRC (2001) standard in cattle farmⅢ. Cattle farmⅠand cattle farmⅢhave more serious anoestrus problems. So the low level of energy, protein and fat in diet was the main cause of anoestrus in dairy cows at postpartum.Experiment two , Thirty dairy cows were selected randomly and divided into estrus group (E) and anoestrus group (A) respectively, 15 cows in each groups。Blood was collected through jugular veint at days of 45, 55, 65, 75 and 85 after calving which were measured. endocrine index(Leptin,LH,FSH,P4,E2,PRL), metabolism index(Glu,NEFA,BHBA,Bun), mineral matter(Ca,P,Se,Mg) and vitamin index(VA,VD,VE), liver index(TG,γ-GT,GOT,T-BIL) in blood plasm of dairy cows. The study indicated that there are no significantly difference in minerals, microelements and vitamins in the plasma and liver function parameters between anoestrus cows and estrus cows, they were not main the cause of anoestrus in dairy cows at postpartum. Anoestrus cow showed low concentration of blood urea nitrogen and glucose, high concentration of nonesterified fatty acids. There are abnormal reproductive hormones content, secretion mode and peak value in plasma of anoestrus cows. The plasma leptin concentration of anoestrus group was significantly lower than estrus group. Those were the direct cause leaded to anoestrus in dairy cows at postpartum.Experiment three ,The high-energy diet (DMI:88.89%,Fat: 4.89%,Crude fiber: 19.39%; Protein: 17.09%,Ca:0.66%,P:0.38%,Energy:24.07 MJ/Kg)and hormonal were treated to anoestrus dairy cows.The study shown that cows fed control diets (Protein: 17.09%, Energy: 24.07 MJ/Kg) could achieved standard plasma hormone levels of estrus. Three types of anoestrus were treated with eligible treat methods. The cured rate of follicle rest was 45 percent, the cured rate of duration corepus luteum was 56 percent, and the cured rate of ovarian cyst was 42 percent. After treatment, hormone level of the anestrus cows reached to normal.Through the investigation of performance trait, breeding performance, nutrition level and analysis of plasma biochemical and endocrine hormone parameters, the results indicated that low energy and protein content in diet and higher milk production of early lactating cows resulted in negative energy balance (NEB) which are characteristic of low concentrations plasma blood urea nitrogen and blood glucose and high concentration of nonesterified fatty acids. NEB was the main cause of estrus interval extension. The reproduction hormones insufficient, secret mode disorder and defect peak value were the direct cause of dairy estrus interval extension.