The effect of blood BHBA level on fertility in sheep

The aim of this study was the effect of pre-synchronization blood BHBA level on pregnancy rates of sheep in the non-breeding season. For this purpose, 100 Merino/Merino crossbred ewe, aged 2-4 years, who have given one birth before, were used in the study. For synchronization purposes, progesterone containing sponges 60 mg Medroxyprogesteron acetate (MPA) analogue, were administered intravaginally for 14 days. BHBA (betahydroxybutyric acid) measurement was made by drawing blood in each animal on the day of administration. 500-700 IU PMSG was injected at the time of sponge withdrawal. Oestrus was observed 24 hours after sponge withdrawal with the help of teaser ram. Animals which was in estrus were hand mated. Pregnancy status was recorded with the help of ultrasound using the transrectal probe in the interval 35-45 days after mating. All of the synchronized animals were determined to be in estrus and their mating were performed. As a result of the pregnancy examination, 57 (57%) of the animals became pregnant and 43 (43%) did not become pregnant. Blood BHBA values were measured in the range of 0.12 mmol/L -0.66 mmol/L (n:100) in present study and the average of BHBA as 0.35±0.083 mmol/L was determined. While blood BHBA level of pregnant animals was found as 0.29±0.005 mmol/L, blood BHBA level of non-pregnant sheep was found to be 0.41±0.073 mmol/L, which was statistically significant (p<0.001). In addition, it was determined that there was a strong negative correlation between blood BHBA level and pregnancy rates in sheep (r = −0.719, p<0.001). As a result, it was concluded that there was no study in the literature about the relationship between the fertility parameters of sheep and the blood BHBA level in the mentioned period, and it was concluded that the presented study made a significant contribution to the literature. It has been concluded that a higher fertility success can be achieved from animals with low BHBA levels, that fertility rates can be increased by regulating the energy balance of animals with high BHBA levels, and that the study can be a criterion to be considered in achieving the target of 3 lambing in 2 years in terms of herd management in sheep breeding.