People say it’s important, like everything else we have on our plate… but large studies show this can be the difference between having 83% of your cows pregnant 40 days after AB, versus 25% if you don’t manage your cows carefully. So read on.
Fricke & Wiltbank studied 1,887 cows under the same timed AB management protocol and showed that cows losing condition were just 25% pregnant 40 days after AB. Cows that maintained condition after calving were 38% pregnant at 40 days. It was the cows that gained condition that achieved the 83% pregnancy rate, that’s where you’d prefer to be.
A smaller study found health events are impacting condition and fertility. Cows that lost weight suffered more than one health event in early lactation more than 66% of the time. 46% of cows that maintained weight had more than one health issue and the cows that gained condition had the lowest (39%) number with more than one health event. Managing health carefully can give you greater control over body condition, impacting repro positively in turn.
In the U.S. embryo work is more widespread, and embryo quality has been analysed to try to better pinpoint how body condition impacts repro. Cow that lost weight had fewer high-quality embryos; less than half were viable. The cows that gained or maintained condition were 75% viable with 60%+ embryos of high grade.
Where early lactation cows get into negative energy balance, stored body fat gets mobilised. Recent research shows eggs maturing (becoming available for AB) while the fatty acids in the blood are at higher levels, result in less robust embryos. Upshot is likely to be poorer survival and lower conception rates, but there is also a possibility of downstream calf development impacts.
All this flags the importance of paying close attention to cow health and body condition that underpins solid reproductive performance.