Keep your cows in comfort
A HEALTHY and comfortable cow is more likely to be a fertile cow, according to Glos-based vet Roger Blowey.
Speaking at a Fertility in Focus seminar in Wales, organised by the MDC, he said there were many reasons for the 1% a year fall in average conception rates. But relatively simple management changes could slow the decline.
Mr Blowey acknowledged the economic pressure to increase herd size and cow yields. But this has meant modifications to feeding regimes to exploit enhanced genetic potential and stockmen tend to be responsible for more cows.
Increased output causes greater stress on animals and those who manage them. Irregular oestrus and embryo expulsion can result where cows are poorly nourished, unfit and uncomfortable during the post-calving period, he said.
"A stressed cow can receive so many extraneous hormone signals that it may not recognise the presence of an embryo and it may be expelled after the release of prostaglandin." Some pregnant cows also falsely appear to come on heat and abort after an attempt to inseminate them, he added.
As most heats start at night and can last for as little as six hours they can easily be missed, he warned. There is also considerable variation in the bulling behaviour of different cows.
"Heat detection becomes a pain as herds get bigger. The best indicator of a cow on heat is another that is about to come on. At the tail end of the bulling period, and where results are poor, synchronisation is worth considering."
He urged producers to identify and minimise the major stresses of calving and early lactation by providing comfortable, spacious housing, careful rationing and health care to ensure good fertility.
A cow that is bullied, or suffering from acidosis, a uterine infection or sore feet is less likely to have regular heat cycles, become pregnant or keep her embryo calf. Slippery surfaces also make cows nervous about standing to be mounted.
Heifers need special care as they are switched to a production ration and are integrated with adult cows, he added. *