23 November 2001

Extended lactations an alternative to culling?

ARE extended lactations an excuse for poor fertility or a profitable alternative to culling high yielding dairy cows?

Speaking at the fertility meeting, milk producer John Downing suggested poor fertility could be the result of trying to manage higher yielding cows within a 365-day calving interval.

"I have a problem with culling cows which are not pregnant following two to three services. Similarly, drying off cows which are still producing 30-40 litres/day seems a waste."

This is shown when comparing the cost of rearing replacements at £900/heifer with the price obtained for a cull cow, currently about £300/cow, said Mr Downing.

One solution is to take their peak milk yield and double it to give the day for first service. Therefore, a cow peaking at 60kg/day would be served for the first time at day 120 onwards. This saves semen costs and time trying to serve her several times before being ready to conceive, he said.

"But this is impractical for some block calving herds. By having two blocks, cows can be allowed to slip into the next calving block." Alternatively, he suggested getting them in-calf then selling them because there is considerable demand for in-calf cows. &#42