13 February 1998


HERDS that suffer high cull rates because of infertility are advised to manage cow nutrition carefully.

ADAS nutrition consultant Pete Kelly says fertility can be managed by minimising the effect of changes in cow diets.

Block calving herds, especially, require good fertility to keep cows calving at the correct time otherwise these herds can suffer high culling rates.

Infertility risks are higher when cow diets change, for example when turnout coincides with the first three weeks after service. It may be more profitable to keep January and February calved cows on a full winter ration until confirmed in-calf, rather than have barreners.

Heat detection aids can help where heat observation is difficult, but do not rush cows along tracks or false readings will lead to confusion, he warns.

A beef bull can also be an option for two months when enough black-and-white heifers have been bred, or consider buying in replacements, he adds.

Receptal injections have also been shown to improve conception rates. But these should not be viewed as a long-term solution.

Synchronisation to avoid having to serve cows in the most difficult period for fertility – the two weeks after turnout – is unlikely to be economic.n

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