Maintaining fertility for July and August calvers needs to be a top priority this summer, claims KW ruminant technical manager Charlotte Ward. 

She said: “According to one study, pregnancy rates as low as 55–70 per cent were recorded for summer calvers, compared to 85–92 per cent for those calving in winter.

“With each additional day beyond a 365 day calving index (CI) costing around £2.50/cow, even a 12 day extension to the CI due to lower fertility represents a loss of around 0.3ppl.” 

Shortening day length means grazing intakes are dropping, as is grass quality, and too often buffer feeds aren’t making up the nutrient shortfall, Ms Ward warns, with periods of heat stress or poor weather further restricting intakes. The result is a loss in body condition and reduced fertility. 

Charlotte continued: “Raising buffer energy density and intakes is the priority, using moist feeds like brewers’ grains or wheat-gluten moist feed, plus a molasses-based liquid feed.

“Balance energy release in the rumen with digestible fibre from soya hulls, and add a protected fat if more energy is needed above that supplied by the rumen. 

“Excess rumen degradable protein (RDP) can also negatively affect fertility, so counter the surplus RDP in grass with feeds high in rumen-bypass protein, such as heat-treated rapeseed expeller.”