Study highlights feeding for fertility

This is according to a study led by SAC Consulting, part of SRUC. Although a commonly used management tool in dairy herds to investigate the nutritional status of pre-calving and early lactation cows, metabolic profile (MP) testing has had little uptake in suckler herds.

The project, funded by the Scottish Government’s Knowledge Transfer Innovation Fund (KTIF), found that MP testing is worth carrying out to highlight nutritional issues in the cows that could affect calving performance, milk production and fertility. It could also pick up on management issues, such as inadequate feed space.

The 12-month study tested 180 cows across 12 farms in Angus and Fife. The testing was carried out at approximately one month before calving and one month after calving to assess nutritional status. Cows were also body condition scored.

The study found that a third of cows were deficient in magnesium pre-calving, which is significant given the impact a lack of magnesium can have on slow calvings and then, potentially, on the health of the calf.

It also showed that a quarter of cows were deficient in magnesium post-calving. Again, this is significant to address, with low magnesium in cows going out to grass exacerbating the risk of grass staggers.

SAC Consulting Nutritionist Karen Stewart, who led the study with Dairy Consultant Lorna MacPherson, said: “Another finding was that over half the cows were short of rumen-available protein in the ration pre-calving which, if left uncorrected, may impact colostrum quality and milk production. The study also highlighted energy deficiencies and, with corrective action, helped to safeguard calving performance and getting cows back in calf.

“In some cases, the ration looked ideal on paper and was based on silage analysis, but feed access issues, weather and other environmental factors negatively affected the animal’s nutritional status.

“We did find that trace elements and other major minerals, except magnesium, were not deficient and cows were generally well supplemented.

“Blood results from two of the 12 farms showed low albumin levels in a number of cows, indicating a potential disease issue. Liver fluke was subsequently diagnosed in these herds which had previously dosed for fluke and highlighted a potential problem with product resistance.”

The study was supported by The Royal (Dick) School of Veterinary Studies at the University of Edinburgh. It was also supported by Graeme Richardson from Thrums Vet Group and Cameron & Greig Vet Practice.

A full report on the project will be available online soon. A podcast on the topic is currently available on the Farm Advisory Service audioboom channel.