26 March 1999

HOWRIGHTRATIONSWILLPAY

FEEDING rations with better energy balance could reduce culling rates and increase profits for UK dairy herds, Trident Feeds nutritionist Matt Witt told the Keenan/Trident meeting.

Herd losses through culling are high, with latest reports indicating an average annual cull of 33% of a dairy herd each year, with 90% of those culls on an involuntary basis.

He believes its often the most productive cows which are culled, while less efficient ones stay in the herd.

Half the involuntary culls are related to infertility, lameness and metabolic or digestive disorders – all of which indicate poor nutrition, said Dr Witt.

Starch reduces intake

"Cow health can be directly affected by whats happening in the cows rumen. For example, rations that are too high in starch content depress microbe activity in the rumen. This causes a reduction in intake and excaberates any lameness problems."

High starch diets can reduce rumen pH, killing off rumen bugs, while also impairing digestion and intakes, reducing milk yield and/or causing body condition loss.

"Its essential to feed palatable diets which contain the correct balance of energy sources – including sugars, starch, long and digestible fibre – for optimum rumen microbial activity." To counteract body condition and milk yield loss sufficient long fibre must be fed. Fibre encourages saliva production to help buffer rumen acid.

He told delegates that cows which are not fed enough fibre produce up to five litres less milk a day, it is therefore, an essential ingredient.

Lameness may also be caused by acidic rumen conditions, leading to the production of toxins which are absorbed in the blood. These toxins destroy the laminae of the foot and lame cows yield 2-3 litres a day less than non-lame cows, he says. &#42