26 March 1999

FEED DRY COWS RIGHT

By Emma Penny

MANAGING and feeding dry cows has important consequences for the next lactation and cows in the late dry period should be offered high-quality silage rather than straw.

Delivering the British Society of Animal Science lecture at the Royal Association of British Dairy Farmers conference, researcher Richard Dewhurst said that the negative effect of feeding inappropriate rations may be seen in two weeks time, or even three months. Correct feeding during the dry period is, therefore, vital as it is a time of intense metabolic activity.

He told the conference that research at the Institute of Grassland and Environmental Research, Aberystwyth, into both low milk protein syndrome and health and welfare shows that negative energy balance in early lactation is a common link.

"The problem at the heart of our research is negative energy balance in early lactation – feed intake lagging behind milk yield. This is a major issue in IGERs high forage systems, and may become more of an issue as cow genetic merit increases."

Trials over the last five years on average cows – rather than high merit animals – allowed researchers to draw four main conclusions for managing cows in the dry period.

"First, in the early dry period, use poorer forage, allowing only moderate liveweight and body condition score gains."

Steaming up before calving often led to cows getting too fat, leading to low intakes and massive liveweight loss in early lactation, he said. "Dry cows find it quite easy to gain condition in a relatively short space of time. Avoid large changes in condition score over the dry period, and avoid having fat cows at calving – condition score 2.5 to three is ideal.

"In the late dry period, provide good forage with high intake potential. Many believe that feeding straw before calving will stretch the rumen and condition microbes, but research shows theres little evidence of either.

"Forage intake before calving is related to intake post-delivery; feeding straw will reduce intakes and milk production until five or six weeks after calving. Its more important for cows to be used to a high throughput of good forage in the late dry period," he said.

"Using concentrates to bolster intakes is very much second best, although they may be a reliable route for ensuring cows receive enough minerals. Weve just finished a trial which seems to suggest that high-quality, high-digestibility silage is the best option – were considering looking at the effect of feeding legume silages next."

Protein supplement

Offering a protein supplement could help replenish body protein and increase milk production in some cows, but can stimulate forage intake, allowing cows to become over-fat.

"Our trials suggest that additional body protein reserves change in response to feeding, but probably dont cause differences in milk production or composition."

Better management of dry cows will pay, said Dr Dewhurst. "Besides helping to avoid low milk proteins, most cow health problems occur round the dry period or as a result of management during it. More attention to nutrition could help reduce concerns." &#42

DRYCOWFEEDING

&#8226 Avoid steaming up.

&#8226 Straw not appropriate.

&#8226 Feed high-quality forage.