Protein warning as heat clobbers cow appetites
By Sue Rider
DAIRY farmers are urged to check milk protein levels as hot weather drives down feed intake of cows.
"Consistently high temperatures have taken the edge of voluntary intake," says Wolverhampton-based independent consultant, Stuart Jones.
Not only are cows eating less in the heat, but herbage available is becoming stemmy and less digestible. "Quality has fallen because grass is maturing so quickly," says Mr Jones.
"Cows eating less than usual and getting less from it will be short of energy, and that will certainly depress milk proteins."
He cites evidence to show this has been the case on many dairy farms across the country.
Shropshire dairy farmer Andrew Teece, for example, saw proteins drop by 0.2% in July.
Mr Teece farms in partnership with his wife and parents at 76ha (188-acre) Haughmond Farm, Uffington, Shrewsbury. The drought-prone, all-grass farm carries 140 Holstein Friesians.
Herd average to June was 5293 litres, at 4.16% fat and 3.23% protein. But a heat-wave in late June halted grass growth and milk dropped. "Milk fell by 300 litres in the tank," says Mr Teece.
He split his herd into high and low yielders on July 10 – a month earlier than usual, and introduced a ration devised with Mr Jones.
High yielders were fed 2kg of a 19% parlour concentrate plus ad-lib big bale silage – and a straights mix comprising beet pulp, soya, distillers, fishmeal, maize meal, and minerals. Low yielders were fed concentrate and straw buffer.
New feed policy
The switch to the new feeding policy coincided with a milk quality test on July 14 which recorded milk proteins down at 3.10%. "It was quite dramatic how the yields came back – but we werent expecting the drop in protein," says Mr Teece. By July 19 proteins were down to 3.05% but a week later back to 3.11%.
"Weve seen dry conditions and grass shortages before," says Mr Jones. "What is new is the combined effect of poor grass quality and reduced appetite which is leaving the cow short of energy."
Mr Jones urges milk producers to ensure plenty of drinking water is available to cows to keep yields up. When grass is short he advises introducing a forage such as grass or maize silage. The difficulty is balancing short-term forage needs with those of the longer-term, especially when there are no carry over silage stocks available.
"Mr Teece is overcoming the problem by buying in silage," he says.
It was also important to consider carefully the quality of parlour compound fed. "Offer a higher energy cake rather than increasing the quantity fed for this will suppress appetite for grass further," he says.
Mr Jones also says that when high temperatures are knocking appetites, it makes sense to offer the better grazing at night.
• Many Welsh farmers have been forced to keep lambs very tightly on fairly bare pastures to provide more grass for dairy cows.
But while the lambs have continued to grow well, dairy consultants report that milk yield and protein level are lower than usual on many units, especially where buffer feeding is not being used (see p??).
The expert management that won the 1995 All-Wales Grassland Farming Award for David Davies had kept plenty of grass in front of his 64 milkers at Gwarffynnon, Silian, Dyfed, but protein has fallen to 3.1%. He attributes the disappointing figure to seasonal effects on herbage quality.