Cow body condition score is king

With dairy farm cashflow under severe strain for most of the past two years, milk producers have been cutting back on costs in every way possible. One of the great dangers of this is that far more costly problems can arise if the cuts actually impinge on cow health, and ultimately herd health issues make the business unsustainable.

This point about the financial effects of herd health was highlighted recently by Professor Finbar Mulligan from University College Dublin (UCD).

He expressed a personal view that cashflow at farm level has a large influence on nutrition provided to the dairy cow even though her needs for correct levels of protein and minerals don’t change when milk prices are low. Saving on nutrition in the short term can cost a huge amount in the longer term due to various health problems.

Prof Mulligan focused on the potential costs of those problems and the vital importance of monitoring and correcting body condition score (BCS) of dairy cows, which is a means of minimising those problems.

“The Dairy Herd Health Group at UCD treats correction of BCS to the desired range as number one priority,” he said.

“This is absolutely paramount to sustainability of milk production of any herd.”

Prof Mulligan gave target BCS for dairy cows at different points of the lactation cycle:

He said that 90% of the herd should meet these targets. This means that when nutrition of the dairy herd is adequate, BCS is 2.75 to 3.25 for 90% of the milking cows and BCS is 3.0 to 3.25 for 90% of the dry cows.

Low BCS at drying-off leads to a whole series of transition cow problems that affect cow health and welfare and reduce profitability. These costly problems include difficult calvings, retained placentas, lameness, ketosis, milk fever, mastitis and displaced abomasums.

Referring to particular research on lameness, Prof Mulligan said that a correlation has been found between BCS and the thickness of the ‘‘digital cushion’’ in the cow’s hoof. It is estimated that 10 severely lame cows for four months adds up to £1,665 loss in milk sales (at 18.5p/l).

Speaking at the same event, United Feeds nutritionist, Bobby Irwin, quoted costs of £215 per case of mastitis, £225 per case of milk fever and £300 per case of retained placenta. For a 7,500-litre cow, these costs amount to 2.9p/l, 3p/l and 4p/l, respectively.

Adequate nutrition

Prof Mulligan said that, at its most basic, adequate nutrition requires the calorie intake of the animal to be equal to the calorie demand that covers milk output and maintenance of body condition. Prolonged under-feeding clearly results in thin cows.

Prof Mulligan quoted results of a Research Challenge Fund project led by AgriSearch and carried out by AFBI Hillsborough, which found that for thin cows (BCS 2.25 and under) supplementing concentrates for eight weeks in the dry period improved conception rate to first service to 43.2% compared with a 25.5% conception rate for thin cows on a forage-only diet.

Bobby Irwin highlighted the United Feeds pre-calver management programme as a means of guarding against most of the problems listed by Prof Mulligan. To put on half a unit of BCS requires 100kg of feed, with double that for a full unit of BCS.

He quoted costs of £15 for four weeks’ feed for the close-up cow and £30 for the eight-week dry period, a relatively small outlay compared with the potential costs of the problems.