Body condition scoring is an objective assessment of cows body reserves at a given point in time, with values ranging from one, extremely thin to five, obese.
Moorepark research has shown that BCS at the time of first service and the loss in body condition from calving to first service affect the reproductive performance of dairy cattle.
“Maintaining the appropriate herd BCS profile should be viewed as a component of the long-term farm management strategy, and sudden losses, for example calving or sudden gains, for example during the dry period, should be avoided when possible,” it said.
Moorepark Teagasc has identified target BCS for key times during the year, which are:
Herd average Range
Drying off 3.0 2.75 to 3.25
Pre-calving 3.25 3.0 to 3.5
Start of breeding 2.9 2.75 to 3.25
According to Teagasc, the key points are that you want your cows to gain very little during the dry period, and hence they must be close to the desired BCS at dry-off.
“Avoid over-conditioning of cows during the dire period. Cows with a BCS of four or more have a high incidence of postpartum disorders, including fatty liver, milk fever, retained placenta, metritis, and ketosis.
“Cows with excessive BCS at parturition will lose a lot of condition after calving. Excessive loss of bodyweight and body condition results in an oestrus, cyclic ovaries, poor expression of oestrus, decreased conception rates and increased incidence of embryonic mortality.”
The Moorepark advisors also note that on the other side of the coin, does that calve down too thin are unlikely to reach the target BCS by the start of breeding.
“This will results in a high proportion of non-cycling (an oestrous) cows at mating start date, which will have a negative impact on submission and conniption rates, and hence six-week in-calf rate.”
They also concluded that it can be difficult to achieve the BCS targets outlined above with cows that have been aggressively selected for increased milk yield. Its research has indicated that high-production type cows lose BC during early lactation, but fail to regain BC during the remainder of the lactation.
“Feeding higher levels of concentrate to these cows results in higher milk production, but doesn’t improve BCS during lactation. In the long term, these cows are unsuitable for seasonal-calving grass-based systems of production,” they cautioned.