7 June 1996

Care with condition scores lifts fertility

Improving cow management in the dry period can pay dividends in the next lactation. Jonathan Riley reports

CAREFUL management of condition score up to and through the dry period has improved fertility and reduced reproductive disorders for one Oxon dairy producer.

Brian Doble runs 150 mainly summer calving cows at Shiplake Farm, Henley-on-Thames. He groups cows throughout lactation according to condition, stage of lactation and milk yield.

"It is important to manipulate condition scores carefully in late lactation to get the cows to the dry period in the condition in which you want them to calve," says Mr Doble.

Cows are fed on a combination of maize and grass silage plus home-mixed concentrate. This is based on Sodagrain and soya and offered at between 8kg and 10kg a head a day in early lactation. Animals that are too fit are transferred to a lower feed rate to reduce condition scores.

Chopped straw is introduced to the ration at about 1kg a day from Christmas. By March the straw content is up to about 2kg a day and magnesium chlorite crystals are added to water troughs. This regime gradually reduces cows to a condition score of 3 at drying off.

After tubing, cows are kept in for five days and off lush grass to speed the drying-off process. Dry cows are then grouped with in-calf heifers and stocked at a rate of 17/ha (7/acre).

Herd manager Tony Potterton puts fitter cows on to bare ground to restrict grass intakes to a minimum and hold condition scores down.

"But great care is taken to provide dry cows with sufficient nutrients and energy so that condition is not lost," he says. "We offer specially formulated low calcium dry cow rolls in troughs at 1kg to 2kg a cow a day." These supply sufficient vitamin A and E as well as magnesium for the cows needs.

"Feeding in troughs also gives us the chance to inspect the cows at close range and we can quickly see if there are any problems with swollen quarters."

The basis of the dry cow ration is chopped straw. This provides long fibre, which helps to maintain gut capacity and hence promotes higher intakes in the next lactation. "Intakes in early lactation are definitely rising and we are trying to push up intakes to 50kg a cow a day. Though this is partly due to genetic improvements, intakes definitely rose after we introduced the straw feeding regime," he says.

That is contributing to a rising average milk yield, which is up from 5700kg to 6300kg over the past 12 months, boosting margins over purchased feed to £1450 a cow.

"As we have fine-tuned dry cow management over the past few years we have seen fewer retained afterbirths – incidence is now down to about 5%. And, by restricting grass and providing low calcium dry cow rolls, milk fever has fallen from about 6% to nil," says Mr Potterton.

"This more than pays for the dry cow rolls and straw because it is not just the call-out fee for the vet to treat a milk fever case, there is a loss of production and the cow suffers generally," he says.

Three weeks pre-calving, cows are inoculated against salmonella and given a selenium booster, which Mr Potterton believes has improved fertility, with 65% of cows in calf after first insemination. "Cows are calved outdoors from the end of June and keeping the cows at condition score 3 throughout the dry period has seen the number needing assistance at calving falling to less than 10%.

"We have also noticed that the herd comes bulling more quickly at about 11 days after calving," he says. &#42


&#8226 Condition score 2.5 to 3.

&#8226 Feed straw and 2-3kg DM forage.

&#8226 Avoid high calcium lush grass.

&#8226 Provide low cal/high phos mineral.

&#8226 Introduce milking ration 10 days before calving.


WHAT TO AIM FOR

Herd manager Tony Pottereton provides dry cows with 1-2kg a head a day of specially formulated low calcium rolls in troughs.

Brian Doble ensures cows start their dry period in the condition in which he wants them to calve.