Milking groups can cause yield drop

Dairy cows often suffer yield drops when moving between milking groups, but changing your system can prevent these losses. Olivia Cooper reports.

Many dairy producers split their cows into different groups for more targeted feeding and cow management. But moving cows from one group to another often results in a sharp yield drop, which remains for the rest of their lactation.

When consultant Robert Cope, a Kingshay associate, was faced with this challenge at McMurren Bros, Banbridge, Northern Ireland, he tried everything to find a solution. “The groups consisted of fresh, highs, mids and lows, and, try as we might, we could not solve the milk drop,” he says. “We tried moving weekly, fortnightly, and in larger numbers; during feeding time, and feeding extra in the parlour. We also reduced yield differences between the groups. All had little effect.”

The brothers, Stuart and Darren, keep 320 Holsteins, which they calve all year round and house during lactation. Initially, they split them into three groups – fresh, highs and lows, but suffered a six-litre yield drop when moving cows giving 30 litres a day into the low yielding group. “We tried a middle group for a while, which seemed to create more problems; we were losing more in milk than we were saving in feed,” says Darren. “The issue seemed to be more about moving the cows than the change in ration.”

Mr Cope suggested changing to a new regime, with a fresh group, two high groups on the same ration, and a tail ender group for drying off. Instead of moving cows at 21 days, 120 and 220 days, they would move at just 21 and 250 days. “It takes cows two to three weeks to get over a change,” he says. “A lot of people like to move cows 35 days after calving, but they will still be getting over that when you start serving them, which will impact on fertility. Also, leaving fresh cows comfy on deep straw for so long makes the move to the main milking group an even greater shock.

“We are keeping the fresh cows together as much as possible so there is less stress; we want to keep the cows happy in their peer groups.” And by moving to the tail-ender group later, the stale cows would be easier to dry off and less likely to become fat. “Before, some cows were getting over-fed in the middle group; having a tail-ender group allows us to reduce yield at the desired time, and control body condition better.”

Before changing the regime, Darren and Stuart were feeding the high yielding group 11kg of meal plus silage and wheat wholecrop; they have since reduced that to 8kg of meal, 8.5kg of grass silage and 4.5kg of wholecrop. “We are making better silage than we had been – this year we decided to cut every five weeks instead of every six; the first two cuts were 12.2ME and 11.9ME. We have 100 cows in each group and they’re averaging 41 litres and 39 litres a day each, and we’re saving £50,000 a year in feed costs.”

The middle group had been receiving a 25-litre total mixed ration, with the lows getting an 18-litre TMR; that has now dropped to a 16-litre TMR with 13kg of forage. “It is simpler now as we only have two diets instead of three,” says Darren.

“It seems to be working well. The lactating cows have better condition on them, and the stale cows are drying off better without getting over-fat. And now we’re not getting the yield drop, we’re saving about 400 litres a cow over the course of their lactation – that soon adds up.”

Of course, every regime has to fit individual farm’s space and management limitations. “We have a calving index of 391 days, and the cows are dry for 42 days,” he adds. “If our fertility dropped and the cows spent more time in milk, we would have too many stale cows in the high yielding group, which would have considerable knock-on effects.”

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