Limiting body condition score loss around calving will increase the likelihood of a cow producing a high-quality embryo 120 days later and boost overall herd fertility.
So says Jo Leroy, from the University of Antwerp, who explained to delegates, at Mole Valley Farmers’ Lifetime Dairy Conference, that the oocyte (egg) that a cow produced, would ‘remember’ the metabolic state of its mother. “And this impacts on fertility success months later. The embryo feels, directly, what we’re doing to the cow.”
He highlighted a recent study that looked at four groups of cows, selected according to body condition, three weeks after calving. Body condition loss was viewed as a measure of metabolic health.
One group lost a lot of body condition, one lost a small amount, one maintained, and one gained. They were all enrolled on an ov-synch programme 120 days later and their embryos were assessed. “The more lipid mobilised by the cow during the first weeks after calving, the worse the embryo quality was many months later,” said Dr Leroy.
He added that minimising weight loss and the negative energy balance (NEB) around calving ultimately came down to ensuring adequate dry matter intakes. But it was also hugely influenced by management during the months prior to drying off.
To reduce the NEB, Dr Leroy urged producers to consider the ‘what, if and when’ of feeding. “The ‘what’ would largely be handled by the nutritionist, but the ‘if’ and ‘when’ is down to the producer,” he said.
If, for example, there is competition for feed, or a lack of availability or freshness, then intakes will suffer. When a cow eats is also vital. “If a cow eats too much in late lactation, she could go into the dry period over-conditioned and will be less inclined to eat around calving. This can lead to greater weight loss and poor metabolic health.”
Dr Leroy said that producers should take a step back and assess whether their management meets the cows’ needs and promote intakes at the right time.
“Leave the unit then come back and be a ‘tourist’ on your own farm and see what you haven’t seen before,” he said. “Think hard before you turn to expensive fertility treatments. There are other options and areas to consider first.”