“The onset of lactation causes a steep increase in nutrient requirements and negative energy balance for dairy cows resulting in lower blood glucose.
“It is absolutely essential the animals avoid massive mobilization of body reserves such as calcium and phosphorus at this time as it results in metabolic perturbations leading to greater incidences of diseases such as ketosis and hepatic lipidosis,” said Dr Pierre Lacasse, research scientist in biology of Lactation for the Agriculture at the Sherbrooke R&D Center in Quebec, Canada.
He was speaking on the first day of the Phileo Global Ruminant Symposium, which was attended by 250 delegates from over 42 countries. It kicked off yesterday in Toulouse.
Nutritional constraints
“Despite decades of research into the deficit between food energy intake and the energy required for milk production, the problem still persists.
“The simple solution would be to increase the cow’s energy intake during the lactation period but feed intake generally is limited in early lactation. The rumen microflora takes several weeks to fully adapt to a high starch diet restricting the amount of grain then that can be included in the diet, while inclusion of fat in the diet can contribute to the accumulation of fatty acid in blood metabolites.
“So we looked at how to decrease the energy requirement instead by slowing down the increase in milk production, to see if this would reduce metabolic disturbance and disease,” said Lacasse.
Studies undertaken
In the first of two strategies evaluated, multiparous Holstein cows were milked either once a day or twice a day for the first postpartum week. The cows milked once a day showed an improvement in their metabolic profile and immune functions. “But the negative impact of this approach was the milk production of cows milked only once a day did not fully catch up with the control cows after twice a day milking was resumed,” said the ruminant expert.
The second approach involved milking cows ‘incompletely’ whereby around one third of expected milk production was collected twice a day until the fifth day after calving. This partial milking strategy improved the metabolic profile and immune functions without affecting subsequent milk production, he said. “The cows were in good health and started to produce milk again in good quantities,” said Lacasse.
He said the partial milking for five days only is economical as it is mainly colostrum in that period. “This is agro-management in practice, with no significant investment needed by the producer,” added the presenter.