Effects of feeding intensity during the dry period. 1. Feed intake, body weight, and milk production
2003
Agenas, S. | Burstedt, E. | Holtenius, K.
The objective of this experiment was to study dry matter intake (DMI), bodycondition, milk yield, and milk composition in cows with different body condition at the time ofparturition. Twenty four multiparous cows with genetic merit for high or low milk fat contentwere assigned to one of three diets during the dry period. The treatments consisted of 6, 9, or14,5 kg dry matter of a total mixed ration providing 71, 106, or 177 MJ/d of metabolizableenergy and are referred to as low (L), medium (M), and high (H) dry period rations, respectively.These diets were introduced when the cows were dried off from the previous lactation, at least 8wk before expected parturition. After parturition all cows were fed another total mixed ration adlibitum. The dietary treatments generated differences between the groups in body weight as wellas in body condition score at parturition. There were no differences in DMI in early lactation, butduring wk 6 to 12 DMI was lower among H cows, which was linked to a prolonged negativeenergy balance in this group. The milk yield was 38.5 +/- 0.8 kg of energy-corrected milk thefirst 4 wk postpartum and did not differ between treatments or selection lines. Body weight lossmainly occurred in lactation wk 1 to 4 and was greatest in H cows. The mobilization of bodytissues was reflected in a higher milk fat content of C18:0 for the H cows during wk 1 to 4. Therewere no marked effects of treatments on milk fat content or milk protein content, which indicatesthat cows in early lactation have a potential to compensate for low nutrient intake during the dryperiod if they are offered a high-quality diet. The observed differences between treatments inDMI wk 6 to 12 could not be explained by differences in milk yield or mobilization of bodytissues. Milk fat content was 4.7% in cows with genetic merit for high milk fat content and 4.2%in cows with genetic merit for low milk fat content. There was a tendency for higher body weightin cows with genetic merit for low milk fat content throughout the experiment.
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