Energy Efficiency

In dairy farming, understanding and managing the energy supply of ruminants in the weeks around calving is fundamental to farm productivity. The pre-calving period is marked by a complex interplay between the animal’s increasing energy needs and its actual energy intake. As calving approaches, energy requirements rise significantly to support foetal growth and the preparation for lactation. However, this higher demand often coincides with a decrease in dry matter intake, creating a gap between what the animal needs and what it eats.

To cover this gap, the animal mobilises its body fat reserves as an alternative source of energy. This is a natural adaptive response that allows milk production to start and rise quickly after calving, even while feed intake is still recovering. How much fat is mobilised, and for how long, depends on the animal’s body condition at calving, on the energy density of the ration and on how quickly feed intake recovers after calving.

Mobilising body reserves means losing weight. When the loss is pronounced or prolonged, body condition falls, and the effects go beyond the transition period: body condition in the weeks after calving is closely linked to milk yield over the whole lactation and to the reproductive efficiency of the herd. Recognising and managing this energy gap before calving is therefore crucial. It involves careful nutritional management, regular monitoring of body condition and feeding practices that help the animal through the transition into lactation, protecting the productivity of the farm.

The energy effort that ruminants make during the transition period has an impact on their reproductive efficiency. This period, which encompasses the weeks shortly before and after calving, sets the stage for the cow’s future reproductive and lactation performance. Cows with a low body condition after calving, as well as cows that reach calving overconditioned, tend to take longer to return to the reproductive cycle, which can delay the breeding schedule of the herd.

Reproductive efficiency has a direct economic impact on dairy farms. A herd that keeps a regular breeding schedule maintains an efficient lactation profile, while delays extend lactations beyond their most productive phase and reduce the overall productivity of the herd and the return on every kilogram of feed.

To manage this period well, sound management practices during the transition period are vital. These include regular body condition scoring and close follow-up of each animal through the reproductive cycle. Monitoring body condition helps identify cows that are becoming overconditioned in late lactation or during the dry period, and allows for timely adjustments to the ration.

In addition to these measures, implementing a comprehensive nutritional plan tailored to the specific needs of each cow during this period is crucial. This involves ensuring adequate energy intake to meet the increased demands of late gestation and early lactation, while avoiding excessive energy that leads to overconditioning.

In small ruminants, late gestation is the most demanding period from an energy point of view. Energy requirements rise sharply, especially in ewes and does carrying twins or triplets, while the space taken up by the growing foetuses limits rumen capacity and, with it, dry matter intake. As a result, the animal increasingly relies on its body fat reserves, and overconditioned animals tend to mobilise them more intensely.

Managing this period well has a direct impact on the flock. Ewes and does that reach lambing or kidding in a balanced body condition, and on a well-adjusted ration, are better prepared for the start of lactation, sustain their milk yield and return to the breeding cycle on schedule. Monitoring body condition in mid and late gestation, grouping animals according to their needs and adjusting the energy content of the ration accordingly are key practices. Overfeeding should also be avoided, as overconditioned animals face this period with greater difficulty.