Nutritional management of the pregnant dairy cow to optimize health, lactation and reproductive performance

Abstract

The late gestation period is often viewed as a rest period between lactations. Management programs for the pregnant dry cow often reflect this view resulting in poor to marginal management and feeding programs being enacted. In contrast, current research suggests the concept of the late gestation period being a critical component to lactation preparation rather than an insignificant rest period between lactations. Required nutrient amounts for the dry pregnant cow are the sum of maintenance, pregnancy and reserve replenishment needs with additional requirements for growth during the first two pregnancies. Maintenance energy requirements can be dramatically increased by level of activity and adverse environmental conditions. A wide variety of feed ingredients can be successfully fed to dry cows as long as rations are appropriately formulated to meet energy, protein, mineral and vitamin requirements. Dry matter intake of the dry pregnant cow varies according to age, pregnancy status and time relative to calving. A substantial decline in intake occurs within the last 2–3 weeks of gestation for all age and pregnancy status groups supporting the need for a two diet dry cow program. Dietary concentration will need to be adjusted accordingly to ensure adequate nutrient intake to minimize potential metabolic disease during the peripartum period. The current model estimating energy requirement for pregnancy appears adequate in contrast to the protein requirement model. Research data would suggest that feeding additional protein in excess of the current requirement results in improvement of a variety of animal parameters critical to postpartum performance. The critical role of protein in the prepartum diet may be related to the role of amino acids providing for both fetal protein synthesis and a substantial amount of energy. A sound late pregnancy program results from integration of quality nutrition and cow management practices. Overall, a sound late pregnancy program is a critical key to improved lactating cow performance.