Short communication: analysis of milk yield and composition for dairy heifers limit-fed lower forage diets during the rearing period.
Methods to improve feed efficiency in dairy heifers have been studied that employ limit feeding and high concentrate or highly digestible diet ingredients. To date, the published studies have used differing daily gains, diet components, and management systems. All of these studies have had limited numbers of animals, which limits the power of each study by itself. The objective of this analysis was to evaluate, using all available studies, the overall effect of limit feeding dairy heifers during the rearing phase on milk production and composition during the first lactation. To accomplish this objective, responses from published experiments were analyzed using random effects meta-analytic procedures. The results of this analysis confirmed the results of the individual experiments in that no significant differences were found in lactation performance between the limit-fed, lower forage diets and the higher forage control diets. Heterogeneity of results between experiments was low to moderate for the response variables evaluated, indicating that the results were reasonably consistent among the trials. Limit feeding of higher concentrate diets represents a viable alternative to traditional high forage heifer feeding systems when environmental or economic conditions favor these systems.
Zanton
G I
GI
Department of Dairy and Animal Science, The Pennsylvania State University, University Park 16802, USA.
Heinrichs
A J
AJ
D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002417:Cattle / Q000502:physiology*; D004032:Diet / Q000662:veterinary*; D005248:Feeding Methods / Q000662:veterinary*; D005260:Female; D007774:Lactation / Q000502:physiology*; D008892:Milk / Q000737:chemistry*; D013997:Time Factors