Optimal Forage Choices for Lactating Murciano-Granadina Dairy Goats: Feed Intake, Behavior Time Budget, Milk Production, and Blood Metabolites

It is important to optimize forage choices for improved milk production and goat health under intensive raising systems. Our hypothesis was that alfalfa hay (AH), corn silage (CS), and wheat straw (WS) can be utilized by lactating Murciano-Granadina goats towards efficient milk production and that feed intake and efficiency and milk quantity and quality responses as well as metabolic parameters would differ among the forage sources. The objective was to determine effects of feeding different major forages on feed intake, behavior time budget, milk production and composition, and circulating blood metabolites in lactating Murciano-Granadina goats. Thirty lactating goats were used in a completely randomized design study with three treatments including diets containing 1) WS, 2) Al], or 3) CS at 40.3% of diet dry matter. Treatment diets were formulated to be isoenergetic (ME) and isonitrogenous (CP). Ten goats were assigned to each treatment. Forage source affected (P<0.01) dry matter intake (DMI), such that the highest intake was for CS (1904 g/d) and the lowest intake was for WS (1406 g/d) with AH being intermediate (1674 g/d). The yields of raw and fat-corrected milk, milk protein, lactose, and solids-nonfat were greater (P<0.01) for CS than for other two forages. Milk contents of fat, total solids, urea nitrogen, unsaturated fatty acids, polyunsaturated fatty acids, and blood concentrations of total proteins were greater (P<0.05) for AH than for other forages. Milk somatic cell counts tended to be lower (P<0.10) for CS than for AH and WS. Treatments did not affect (P>0.10) times spent standing, lying and ruminating, and blood concentrations of glucose, albumin, and non-esterified fatty acids. Total protein concentrations in serum were, however, greater (P<0.05) for All than for CS and WS. In conclusion, different forage choices can be fed to lactating Murciano-Granadina goats with different aims; CS for increased milk yield, AH for improved milk fat content, and WS for lower feed cost. Changes in forage cost and availability, production systems and strategies, and consumers' demand will determine how to optimize forage choices for lactating goats.