Effects of Feeding Multinutrient Blocks Including Avocado Pulp and Peels to Dairy Goats on Feed Intake and Milk Yield and Composition.

Abstract

Simple SummaryThe high and volatile prices of conventional ingredients for animal feeding has directed the attention of ruminant nutritionists toward local alternative resources such as agroindustrial by-products and fruits wastes. The inclusion of these resources in the diet might contribute to reducing feeding costs and environmental issues associated with both livestock production and by-products and wastes accumulation might be prevented. The global production and consumption of avocado have risen sharply in recent years, partly due to the recognition of its health-promoting potential in humans. The increased consumption of avocado and its derivatives is producing great amounts of wastes and by-products that might be reutilized in ruminant feeding. Our hypothesis was that avocado wastes (a mixture of pulp and peels) could be included in multinutrient blocks for dairy goats and improve the quality of the milk fatty acid profile without negatively affecting milk yield. However, the intake of multinutrient blocks containing 14.8% avocado wastes was low probably due to avocado lipids oxidation and rancidity. No changes were observed in milk production, but feeding blocks with avocado wastes increased milk fat content with only subtle changes in the fatty acid profile of fat milk.Twelve Murciano-Granadina dairy goats were divided into two homogeneous groups, which were fed either a control diet composed of 40% alfalfa hay and 60% concentrate or a diet based on 40% alfalfa hay, 40% concentrate and 20% multinutrient blocks, including 14.8% avocado pulp and peels (APP). Total dry matter (DM) intake was similar (p = 0.709) for both diets, but APP-fed goats had lower (p = 0.024) concentrate intake and tended (p = 0.063) to have lower fat intake compared with those fed the control diet. The average intake of blocks was low (66.4 g DM/d), which was attributed to avocado lipids oxidation and rancidity. Neither milk yield (p = 0,921) nor the efficiency of energy and nitrogen use were affected (p = 0.909 and 0. 840, respectively) by the diet, but milk fat tended to be greater (p = 0.057) in the APP-fed goats compared with the animals fed the control diet. Other milk components were similar (p ≥ 0.110) for both diets, and only subtle changes in the milk fatty acid profile were observed. In summary, the intake of blocks containing avocado wastes by dairy goats was low probably due to avocado lipids oxidation causing off-flavors and reduced palatability.