Composition and Technological Quality of Malagueña Goat Milk. Effect of Genotype for Synthesis of αs1-Casein in Milk and Protein Content in the Diet

Abstract

The aim of this study was to identify the possible interaction between protein content in the diet and animal genotype, with respect to its higher or lower capability to synthesis α S1-casein in milk, in relation to the production, composition, and technological quality of the goat milk. Twenty-five goats of the Malagueña breed were used, with 13 of them belonging to genotypes with a high capability for synthesis of αS1-casein, and 12 belonging to genotypes with a low capability. The protein content in the diets were: 136 (D1) and 177 (D2) g/kg dry matter. Within each group, a milk production assay was conducted using the two different diets in a two-period balanced changeover design. Within each period, half of the animals consumed the D1 and the other half consumed the D2 diet. According to the results obtained it is deduced the change from D1 to D2 can be considered positive. In the low capability animals, this change would lead to the production of a greater amount of milk. In those with a high capability, this change would either give rise to the production of a greater amount of milk or to the production of a similar amount of milk but one presenting a higher αS1-casein content and, therefore, a milk with better technological quality.