The Girgentana Goat Breed: A Zootechnical Overview on Genetics, Nutrition and Dairy Production Aspects

In recent years, there has been a great interest in recovering and preserving local livestock breeds. An interesting situation is represented by the Girgentana goat, an ancient local breed reared in Sicily. Over recent years, this breed has become almost extinct, in part as a consequence of the marked decrease in fresh goat milk consumption. On the basis of these considerations, several studies on its genetic structure and management aspects have been conducted in order to protect the Girgentana goat from the risk of extinction and recover its genetic and economic value. In this context, information on genetics, nutrition and dairy production aspects may have a crucial role in the improvement and management of the breed. Thus, this chapter describes some points of these applications through recent investigations on this goat breed

Interacción entre el genotipo de la Alfa s1-caseína y el nivel de proteína de la dieta. Utilización nutritiva, producción y composición de la leche en cabras de raza malagueña

Tesis Univ. Granada. Departamento de Fisiología. Leída el 14 de julio de 200

Nitrogen and energy utilization in lactating dairy goats fed diets with different legume seeds

The N and energy utilization of diets with different legume seeds was analysed in lactating goats. Four isonitrogenous and isoenergetic diets were used and in each case 30% of the protein was supplied by one of four different legume seeds: lupins (L), faba beans (FB), bitter vetch (BV) and vetch (V). A group of eight Granadina goats, allocated to a replicated 4 × 4 Latin Square, were used. The N and energy utilization of the different diets may be considered adequate; milk N/intake N was approximately 0.20, milk N/N balance was approximately 0.50 and milk energy/metabolizable energy was approximately 0.30. Under similar N and energy intakes, faecal and urinary excretion of N and the quantities in milk did not vary significantly. However, the partition of the N balance between milk production and deposit within the body varied depending on the diet. Although this N available to the metabolism was the highest for the FB diet, the quantity of this directed to milk was the lowest. Finally, the faecal and urinary excretion with respect to the quantity directed to milk production did not vary significantly among the different diets.This study was supported financially by the Ministry of Science and Technology, Spain (Project: INIA: RTA02-020).Peer reviewe

Nutritional utilization in Malagueña dairy goats differing in genotypes for the content of αS1-casein in milk

A study was carried out with 20 goats of the Malagueña breed, half with a high (HG) and half with a low (LG) genetic capability for αS1-casein (AS1-CN) synthesis, to determine whether the 2 different genotypes (that cause differences in goat milk composition) are related to differences in nutritional feed utilization. Among the 10 HG goats, 7 had BB and 3 had AB genotypes for AS1-CN, whereas there were 7 EF and 3 FF genotypes in the 10 LG goats. The goats were fed diets differing in crude protein content (13.6 vs. 17.7% dry matter for diets 1 and 2, respectively). For each genotype group, a balance trial was conducted with each of the 2 diets in a 2-period balanced changeover designed with half the animals consuming diet 1 and the other half diet 2, determining individual feed intake and the utilization of N and energy in the diets. Greater voluntary feed intake on a metabolic body weight basis among the HG goats was identified as the first possible cause of their milk production. The HG goats also had a greater level of feed utilization, on a metabolic body weight basis, for N and energy intake. Greater ratios of N balance/ digestible N, milk protein N/digestible N, milk energy/ digestible energy, and milk energy/ME were found for HG goats compared with LG. These effects appear to be dependent on the level of protein in the diet, indicating interactive effects. The greater N and energy utilization of HG versus LG goats may explain the differences in milk composition between the 2 genotype groups.This study was supported financially by the Ministry of Science and Technology, Spain (Project INIA: RTA02-020).Peer reviewe

Milk production and composition in Malagueña dairy goats. Effect of genotype for synthesis of αs1-casein on milk production and its interaction with dietary protein content

A study was carried out to analyse the production and composition of milk from Malagueña goats of different genotypes for the content of αs1-casein. Twenty goats were used, half of them with a high (HG) and half with a low (LG) genetic capability for αs1-casein synthesis. Among the ten HG goats, seven had BB and three had AB genotypes, whereas there were seven EF and three FF genotypes among the LG goats. The goats were fed a diet differing in crude protein content, 136 and 177 g/kg dry matter for diet 1 (D1) and diet 2 (D2), respectively. For each genotype group, a trial was conducted, with each of the two diets in a two-period balanced change-over design, in which the milk production and composition were analysed. The genotype was found to determine milk composition, with that produced by the HG goats being higher in total solids, protein, αs1-casein, αs2-casein and fat. Analysis of milk production values and, especially, those of the yields of the different components, revealed an interaction between the factors. HG goats that consumed D1 were more productive than LG goats, but this ceased to be so when the D1 diet was replaced by D2. However, LG goats, although less productive than HG ones when the D1 diet was consumed, showed increased productive capacity when D1 was replaced by D2. The main difference for the fatty acid profile of the dairy fat is that the milk fat produced by the HG goats contained higher levels of short and medium-chain fatty acids. From these results, it is concluded that, in terms of favouring production, the advantage of replacing animals with a low capacity for αs1-casein synthesis with those of a high capacity seems to depend on the protein level in the diet. Similarly, the advantage of changing to a diet of higher protein content depended on the animal's genotype.Peer reviewe

Composition and technological quality of Malagueña goat milk. Effect of genotype for synthesis of αs1-casein in milk and protein content in the diet

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.Peer reviewe

Composition of goat and cow milk produced under similar conditions and analyzed by identical methodology

The aim of this study was to identify, under the best possible conditions, the interspecific differences between the proteins, fat and minerals in goat and cow milk. The protein fractions presented evident differences, especially concerning the amount of αS1-casein, which was lower in the goat milk (62.8%; P 0.05). The composition of fats was well-differentiated, mainly as concerns the content of medium-chain fatty acids (C6–14), which were higher in the goat milk (28.8%; P < 0.05). The same was true for n-6 polyunsaturated fatty acids (10.0%; P < 0.05) and n-3 polyunsaturated fatty acids (51.0%; P < 0.05), and also the total level of conjugated linoleic acid (33.8%; P < 0.05). The quantities of Ca, P, Mg and Cu were greater in the ash derived from goat milk (17.4, 15.6, 16.3 and 66.6%, respectively; P < 0.05). Due to the greater quantity of total solids present in goat milk (16.3%; P < 0.05), all of the above-mentioned differences would be considerably increased by the fact that they refer to the amounts present in a given volume. The differences detected between cow and goat milk mean that the latter constitutes a food of particular interest, in terms of both health and nutrition.Peer reviewe