Effects of supplementary diet protein on growth performance and reproductive health of Tswana goats

Abstract

The aim of the study was to evaluate of nutritional supplementation environments of the North West Province of South Africa. To achieve this, several objectives were identified. The first objective was to assess the impact of goats' farming and challenges faced by farmers in rural areas of Mahikeng Local Municipality, North West Province. Data were randomly collected by interviewing 75 farmers from three villages (Ramatlabama 600, Tsetse and Lokaleng) using a structured questionnaire. The interviews focused on production systems, management and marketing strategies of Tswana goats in semi-arid areas around Mahikeng, North West Province. Descriptive statistics were generated using Statistical Package for the Social Sciences (SPSS) version 22. Nearly 60% of farmers sold animals without weighing and were also affected by low market value for livestock. About 29% of goat owners experienced abortions due to droughts and mineral deficiencies. Other factors included poor housing and low soil fertility for forage production. In addition major constraints for goat productions were as follows: stock theft (45%); malnutrition (33%); and diseases (32%). A significant correlation (P<0.05) was observed between grazing system (communal grazing areas) and access to veterinary services. There is the need to empower farmers with knowledge and skills to improve their farming management practices and marketing. In addition, there is need to improve access to veterinary care to reduce diseases and the mortality of kids in rural areas. This will make significant contribution towards addressing the issue of goat management to obtain optimum production under the extensive management system. The aim of the second experiment was to determine the impact of protein supplementation on goat reproductive performance, health and on blood and hormonal parameters. To achieve this objective, an experiment was conducted using 24 weaned female Tswana goats (three months of age). The experiment was done completely randomized. Blocking was done according to body weight and animals were allocated into three treatment groups of eight goats per treatment and their feeding regime consisted of protein (23.51%) and energy (8.55%) per kg of the body weight. The first group was given Maintenance protein requirement (Diet 1); the second group was given twice the Maintenance requirement (Diet 2) and the third group was fed three times the Maintenance X3 (Diet 3). All animals had ad lib access to the basal diet of hay, water and salt. Blood samples were collected and serum metabolites and reproductive hormones measured at the beginning of the experiment and weekly. One-way analysis of variance (ANOVA) was carried out on blood nutritional metabolites, hormonal, growth and reproductive performance data using the General Linear Model (GLM) procedure of the Statistical Analysis System. The results obtained showed that different levels of protein supplementation had significant (P<0.05) effects on glucose, albumin, albuglobulin and urea levels. The level of progesterone in Diet 2 was significantly higher with the value of 13.45 ppb, while for the other weeks, no significant effects were observed from week 0 up to week 20. The uses of high levels of dietary protein supplements boosted the levels of progesterone in the study. The body weights reported in the study (in all three treatment groups) increased with advancement in pregnancy until birth ranging from 1.40 kg to 9.46 kg. The high levels of dietary protein influenced the levels of blood progesterone, body weight and other blood metabolite parameters. The levels of progesterone were significantly influenced by the protein diet. Treated animals showed higher concentrations compared to the control group. There was a significant difference (P<0.05) in body weights between three treatments with animals supplemented with protein, having higher body weights as compared to the control group. There was also a significant influence of protein supplementation on the twinning of kids. A significant difference (P<0.05) was observed between different treatments with 50% of animals that received high concentrations of protein, having twins, while no twining was registered in the other two treatment groups. In addition, protein supplementation in Tswana goats showed a significant (P<0.05) effect between treatments from different groups (regarding live weight of kids). Feeding of goats with high protein diet significantly (P<0.01) increased growth (Diet 3 vs Diet 1) compared to low protein diet. In conclusion, supplementation with three times maintenance level improved growth and reproductive performance and health and concentrations of serum metabolites and hormones, which subsequently, improved reproductive hormones (progesterone) and some blood metabolites (blood glucose, albumin total protein and albumin) during oestrus cycle. These findings provide important information in terms of the design of nutritional strategies to increase reproductive outputs, mainly through precision supplementation or focus feeding. Supplementation of high protein diet (three times maintenance) to Tswana goats increased growth performance and reproduction of goats. Despite the cost of the source of protein in the diet of animals, there is need to educate farmers on feed formulations, balanced feeding to animals to increase productivity. To optimise the productive potential of Tswana goats, it is important to implement the reproductive management programme for the improvement of reproductive aspects of goats. It could, therefore, be concluded that improved feeding with better management could ensure improvement in the reproductive performance of Tswana goats.