J. Gusha

Calving Period Affects Cow And Calf Performance In Semi-Arid Areas In Zimbabwe.

One hundred and twenty cow records of communal reared beef cattle were used to evaluate cow and calf performance. The animals were group according to calving period and there were three calving periods namely January to April, M ay to August and the September to December period. The result showed that there was significant difference (P<0.05) on performance for calving down on different months. High postpartum weight loses were observed on dry season calvers and mid rain season calvers as well. The time taken to recover and recommencement of oestrus was significantly different as shown by the conception rate values. High calf and cow mortality was observed in May to August calving and January to April calving. Results demonstrate that poor resource farmers in region that experience April to November dry season should embrace the September to December calving period in order to succeed. If all other seasons are to be used more investment in feed supplement and drugs is needed.

Apparent digestibility and microbial protein yield of Desmodium uncinatum, Mucuna pruriens and Vigna unguiculata forage legumes in goats

This study examined the effects of adding forage legumes as protein supplements to poor-quality natural pasture (veld) hay offered to goats on microbial protein yield and nitrogen metabolism. Four indigenous Nguni-type goats were used in a 4×4 Latin cross-over design experiment. Goats were randomly allocated to four dietary treatments comprising commercial goat feed (GF), veld hay supplemented with cowpea (CW), velvetbean (VB) or silverleaf desmodium (SD). Microbial protein yields were determined using the purine derivatives technique and nitrogen retention was calculated from the digestible organic matter intake. Total nitrogen intake was significantly higher in the GF followed by CW, SD and VB, respectively. Microbial protein supply, calculated microbial true protein and digestible microbial true protein were affected (P<0.05) by legume supplementation. Animals on poor-quality forages had the most efficient microbial protein synthesis. However, supplementation of hay failed to meet the maintenance requirements of animals as evidenced by negative nitrogen balances in VB and SD. The efficiency of utilisation of nitrogen in the supplements could have been limited by unavailable fermentable metabolisable energy in the diets. Supplementation of poor-quality veld hay with legume forages could improve utilisation, especially in the dry season.

Management and control of gastrointestinal nematodes in communal goat farms in Zimbabwe

Goats are an important source of livelihood especially in smallholder communities. Infections with gastrointestinal nematodes (GIN) remain the most prevalent parasitic diseases affecting small ruminants. The study was conducted to assess management, the level of knowledge and control of gastrointestinal nematodes. Surveys were conducted in Chipinge, Shurugwi, Binga, Tsholotsho and Matobo districts, representing the five natural/agro-ecological regions (NR) in Zimbabwe. Data was collected in 135 households using a pre-tested semi-structured questionnaire. Results indicated that goats were ranked the most important livestock species, with high flock sizes in NR IV and V. Partitioning of roles was such that the adult males were involved in decision-making while females and children were involved in day-to-day management of animals. Farmers showed low levels of input use, with natural pasture (98.4%) being the main feed source and indigenous breeds (73.2%) being kept. Farmers ranked food and financial benefits as the main reasons for keeping goats. Gastrointestinal nematodes ranked the highest as the most common disease, with majority of farmers (57%) not controlling or treating animals and 63% of farmers not having knowledge on the spread of GIN. Access to veterinary services, anthelmintic class used and breeds used by the farmers had the highest effects on parasitic infections in households. Farmer education is required for capacitation of farmer in terms of disease prevention and control so as to improve goat production.

Performance of growing cattle on poor‐quality rangelands supplemented with farm‐formulated protein supplements in Zimbabwe

Farmers use different non-conventional protein supplements and different feeding strategies to aid their animals survive the dry season in Zimbabwe. The strategies can be giving supplements once a week or once every other day up to very little supplement daily. Supplements are either legume crop residues or forage legumes. However, the efficacy of the use of non-conventional protein supplements in promoting growth and at the same time lowering the age at first calving is little understood. The study tested whether supplementing with farm-formulated non-conventional feeds could reduce live weight loss during the dry season and promote live weight gain as well as early development of sexual maturity in beef cattle. In a completely randomized design, thirty dams with calves on hooves were allocated to five different treatments which were repeated during the dry season for 3 years. The 3-year study results show that weight loss can be controlled, resulting in positive growth in both the pre-weaning and post-weaning phases of growing cattle. Yearlings fed solely on natural pasture lost significant weight during the dry season as compared to supplemented groups. The period to puberty and first calving was achieved at 18 and 27 months, respectively. Using non-conventional protein supplements could thus improve livestock productivity in resource-poor farming communities. It was concluded that smallholder farmers can supplement cattle with a kilogram per day of low-cost farm-based non-conventional legume meal to improve livestock productivity in semi-arid regions of Zimbabwe.

Degradability of amino acids in selected legume forages using the in situ nylon-bag technique

This study was conducted to determine the amino acid profiles and rumen degradability of amino acids of three cultivated forage legumes – velvet bean (Mucuna pruriens), cowpea (Vigna unguiculata) and silverleaf desmodium (Desmodium uncinatum) – using the in situ nylon-bag technique. Two Friesian cows fitted with 10-cm-diameter rumen cannulae on a complete dairy feed ration (19% crude-protein dairy meal and maize silage) were used. Silverleaf desmodium had significantly (p < 0.05) higher concentration of amino acids compared with cowpea and velvet bean. Aspartic acid showed the highest (p < 0.05) concentration in all legumes and cysteine showed the lowest concentration. Legume forage of cowpea showed the highest (p < 0.05) level of degradability of amino acid followed by silverleaf desmodium and then velvet bean. Readily and slowly degradable components in all amino acids were highest (p < 0.05) in cowpea followed by silverleaf desmodium and then velvet bean. Moreover, silverleaf and cowpea showed higher (p < 0.05) levels of effective degradability of amino acids (at outflow rates p = 0.02, 0.04 and 0.06 h−1) than velvet bean. Total amino acid disappearance was the least in velvet bean, which suggests that it can be used to supply bypass protein to the duodenum of the ruminant animal.

Impact of grazing system on rangeland condition and grazing capacity in Zimbabwe

The influence of different land tenure and rangeland management systems on rangeland condition and livestock grazing capacity in African rangelands is not well documented. A rangeland condition assessment was carried out at 15 sites located in the communal grazing system, small-scale commercial grazing system and the large-scale commercial grazing system in Zimbabwe. Rangeland indicators assessed were: floristic composition, herbaceous biomass yield, shrub stem density and grazing capacity. Grass species composition and forage value were analysed using PROC FREQ procedure of SAS 9.3. Fisher’s exact test was performed to test for independence of the grass variables between grazing systems. A one-way ANOVA was used to test for significant differences (P < 0.05) in floristic composition, shrub stem density, herbaceous biomass yield and grazing capacity among the three grazing systems. It was observed that communal rangelands had significantly high levels of woody species, unpalatable wiry grass species, low biomass yield and were dominated by the invading shrub Helichyrsum kraussii compared with the other rangeland management systems. These results suggest that if control measures are not put in place, livestock production may not be feasible in communal rangelands in the near future because of high levels of rangeland deterioration when compared with the commercially managed rangelands. Furthermore, the observed high stem density of unpalatable woody species and the low grazing capacity of communal rangelands affect livestock production, a primary source of livelihood. This warrants a change in rangeland management system in favour of the rest-rotation grazing system, which is beneficial to both livestock and the range.

Performance of cattle reared on rangelands supplemented with farm-formulated diets during the dry season in Zimbabwe

Feed quality in rangelands reaches an all-time low during the dry season thus affecting animal performance. The use of farm-formulated supplements is an alternative which can be adopted to minimise the effects of nutritional stress. However, the effects of supplementing nursing cows, twice a week with farm-formulated diets; on cow maintenance, calf weaning weight and conception rate is little known. Thirty indigenous Mashona cows were allocated to five treatments of a commercial supplement known as beef survival meal, urea-treated maize stover, Leucaena leucocephala meal, mixed forage meal and without supplements. The study was repeated with a new set of nursing cows each year for 3 years. Nutrient composition of treatment diets varied with Leucaena leucocephala having more crude protein than the other diets. Forage-supplemented groups had higher (P < 0.05) rate of weight increase and weaning weights with Leucaena leucocephala and beef survival meal having better results among the groups. Nursing cows that were in protein-supplemented groups had significantly higher (P < 0.05) conception rate than the group of nursing cows, which were not offered the protein supplements. We concluded that, with farm-formulated supplements given twice per week, nursing cows can maintain better body condition, wean heavier calves and successful conceive every year thus improving animal productivity.