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.

Prevalence and risk factors of gastrointestinal parasitic infections in goats in low-input low-output farming systems in Zimbabwe.

A longitudinal study was conducted in low-input low-output farming systems to determine the prevalence of gastrointestinal parasitic infections in different age groups, sex and associated risk factors in goats. A total of 580 indigenous goats were randomly selected in areas representing the five agro-ecological regions of Zimbabwe in the dry and wet seasons. Blood and faecal samples were collected from each animal and egg/oocyst per gram of faeces (epg/opg), larval culture, and packed cell volumes (PCV) were determined. Factors affecting parasitic infections were evaluated. Highest prevalence was determined for Eimeria oocysts (43%), strongyles (31%) and lower levels in trematodes and cestodes. Parasites identified were Haemonchus, Strongyloides and Oesophagostomum. Area, season, sex and age significantly influenced patterns of gastrointestinal infections (P < 0.05). Cannonical correlations indicated that parasite species composition varied by area and impacts of risk factors also differed. Risk of infection was very high for goats sampled in Natural regions (NR) I, II, III (OR = 6.6-8.2; P < 0.05) as compared to those in NR IV and V. Highest helminths and Eimeria infections were observed in the wet vs. dry season (P < 0.05). Young animals were more susceptible to parasitic infections (P < 0.05). Prevalence was higher in males than females, with odds of infection for males being almost three times to that for females (P < 0.0001). Knowledge concerning gastrointestinal helminth biology and epidemiological infection patterns caused by these parasites is essential in the development of appropriate control strategies and this has a potential to reduce production losses.

Breeding for resistance to gastrointestinal nematodes - the potential in low-input/output small ruminant production systems.

The control of gastrointestinal nematodes (GIN) is mainly based on the use of drugs, grazing management, use of copper oxide wire particles and bioactive forages. Resistance to anthelmintic drugs in small ruminants is documented worldwide. Host genetic resistance to parasites, has been increasingly used as a complementary control strategy, along with the conventional intervention methods mentioned above. Genetic diversity in resistance to GIN has been well studied in experimental and commercial flocks in temperate climates and more developed economies. However, there are very few report outputs from the more extensive low-input/output smallholder systems in developing and emerging countries. Furthermore, results on quantitative trait loci (QTL) associated with nematode resistance from various studies have not always been consistent, mainly due to the different nematodes studied, different host breeds, ages, climates, natural infections versus artificial challenges, infection level at sampling periods, among others. The increasing use of genetic markers (Single Nucleotide Polymorphisms, SNPs) in GWAS or the use of whole genome sequence data and a plethora of analytic methods offer the potential to identify loci or regions associated nematode resistance. Genomic selection as a genome-wide level method overcomes the need to identify candidate genes. Benefits in genomic selection are now being realised in dairy cattle and sheep under commercial settings in the more advanced countries. However, despite the commercial benefits of using these tools, there are practical problems associated with incorporating the use of marker-assisted selection or genomic selection in low-input/output smallholder farming systems breeding schemes. Unlike anthelmintic resistance, there is no empirical evidence suggesting that nematodes will evolve rapidly in response to resistant hosts. The strategy of nematode control has evolved to a more practical manipulation of host-parasite equilibrium in grazing systems by implementation of various strategies, in which improvement of genetic resistance of small ruminant should be included. Therefore, selection for resistant hosts can be considered as one of the sustainable control strategy, although it will be most effective when used to complement other control strategies such as grazing management and improving efficiency of anthelmintics currently.

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.

Dietary effects of Moringa oleifera leaf powder on growth, gastrointestinal morphometry and blood and liver metabolites in Sprague Dawley rats.

We investigated the effects of Moringa oleifera leaf powder (MOLP) as a dietary supplement on growth performance, gastrointestinal (GIT) morphometry and liver function using weanling Sprague Dawley rats to model humans under ad libitum and restricted feeding. An MOLP-based diet was generated by supplementing normal rat feed with the leaf powder at 20%. Four dietary regimens included normal rat feed fed at 20% of body mass (NRF: ad libitum), NRF fed at 14% of body mass (NRFR, restricted), Moringa-supplemented feeds fed at 20% and 14% of body mass (MOF: ad libitum and MOFR: restrictedly) respectively. Thirty-two pups were randomly assigned to the diets and fed for 5 weeks, after which they were fasted, euthanased and GIT viscera masses, lengths and histology were assessed. Blood was collected for metabolite and markers of liver function assays. Tibiae and femora lengths were used to determine linear growth. Rats fed the restricted diets had lower weekly body mass gains (p = 0.0001) than those on ad libitum feeding; however, they showed compensatory growth by 5 weeks. Terminally, the rats fed MOFR had shorter (p < 0.05) femora and tibiae than their counterparts on the other diets. Except on the caeca, diet had no effect on the absolute masses and lengths of GIT viscera. Relative to tibia length, rats on the MOF had significantly heavier stomachs and caeca and longer small and large intestines than their counterparts on NRF, but this was not supported histologically. Level of feeding and supplementation did not affect blood metabolite concentration, liver glycogen and lipid storage nor the plasma activities AST and ALP in the rats. Supplementing diets with MOLP under restricted access to feed (low calorific supply) might compromise linear growth.