Effects of a digestive modifier, browse plus on ruminal and intestinal breakdown of forages containing high tannin levels

A journal article on the effects of a digestive modifier.The potential for enhancement of forage utilization of two high tannin containing tropical browse trees and three legumes through the use of a digestive modifier called Browse Plus was investigated in this study. The study was carried out in 1995. The main objective of the study was to evaluate the potential for improving digestibilities of dry matter (DM) and crude protein (CP) of two browse tree species, namely; Acacia albida and Colophospermum mopane and three herbaceous legumes, namely; Chamaecrista rotundifolia, Stylosanthes scabra, and Stylosanthes guif/iensis by use of Browse Plus. The legumes were sampled at three’phases of growth in 1994, making a total of nine samples. Forages were obtained from Sanyati, a semi-arid area of Zimbabwe. Total tannin levels in the forage samples were determined using the radial diffusion technique and in WvoDM and CP digestibilities were determined using the mobile nylon bag technique following infusion of 0-3 g of Browse Plus Into rumens of each of the three cannulated Holstein steers that were used. Ruminal infusion of Browse Plus enhanced (P0.05) between total tannin level, DM and/or CP digestibilities. The results from this study indicated that Browse Plus can improve DM and CP digestibilities of forages containing high tannin levels. This is likely to increase nutrient availability at the level of the small intestines, thereby enhancing utilization of such forages by ruminants. From the results, we recommend that Browse Plus be utilized at an inclusion rate of 2 g per animal per day in order to realize benefits from improved utilization of forages high in tannins

Effect of Acacia angustissima leaf meal on performance, yield of carcass components and meat quality of broilers

The study determined the appropriate levels of including Acacia angustissima leaf meal in broiler diets for optimum performance, carcass part yield, and meat quality characteristics. One hundred and fifty broiler chicks were allocated to 0%, 5%, and 10% A. angustissima leaf meal-based diets in a completely randomized design, with five replicates per treatment. Weekly feed intake and live weights were measured. Weekly weight gains and feed conversion ratios were calculated. At six weeks, two birds per replicate were slaughtered and dressed. Carcass and portion yields were determined. Breast proximate components, CIELAB colour variations, cooking loss and shear force were estimated. Consumer preferences for colour, aroma, taste, flavour and tenderness were determined. Voluntary feed intake (VFI), weekly weight gain, weekly live weights and feed conversion ratios (FCR) were the same across treatments at two weeks. At weeks 4 and 6, the control and 5% groups outperformed the 10% group. Increasing dietary leaf meal had no effect on dressing out percentage, but decreased carcass weight from 1456 g to 1060 g, breast yield from 36.83% to 32.69%, breast meat to bone ratio from 4.77% to 2.94%, and proportion of drumstick skin from 11.57% to 7.92%. It also resulted in increased yield of thighs from 14.63% to 15.97%, proportion of thigh skin from 11.50% to 14.31% and breast skin proportion from 5.37% to 7.95%. The leaf meal had no effect on the proximate components of breast meat. The L* values decreased from 53.66 to 49.23; the b* values increased from 12.93 to 19.97; shear force increased from 14.14 N to 14.54 N; and cooking loss increased from 5.95% to 7.64% with increasing leaf meal levels. It was concluded that up to 5% A. angustissima leaf meal inclusion has no negative effect on performance, yield of carcass parts and meat quality characteristics of broilers.Keywords: Breast, colour, cooking loss, shear force, tast

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

AbstractThe 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

Pig genetic resource conservation: The Southern African perspective

Local pigs in Southern Africa are an important component of resource-based subsistence farming systems and contribute substantially to the improvement of livelihoods of farmers. In addition to utilising by-products and feed resources that are otherwise of no use, they serve various socio-economic functions. The numbers, breeds and population genetic structures, attributes and risk status of these pigs are understudied. In the few studies to date, they have been shown to be tolerant to parasites that are endemic in their production environment. They also have a better chance to survive various disease outbreaks and have a higher capacity to utilise fibrous and poor quality feed resources compared to exotic breeds. Their production environment has also been described with women owning most of the pigs. The farmers tend to keep the herd sizes small in order to adequately meet the animals' nutrition needs. This leads to small populations that are vulnerable to inbreeding and disasters. In addition, there are no incentive systems in place to promote conservation of the pigs. There is an urgent need to address research and policy gaps, and to formulate strategies for the conservation of this resource.Local pig breeds Mukota Kolbroek Windsnyer

Promoting the use of home-mixed supplements as alternatives to commercial supplements in smallholder beef production systems in the subhumid region of Zimbabwe

The economic and performance effect of supplementing smallholder cattle by substituting commercial feed with iso-nitrogenous and iso-energetic diets based on alternative protein sources was investigated in two trials. In trial 1, three diets (commercial concentrate, commercial concentrate partially substituted with mucuna, and commercial concentrate partially substituted with lablab–cowpea) compared with veld grass were allocated to 12 cattle in a complete randomised block design. In trial 2, a double complete randomised block design with 40 cattle assigned to four forage legume-based diets, a poultry-based diet and a commercial beef concentrate was carried out. Diets were offered at 1.5% of body weight daily over 56 d. Average daily weight gain (ADWG) was measured weekly in trial 1 and fortnightly in trial 2. In trial 1, ADWG was significantly (p < 0.05) higher for animals on supplements compared with non-supplemented cattle. In trial 2, ADWG was significantly highest on the groundnut stover-based diet and least on the poultry litter diet. Supplementation had a positive effect on ADWG and economic performance of smallholder beef cattle. Substitution of commercial concentrates with alternative protein sources reduced diet costs and significantly improved gross margins