Growth performance, carcass and non-carcass characteristics of Mubende and Mubende×Boer crossbred goats under different feeding regimes

Application of growth models to South African Boer goat castrates and does under feedlot conditions

Mathematical models may aid researchers in describing biological processes, like growth, in animals. This study aimed to collect the body weight data of 18 Boer goat castrates and 20 Boer goat does, from birth until maturity, to model growth and determine growth trends. This is a novel investigation as sufficient information on an age-weight database for these two Boer goat sexes from birth to maturity, is lacking. Using age-weight data, four nonlinear models, namely the Brody, Gompertz, Logistic and Von Bertalanffy growth models, were plotted and evaluated. The model parameters of each growth model were compared for differences between the two sexes. The statistical effectiveness of fit was determined for each model using AIC and RMSE, with R2 also being considered. All models except the Brody model, predicted significantly heavier mature weights for castrates. The Brody model was deemed unfit to describe Boer goat growth as the function severely over-predict weights from birth until maturity for both sexes. The Von Bertalanffy (R2 = 91.3) and Gompertz functions (R2 = 91.3) showed the best fit for Boer goat castrates, while the Gompertz model (R2 = 95.1) showed the best fit for Boer goat does. The Gompertz function is the preferred model to depict Boer goat growth overall, as it accurately characterized growth of both sexes. According to the Gompertz model the age at which the inflection point of the growth curve was reached, did not differ significantly between castrates and does (141.80 days versus 136.31 days). There was also no significant difference in maturation rate between the two sexes.

Feed resources used for small ruminant nutrition in Sub-Saharan Africa: a case study of Uganda

Small ruminants are of great importance to the livelihoods of many people in Sub-Saharan Africa (SSA) since they act as a source of meat, income, hides and skins and for cultural identity. Despite their great importance, especially to rural smallholder farmers, their production in Africa is hindered by poor nutrition. The first stage of establishing development strategies to increase feed quality and quantity is to conduct a comprehensive inventory of the feed resources that are currently available, especially in SSA. Therefore, this study aims to evaluate the availability and nature of the common feed resources that are used in the feeding of small ruminants in Uganda. This study involved a comprehensive review of various scientific, technical and economic literature that has been published up to date. Our results show that the available feed resources in Uganda can be grouped mainly into:- crop wastes and residues, agro-industrial by-products, conserved feeds, natural pastures and browse. The main feed resources for small ruminants in Uganda have been identified as natural pastures, which are generally characterised by a low nutritive value. However, browses are seen to have a high crude protein content and could be used as a supplement to grass forages and crop residues. It has been noted that farmers lack knowledge related to feed processing and management, in addition to a lack of policy governing feed quality. Therefore, there is a need to train farmers on how to process and utilise crop residues, in addition to proper feed management practices like pasture cultivation and conservation. It is also necessary to introduce widely new pasture species with better nutritional values that are suitable for the local production systems.

Feeding regimens affecting carcass and quality attributes of sheep and goat meat - A comprehensive review

Sheep and goats can efficiently convert low quality forage into high-quality meat which contains specific nutrients and quality traits. Carcass traits and quality attributes of sheep and goat meat depend upon several factors and one of most effective strategies amongst these is feeding regimens. In this review, the major aspects of feeding regimens affecting growth rate, carcass traits and quality attributes of sheep and goat meat are thoroughly discussed, with a particular focus on physical-chemical composition, flavor profile, and fatty acid (FA) profile. Grazing lambs and kids receiving concentrate or under stall-feeding systems had greater average daily gain and carcass yield compared with animals reared on pasture only. However, growth rate was higher in lambs/kids grazing on pastures of improved quality. Moreover, the meat of grazing lambs receiving concentrate had more intense flavor, intramuscular fat (IMF) content, and unhealthy FA composition, but comparable color, tenderness, juiciness, and protein content compared to that of lambs grazed on grass only. In contrast, meat of concentrate-fed lambs had more intense color, greater tenderness and juiciness, IMF and protein contents, and lower flavor linked to meat. Additionally, the meat of kids grazed on concentrate supplementation had higher color coordinates, tenderness, IMF content and unhealthy FA composition, whereas juiciness and flavor protein content were similar. In contrast, kids with concentrate supplementation had superior color coordinates, juiciness, IMF content and unhealthy FA composition, but lower tenderness and flavor intensity compared to pasture-grazed kids. Thus, indoor-finished or supplemented grazing sheep/goats had higher growth rate and carcass quality, higher IMF content and unhealthy FA composition compared to animals grazed on grass only. Finally, supplementation with concentrate increased flavor intensity in lamb meat, and improved color and tenderness in kid meat, whereas indoor-fed sheep/goats had improved color and juiciness as well as reduced flavor compared to pasture-grazed animals.

Meta-analysis quantifying the potential of dietary additives and rumen modifiers for methane mitigation in ruminant production systems

Increasingly countries are seeking to reduce emission of greenhouse gases from the agricultural industries, and livestock production in particular, as part of their climate change management. While many reviews update progress in mitigation research, a quantitative assessment of the efficacy and performance-consequences of nutritional strategies to mitigate enteric methane (CH₄) emissions from ruminants has been lacking. A meta-analysis was conducted based on 108 refereed papers from recent animal studies (2000–2020) to report effects on CH₄ production, CH₄ yield and CH₄ emission intensity from 8 dietary interventions. The interventions (oils, microalgae, nitrate, ionophores, protozoal control, phytochemicals, essential oils and 3-nitrooxypropanol). Of these, macroalgae and 3-nitrooxypropanol showed greatest efficacy in reducing CH₄ yield (g CH₄/kg of dry matter intake) at the doses trialled. The confidence intervals derived for the mitigation efficacies could be applied to estimate the potential to reduce national livestock emissions through the implementation of these dietary interventions.

Evaluation of non-carcass components of goat grazing in Caatinga rangeland supplemented with spineless cactus and native plants

The objective of this study was to evaluate non-carcass components of goats submitted to grazing in the Caatinga rangeland and supplemented with spineless cactus (Nopalea cochelinifera Salm Dick), Jitirana hay (Merremia aegyptia L. Urban) and Mororó hay (Bauhinia cheilanta Bong Stend). Thirty male goats (castrated), with no defined breed, with an initial mean body weight of 19 ± 0.35 kg and approximately 90 days of age were used. The treatments consisted of grazing without supplementation (GWS), grazing + Jitirana hay (GJ); grazing + Jitirana hay + spineless cactus (GJSC); grazing + Mororó hay (GM); grazing + Mororó hay + spineless cactus (GMSC). The means of the variables were tested by Tukey's test at 5% probability. The goats fed GWS, GJSC, GM and GMSC presented higher weights and yields of the diaphragm, and the spleen weight (p < 0.05). The highest yield of omasum (p < 0.05) occurred with goats fed GJ treatment. There were treatments (p < 0.05) on omental fat weight and leg yield, with the highest values for goats, fed GWS, GJSC, GM, and GMSC. The "Buchada" EBW-1 yield was higher (p < 0.05) for animals fed GWS. Feeding supplementation of goats grazing in the Caatinga had few influences on weights and yields of non-carcass components.

Genotype effects on energy and protein requirements in growing male goats

Goat genotype may alter the net energy and protein requirements for maintenance (NEm and NPm, respectively) and weight gain (NEg and NPg).This study was designed to investigate and quantify the effect of goat type on NEm, NPm, NEg and NPg, and quantify the net requirements for energy and protein for dairy, meat and indigenous growing male goats. For that, comparative slaughter studies were gathered and a meta-analytical approach was used. Two distinct databases were organized: one composed of 233 individual records from 11 studies of meat (n = 81), dairy (n = 97) and indigenous (n = 55) growing male goats weighing from 4.50 to 51.0 kg, to depict NEm and NPm; and another database composed of 239 individual records from nine studies of meat (n = 87), dairy (n = 97) and indigenous (n = 55) growing male goats weighing from 4.30 to 51.0 kg, to depict NEg and NPg. Our findings showed that NEm of meat goats was 8.5% greater (336 ± 10.8 kJ/kg0.75 of empty BW; EBW) than dairy and indigenous goats (310 ± 8.20 kJ/kg0.75 EBW; P < 0.05). Whereas, NPm was not affected by goat type (1.92 ± 0.239 g/kg EBW; P = 0.91). The NPg was 185.1 ± 1.82 g/kg of EBW gain for goats weighing 5 kg BW and 192.5 ± 4.33 g/kg of EBW gain for goats weighing 45 kg BW, and thus did not change across goat type (P = 0.12). On the other hand, NEg increased from 7.29 ± 0.191 to 11.9 ± 0.386 MJ/kg of EBW in male dairy goats, and from 7.32 ± 0.144 to 15.7 ± 0.537 MJ/kg of EBW in meat and indigenous growing male goats weighing between 5 and 45 kg BW. When body protein was used as a predictor in the allometric equation instead of EBW seeking to account for the degree of maturity, goat type differences disappeared; however, this predictor showed a high variation among individuals. In conclusion, energy and protein requirements for gain in distinct goat types reflect on body composition differences. Future research should focus on better understanding the maturity degree and its consequences in the energy requirement of growing male goats and better depict the goat type effect on it, as well as on the efficiency of utilization.

Effect of protein and energy levels in sweet sorghum bagasse leaf residue-based diets on the performance of growing Deccani lambs

Sweet sorghum bagasse with leaf residue (SSBLR) based complete diets with high or low protein and high- or low-energy levels were evaluated in a 60-day growth trial using growing sheep. Twenty-eight Deccani ram lambs were divided into four groups (16.0 ± 0.59 kg) of seven each and fed low-protein high-/low-energy and high-protein high-/low-energy diets ad lib. Average daily gain (g; P < 0.05) and feed efficiency (P < 0.01) were significantly higher in lambs fed high energy than those with low-energy diets, and cost per kg gain ($) was significantly lower (P < 0.05) in low protein than high-protein diets. Dry matter intake (DMI) (g/day) was not significantly affected either by protein or energy level in the diet, but dry matter (DM), organic matter (OM), protein, and neutral detergent fiber (NDF) digestibilities were higher significantly (P < 0.01) in high protein/energy diets than low protein/energy diets. Crude protein (CP) intake (g/day) was significantly (P < 0.001) higher in lambs fed high protein than low-protein diets. However, N balance (g/day) was significantly (P < 0.001) higher in lambs fed low protein than high-protein diets. It is concluded that feeding of SSBLR-based diet with low protein (CP 12.9 %) and high energy (9.4 MJ metabolizable energy (ME)/kg DM) was recommended for better performance, nitrogen retention, and returns from growing Deccani ram lambs.