Ruminant livestock are important sources of human food and global greenhouse gas emissions. Feed degradation and methane formation by ruminants rely on metabolic interactions between rumen microbes and affect ruminant productivity. Rumen and camelid foregut microbial community composition was determined in 742 samples from 32 animal species and 35 countries, to estimate if this was influenced by diet, host species, or geography. Similar bacteria and archaea dominated in nearly all samples, while protozoal communities were more variable. The dominant bacteria are poorly characterised, but the methanogenic archaea are better known and highly conserved across the world. This universality and limited diversity could make it possible to mitigate methane emissions by developing strategies that target the few dominant methanogens. Differences in microbial community compositions were predominantly attributable to diet, with the host being less influential. There were few strong co-occurrence patterns between microbes, suggesting that major metabolic interactions are non-selective rather than specific.

The availability and sustainability of suitable and good quality drinking water is a global concern. Such uncertainties threaten livestock production with an attendant ripple effect on food security. Small ruminants, including sheep and goats, appear to be promising to smallholder farmers in solving this problem because of their ability to survive in water-limited areas and harsh environment when compared with large ruminants. Their small body size is also seen as an advantage, because less water will be required for proper digestion and feed utilization. Therefore, this review will provide information regarding the adaptive responses of small ruminants on thermoregulation, blood metabolites, immune status, drug pharmacokinetics, reproduction and hormonal indices during the period of water stress. Adaptable and indigenous breeds are known to be more tolerant to water stress than selected breeds. A drop in feed intake and weight reduced respiratory rate and increased concentration of blood metabolites are the general effects and/or observations that are encountered by small ruminants during the period of water stress. The concept of water tolerance either as deprivation and/or restriction of indigenous and adaptable breeds of small ruminants is gaining ground in research studies around the world. However, more research, however, seeking to explore water tolerance capacity of adaptable breeds especially in arid and water limiting areas are still needed.

Ruminant livestock are important sources of human food and global greenhouse gas emissions. Feed degradation and methane formation by ruminants rely on metabolic interactions between rumen microbes and affect ruminant productivity. Rumen and camelid foregut microbial community composition was determined in 742 samples from 32 animal species and 35 countries, to estimate if this was influenced by diet, host species, or geography. Similar bacteria and archaea dominated in nearly all samples, while protozoal communities were more variable. The dominant bacteria are poorly characterised, but the methanogenic archaea are better known and highly conserved across the world. This universality and limited diversity could make it possible to mitigate methane emissions by developing strategies that target the few dominant methanogens. Differences in microbial community compositions were predominantly attributable to diet, with the host being less influential. There were few strong co-occurrence patterns between microbes, suggesting that major metabolic interactions are non-selective rather than specific.

________________________________________________________________________________ AbstractThe aim was to determine the effect of tannin on the nutritive value and microbial enzyme activity in vitro. The leaves and pods of the Acacia sieberiana and Acacia nilotica trees were subjected to chemical analysis and in vitro fermentation with and without polyethylene glycol (PEG; 35 mg/g). Gas production (GP), true degradability (TD) and the proteolytic and fibrolytic enzyme activities in digesta were determined. Data analyses accounted for the effects of feed type, feed fraction, PEG and their interactions. Leaves and pods had similar NDF and ADF contents in A. sieberiana but differed in both attributes in A. nilotica. The leaves had a higher protein, but lower condensed tannin (CT) contents than the pods. A. sieberiana had more CT than A. nilotica, but both had a similar maximum GP. PEG increased the maximum GP, stimulated GP from the soluble fraction and shortened the lag phase. PEG increased the TD for leaves and pods of A. sieberiana, but suppressed TD in fractions of A. nilotica. PEG also increased the activity of protease enzymes, xylanase, endo-and exocellulases, indicating that tannins depress the digestibility of feeds partly by suppressing the activity of these enzymes. Consequently, condensed tannin depressed the digestibility of feed in the rumen by affecting the activity of enzymes involved in carbohydrate and protein breakdown, the effects of which could be reduced with the use of PEG._______________________________________________________________________________

Water restriction in small ruminants is usually accompanied by a drop in feed intake, body weight, and disturbances in the normal internal milieu. However, attempts to lessen the burden of water stress with vitamin C (VC) supplementation have been greeted with conflicting reports. Therefore, this experiment was conducted to evaluate the effect of single and/or multiple VC supplementations in water-restricted Xhosa goats by evaluating their performance, heat tolerance, and blood metabolites. In total, 42 does, 12 mo old and with an average weight of 15.92 ± 2.12 kg were evaluated for 75 d. The does were distributed according to a complete randomized design into seven groups of six comparable animals: W0, without water restriction (control); W70, water restriction of 70% of ad libitum water intake (WI); W50, water restriction of 50% ad libitum WI; W70+, water restriction of 70% of ad libitum WI plus 3 g VC daily; W50+, water restriction 50% of ad libitum WI plus 3 g VC daily; W70++, water restriction of 70% of ad libitum WI plus 3 g VC and extra 5 g VC given every eighth day; and W50++, water restriction of 50% of ad libitum WI plus 3 g VC and extra 5 g VC given every eighth day. Goats under the W50 group were the most affected (P < 0.05) and the effect was more pronounced in their body condition scores (BCs). Weight loss due to water restriction was reduced by VC supplementation in treated groups. Changes in body thermal gradient, rectal temperature, cholesterol, and bilirubin were similar (P > 0.05) across the various experimental groups. The attenuation effect of VC was significant (P < 0.05) in responses to respiratory rate, Na+, K+, Mg2+, Cl−, Ca2+, and urea. Supplementation of VC (either single or multiple) did not significantly (P > 0.05) improve the effect of water restriction on BCs, FAMACHA, glucose, globulin, alanine aminotransferase, and high-density lipoprotein. The additive effect of multiple VC significantly influenced (P < 0.05) Na+ and Mg2+. Limited WI affects growth and other physiological parameters in Xhosa goats. However, supplementation of VC may be beneficial at modulating the stressful stimuli imposed by water stress.