U. ter Meulen

The effect of oral administration of polyethylene glycol on faecal helminth egg counts in pregnant goats grazed on browse containing condensed tannins.

Thirty yearling F1 Anglo-Nubian×Mubende goats, averaging 21±0.45 kg, kept on free-range feeding in the Ankole range land, Uganda, were screened for health and nutritional status, effectively treated against helminth parasites, mated, and randomly divided into two equal groups during a 3-month preparatory phase. During the 6 months that followed, the goats in one group received a daily oral dose (50 g/goat) of poly(ethylene glycol) (PEG), while the other group acted as the control (no PEG). The goats were monitored for faecal nematode egg counts and body weight gains, along with the quality of their diet, nematode contamination of the pasture, and the prevailing climatic factors in the area. Goats treated with PEG had significantly (p<0.05) higher faecal helminth egg loads. The mean nematode eggs per gram of faeces (epg) of the PEG group (290 epg) was more than double that of the control group (129 epg). All the PEG-treated goats exhibited moderate to severe infections at the end of the experiment. The gain in body weight during gestation was lower (p<0.05) in the PEG group (70.4 g per goat per day) than in the control group (91.8 g per goat per day). The PEG group lost 2.3 g per goat per day in the fifth month. PEG deactivates condensed tannins, and it was concluded that condensed tannins play a significant role in reducing the negative effects of gastrointestinal helminth burdens in the natural free-range feeding system of the Ankole range land in Uganda. Selective feeding on such range lands might expose goats to optimal concentrations of dietary condensed tannins with resultant beneficial effects.

Ruminal fermentation kinetics in ewes offered a maize stover basal diet supplemented with cowpea hay, groundnut hay, cotton seed meal or maize meal.

The effect on ruminal digestive kinetics of supplementing maize stover (MS) with cowpea hay (CW), groundnut hay (GN), cotton seed meal (CSM) or maize meal (MM) was evaluated in a 5×5 Latin square using five Merino ewes with ruminal cannulae. CW and GN were offered at 30% w/w to MS, while CSM and MM were given at 15 g/kg0.75 per day. There were significant time (p<0.001) and time×diet (p<0.05) effects on pH but the effect of diet alone was not significant (p>0.05). There was a significant (p<0.05) increase in the concentration of ammonia with time on the supplemented diets. There were no significant (p>0.05) differences in the concentrations of total volatile fatty acids (VFAs). Butyrate increased with supplementation (p<0.05). Supplementation increased the concentrations of branched-chain and total VFAs with time (p<0.05). The non-glucogenic ratio was not significantly (p>0.05) lower on supplemented diets owing to the higher butyrate concentration. The degradation curve constants were not significantly different (p>0.05), the average effective dry matter degradation being 27.80%±0.618% at 0.05 h–1 flow rate. The chemical and physical characteristics of the cell wall of MS may have presented few sites for microbial colonization, so limiting degradation. These results showed that small quantities of forage supplements can improve the ruminal environment in animals subsisting on low-quality forages and form a basis for comparison with bought-in protein and energy sources.

Effect of Cowpea Hay, Groundnut Hay, Cotton Seed Meal and Maize Meal Supplementation to Maize Stover on Intake, Digestibility, Microbial Protein Supply and Acetate Kinetics in Weaner Lambs

Ten weaner lambs were used in a double 5×5 Latin square design to evaluate the effect of supplementing maize stover (MS) with cowpea hay (CW), groundnut hay (GN), cotton seed meal (CSM) or maize meal (MM) on the intake, digestion kinetics and acetate clearance rate. CW and GN were offered at 30% w/w to MS, while CSM and MM were given at 15 g/kg0.75 per day. Supplementation reduced (p<0.01) MS intake but enhanced (p<0.01) total dry matter intake. There were no significant differences (p>0.05) in digestibility. However, the estimated ME intake was significantly (p<0.05) improved by supplementation. The estimated microbial protein supply was almost significantly (p<0.06) improved by 22.68%, 5.35%, 17.58% and 47.90% on the CW-, GN-, CSM- and MM-supplemented diets, compared to the control (7.85 g/day). Microbial protein synthesis efficiency was not significantly affected (p>0.05) by diet, and nor were the acetate clearance rates (p>0.05), which averaged 0.0475±0.0078/min. The improvement in ME intake may have been due to a faster flow rate of digesta and a better balance of nutrients in the end-products of digestion. These results demonstrate that small amounts of forage supplements can improve nutrient intake when animals consume low-quality forages and provide a basis for comparing such supplements with bought-in protein and energy supplements.

The mineral scoring technique and evaluation of indigenous browse species as natural mineral phytocentres for goats in African rangelands.

The utilization and evaluation of indigenous browse species as natural mineral phytocentres for goats was examined by the combined use of mineral concentrations, mineral scores, browse accessibility and abundance in the Ankole rangeland, Uganda. The species Grewia bicolor and Carissa edulis with <140% mineral scores and <70% accessibility were the most valuable mineral phytocentres and were the victims of overgrazing. Acacia albida and Acacia abyssinica with <130% mineral scores but <30% browse accessibility were valuable for the cut-and-carry feeding system. Species mineral scores at average and maximum dietary recommendations were <60%, highlighting the mineral insufficiency of range browse for high-performance goats. Mineral supply potential was highest (35.0%) in the genus Acacia and lowest (5.3%) in Dichrostachys. Browse accessibility was <35% in 69.2% of species. Acacia hockii was the most abundant species (24.5%) but had the lowest mineral score (17.7%). Browse species (90–100%) were deficient in Fe, Mn, Cu and Zn. The combined use of mineral concentrations and mineral scoring technique was superior to the use of mineral concentrations alone in defining mineral adequacy, deficiency and supply potential, making the mineral scoring technique a valuable tool in browse management.

The Role of Bioactive Tannins in the Postpartum Energy Retention and Productive Performance of Goats Browsed in a Natural Rangeland

The role of bioactive tannins in browse in the postpartum performance of goats grazed under natural range conditions was studied using 40 yearling Mubende goats (20±0.32 kg). In a completely randomized design, goats of one group (n = 20) received a daily drench of 50 g per goat of polyethylene glycol (PEG) of molecular weight 4000 given as a condensed tannin (CT) deactivator, and goats of the other group (n = 20) acted as the control (no PEG). Mean birth weights, live weight gains, abortion and twinning rates, litter size and tissue energy retention were measured. The PEG drench resulted in lower postpartum weight gains and tissue energy retention (p<0.05). Postpartum weekly weight loss per doe was 0.65 kg in the PEG group and 0.46 kg in the control group, while tissue energy loss was 17.7 MJ per goat in the PEG group and 10.23 MJ per goat in the control group in the first 8 weeks. Net weight gain was observed in the control group at the 11th week but was delayed in the PEG group (15th week). The PEG group had lower birth weights and higher kids mortalities (p<0.05). Selective feeding in the Ankole rangeland exposes goats to beneficial concentrations of dietary CT with apparent cumulative effects leading to improved postpartum performance of does and kids.

Growth performance of weaner lambs offered maize stover supplemented with varying levels of maize and cottonseed meals

Abstract The effect of supplementing maize stover (MS) with 0, 15 and 30 g/kg metabolic weight per day each of maize meal (MM) and cottonseed meal (CSM) on growth performance in Dorper lambs was evaluated in a randomised complete block design with a 3×3 factorial arrangement of treatments. There were no significant ( P >0.05) interaction effects between MM and CSM. There was no significant ( P >0.05) effect of CSM on MS intake but MM significantly ( P P P P P P P >0.05) whereas MM increased fat ( P P >0.05). MM promoted higher subcutaneous fat accretion compared to CSM. These results suggest that responses to protein supplementation depend, among other factors, on level of energy supplied. Offering a single optimal combination for all situations is therefore an over-simplification of a complex scenario.

The influence of fermented putak on diet digestibility and growth performance of weanling pigs

The use of fermented putak (prepared from the stalk of the palm tree; Corypha elata robx) as a substitute for maize meal in pig-fattening diets was evaluated in two experiments in the East Nusa Tenggara province of Indonesia. Boiled putak was fermented with Saccharomyces cerevisae for 2 weeks and incorporated into pig-fattening rations at zero (control), 100 g raw putak in place of maize meal (UFP), 100 g fermented putak in place of maize meal (LFP) and 200 g fermented putak in place of maize meal (HFP) kg -1 In the first experiment, digestibility of the feeds was evaluated in a Latin Square design using four weaner pigs. In the second experiment, four groups of eight weaner pigs each were randomly allocated to the four diets in a complete randomised design and fed individually for 84 days. In the digestibility trial there were no significant (P > 0.05) differences in feed intakes which were in g per day: 450 (control), 460 (UFP), 448 (LFP) and 453 (HFP). However, there were significant (P < 0.05) differences in intake in the growth study. The intakes were in g per day: 752 (control), 581 (UFP), 828 (LFP) and 694 (HFP). There were significant (P < 0.05) depressions in nutrient digestibility on the UFP diet, whereas, the LFP ranked higher than the control except in organic matter digestibility. Apparent digestibility of crude protein was 0.697, 0.639, 0.705 and 0.694 while for crude fibre it was 0.672, 0.546, 0.680 and 0.657 on the control, UFP, LFP and HFP diets, respectively. Gains in body weight during the growth study were 247, 145, 263 and 211 g per day. Results from the study show that 100 g fermented putak kg -1 can be included in pig-fattening diets in place of maize meal with no deleterious effects on the animal, thus releasing the maize meal much needed for human consumption in the Indonesian province of East Nusa Tenggara.