L.R. Ndlovu

Nutrient intake and utilisation by goats fed dried leaves of the shrub legumes Acacia angustissima, Calliandra calothyrsus and Leucaena leucocephala as supplements to native pasture hay

Thirty-six indigenous goats were used to determine the potential of sun-dried leaves of the shrub legumes Acacia angustissima, Calliandra calothyrsus and Leucaena leucocephala as supplements to native pasture hay (NPH). The dried leaves were included at the rates of 80, 160 and 320 g/head/ day. Cottonseed meal fed at the same levels, and NPH fed alone were included as controls. Among the browses, C. calothyrsus had the lowest N content of 19.0 g/kg dry matter (DM) and A. angustissima the highest of 35.0 g/kg DM. The leaves from the legumes had significantly less N and higher cell wall, neutral detergent insoluble N (NDIN) and acid detergent insoluble N (ADIN) contents than cottonseed meal. The values of NDIN as a fraction of total N were 19, 456, 526 and 816 g/kg for cottonseed meal, L. leucocephala, A. angustissima and C. calothyrsus, respectively. Proanthocyanidin contents were 33, 196 and 134 g/kg DM for A. angustissima, C. calothyrsus and L. leucocephala, respectively. Type of supplement did not affect (P > 0.05) NPH, total and digestible DM intakes although NPH intake was depressed (P < 0.05) at the highest level of supplementation compared to the first two levels. Animals fed legumes excreted significantly more (P < 0.001) faecal N (g/kg N intake) than animals consuming cottonseed meal. The reverse was observed for urine N. Among the legumes, C. calothyrsus had significantly higher (P < 0.001) N in faeces (958 g/kg N intake) than A. angustissima (630) and L. leucocephala (615). Significant (P < 0.05) correlation coefficients were obtained between proanthocyanidins (PAs) intake and faecal N, NDIN and ADIN (0.535, 0.501 and 0.786, respectively). Regressing digestible N on N intake indicated that A. angustissima and C. calothyrsus tannins had significant effects on the digestion of dietary N. The animal responses were discussed in relation to PAs content. It was concluded that both the type and level of PAs were important determinants of the animal responses.

Proanthocyanidins and other phenolics in Acacia leaves of Southern Africa

Four provenances each of Acacia karroo, Acacia nilotica, Acacia tortilis, Acacia Senegal, Acacia erioloba and Faidherbia albida were sampled at Cyrene, Lucydale and Mahiye in the Matopos Research Station. Provenances were not replicated within site. The leaves and leaf stalks sampled were dried at 55°C and then analysed for total phenolics and proanthocyanidins (PAs). Variations in content of PAs and total phenolics of the Acacias were studied. Three assay methods for phenolics were evaluated. Total phenolics were estimated by precipitation with trivalent ytterbium after extraction with acetone:water (7:3 v/v) or colorimetrically by the Folin-Ciocalteu method. PAs were estimated colorimetrically by the butanol-HCI method. The results from the colorimetric methods are reported as absorbance units (au). A. Senegal contained the lowest level of ytterbium precipitated phenolics (Ybppt) (mean = 47 g/kg DM), while A. nilotica contained the highest (mean = 298 g/kg DM). Amounts of Ybppt for A. karroo, A. erioloba and F. albida were not significantly different (P > 0.05) from one another. The amount of Ybppt for A. tortilis was significantly different (P 0.05). A. senegal was again the lowest in total phenolics detected by the Folin-Ciocalteu method (A 675 = 0.370 au/g DM), while A. nilotica was the highest (A 675 = 5.261 au/g DM). A. karroo, F. albida and A. tortilis were not significantly different (P > 0.05) from one another. PAs were lowest for A. senegal (A 550 = 0.040 au/g DM) and highest for A. karroo (A 550 = 2.011 au/g DM). Values for A. tortilis, F. albida and A. erioloba were not significantly different (P > 0.05) from one another. For all the three assay methods, there were no significant differences (P > 0.05) between Cyrene and Mahiye sites. The regression analysis of PAs on Ybppt showed the relationship to be highly significant (P < 0.05) for A. karroo, F. albida and A. erioloba (R 2 =0.904, 0.892, 0.884, respectively, and significant for A. tortilis (R 2 = 0.680). It was poor for A. Senegal and A. nilotica (R 2 = 0.347 and 0.460, respectively). The relationship between total phenolics and Ybppt was similarly good for F. albida, A. erioloba, A. nilotica and A. karroo (R 2 = 0.957, 0.808, 0.792, and 0.725, respectively) but poor for A. senegal, and A. tortilis (R 2 = 0.413 and 0.004, respectively).

Chemical composition and relationship to in vitro gas production of Zimbabwean browsable indigenous tree species

Abstract Seventeen Zimbabwean browse species were analysed for crude protein (CP), neutral and acid detergent fibre (NDF and ADF), acid detergent lignin (ADL), insoluble proanthocyanidins (IPAs) and protein precipitating polyphenolics (PPPs). Gas production of the species was measured over 96 h and gas-production constants estimated using the equation: gas produced = b (1 − e − ct ). The browse varied greatly in their CP, fibre and phenolic content. Crude protein ranged from 56 to 210 g kg −1 dry matter (DM), NDF from 294 to 835 g kg −1 DM and PAs from 14.2 to 389 A 550 nm g −1 NDF. None of the polyphenolics assayed were related to gas-production constants ( P > 0.05) but NDF, ADF and ADL were negatively correlated ( P

Effect of different dietary energy level intakes on efficiency of estrus synchronization and fertility in Mashona goat does

The objective of the study was to determine the effects of three dietary energy levels: 0.27 (low level: LL); 0.53 (medium level: ML), and 1.06 (high level: HL) MJMEkg(-1)W(0.75) on estrus synchronization and fertility in Mashona goat does. Forty-five multiparous Mashona goat does of average bodyweight 19.9+/-2.5kg were randomly allocated in equal numbers to the three dietary energy levels. The diets were made from a complete feed ration providing 9.83MJMEkg(-1)DM and 15.5% CPkg(-1)DM. Does were fed initially during a 60-day pre-synchronization period, and blood samples were collected twice a week for the determination of plasma progesterone concentrations to ascertain ovarian activity. Intramuscular injections of cloprostenol (100µg each) were administered 11 days apart. Immediately after the second injection of cloprostenol, three fertile bucks were introduced to the does and were left with the does for 21 days. The does were maintained on their dietary treatments throughout gestation except for those does in the LL treatment. Pregnancy was diagnosed 90 days post-mating using an ultrasound scanner. After pregnancy diagnosis, does on the LL treatment were randomly allocated to ML (n=7) and HL (n=8) treatments. During the pre-synchronization period, does on the LL treatment lost 12.3% whereas those on ML and HL treatments gained 2.1 and 28.8% of their initial bodymasses, respectively. The proportion of does exhibiting overt estrus within 96h after the last cloprostenol injection was significantly lower (P<0.05) for does on the LL treatment (60%) than for those on ML (93%) or HL (100%) treatments, respectively. However, based on plasma progesterone concentrations, the percentage of does on the LL treatment that exhibited ovarian cycles was numerically lower than that of does that were bred (40 versus 73%). Conception, fecundity and twinning rates were significantly lower (P<0.05) on the LL treatment than on the ML and HL treatments. These results indicate that feeding Mashona goat does 0.27MJMEkg(-1)W(0.75) compared to 0.53 and 1.06MJMEkg(-1)W(0.75) reduces the expression of estrus, conception, fecundity and twinning rates, and that feeding 0.53MJMEkg(-1)W(0.75) suffices for optimum reproduction. In addition, the results suggest that cloprostenol administration may induce ovarian cycles in reproductively quiescent does on dietary energy restriction.

Effect of season of birth and sex of kid on the production of live weaned single born kids in smallholder East African goat flocks in North East Zimbabwe

Abstract An amalgamated flock of traditionally managed Mashona Small East African goats was monitored over a 6 yr period. Kids born in the hot dry season were heavier (P 0.05) on weight increase. There was a steady decline in growth rates from age 15 d (60.2 g/d) to weaning age of 180 d (41.7 g/d). Overall, 19.4% of the 294 kids born during the study period exited the flocks before age 180 d. Major causes of exits were lost kids and predation, which together accounted for 61% of exits by kids. Seasonal effects on exits were mainly at ages below 30 d where 10.3% of kids born in the hot dry season exited compared to 4.3% and 4.6% for the hot wet and cool dry seasons. Kidding intervals were 321 (s.e. 23.6), 325 (s.e. 30.9) and 259 (s.e. 50.1)d for does kidding in the hot dry, hot wet and cool dry seasons, respectively. Due to the slow growth rates and long kidding intervals the flock productivity in terms of weaned live kid weight (kg) per doe per year was low.

Dry matter intake, apparent digestibility and excretion of purine derivatives in sheep fed tropical legume hay

Four ruminally cannulated wethers (31+/-1.3kg) were used in an experiment with a 4x4 Latin square design to estimate the DM intake, apparent digestibility, nitrogen balance, rumen ammonia and microbial protein production. The sheep had ad libitum access to either Cassia rotundifolia (Cassia), Lablab purpureus (Lablab), Macroptilium atropurpureum (Siratro) or Stylosanthes guianensis (Stylo). Dry matter intake of cassia was lower (P<0.001) than that of lablab, siratro and stylo hays. Organic matter intake was greater (P<0.001) for lablab, siratro and stylo hays than that of cassia. Dry matter digestibility was higher (P<0.05) for lablab hay, than that of cassia, siratro and stylo hays. The organic matter digestibility ranged from 0.579 for cassia hay to 0.617 for stylo hay and there were no differences (P0.05) among the legume hays. Nitrogen intake was highest (P<0.05) in sheep given stylo hay and least in sheep fed cassia hay. Animals given lablab, siratro and stylo hays had higher (P<0.05) faecal and urinary N compared to those on cassia hay. Rumen ammonia N concentration was highest (P<0.05) in sheep given lablab while sheep offered siratro and stylo had intermediate values, and least in animals fed cassia hay. The ammonia levels were above the recommended optimal level of 50mg N/l. The total purine derivative excretion in the urine and microbial N supply was not different (P0.05) among treatments. From the presented findings it is concluded that the intake and digestibility in sheep of the four legume hays are variable and provide adequate rumen ammonia N for maximum rumen microbial growth making then ideal protein supplements to ruminants fed low quality roughages.

The effects of sorghum proanthocyanidins on digestive enzyme activity in vitro and in the digestive tract of chicken

The effects of sorghum grain proanthocyanidins (PAs) on the digestive enzyme activity of broiler chickens were investigated in vitro and in vivo using seven sorghum varieties grown in Zimbabwe. All seven sorghum varieties, classified as either high-PA (DC-75, Mutode, Red Swazi and Chirimaugute) or low-PA (SV2, Brown Tsweta and Chibonda), were used to assess the PA–protein binding capacity and inhibition of trypsin and amylase in vitro. Three of the varieties (Chirimaugute, Chibonda and Brown Tsweta) were subsequently used in broiler diets to test the effects of PAs on the growth performance and digestive enzyme activity of 48 broiler chicks at 42 days of age. Protein precipitation and trypsin and amylase inhibition increased (P < 0.05) with an increase in level of PAs from the low-PA varieties (by 1–10%) to the high-PA varieties (by 40–70%). The activity of trypsin in the duodenal lumen of chicks fed the control diet was almost double that of chicks fed Chirimaugute. Amylase activity in the high-PA group was lowered significantly (P < 0.01) relative to the control and low-PA groups. The difference between in vitro and in vivo residual enzyme activities was 10–20% for amylase and 5–10% for trypsin. Chicks fed the high-PA diet showed lower performance than chicks fed the control and low-PA diets. Mean body weight gains were 59.9, 34.4, 57.3 and 61.4 (SE 4.02) g day−1, final weights were 1936.4, 1363.3, 1773.2 and 1857.0 (SE 78.5) g and feed efficiencies were 1.85, 2.26, 1.65 and 2.13 (SE 0.014) for the control, Chirimaugute, Brown Tsweta and Chibonda groups respectively. The results indicate that PA–enzyme interaction, in addition to dietary protein–PA binding, contributes to the poor performance of chickens fed high-PA sorghum diets. © 2000 Society of Chemical Industry

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.

The use of groundnut hay as a supplement for sheep consuming poor quality natural pasture hay

Abstract A 5 × 5 latin square design experiment using five male sheep (60–70 kg live weight) was carried out to assess the effects of supplementing poor quality veld hay with groundnut hay on intake, digestibility, rumen environment and digesta kinetics. Five diets were formulated in which veld hay with 1% urea was fed alone (Control) or together with 100 g, 200 g or 300 g groundnut hay (100Gnut, 200Gnut or 300Gnut, respectively) and groundnut hay fed alone (Gnut). The forages were coarsely chopped prior to feeding. The groundnut hay supplements increased total feed intake and in vivo digestibility of the diets ( P

Potential of dolichos lablab (Lablab purpureus) and Acacia tortilis pods in smallholder goat kid feeding systems in semi-arid areas of Southern Africa

Abstract Two feeding trials of 112 and 84 days duration were conducted with indigenous goat kids with average liveweight of 11.5 ± 0.3 kg to evaluate the potential of dolichos lablab and Acacia tortilis pods in mitigating liveweight losses and improving survival. In Trial 1, the kids were offered 200–300 g day −1 of dolichos lablab or lucerne hay, while in Trial 2 they were offered 300–400 g day −1 of Acacia tortilis pods or dolichos lablab hay. Weight gains, though low (31 g day −1 for lucerne and 23 g day −1 for dolichos lablab), were positive and there was no mortality. In Trial 2, A. tortilis pods resulted in growth rates of up to 67 g day −1 . It is concluded that A. tortilis pods are a suitable supplement in a feeding system where kids are penned for most of the day and only released in the afternoon to graze near the home.