Veld Hay Research Articles

Removal of sorghum stover from feed choices has no confounding effect on the quantity and quality of diets selected by group or individually fed sheep

ABSTRACT The study determined the effect of reducing dietary ingredients and group feeding on diet selection, nutrient intake and digestibility in choice-fed sheep. Three feeds comprising of veld hay (VH), sorghum stover (SS) and maize stover (MS) were offered ad-libitum while lucerne hay (LH) and bean straw (BS) were offered at restriction. Twelve sheep were allocated into three groups (i) group-fed in 3 sheep per pen, (ii) individually fed and, (iii) individually fed with SS exclusion. Sheep were rotated across the groups in four periods of 10 days. Diet selected, intake, refusals, spillages and faeces were monitored for seven days. The proportion of BS and LH consumed did not differ between group-fed and individually fed sheep with or without SS inclusion. Intake of MS and SS was lower in individually fed sheep while intake of VH was higher (p < 0.05). The proportion of BS and MS selected among individually fed sheep was similar with or without SS inclusion (p > 0.05). Diet selection was influenced by group feeding, but not the removal of SS. The scarcity of one dietary component may not result in the selection of undesired but available feeds if the quality is similar or poorer to the absent feed.

EFFECTS OF FEEDING Lantana camara LEAF HAY ON ANIMAL PERFORMANCE AND HEALTH IN SMALL EAST AFRICA GOAT BREEDS

&lt;p&gt;&lt;strong&gt;Background:&lt;/strong&gt; &lt;em&gt;Lantana camara&lt;/em&gt; is listed as one of the worst invasive species worldwide and is considered poisonous to livestock. However, in invaded Zimbabwean rangelands, voluntary intake by domestic livestock especially goats of this shrub is common, yet, little is understood about the effect of this browse on animal performance. &lt;strong&gt;Objectives:&lt;/strong&gt; To assess the effects of feeding graded levels of &lt;em&gt;L. camara&lt;/em&gt; (LC) leafy hay on the performance, digestibility, nitrogen balance and microbial protein synthesis in Small East Africa Goat Breeds. &lt;strong&gt;Methodology:&lt;/strong&gt; Eighteen, six to ten months old castrated goats with a mean± (SD) weight of 13.6±4.9 kg were randomly assigned to the six treatment diets in a completely randomised design. Each goat was housed separately in a metabolism cage for the entire experimental period of 21 days. &lt;em&gt;Lantana camara&lt;/em&gt; leaf hay was incorporated in goat feed as a protein source at 5%, 10%, 15%, 20%, and 25% inclusion levels. Commercially bought, goat feed was used as the sixth and control treatment diet. Veld hay was used as a basal diet and water were offered &lt;em&gt;ad-libitum&lt;/em&gt;. &lt;strong&gt;Results&lt;/strong&gt;: The average daily dry matter intake was above the minimum recommended of 3% of the animal’s metabolic body weight (kg&lt;sup&gt;0.75&lt;/sup&gt;). Goats fed on 10%LC consumed significantly lower quantities of hay than 5%LC but were not significantly different from goat feed (GF), 15%LC, 20%LC and 25%LC. Apparent digestibility coefficient values ranged from 62% to 71%. Higher nitrogen intakes was observed with diets that were highly palatable such as commercial goat feed and 5% &lt;em&gt;L. camara&lt;/em&gt;. Higher microbial protein supply was observed in groups fed diets with high levels of &lt;em&gt;L. camara&lt;/em&gt;. &lt;strong&gt;Implications:&lt;/strong&gt; The use of invasive &lt;em&gt;L. camara&lt;/em&gt; biomass as a source of goat feed at 5% inclusion is a promising method to control its spread in while addressing the nitrogen deficiencies experienced by livestock that subsist on poor quality feeds in invaded rangelands. &lt;strong&gt;Conclusion:&lt;/strong&gt; Supplementing goats with &lt;em&gt;L. camara&lt;/em&gt; leafy hay improves dry matter feed intake and degradability. Contrary to expectations, no negative effects were observed with &lt;em&gt;L. camara &lt;/em&gt;leafy meal inclusion in goats diets at 5 to 25 percent inclusion level.&lt;/p&gt;

Stocking Rate Has No Confounding Effect on the Use of Internal and Inert Markers to Predict Botanical Composition, Diet Quality, Degradability and Passage Rate Kinetics in Sheep

Simple SummaryInternal markers are components of diets recovered to different degrees in faeces of animals. These feed components maybe helpful in predicting diet selection, nutrient intake and digestibility in animals. The development of sustainable grazing management and practices to prevent the depletion of natural grasslands as a result of overgrazing depends on the knowledge of feed intake, chemical and botanical composition of diets selected and consumed by ruminants. Determination of the botanical composition of diets selected by free ranging ruminants by visual observation is time consuming and tedious, while the use of oesophageal cannulated animals is invasive and impairs animal welfare. Therefore, it is imperative to use non-invasive methods, such as internal markers to predict feed preferences and composition of diets that ruminants consume. However, it is unclear if the accuracy of results obtained using internal markers is confounded by other factors, such as stocking rate, which is expected to determine the availability and botanical composition of pasture, which, in turn, may exert its influence on the diet selected and consumed by grazing animals. The findings of this study, however, showed that stocking rates did not affect diet selection and nutrient intake in sheep, while a combination of internal markers can be used to estimate the quality of diet selected by animals under cafeteria feeding conditions, regardless of the stocking rate used. Thus, the use of modified acid detergent fibre, acid insoluble ash and acid detergent lignin contents in feeds achieved high accuracy and precision in estimating diets selected by sheep. This approach serves as a proof of concept that these markers can be also used in free ranging animals.This study investigated if there is any confounding effect of stocking rate on the use of internal markers to determine and predict the dietary ingredient composition, dry matter intake (DMI) and digestibility of diets consumed by sheep. Fifteen sheep were randomly allocated to stocking rate treatments of one (SR1), two (SR2), four (SR4) and eight (SR8) sheep per pen (space allowance: 31.04 m2, 15.52 m2, 7.76 m2 and 3.88 m2 per sheep, respectively) and fed ad libitum maize stover, sorghum stover and veld hay by supplying 110% of previous day’s intake. Sheep were rotated across the treatments in four periods of 10 days. The proportion of feeds selected and total DMI were similar across all stocking rate treatments. However, diets selected by sheep in SR2 had the highest digestibility compared to other treatments. The prediction of the effective degradability of dry matter using acid detergent fibre content achieved an accuracy of 84.6%. A combination of crude protein and neutral detergent fibre contents achieved 63% accuracy in the prediction of the rate of degradation of feeds. The use of acid insoluble ash (AIA) as an internal marker to predict nutrient intake, digestibility, DMI and dietary ingredient intake accounted for 84.3%, 81.2%, 53.0% and 64.1% of the variation, respectively. The predictions of dietary feed proportions and nutrient quality selected obtained with least squares procedure using a combination of modified acid detergent fibre (MADF), acid detergent lignin (ADL) and AIA accounted for 81.0% and 72.4% of the variation, respectively. In conclusion, regardless of the different stocking rate tested in this study, a combination of MADF, ADL and AIA as internal markers can be used to estimate diet and nutrient selection by sheep using the least squares procedure. Hence, these markers can be used to predict ingredient composition of diet, diet and nutrient selection, nutrient intake and digestibility in free ranging animals.

Effects of diet and roughage quality, and period of the day on diurnal feeding behaviour patterns of sheep and goats under subtropical conditions.

ObjectiveThis study investigated the effect of diet and roughage quality (RQ) on dry matter intake, duration and number of daytime and night-time eating bouts, idling sessions and ruminating activities in small ruminants.MethodsIn Exp 1 and 2, RQ was improved by urea treatment of veld hay, while diet quality was improved by supplementing with Lucerne hay (Exp 3), sunflower meal and lespedeza (Exp 4), fish meal (Exp 5a), and sunflower meal (Exp 5b). In all experiments goats and sheep were blocked by weight and randomly allocated to experimental diets. Day-time (06:00 to 18:00 h) and night time (18:00 to 06:00 h) feeding behaviour activities were recorded.ResultsRQ affected rumination index in Exp 1, but not in Exp 2, 3, and 5. Time spent eating and ruminating was affected by RQ (Exp 1, 3, and 4), period of day (all experiments) and their interaction (Exp 1). Intake rates (g/bout and g/min) were similar across diets. Period of day affected the duration of rumination sessions (Exp 1, 2, and 3); diet or RQ affected the duration of eating bouts (Exp 3) and rumination sessions (Exp 1 and 2). RQ had a significant effect on the duration of eating sessions in Exp 3 only, whilst period of day affected this same behaviour in Exp 2 and 3. Generally, goats and sheep fed on roughage alone ruminate at night and eat more during the day but those fed a roughage and supplemented with Lucerne hay spent more time ruminating than eating. Time spent eating and ruminating had positive correlations to crude protein and feed intake. Intake rates had strong positive correlations to intake.ConclusionChewing time, number of eating and ruminating sessions, and duration of eating bouts are physiologically controlled in small ruminants, though chewing time requires isometric scaling during modelling of intake.

Milk Production in Goats on Veld Hay Supplemented with Selected Legume Forages

This study was designed to investigate the effects of supplementing silverleaf (Desmodium uncunatum), velvet bean (Mucuna pruriens) and cowpea (Vigna unguiculata) forage legumes to low quality veld hay on milk production in indigenous goats. Sixteen Mashona indigenous lactating goats (weighing 30±2 kg) in their third parity were divided into four dietary treatment groups and used in a completely randomized design experiment. The daily feed intake on the treatment diets and hay was significantly (P 0.05) different among the dietary groups. Milk yield was significantly different among the legume supplemented diets. Daily BW loss was significantly higher in goats supplemented with cowpea, as compared to those supplemented with commercial concentrate feed, silverleaf and velvet bean. The levels of milk production attained in this study implied that commercial concentrate feeds can be substituted with forage legumes without affecting either the milk yield or composition in goats and at lower cost especially for resourceconstrained farming areas.

Apparent digestibility and microbial protein yield of Desmodium uncinatum, Mucuna pruriens and Vigna unguiculata forage legumes in goats

This study examined the effects of adding forage legumes as protein supplements to poor-quality natural pasture (veld) hay offered to goats on microbial protein yield and nitrogen metabolism. Four indigenous Nguni-type goats were used in a 4×4 Latin cross-over design experiment. Goats were randomly allocated to four dietary treatments comprising commercial goat feed (GF), veld hay supplemented with cowpea (CW), velvetbean (VB) or silverleaf desmodium (SD). Microbial protein yields were determined using the purine derivatives technique and nitrogen retention was calculated from the digestible organic matter intake. Total nitrogen intake was significantly higher in the GF followed by CW, SD and VB, respectively. Microbial protein supply, calculated microbial true protein and digestible microbial true protein were affected (P<0.05) by legume supplementation. Animals on poor-quality forages had the most efficient microbial protein synthesis. However, supplementation of hay failed to meet the maintenance requirements of animals as evidenced by negative nitrogen balances in VB and SD. The efficiency of utilisation of nitrogen in the supplements could have been limited by unavailable fermentable metabolisable energy in the diets. Supplementation of poor-quality veld hay with legume forages could improve utilisation, especially in the dry season.

Performance of goats fed on low quality veld hay supplemented with fresh spiny cactus (Opuntia megacantha) mixed with browse legumes hay in Zimbabwe.

Nutrition is a major constraint in smallholder livestock production; hence, the use of alternative sources which are adaptive to long dry seasons is imperative. The study was conducted to establish options of improving nutrition and palatability and also to determine the performance of goats fed on cactus-browse hay as dry season supplements. Palatability and adequacy of nutrition was investigated using 32 castrated male goat kids. The kids were housed in individual metabolism cages for 84 days in a complete randomised design (CRD) with eight replicates for the four treatment diets. Daily experimental diet, basal diet and water intake were measured, and live mass was measured at weekly intervals. Daily diet intake was significantly different (P < 0.05) among treatments. Kids that were supplemented with cactus-Leucaena leucocephala meal (CLLM) consumed more than those on cactus-Acacia angustissima meal (CAAM), cactus-Gliricidia sepium meal (CGSM) and cactus-Pennisetum purpureum meal (CPPM) in that order. CGSM was not readily palatable as goat kids refused to take it when mixed with fresh cactus. Animals that were not supplemented with a source of nitrogen together with those that were supplemented with less palatable diet of CGSM lost weight significantly (P < 0.05) initially but gained weight slightly towards the end of the study. Significantly higher weight gains (P < 0.05) were observed in animals in CLLM and CAAM treatment. It was concluded that fresh cactus could be used to improve poor quality roughage intakes in goats, and therefore, there is need to promote its use in periods of feed deficit especially in smallholder sector.

Microbial Protein Yield in Sheep Fed Forage Legume Hays as Supplements to Veld Hay

This study examined the effects of feeding forage legumes as protein supplements to poor quality natural pasture (veld) hay offered to sheep on microbial protein yield and nitrogen metabolism. Four female Sabi cross-bred sheep were used in a 4 x 4 Latin cross-over design experiment. The sheep were randomly allocated to four dietary treatments comprising veld hay alone (V), veld hay supplemented at 25% of expected feed intake with either cowpea (VC), fine stem stylo (VF) or silverleaf desmodium (VS). Microbial protein yield was determined using the purine derivatives technique. Total nitrogen (N) intake increased with supplementation by approximately 9, 11 and 17 fold for VS, VF and VC, respectively. The microbial protein supply, the calculated microbial true protein and the digestible microbial true protein were not affected (P>0.05) by legume supplementation. It was concluded that supplementation of legume forages to poor quality veld hay increased nitrogen utilisation in the sheep. Animals on poor quality forages tended to show the most efficient microbial protein synthesis. However, feeding of veld hay failed to meet the maintenance requirements of the animal as evidenced by negative nitrogen balance.

Production and economic performance of F1-crossbred dairy cattle fed non-conventional protein supplements in Zimbabwe

The effects of supplementing crossbred cows with non-conventional protein sources on dry matter intake, milk yield parameters and economic returns were investigated. Twenty-five lactating F1 Holstein-Mashona crossbreds averaging 115 ± 24 days in milk were used. Five treatments, total mixed ration (TMR), urea-treated maize stover, untreated maize stover, Macroptilium atropurpureum (Siratro) hay and veld hay, were randomly assigned to cows and replicated five times in a completely randomised design. Nutrient composition, intake, milk yield and economic returns were determined. M. atropurpureum hay, urea-treated maize stover and TMR had equal crude protein content. Daily dry matter intake and yield differed significantly among the treatment diets (P < 0.05). Cows on TMR, urea-treated maize stover and M. atropurpureum consumed more (P < 0.05) than cows on untreated maize stover and veld hay. Supplementing with TMR, urea-treated maize stover and M. atropurpureum hay increased (P < 0.05) milk yields. Mean daily milk yield was highest for cows supplemented with urea-treated maize stover. Percent fat, protein and total solids in milk from cows fed urea-treated stover compared favourably to that of milk for cows supplemented with TMR. Income over supplement cost was highest for cows supplemented with M. atropurpureum hay and urea-treated maize stover. Urea-treated maize stover and M. atropurpureum can therefore be used as a replacer protein supplements for dairy cattle in Zimbabwe.

The effect feeding forage legumes as nitrogen supplement on growth performance of sheep

The effect of feeding forage legumes, Cowpea, Silverleaf desmodium and Oxley fine stem stylo, as protein supplements to natural pasture (veld) hay on intake, growth rate and nitrogen metabolism in growing lambs was evaluated. Thirty growing lambs were stratified according to body weight and randomly assigned, within a stratum, to five diets in a completely randomised design. The diets were veld hay alone (V), veld hay supplemented with either 10 g/kg of urea (VU), veld hay supplemented with 250 g/kg Cowpea (VC), 250 g/kg Silverleaf desmodium (VS) or 250 g/kg Oxley fine stem stylo (VF) forage legume hays. The V and the VU groups were used as control diets. Animals supplemented with either urea or the forage legume had higher (P < 0.01) total dry matter intake compared with the animals on V. The animals supplemented with the forage legumes had higher (P < 0.01) nitrogen intake and faecal nitrogen output than the non-supplemented group. All animals, across the treatments, lost body weight; lambs on V had higher (P < 0.01) body weight losses than those in the other treatments. The forage legume supplemented groups lost less (P < 0.01) body weight than those on the V and VU diets. Although supplementation with forage legumes enhanced feed intake and reduced weight losses it did not maintain body weights of lambs fed a basal diet of poor quality roughages.

Scrotal, testicular and semen characteristics of young Boer bucks fed winter veld hay: The effect of nutritional supplementation

The aim of the work was to determine the effects of feeding winter veld hay plus a supplement on scrotal, testicular and semen characteristics in young Boer goat bucks. Fifteen Boer goat bucks (6–8 months of age), were allocated to two groups and fed ad libitum for a period of 29 days. The WH group (winter hay or control group; n = 8) received a chopped diet consisting of grass hay, predominantly Themeda triandra grass (cut during the winter) from natural pastures (veld). The WH + S group (winter hay plus supplement; n = 7) received the same diet consisting of Themeda triandra veld hay and supplemented with maize meal, molasses meal and urea. Body weights and feed intake were recorded, as well as scrotal, testicular and semen characteristics. Results indicate a detrimental effect of winter veld hay feeding on characteristics such as sperm cell abnormalities (43% in the WH group versus 24% in WH group), testicular volume (156 ml in the WH + S group versus 104 ml for WH animals) or scrotal circumference (20.7 cm in WH + S group versus 17.7 cm in WH group). It is essential to supplement the nutrition of small ruminants under winter environments, to maintain scrotal, testicular and semen characteristics, especially if the animals are to be used in the subsequent breeding season.

Voluntary intake, nitrogen metabolism and rumen fermentation patterns in sheep given cowpea, silverleaf desmodium and fine-stem stylo legume hays as supplementary feeds to natural pasture hay

The effect of feeding legumes as protein supplements to veld hay on voluntary feed intake, nitrogen metabolism and rumen fermentation patterns was evaluated. Four sheep were randomly allocated to the four dietary treatments of either veld hay alone or veld hay supplemented with either cowpea, fine-stem stylo or silverleaf desmodium. Total dry matter intake was highest with cowpea (P < 0.05), and the lowest increment (P < 0.01) was with silverleaf desmodium. The pH of the rumen fluid was lower (P < 0.01) in sheep given the supplemented diets than the veld hay alone. The cowpea-supplemented diet produced higher (P < 0.05) levels of ammonia N than the other diets. The silverleaf desmodium diet produced the highest level of total volatile fatty acids (VFA) (P < 0.05). Supplementation with the legumes improved the nitrogen retention, although animals on all treatments were in negative nitrogen balance. Legume supplementation to the veld hay also enhanced rumen fermentation, as reflected by an increase in ruminal ammonia N and VFA concentrations. These results suggest that although the legume hay increased dry matter and nitrogen utilisation, the negative nitrogen retentions might indicate the inadequacy of the specific legume hays used as nitrogen supplementary feeds to sheep fed a basal diet of veld hay.

The effect of supplementation on productive performance of Boer goat bucks fed winter veld hay

Fifteen Boer goat bucks, (6-8 months old), were allocated into two groups and fed ad libitum for a period of 29 days. The WH group (winter hay; n = 8) received a chopped diet consisting of grass hay, predominantly Themeda trianda grass (cut during the winter) from a natural pasture (veld). The WH+S group (winter hay plus supplement; n = 7) received a chopped diet consisting of Themeda trianda veld hay, supplemented with maize meal, molasses meal and urea. Body weights and feed consumption were recorded. Animals were slaughtered and carcass characteristics (weight and percentages of selected carcass cuts) and the carcass chemical composition were determined. The WH+S animals showed a higher live weight and cumulated feed intake. Carcass cuts from WH animals represented a higher percentage of the total carcass, especially cuts where muscle depots are higher (legs, best end chops and prime cuts). There is an attempt by non-supplemented animals to preserve the body's nitrogen reserves under prolonged nutritional stress conditions, and there is consequently a necessity to supplement feeding of small ruminants fed winter veld hay, especially if the animals are to be used in subsequent breeding seasons.

In vitro digestibility using caecal liquor of diets containing poor quality roughages and green forages fed to domesticated ostriches ( Struthio camelus var. domesticus)

The objective of this study was to compare in vitro organic matter digestibility (IVOMD) of ostrich diets using the normal (NTT) and reverse (RTT) modified Tilley and Terry methods of in vitro digestion. The IVOMD values of green forages were determined using the RTT method only. Four ostrich diets and four green forages were digested in vitro using caecal liquor collected from ostriches slaughtered at the Norton Commercial ostrich producers (Copro) abattoir. The diets included a control diet of a concentrate and legume hay, silverleaf desmodium uncinatum (CN), and the three others consisting of a concentrate with either veld hay (VH), Katambora Rhodes grass hay (RG) or maize stover (MS). Lucerne (LU), Midmar Rye grass (MRG), Russian Comfrey (RC) and Kenyan White clover (KWC) were the green forages used. The forages were grown under the recommended management levels and were cut before flowering. There was no interaction ( P>0.05) between diet and method of digestion. The RTT gave higher ( P<0.01) IVOMD than the NTT method. However, both methods showed a similar trend in the digestion of the diets. The MS and RG diets had similar and greater ( P<0.05) IVOMD than the control and veld hay diets. The amounts of organic matter (OM) digested differed ( P<0.01) with either diet or forage type. Kenyan White clover and MRG had similar and greater ( P<0.05) IVOMD than LU and RC, which were not different ( P>0.05). The values of IVOMD in dry matter for the forages were: MRG > KWC > LU > RC, and all the differences were significant ( P<0.05). The study showed that the NTT method needs to be modified to suit hind gut fermenters and IVOMD can, therefore, be used to rank the nutritive value of ostrich feeds.

Effect of supplementing veld hay with a dry meal or silage from pods of Acacia sieberiana with or without wheat bran on voluntary intake, digestibility, excretion of purine derivatives, nitrogen utilization, and weight gain in South African Merino sheep

The study evaluated the synergism between wheat bran and tanniferous feeds (dry meal or silage from pods of Acacia sieberiana) on intake and digestibility of various nutrients as well as weight gain in sheep fed a basal diet of veld hay ( Cynodon dactylon). Dietary treatments comprised veld hay given ad libitum and supplemented with: 270 g of wheat bran (WB) alone (T 1), 203 g of WB plus 83 g of silage (T 2), 135 g of WB plus 165 g of silage (T 3), 330 g silage without WB (T 4) or 306 g of dry pods without WB (T 5). The silage was prepared by mixing ground pods with water in a ratio of 40:60 (weight of pod:weight of water) and ensiling in 200-l drums for 35–45 days. Thirty young South African Merino sheep (15 males and 15 females), averaging 24 kg liveweight and 8 months of age, were blocked by sex and weight and within block, randomly distributed to the dietary treatments. A growth study was followed by a metabolism phase. All animals were slaughtered at the end of the trial to evaluate the weight of the dressed carcasses and some body organs. Faecal samples were examined at the beginning and at the end of the trial in order to evaluate the effect of tannins on endoparasites. Dry matter intakes for treatments 1, 2, 3, 4 and 5 were 1017, 1087, 1169, 1238 and 1214 g, respectively. Average liveweight gains (ADG) were 97, 114,114, 132 and 123 g in the same order. The addition of silage increased ( P<0.01) hay and DM intake but had no effect ( P>0.05) on liveweight gain and feed conversion efficiency. Increasing the levels of silage in the diet linearly ( P<0.01) increased ADG. Sex did not influence intake or ADG. The digestibilities of DM, OM and detergent fibres as well as excretion of purine derivatives were similar ( P>0.05) among treatments but the WB diet promoted higher N digestibility. The pod and silage diets increased ( P<0.01) faecal N and lowered ( P<0.05) urinary N excretion by sheep. N retention was similar among treatments. Carcass, liver and kidney weights were similar ( P>0.05) among treatments and the organs had no lesions. The results show that combining WB and silage did not show significant synergism but condensed tannins present in the silage and pod supplements produced beneficial effects probably by forming tannin–protein complexes which by-passed the rumen and were digested at the lower segments of the gastro-intestinal tract. The results of the study have shown that the pods of Acacia sieberiana can constitute an important source of nitrogen to livestock and the liveweight gains are indications that, if legume pods are well managed, they can reduce weight loss in animals grazing low quality rangelands and enhance production.

Condensed tannin and saponin content of Vigna unguiculata (L.) Walp, Desmodium uncinatum, Stylosanthes guianensis and Stylosanthes scabra grown in Zimbabwe.

Samples of the tropical forage legumes Vigna unguiculata (L.) Walp (cowpea), Desmodium uncinatum (silverleaf desmodium), Stylosanthes guianensis (oxley fine stem stylo) and Stylosanthes scabra (fitzroy) and of natural pasture (veld) hay were analysed and ranked according to their proanthocyanidin (PA) and saponin content. Silverleaf desmodium and fitzroy leaf and stem samples of different ages were also separately analysed for the PA contents. All the samples analysed contained some PA but no saponins. High levels of PA were detected in silverleaf desmodium and very low levels in veld hay and cowpea. In all samples, more of the tannins were bound to protein or neutral detergent fibre (NDF) than were extractable, most being bound to proteins. The proportion of the unextractable PA was greater in younger than in mature materials.

The nutritive value, intake, digestibility and nitrogen balance of farm-grown and prepared sunflower-based dairy calf meals.

The dry matter intake (DMI), digestibility and nitrogen balance of three sunflower-based farm-grown calf meals with different roughage sources (maize stover, MSM; groundnut tops, GTM; and veld hay, VHM) and a commercial calf starter meal (control; CSM) were studied for 47 days (26 days pre- and 21 days post-weaning) in calves. The DMI was lower (but p > 0.05) with CSM (0.369 kg/day) than with the farm-grown meals (mean 0.559 kg/day), and the daily weight gain (kg/day) did not differ significantly (p > 0.05) between CSM (0.107), GTM (0.053), MSM (0.157) and VHM (0.217). Dry matter, organic matter and protein digestibility were higher (p < 0.07) on the CSM than on the GTM treatment. Nitrogen retention was least (p < 0.05) in calves fed GTM (3.0 g N/day) compared to those fed MSM (10.4), VHM (5.0) or CSM (3.9). These results indicate that farm-grown and prepared sunflower-based meals are suitable for feeding young calves.

Effect of supplementing veld hay with tropical legumes Desmodium uncinatum, Stylosanthes guianensis and Macroptilium atropurpureum on intake, digestibility, outflow rates, nitrogen retention and live weight gain in lambs

In 2 consecutive years using fresh batches of lambs, poor-quality veld (natural pasture) hay dominated by Hyparrhenia grasses (23 g crude protein per kg dry matter) was fed ad libitum either alone or with one of three herbaceous tropical legumes at the rate of 0.25 of total feed consumed. The legumes Desmodium uncinatum (Silverleaf desmodium), Stylosanthes guianensis (Oxley fine-stem stylo) and Macroptilium atropurpureum (Siratro) contained 143, 114 and 159 g crude protein per kg dry matter, respectively, and, to varying degrees, increased feed intake, digestibility, energy intake and nitrogen retention and reduced live weight loss ( P < 0.05). Legume supplementation also marginally increased the fractional outflow rate of particles from the rumen from 0.015 to 0.020 per hour ( P > 0.05). Average daily consumption of total dry matter was 465 g in animals given veld hay alone compared with 636, 681 and 754 g in those supplemented with D. uncinatum, S. guianensis and M. atropurpureum, respectively. The daily intake of the basal veld hay was significantly increased ( P < 0.05) by M. atropurpureum (574 g) but not by S. guianensis (514 g) and D. uncinatum (480 g). Average apparent digestibility coefficients of organic matter were 0.394, 0.440, 0.466 and 0.464 with veld hay alone, veld hay/ D. uncinatum, veld hay/ S. guianensis and veld hay/ M. atropurpureum, respectively. Proportions of metabolisable energy intake relative to that required for maintenance were 0.61, 0.96, 1.11 and 1.20 in animals given veld hay alone and with D. uncinatum, S. guianensis and M. atropurpureum, respectively. Average calculated microbial nitrogen production was 3.46, 5.33, 6.07 and 6.58 g per day, respectively, in animals given veld hay alone and with D. uncinatum, S. guianensis and M. atropurpureum. Respective values for nitrogen retention and live weight gain were −1.44, 0.29, 0.70 and 1.06 g per day, and −98, −32, 0 and −8 g per day. Relative to nitrogen consumed per day, animals given D. uncinatum tended to excrete more nitrogen in their faeces (0.83) than those given S. guianensis and M. atropurpureum (0.71) probably due to a higher content of acid detergent insoluble nitrogen in D. uncinatum (608 g per kg total nitrogen) than in the other legumes (273 to 285 g per kg total nitrogen). Overall, M. atropurpureum appeared to be the best legume supplement for veld hay, followed by S. guianensis.

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

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 < 0.05). Intake of veld hay tended to decline with increasing levels of groundnut hay in the diet. This decline in veld hay intake was however less than anticipated if there had been simple substitution. Supplementation increased the concentration of ammonia and volatile fatty acids in the rumen fluid, but had no significant effect on in sacco degradation of veld hay. Measurements using chromium-mordanted hay and Co-EDTA, showed that rumen digesta volume/pool size were not affected by supplementation, while digesta outflow rate was increased. In the absence of positive associative effects on digestion of the poor quality forage, the increase in digesta outflow rate was probably the mechanism facilitating an increase in feed intake.

The effect of diet and frequency of watering on rumen degradability and outflow rate of low-quality veld hay and dry-matter apparent digestibility in steers given food at maintenance

AbstractThe effect of water restriction on rumen degradability and outflow rate of low quality veld hay and dry-matter apparent digestibility was investigated in four rumen cannulated Tuli × Friesian steers (mean weight 329 (s.d. 36·6) kg) given food at maintenance (metabolizable energy allowance (maintenance) (MJ) = 8·3 + 0·091 M). Two diets with 20: 80 (low, L) and 80:20 (high, H) roughage to concentrate ratios were used in combination with free access to water for 2·5 h once daily or once every 3rd day. A 4 × 4 Latin-square design with a 2 (diets) × 2 (watering frequencies) factorial arrangement of treatments was used.The degradation pattern of veld hay was not affected by the type of diet and the watering frequency. Although the effective degradabilities of hay in steers given the two diets were low (177 and 258 g/kg for L and H, respectively), they were significantly different (P &lt; 0·05) from each other. However, watering frequency did not affect the effective degradability of hay (218 and 217 g/kg). While the low roughage diet had a higher rumen outflow rate for Crmordanted hay than the high roughage diet (0·047 per h and 0·031 per h), this was not statistically significant. The same outflow rate was obtained for the two watering frequencies (0·039 per h).