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Feed and grazing management affect both the quantity and quality of animal manure and consequently nutrient cycling in the mixed crop-livestock systems in West Africa Sahel. Dietary measures can significantly influence the composition of manure and hence it’s agricultural value. High nutrient feed will generally result in higher nutrient content of the manure whereas a decline in feed quality will generally lead to increase in the indigestible fractions in the feeds. Apart from feed and feeding practices, grazing management also affects the amount and nutrient contents of manure that can be recycled to the cropland. When animals are used to deposit manure in the crop field, conflicts often arise between the need for animals to graze long enough for adequate feed intake and the need to collect manure. This paper examines the effects of feed and grazing management on livestock-mediated nutrient transfers in mixed crop-livestock systems in West Africa Sahel. Results from grazing trials in Niger showed that nitrogen voided in faeces follow the trend of nitrogen contents in the feed for grazing cattle. Animals that had additional grazing time in the night consistently had higher forage intake and consequently, higher average daily gain than those that grazed only during the day in all seasons. However, additional grazing at night reduced the amount of manure that could be collected for crop fields unless the grazing location is crop field. It is therefore necessary to optimize the animals’ time for foraging to maintain or increase livestock output in terms of meat and/or milk, and for manuring to sustain soil fertility and hence crop production.

Sesbania sesban is one of the exotic multipurpose fodder trees introduced in the Ethiopian highlands for livestock feed and soil conservation. Several on-station studies showed that supplementation with Sesbania improved intake and digestibility of basal diet and growth rate of animals. However, information about farmers' feeding practices of Sesbania and farmers' perception of the effect of Sesbania feeding on animal performance is limited. The present study was conducted to assess farmers' feeding practices and their perception about effects of Sesbania supplementation on sheep performance in annual (one wheat-based (WheatCL) and one teff-based (TeffCL)) and perennial (coffee-based (CoffeeCL)) crop-based livestock systems in the Ethiopian Highlands. Data were collected from 98 households by interviews using a structured questionnaire. Farmers had on average 6.9 years of experience using Sesbania as a cut and carry supplementary feed. Farmers in the WheatCL and TeffCL fed Sesbania throughout the dry season while farmers in the CoffeeCL had no specific season for feeding Sesbania. Farmers in WheatCL and TeffCL offered significantly (P

The present experiment was conducted to study the effects of supplementation of Sesbania sesban on the milk yield of ewes and growth rate of their lambs. The experiment was done with animals that had been fed for 16 months on a basal diet of teff straw supplemented with concentrates alone (0% S. sesban) or 95% of supplementary protein provided by S. sesban (accession 15019). Thirty lactating ewes and their single lambs of Ethiopian highland Menz sheep were used in this study. The post partum weight of ewes and birth weight of their lambs ranged between 16¿22 kg and 1.3¿2.4 kg. The ewes continued to be fed a teff straw basal diet and supplemented with two levels of S. sesban (0, and 95% of supplementary protein provided by S. sesban and the rest being provided by concentrates) for 3 months. Three weeks after birth lambs were offered a succulent green grass¿legume mixture ad libitum. Dry matter and organic matter intake of basal feed and total feed, live weight at weaning and post partum daily body weight gain of ewes were not significantly different (P > 0.05) between treatments. The milk yield of ewes was significantly affected (P

Most supplementation experiments with fodder trees including S. sesban have been of short duration and focused mainly on feed intake and growth rate. Long-term studies regarding the effects of feeding S. sesban on reproductive performance of sheep particularly in both sexes are scanty. This study was conducted to investigate the effects of S. sesban on feed intake, post-weaning growth rate, and onset of puberty of male and female lambs. Sixty weaned female and 60 male Ethiopian highland sheep in weight and age ranging between 7.2 and 11.8 kg and 4 and 5 months respectively were evaluated for a period of 9 months supplemented with three levels of S. sesban (0, 47.5 and 95% of supplementary protein provided by S. sesban and the rest being provided by a mix of concentrates). Between sex groups male sheep, and among treatments animals fed with 47.5 and 95% Sesbania in the supplement had significantly (P 0.05) among treatments. Mean P4 (progesterone) concentrations during the first behavioural oestrus ranged from non-detectable levels to a peak of 4.32 ng/ml at mid-cycle without significant difference (P > 0.05) among treatments. Therefore, it can be concluded that inclusion of S. sesban as a supplement up to 30% of the ration improved feed intake, growth rate, onset of puberty and sexual development of male and female sheep without adverse effects.

To address the problem of restricted access to grazing by cattle in wet season in the Sahel, a grazing trial was conducted to study the effect of duration of grazing and grazing method on cattle nutrition and performance. Twenty-four intact steers weighing 259 kg (SD=62) were randomly allotted to four treatments to study the effect of the combination of grazing method (tethering and close herding) and grazing duration (6 and 9 h per day) on diet selection, faecal output, forage intake, grazing behaviour and weight changes in the wet season. Three esophageally fistulated steers were used in a cross-over design to sample diet selected by tethered and herded animals. Extrusa samples from esophageally fistulated steers and faecal output from intact steers were collected in weeks 6 and 9 of the experiment and grazing behaviour of the intact steers was observed in week 6. Tethered animals selected diets of lower organic matter digestibility (OMD) but tethering had no significant effect on crude protein. Close herded steers consistently consumed more forage than those tethered in both periods. Both grazing method and duration had significant effect on ingestion rate by the steers. Tethered steers had lower average daily gain than those herded. The results demonstrate that the common practice of tethering sedentary cattle in the wet season in the southern Sahel in West Africa reduces forage intake and consequently average daily gain.

This study compared the effect of supplementing maize stover (MS) with cowpea (Vigna unguiculata) haulms or commercial concentrate (CC) on feed intake, nutrient digestibility, live weight gain and carcass yield of male Ethiopian Highland sheep. Two cowpea genotypes, 12688 (forage) and IT96D-774 (dual-purpose), were used. A randomised block design was applied with groups of eight sheep, blocked by weight, allocated to one of six treatments; MS ad libitum either unsupplemented or supplemented daily with 150 or 300 g dry matter (DM) of either cowpea or CC. MS contained more neutral detergent fibre (NDF), acid detergent fibre (ADF) and lignin than either cowpeas or CC. Crude protein (CP) content of the forage-type cowpeas was higher than either dual-purpose or CC, while MS had the lowest CP content. Relative to the negative control group, cowpea at either level significantly (P < 0.01) increased both MS intake and total NDF and lignin. Supplementation significantly (P < 0.01) increased nitrogen (N) intakes relative to the negative control, with N intake for CC and dual-purpose cowpea (high level) being similar to the intakes for cowpeas at 150 g. N intake with the forage-type cowpea offered at higher levels was significantly (P < 0.01) greater than the other groups. No significant differences (P > 0.01) in MS intake were identified between cowpeas at either level or CC and, although intake level of CC increased, it did not differ significantly from the negative control group. Supplementation significantly (P < 0.01) improved average daily gain, with the negative control group losing weight over the experimental period, and increased final live weight, carcass cold weight and dressing percentage. Supplementation significantly improved the apparent digestibility of DM, organic matter and NDF, with no significant difference found between cowpeas at either level. N retention was negative for sheep offered only MS, but positive with all supplements, with cowpeas improving N retention to a greater extent than CC. Interestingly, N retention/N intake was higher with cowpeas offered at the lower level suggesting an improvement in utilisation efficiency. The results indicate that the supplementation of MS with cowpea enhanced ruminant production through improvements in digestibility and intake. Further, as production improvements associated with the two levels of supplementation did not differ significantly, it is suggested that where limited quantities of cowpea are available, it may be of greater nutritional benefit to offer smaller quantities over an increased number of animal days.

Green and dry pasture vegetation and millet crop residues are the main feed for domesticated ruminants across the West African Sahelian zone. Studying their gastrointestinal passage is important for modelling livestock-mediated nutrient flows in these agro-pastoral systems. Intake, passage, digestion and excretion were studied in 16 cattle, 16 sheep and 16 goats offered these feeds at levels corresponding to 0.8 and 1.3 times voluntary feed intake. Parameters of particle passage were derived from faecal excretion of a pulse-dose of short (1–2 mm) and long (>2 mm) particles labelled with Ytterbium, using age-dependent Gamma-2 single-compartment models. Across the three species, mean retention time of particles in the mixing compartment (CMRT) varied between 39–50 and 54–66 h in green and dry pasture vegetation and between 66 and 88 h in millet leaves, and was always longer in cattle than in small ruminants (P λ ), particle half life ( T 50 ) and total tract mean retention time (TMRT) were correlated to the dry matter digestibility and to the contents of nitrogen and neutral detergent fibre of the ingested diet, while particle size had no and feed intake only a weak influence on these parameters. The results suggest that seasonal and species-specific differences in gastrointestinal passage of feed particles should be taken into account when addressing the temporal aspects of livestock-mediated matter and nutrient flows across the agro-pastoral landscapes of the Sahel.

This study tested the hypothesis that purebred Boran (Bos indicus) cows and crossbreds of Boran and Holstein respond differently to long-term changes of feeding level in nutrient partitioning to milk and body fat stores. A total of 27 cows of these two genotypes were subjected either to a low or a high feeding level from their first oestrus as heifers until birth of their third calf. Half of the cows of each genotype were then switched to the other feeding level during the third reproduction cycle. If at all, Boran cows responded to a change in the feeding level almost exclusively by a corresponding change in body weight but not milk yield. Crossbred cows kept continuously on the low feeding level had a lower milk yield than those continuously fed the high level, but lost similar amounts of body weight. In crossbred cows, changing the feeding level from high to low was accompanied by a mobilization of body reserves, whereas a change from low to high level resulted mostly in an increase in milk yield. Certain other genotype differences in metabolic response were obvious from differences in body composition and from the metabolic profile either reflected in blood (particularly insulin-like growth factor I) or in adipose tissue (lipoprotein lipase). Reproductive performance differed between genotypes, with shorter lactations associated with earlier occurrences of the first oestrus in the Boran cows. Generally, feeding history appeared to have at least as much influence on energy partitioning as the actual feeding level. In conclusion, purebred Boran cows seem to react to long-term food fluctuations mainly by mobilizing and restoring body fat reserves, whereas cows crossbred with Holstein tend to spend extra energy preferentially for milk production.

Forty-eight heifers of two genotypes, Boran ( Bos indicus ) and Holstein×Boran, were allocated to three feeding levels equivalent to 1.0, 1.2 and 1.4 times calculated metabolisable energy requirements for maintenance (ME m ). The experiment started at the onset of reproductive activity, when the Boran and crossbred heifers were 4.4 and 2.2 years old, respectively. The response to feeding level was investigated in three physiological states: (i) puberty and growth (87 days), (ii) work and growth (94 days, 51 days thereof with work), and (iii) pregnancy and recovery from work (115 days). Neither genotype nor feeding level had effects on nutrient digestibility, digesta passage rate and reproductive performance. Daily gains and feed conversion efficiency were higher in well-fed heifers ( P P m was 0.54 MJ/kg metabolic weight ( W 0.75 ) in both genotypes during puberty and growth. Imposing work required additional 0.20 and 0.10 MJ ME/kg W 0.75 in Boran and crossbreds, respectively. Recovery from work, associated with early pregnancy, apparently reduced ME m to 0.30 MJ/kg W 0.75 . This could be explained as a result of compensatory growth. The efficiency of utilisation of metabolisable energy for growth (0.28) did not differ ( P >0.1) between genotypes and physiological states.

Indigenous cows adapted to harsh environments are producing only limited amounts of milk and do not respond to additional feed supply with increases in milk production. Leptin, a regulator of body fat stores, may be differently expressed in indigenous Boran compared to crossbred cows, and hence be responsible for different nutrient partitioning. Body condition score (BCS) and body fat was estimated in 20 Boran and 21 crossbred cows and leptin expression was quantifi ed in fat cells. Results revealed a signifi cant relationship of leptin expression and BCS as well as body fat. However, relationships of the measured variables were only slightly (P

In an experiment lasting from 1.5 years before first calving until third parturition, 24 purebred indigenous Bos indicus (Boran) cows and 24 Boran crosses with Holstein (proportionately 0.50 and 0.75 Holstein blood level) were given a diet composed of Bermuda grass hay and wheat bran (0.65: 0.35) offered at low, medium and high level. This level was adapted in amount to actual body weight every 2nd week corresponding to assumed 1.0, 1.2 and 1.4 times maintenance energy requirements. Cows were subjected to working exercise before and after first parturition. Body weight differences (lower with low and medium feeding level) developed mostly before calving for the first time and showed the typical decline at the start of lactation and increase in the dry period. Additionally, Boran cows given the high level increased their body weight from the first to the second lactation cycle. Body condition scores were higher in the Boran cows and, in both genotypes, with high feeding level. Independent of feeding level and genotype, calving intervals in cycles 1 and 2 were 530 and 421 days, respectively. Lactation length was considerably shorter in the Boran cows than in the crossbred cows. Milk yield, calculated over the first 13 weeks of lactation and over the whole lactation in both cycles, was 2.06 and 3.06 times higher in the crossbreds than in the Boran. Milk of Boran cows had 1.30, 1.15 and 1.20 times higher contents of fat, total solids and protein. In the first 13 weeks of lactation, milk yield of crossbreds with high feeding level (8.7 kg/day) was higher (P < 0.05) than that of the crossbreds with medium (6.5 kg/day) and low feeding level (5.4 kg/day), respectively. Boran cows never showed a significant response in milk yield to feeding level. Accordingly, the amount of organic matter intake required per kg milk increased with feeding level in the Boran cows while it remained unaffected in the crossbreds. Organic matter digestibility, as measured in lactation cycle 1, was higher (P < 0.01) in Boran. Response to high feeding level and estimated maintenance requirements of crossbred cows corresponded with current assumptions, but crossbreds subjected to medium feeding level expressed unexpectedly little difference from those receiving the low level. It seems that current recommendations are not generally applicable to indigenous tropical breeds as these responded differently from crossbreds to feeding level.

Cowpea (Vigna unguiculata (L.) Walp.) is an important food legume and an integral part of traditional cropping systems in the semi-arid regions of the tropics. The estimated worldwide area under cowpea is about 14 million ha of which West Africa alone accounts for about 9.3 million ha with annual production of about 2.9 Mt. Cowpea grains are consumed as food and the haulms are fed to livestock as a nutritious fodder. Farmers often grow a short-duration spreading variety for grain and a long-duration spreading variety for fodder, but the grain and fodder yields are poor due to low yield potential of the spreading varieties and also due to early cessation of rains. Therefore, IITA in collaboration with ILRI has initiated a systematic programme to develop medium-maturing, semi-erect, dual-purpose varieties with higher grain and fodder yields and with enhanced fodder quality. By crossing the late, traditional spreading varieties with improved early, semi-erect varieties, a semi-erect group of medium-maturing, dual-purpose varieties has been developed which yield over 1.5 t ha−1 grain and 2.5 t ha−1 haulms. Despite the high grain and fodder yields, the haulms of improved dual-purpose varieties have similar crude protein content (17–18%) and dry matter digestibility (64–71%) compared to the local varieties. Controlled sheep feeding experiments have shown an average live weight gain of about 80 g per animal per day with 200–400 g per day of cowpea haulms as a supplement to a basal diet of sorghum stover. This was 100% higher than the average live weight gain of animals fed sorghum fodder alone. These results indicate that improved dual-purpose varieties can play an important role in enhancing crop–livestock integration in West Africa.

This paper synthesizes the key findings presented in the previous 15 papers, and presents a summary of a discussion on best approaches, strategies and partnerships to improve the utilization of food–feed crops. The synthesis provides guidance for future research and development in crop–livestock systems in developing countries. It also stresses the need for greater integration, focus, coordination of efforts to improve the utilization of food–feed crops, if the benefits from advances in research and output delivery are to reach the hundreds of millions of resource-poor livestock keepers in developing countries.

The influence of 0, 60 or 120 min access to a grove of either Ziziphus mauritiana (Ziziphus) or Combretum aculeatum (Combretum) on forage intake and on the digestibility, growth and excretion of nutrients was determined using 40 Oudah rams grazing for 7 h/day on poor-quality dry season pasture in the Sahel. The effects of browse species and browsing duration (0, 30, 60 or 120 min) on the ruminal ammonia content were also evaluated using 8 mature fistulated rams. Ziziphus increased both total digestible organic matter and total dry matter intakes per (kg live weight)0.75 without decreasing herbage intake, whereas 60 or 120 min access to Combretum reduced herbage intake by 6.3% and 4.2%, respectively. The digestibility of the diet decreased (p < 0.05) with the duration of access to the groves. Despite the provision of more nitrogen (N) than in the control diet, ruminal NH3-N decreased 24 h after browsing commenced. The reduced live weight gain of sheep browsing Combretum may indicate more deleterious compounds in Combretum than in Ziziphus. Ziziphus appears to have more potential than Combretum to increase sheep production in low-input crop/livestock systems.

An experiment was conducted in 1996 and 1997 in semi-arid Niger, to determine the influence of supplementation (no supplement, supplemented with millet bran + simple superphosphate + blood meal) of cattle and mulching (0 or 3 t ha−1 of Aristida sieberiana straw) on soil fertility and millet yield. Manure was applied through corralling at a rate of 3 t faecal dry matter (FDM) ha−1 alone or associated to mulching. The residual effects of the treatments were measured on a second millet crop in 1997. Compared to control, the association of mulching and corralling of supplemented as well as non supplemented cattle increased soil pH (KCl) (P < 0.01), Bray1-P (P < 0.05) and NH4-N (P < 0.05); grain by 136% (P < 0.01) stover yeild by moer than 150% (P < 0.05); and N and P uptake (P < 0.01) during the two cropping seasons. The association of mulching and corralling increased soil NH4-N (P < 0.01) and soil pH (P < 0.01), compared to the sole corralling. The improvement of soil chemical properties resulted in grain yield increases of 54% (P < 0.01) and stover increases of 42% (P < 0.01). The effect of mulching and corralling association on grain and stover yeilds was higher when cattle were supplemented (67 and 50%) than when they were not supplemented (30 and 26%). The effects of the supplementation on grain and stover yields, and N and P uptake by millet, were restricted, when animals were corralled on bare soil (no mulching). The residual effects of supplementation were minimal.

A greenhouse trial was carried out at the International Crop Research Institute for the Semi-Arid Tropics (ICRISAT), at Sadore (13°15′ N, 2°18′ E), Niger. Experiments were conducted in conjunction with a feeding trial. The feeding trial yielded eight types of compost made from faeces and leftovers with or without urine addition from sheep fed either bush straw or millet stover offered at 60 or 80 g dry matter (DM) kg−1 live weight (LW). In the second trial the agronomic value of composts to a millet crop was evaluated. The level of roughage on offer did not affect compost quality. Urine addition increased N content in composts (P

Sixty-four Azawak male weaned calves were allotted to eight treatments (T) in two trials to study the effect of timing (day or day-and-night) and duration of grazing on diet selection, faecal output, eating time, forage intake and weight changes. Grazing time during the day was 6 h for T 1, 2 and 3; 9 h for T 4, 5 and 6; and 12 h for T 7 and 8. Night grazing time was 0 h for T 1, 4 and 7; 3 h for T 2, 5 and 8; and 6 h for T 3 and 6. The trials were conducted from July 1995 to May 1996 covering the wet (WS), early dry (EDS) and late dry (LDS) seasons. Eight oesophageally fistulated steers were used in a cross-over design to sample the diet selected by day-grazers (D1) and by day-and-night-grazers during the day (D2) and at night (N2). Forage intake was determined from individual data on faecal output from all the calves and means of in vitro organic matter digestibility of extrusa of the fistulated steers. Water intake and eating time were measured in LDS. In WS there were no differences (P> 0·05) in the quality of the diet (extrusa) selected for D1, D2 and N2. In LDS, crude protein content for D1 was lower than for D2 (73 v . 79 (s.e. 2) g/kg dry matter,P< 0·05). In all seasons, faecal output and forage intake increased with total duration of grazing. Total time spent eating increased linearly with increasing total time allowed for grazing. These results suggest that allowing additional grazing time during the night leads to increased forage intake and consequently provides an opportunity for better animal production, especially in the dry season.

Sixty-four Azawak male calves were used to study the effect of nocturnal grazing (NG) and supplementation (S) in the dry season on forage and water intake, faecal output, eating time and weight changes of cattle in the Sahel. Treatments were factorial combinations of four levels of NG (0, 2, 4 and 6 h/day) and two levels of S (0 and 608 g dry matter (DM) per animal per day). All animals were allowed to graze 10 h during the day and were weighed every 2 weeks during the 70-day experimental period. Eight oesophageally fistulated steers were used in a cross-over design to sample the diet (forage) selected during the day and at night by supplemented and non-supplemented animals. Extrusa crude protein and in vitro organic matter digestibility were not influenced by supplementation (P > 0·05). Time spent eating during the day or at night were not affected by supplementation but total eating time increased by 39·4 (s.e. 2·1) min/h of NG. Forage intake increased with increase in NG, while total food intake (forage + supplement) increased with supplementation (82·4 v. 92·1 (s.e. 2·4) g DM per kg M0·75 per day). The supplemented animals also drank more water than the non-supplemented (26·2 v. 24·8 l per animal per day). Average live-weight change (LWC) increased by 24·4 (s.e. 8·7) and 9·3 (s.e. 6·2) g/h of NG in non-supplemented and supplemented animals, respectively. Supplementation improved LWC (–107 v. 99 g/day, s.e. 14, P < 0·05). Night grazing improves dry season performance and its effect decreases when cattle are supplemented.

A survey was conducted from February to June of 1997 among livestock herders in two villages of Niger, Kodey and Toukounous, on their perceptions, practice, and problems of night grazing. Cattle and sheep were the species that were taken out for night grazing by the herders. Small herd size and labor constraints were mentioned as the principal reasons for not practicing night grazing. Major benefits of night grazing included good body condition, herd growth, increased milk production, prevention of diseases, and reduction in herd mortality. Insecurity, difficulty in staying awake at night, labor constraints, and damage to crops by animals were given as problems of night grazing. According to the herders, grazing time (duration) during the day and night was shorter in the wet season than in the dry season. In the wet season animals were herded (followed and closely supervised by herders), whereas in the dry season, animals were mostly left to range freely in both villages. In general, children herded the animals during the day, while adults were responsible for night-time herding. Herders' perceptions on night grazing as regards animal production parameters such as weight development, water consumption, fecal output and feeding behavior are consistent with available experimental results. Therefore, future technical research needs to recognize the constraints faced by herders and determine how to overcome them to improve technical and economic efficiency.

The selective use by cattle of range resources in the Sahel was assessed in terms of quantity and nutritional quality of the herbage grazed and diet selected. Peak standing crop was 1951 kg ha-1 dry matter (DM) with 47.9 kg nitrogen (N) ha-1 and 7.4 kg phosphorus (P) ha-1. Esophageally fistulated cattle diets were consistently (p < 0.05) higher in N, P and organic matter digestibility (OMD) than the herbage grazed. Cattle consumed 48% of the mean annual herbage production. The results indicate grazing ruminants select a higher quality diet from Sahelian rangelands than can be predicted on the basis of pasture evaluation alone. Therefore, the foraging behaviour of the animals needs to be considered in the evaluation of Sahelian rangelands for animal production.

Eighteen oxen were allotted to three treatment groups according to their body condition: poor, medium and good. Work output, speed, live weight and body condition were measured during 7 weeks when animals worked 4 days/ week, 4 h/day, pulling loads equivalent to 12-5 kgf/100 kg live weight. The animals were given millet stover ad libitum during hours they did not work plus 10 g/kg M of a concentrate mix. Work did not influence intake of millet stover. However, food intake improved as work progressed and animals in bad condition ate more millet stover than animals in good body condition. Work performance was affected by live weight but not body condition. Live-weight losses did not have a detrimental effect on work performance. Power output improved during the course of the experiment while animals were losing weight Animals in all treatment groups lost body weight during the 7 weeks of work but weight losses were more pronounced in oxen in good than in poor body condition. At the end of the working period, animals were put on natural pastures without supplementation. It took 4 weeks for animals in poor and medium body condition and 6 weeks for animals in good body condition to reach their pre-work live weight.

Two experiments were conducted to investigate the relationships between work and intake and digestion of food by draught oxen given millet stover. In the first experiment, intake of millet stover, water intake, live weight, plasma concentrations of triiodothyronine, thyroxine and urea-nitrogen were measured in 18 animals that worked 0, 2 or 4 h/day in sequence during three 3-week experimental periods. Digestibility and rate of passage of food residues through the digestive tract were measured in a second experiment on 12 animals working either 0, 2-5 or 5 h/day in sequence during three 2-week experimental periods. Feeding behaviour was monitored on six animals working either 0, 2-5 or 5 h/day. Work did not affect intake of millet stover, apparent digestibilities and the rate of passage of digesta through the gastro-intestinal tract. This suggests that the nutrient supply from intake of roughages by ivorking oxen is unlikely to be sufficient to compensate for the extra energy expended during work. Food intake was affected by the quality of the millet stover offered. The level of intake of millet stover ivas proportional to the amount of leaves in the stover. Food intake increased also as work progressed. However, animals mobilized their body reserves to perform work. Animals consumed more water on working days than on days they were at-rest in shade. The heat stress that working animals were subjected to did not appear to interfere with their digestive function.

Metadata only record In the Sahel of West Africa, the productivities of rangelands, croplands and livestock are inextricably linked. Cattle, sheep and goats graze rangelands and crop residues, and their manure/urine is used to fertilize crops. Rangelands provide important feeds during the manuring period, resulting in a net nutrient transfer from rangelands to croplands. This paper examines the sustainability of nutrient transfers in integrated rangeland/cropland systems of the Sahel by examining the impact of grazing on rangeland vegetation structure and floristic composition, the impact of livestock on nutrient balances of rangelands and croplands, and the role of livestock in offsetting nutrient deficits through manuring. Rangeland nutrient balances are in equilibrium (inputs = offtakes) whereas croplands lack the internal capacity to replenish nutrient offtakes in grain (as food) and crop residues (as feed). Although soil nutrient mining is of general concern for the Sahel, local management practices of some farmers (e.g. corralling animals overnight on fields between cropping seasons, use of fertilizers) offset cropland nutrient deficits. The number of additional livestock, and their feed requirements needed to supply sufficient manure to offset cropland nutrient deficits, depend on rangeland and cropland productivity, livestock production goals, and management strategies of farmers. Livestock must be managed so they do not deplete the nutrient supply of rangelands in order to increase the manure supply for improving cropland productivity. Sustained rangeland productivity in the Sahel will depend largely on producing alternative feeds derived mostly from croplands. Land use and tenure policies that inhibit livestock mobility and, therefore, farmers' access to the manure of pastoralists herds, will greatly undermine the resilience of Sahelian rangelands, and increase the need for other external nutrient inputs such as fertilizers to prevent declines in soil fertility and crop yields. (CAB Abstract)

A solid sampling strategy for plant material is the first step in screening forages for nutritional analysis and extra-nutritional attributes to determine if potential forage species, with good adaptation and biomass production are suitable for use as livestock feeds. Since the morphological phenotype is rarely a good indicator of nutritional traits, nutritional analysis is essential when selecting plants as feeds. It is not possible to select forages based solely on biomass production without taking into account the nutritional and anti-nutritional attributes. Some species with leafy and high productivity may contain plant secondary metabolites that may be toxic and make them unsuitable for use as feeds. A good example of this is Leucaena, which is fast growing and yields up to 15 tons/ha of forage dry matter per year, but because of the mimosine in the leaves could initially only be fed in quantities up to 30% of the diet without causing toxicity symptoms. This was not apparent from looking at the plant and emphasizes the need to do a thorough nutritional evaluation before introducing new species as livestock feeds. However, identification of mimosine degrading rumen microbes now allows livestock to consume larger quantities [5] and makes this both a productive and nutritionally useful forage plant in many tropical livestock systems.

Two successive experiments were conducted to investigate the long-term effects of supplementation of Sesbania sesban on reproductive performance of Ethiopian Menz sheep. Forty ewes and 40 rams ranging in weight and age between 16¿20 kg and 14¿15 months respectively were fed a teff straw basal diet and supplemented with two levels of Sesbania (0, and 95% of supplementary protein provided by Sesbania and the rest being provided by concentrates) for 7 months. In experiment 1 (mating period), 4 paired female¿male groups (diet of the male with or without Sesbania, and diet of the female with or without Sesbania) consisting of 20 animals each were formed and assigned for mating. Ewes that were mated and did not return to heat in subsequent cycles during the 70 days mating period continued in experiment 2 receiving similar supplementary diets (concentrate alone or Sesbania) for the study of pregnancy and lambing. During the mating period, males and animals supplemented with Sesbania were superior (P 0.05) between treatments. Supplementation with Sesbania promoted an increase in testicular size by 13%. Except semen concentration, the other seminal characteristics were not significant (P

Many organizations in Ethiopia have for many years promoted exotic multipurpose fodder trees (EMPFT) for livestock feed and soil improvement. Despite the apparent benefits, the number of farmers planting these trees was low. The objectives were to elucidate farmers’ perceptions about their use value, management practices and constraints to adoption in three districts representing annual (one wheat-based and one teff-based) and perennial (coffee-based) crop-livestock systems in the Ethiopian highlands. Data were collected from 235 farm households. Most farmers (95.3%) had awareness of EMPFTs and the principal information sources were development agents (75.3%). Over half of the farmers were motivated to plant EMPFTs for feed value. Motivation for other purposes depended on cropping system, vegetation cover and availability of alternative local fodder trees in the area. Farmers had positive perceptions about EMPFTs for their feed value and contribution to soil conservation. Current adopters had a mean number of 587 (SE ± 84) EMPFTs per farm. Major constraints to adoption of EMPFTs were agronomic problems, low multipurpose value, and land shortage. Majority of farmers (89.8%) were interested to either continue or begin fodder tree development. Of the interested respondents, 44.5% preferred local fodder trees whereas 55.5% preferred EMPFTs. We conclude that farmers are aware of use values of EMPFTs while perceived constraints suggest that introduction of EMPFTs need consideration of farmers multiple criteria, but also awareness of feeding fodder trees and resource availability. Moreover, current development approaches have to recognize the importance of involving the end-users at all stages through participatory approaches to enhance adoption.

In the tropics, numerous organizations have promoted multipurpose fodder trees (MPFT) with an emphasis on exotic species. These species have generally been selected and recommended by the research system through the conventional nutritional and agronomic experimentation for use as animal feed and soil conservation. In Ethiopia, the introduction of exotic MPFT started in the 1970s. However, despite its apparent benefits, the adoption of exotic MPFT by smallholder farmers has been slow and in some cases farmers ceased using exotic MPFT in their farming systems. The objectives of the present study were to assess farmers’ preference criteria, compare their preference between exotic and local MPFT, and evaluate the relationship of farmers’ knowledge of feed value assessment with laboratory indicators. Focus group discussions and preference ranking and scoring by a total of 40 farmers were conducted in two districts representing two production systems (cereal and coffee-based livestock production systems) in the Ethiopian highlands. The comparison between exotic and local MPFT for their benefits and desired tree characteristics showed that farmers preferred local MPFT to exotics for biomass production, multi-functionality, life span, and compatibility to the cropping system. In terms of feed value, ease of propagation, and growth potential local MPFT were ranked lower than or comparable to exotics. There was also a strong correlation between farmers’ feed value score and laboratory results. Farmers were able to discriminate effectively MPFT species that had high and low protein and fibre content using their indigenous feed value indicator system for all pairwise comparisons. We concluded from this study that farmers’ preference criteria encompass multiple objectives beyond feed value and soil rehabilitation. The different merits that farmers associate with exotic and local MPFT could provide the opportunity to use both MPFT types and to improve farm bio-diversity. Hence, incorporating locally available MPFT, farmers’ indigenous knowledge and preference criteria at the research inception process is vital to maximize the likelihood of farmers’ adopting and maintaining these technologies.

Groundnut haulms along with cowpea hay are major crop residues used for animal fattening in the West African Sahel. In traditional sheep fattening, feeds are always provided ad-hoc and in an unregulated fashion, which is rather wasteful. As a preliminary study to establish the optimal feeding levels of groundnut haulms for profitable sheep fattening, a feeding trial was conducted for 70 days with four levels of groundnut haulms (0, 150, 300 and 450 g/day) and a basal diet of bush hay. The effects of supplementation with groundnut haulms on feed intake, water consumption, live weight changes and economic return were determined. Twenty-four Peuhl Oudah rams with average initial weight of 28.6 kg (SD = 1.4) were randomly allocated to four treatments defined by the four levels of groundnut haulms in the diet. Faeces and urine were collected in weeks 5 and 9 of the trial. Digestible organic matter intake (g/(kg LW)0.75) and nitrogen intake (g/day) increased linearly with the level of groundnut haulms offered. Sheep that were fed only bush hay lost 18.4 g/day, while those that were offered 150, 300 and 450 g of groundnut haulms gained 1.4, 19.3 and 40.2 g/day, respectively. The gross return ranged from 1883 to 4946 FCFA per ram. Net benefit, after removing the feed and veterinary costs from the gross return, ranged from 368 to 1400 FCFA per ram.

Ruminant livestock populations in developing countries are increasing in response to increasing demand for meat and milk. These animals are a major global source of methane, a greenhouse gas produced during the degradation of organic matter by micro-organisms in the foregut of ruminant livestock. Chemical inhibition of methanogenic micro-organisms has been reported; however, associated improvements in feed digestion and livestock productivity have not been consistently demonstrated. Gene-based technologies have the potential to contribute new knowledge of the rumen microbial populations involved in these processes, which will assist in identifying feeding practices that lead to methane abatement and improved livestock productivity. For small-scale farmers, feeding interventions that achieve greenhouse gas abatement need also to be associated with improved feed conversion efficiency and enterprise profitability. During the adoption of methane abatement technologies, other regionally important issues such as poverty, food security, sustainable agriculture production systems and environmental management must also be addressed.

The effects of grazing by livestock on soil surface features, bulk density and chemical properties were studied at the completion of a 4-year grazing experiment carried out in Sadoré, Niger. Grazing treatments were a factorial arrangement of two stocking rates (62.5 and 125 kg live weight/ha) and four sheep:goat ratios (0:6, 2:4, 4:2 and 6:0 animals per pasture), with two pastures per treatment and two ungrazed controls. Observations were also made in a fallow subjected to 9 years of intense and uncontrolled mixing grazing, and in a site that had been protected from grazing for 15 years. The topsoil was sampled (at depths of 0-2, 2-6, 6-14 and 14-30 cm) below shrub canopy in herbaceous vegetation and in bare soil patches within each of 20 paddocks for determination of pH, organic C, and total N and P concentrations. Soil bulk density was measured in a subset of soil profiles. The areal extent of different types of soil crusts and other soil surface features was assessed in one-half of the paddocks. Grazing resulted in a reduction (p is less than 0.01) and fragmentation of the area of crusted soils. However, this trend was partially compensated for by an increase of newly formed crusts. As a result, the soil infiltration index slightly increased with moderate grazing, but decreased at higher stocking rates. Compaction due to trampling was observed in the topsoil beneath the shrub canopy and also in vegetated patches, but only under intense grazing pressure. Soil bulk density was not affected by grazing except for an increase observed below 10 cm depth at the understorey of shrubs which is therefore unlikely due to trampling. When compared to the ungrazed control, pH, organic C and N concentrations, and to lesser extent P concentration, decreased after 4 years of grazing. Soil P and pH further decreased after 9 years of very high grazing pressure. However, neither H nor organic C decreased further. (Résumé d'auteur)

To develop strategies for improved food production without concomitant degradation of the basic natural resources, especially soils, is a challenge for all countries, but in particular for those experiencing spurts in population. For many observers and members of the Technical Advisory Committee (TAC) of the Consultative Group on International Agricultural Research (CGIAR), such strategies should have an eco-regional spread, and in order to sustain productions a balance should be maintained between research on crop improvement and management of natural resources.

L’embouche ovine est économiquement importante dans les systèmes agriculture - élevage dans le Sahel ouest africain. Elle est particulièrement attrayante pour les paysans pauvres y compris les femmes en raison du faible investissement requis et de la rapidité de cycle. Un essai d’alimentation a été mené pendant 56 jours pour déterminer les niveaux optimums des fanes d’arachide et de son de mil pour un engraissement profitable des moutons. Quarante-huit béliers Peuls Oudah, achetés dans un marché de bétail, d’environ 12-15 mois d’âge et d’un poids initial moyen de 20,3 kg (écart-type = 1,7) ont été alloués aléatoirement, par groupes de six, à huit traitements définis par une combinaison factorielle de quatre niveaux de fanes d’arachide (0, 300, 600 et 900 g par animal par jour) et deux niveaux de son de mil (0 et 400 g par animal par jour). La paille de brousse a été offerte à volonté comme alimentation de base à 40 g/kg de poids vif. L’ingestion totale de matière sèche et l’ingestion de matière organique digestible ont été linéairement associées au niveau des fanes d’arachide et de son de mil offert. Les gains moyens quotidiens (gmq) de poids pour les moutons qui ont reçu 0, 300, 600 et 900 g/jour de fanes d’arachide sans son de mil ont été respectivement de -27,5, 10,4, 30,8 et 35,7 g/jour. Avec 400 g/jour de son de mil, les gmq ont été respectivement de 40,3, 59,5, 91,7 et 63,4 g/ jour pour les quatre niveaux de fanes d’arachides. La complémentation avec 600 g/jour de fanes d’arachide et de 400 g/ jour de son de mil a donné le bénéfice net le plus élevé.

The influence of night grazing on feeding behavior, nutrition and performance of cattle was studied. Twenty-four steers weighing 367 kg (SD = 76) grazed either from 0900 to 1900 (day grazers), 2100 to 0700 (night grazers) or 0900 to 1900 and 2400 to 0400 (day-and-night grazers) during 13 weeks. Four esophageally fistulated steers were used in a cross-over design to sample the diet selected during the day and at night. No differences (P > 0.05) were observed in the diet selected in the day or at night. As the season progressed the fiber components of the diet increased (P < 0.01) significantly while nitrogen and in sacco dry matter disappearance declined (P < 0.01). Actual grazing time (min day(-1), SE = 16) were 352, 376, and 476 for day, night, and day-and-night grazers, respectively. Day-and-night grazers had a higher intake of organic matter than either day or night grazers. Night grazers had the lowest forage intake and also the slowest rate of consumption. Steers that grazed in the night had the lowest water intake: 22.7 liter day(-1) (SE = 1.5) in week 4; 19.9 liter day(-1) (SE = 1.1) in week 8. Average weight changes (g day(-1), SE = 62) were -435, -548 and -239 for day, night, and day-and-night grazers, respectively. These results show that during the dry season, grazing exclusively in the night cannot substitute for day time grazing, but that it is rather complementary to the latter. Timing (day or night) of grazing did not affect diet selection but nocturnal grazing decreased the need for water. DOI:10.2458/azu_jrm_v55i2_ayantunde

Three grazing trials were conducted to evaluate yield, relative plant part composition, quality and utilization (disappearance) of corn crop residues by growing cattle in both dryland and irrigated cornstalk fields. More (P less than .05) total residue was available from irrigated than from dryland cornstalks, but dryland cornstalks had a higher (P less than .05) proportion of leaf plus husk. In Trial 1, 18% of the residue disappeared in 53 d in irrigated fields grazed at 2.47 calves/ha, whereas 32 and 47% disappeared in dryland fields grazed at 1.54 and 2.47 calves/ha, respectively. Leaf plus husk accounted for 69% (Trial 1) and 65 to 72% (Trial 2) of the utilized residue. Utilization rate increased (P less than .05) with stocking rate. All plant parts and leaf plus husk from dryland cornstalks had more CP (P less than .05) and less NDF (P less than .05) than did these plant parts from irrigated fields. In vitro DM disappearance (IVDMD) was decreased (P less than .05) by grazing; this decrease was greater (P less than .05) at higher stocking rates. Husk IVDMD, CP and NDF from 13 corn hybrids differed (P less than .05).

Diet composition and the relationships between daily gain of calves grazing cornstalks and certain characteristics of the available residue and diets selected by esophageally fistulated cattle were studied in two trials during November and December of 1984 (Trial 1) and of 1986 (Trial 2). Eight adult steers and four esophageally fistulated calves were used in Trials 1 and 2, respectively, to collect extrusa samples from dryland and irrigated fields grazed at several stocking rates. Steers grazing irrigated cornstalks selected a diet with more (P less than .05) starch and less (P less than .05) CP than those grazing dryland fields. As grazing continued, extrusa starch content decreased (P less than .05). In vitro DM disappearance (IVDMD) of both diet and the roughage fraction of the diet decreased (P less than .05) with days of grazing; this decrease was greater (P less than .05) at higher stocking rates. Calves grazing dryland fields gained faster (P less than .05) than calves grazing irrigated fields. With a low level of protein supplementation (213 g CP/d, Trial 1), daily gain was positively correlated with CP of both diet (extrusa) or available leaf plus husk but not with grain available per animal or with extrusa IVDMD, suggesting that protein was first limiting. With a higher level of protein supplementation (458 g CP/d, Trial 2), daily gain was correlated positively with residue available per animal and IVDMD of extrusa at the end of the grazing season. The energy value of feed consumed by cattle grazing cornstalks decreases with time, and complex interactions between protein needs and energy intake may occur.

A simulation model was developed to predict corn crop residue yield and quality and intake and performance of growing cattle grazing cornstalks. The model is wholly deterministic and integrates the effects of weather, residue supply and animal components. Low temperatures increase animal energy requirements, whereas snow cover decreases residue available. Residual grain and leaf are calculated from grain yield. Residue quantity and quality are reduced daily by environmental losses and animal consumption. Daily performance is predicted based on the nutrients obtained from residue and supplemental feed. Under unlimited roughage supply, leaf, husk and grain are primary diet components. Grain consumption decreases as the supply diminishes and forage quality decreases with time. Intake is calculated based on digestibility and fecal output = .0365 W.75. Forage availability affects intake in a curvilinear fashion. Energy gain is predicted by NRC equations and protein gain from metabolizable protein supply. The model underestimated intake of calves measured with chromic oxide and in vitro DM disappearance. Simulated daily gain (y, kg) of calves grazing at several stocking rates was related to observed daily gain (x, kg) by the equation y = .012 + .853 x (R2 = .71, Sy.x = .077). The model overestimated response to protein supplementation. Severe cold weather was predicted to reduce gains or cause weight loss due to increased energy requirements for maintenance. The model can be used as an aid in both research planning and cattle management.

Two trials were conducted to study the protein requirements of growing cattle grazing cornstalks. Diet composition and forage intake were determined at different periods during the grazing season. Residue intake and dietary CP content decreased (P less than .05) .079 kg and .044 percentage units per day of grazing, respectively. In vitro DM disappearance of the roughage fraction of the diet remained high early in the grazing period when husk availability was high, then declined in a curvilinear pattern. Calves required time to learn to find and consume the residual grain. During 54 d of grazing in Trial 1, calves supplemented with 409 g CP gained .105 kg/d more than those supplemented with 213 g CP. Maximal daily gain (.308 kg) in Trial 2 was obtained with 163 g/d of ruminal escape protein. Growing cattle grazing cornstalks responded to protein supplementation at levels above current National Research Council recommendations for 250-kg calves gaining .3 kg/d.