Dairy goat grazing systems in Mediterranean regions: A comparative analysis in Spain, France and Italy

In order to maintain small ruminant grazing systems it is necessary to know precisely how they work and what actions can be taken to improve them. The objective of this paper was to characterize, classify, analyse and propose improvements for the dairy goat grazing systems in three countries from the western Mediterranean area: Spain, France and Italy. A multivariate analysis was conducted with 21 indicators obtained from the data collected from 45 farms. As a result of the multivariate analysis, 82.5% of variance was explained by two principal components. The first component included proportion of cultivated pasture area and cultivated pasture area per goat. The second included goats present and forage supply per goat. After conducting a cluster analysis based on these two principal components, farms were classified into four groups. Group 1 was made up of French and Italian farms, which had a smaller territorial base but a high cultivated pasture area per goat, contributing to greater self-sufficiency in feed. However the concentrate per goat was too high in relation to milk production, which was medium. The difference between milk income and feed cost is also medium. Group 2 was basically made up of Italian farms. The farms in this group had the most extensive management systems, with a low use of inputs. However, the milk production was low, meaning that the difference between milk income and feed cost was also low. Group 3 was mainly made up of Spanish farms. On these farms the concentrate supply was excessive and the forage supply was low. The milk production per goat was medium and the difference between milk income and feed cost was small. Group 4 was made up mainly of French farms. The farms of this group had a moderate supply of concentrate although the forage supply was very high. They had a high milk production, which lead to a large difference between milk income and feed cost per goat.The main weaknesses observed are related to feeding management, particularly grazing, and to the goat productivity. In the former case research on the nutritional utilization of rangelands and pastures and correct feed supplementation is to be encouraged. In the latter, the production capacity of the goats present in these systems should be improved, without forgetting the balance between hardiness and general productivity.     

Adjusting homestead feeding to requirements and nutrient intake of grazing goats on semi-arid, subtropical highland pastures

Intensive livestock grazing can largely deplete the natural fodder resources in semi-arid, subtropical highlands and together with the low nutritional quality of the pasture vegetation limit the growth and production of grazing animals. To evaluate the contribution of homestead feeding of grazing goats to rangeland conservation and animal nutrition, two researcher-managed on-farm trials were conducted in a mountain oasis of Northern Oman. Goats' feed intake on pasture in response to four rations containing different levels of locally available green fodder and concentrate feeds was determined in six male goats each (35 ± 10.2 kg body weight (BW)). Total feed intake was estimated using titanium dioxide as external fecal marker as well as the diet organic matter (OM) digestibility derived from fecal crude protein concentration. The nutritional quality of selected fodder plants on pasture was analyzed to determine the animals' nutrient and energy intake during grazing. The pasture vegetation accounted for 0.46 to 0.65 of the goats' total OM intake (87 to 107 g/kg0.75 BW), underlining the importance of this fodder resource for the husbandry system. However, metabolizable energy (7.2 MJ/kg OM) and phosphorus concentrations (1.4 g/kg OM) in the consumed pasture plants were low. Homestead feeding of nutrient and energy-rich by-products of the national fishery and date palm cultivation to grazing goats increased their daily OM intake (R2 = 0.36; P = 0.005) and covered their requirements for growth and production. While the OM intake on pasture was highest in animals fed a concentrate-based diet (P = 0.003), the daily intake of 21 g OM/kg0.75 BW of cultivated green fodder reduced the animals' feed intake on pasture (R2 = 0.44; P = 0.001). Adjusting homestead supplementation with locally available feedstuffs to the requirements of individual goats and to the nutritional quality of the pasture vegetation improves animal performance and eases the grazing pressure exerted on the natural vegetation. This management strategy therefore appears to be a valuable alternative to intensive livestock feeding in zero-grazing systems and may contribute to sustainable livestock production in ecologically fragile, semi-arid mountain regions.     

Ingestive behavior of goats grazing in the Southwestern Argan (Argania spinosa) forest of Morocco

This study, conducted in the southwestern Argan forest of Morocco, aimed to assess goat feeding behaviour and goat diet composition. Overall grazing time averaged 387 min/day and represented on average 70% of total time when the goats were released on pasture. Grazing time was higher during winter months. Bipedal grazing was low and never exceeded 10%. Soil grazing varied according to the period of the year. Aerial grazing increased when herbaceous layer was depleted. Walking activity that accounted for 24% of the presence of goats on pasture, varied with the period of the year. Resting time accounted for less than 39 min contributing less than 6% of the temporal behavior budget. The contribution of all argan to the goat's diet ranged from a minimum of 47% in June to a maximum of 84% in December. Aerial argan leaves contributed continuously to goat diets a proportion from 35% to 68%. Under-tree grazing accounted for 50% during June when herbaceous plants and stubble were available, but less than 15% when they were depleted. Total intake changed with advance in season. Total goat intake reached its lowest level when animals spent large amounts of their time grazing argan trees in response to shortage of feed on the ground. Variation of the intake rate was mainly due to bite size, since rate of biting varied little among months. Goats ingested larger bite size from March through June when argan fruits were available and when diversity of availability was the highest. The goats adaptation capacity in argan forest allows a kid meat production when other ruminants such as sheep probably would not be able to do.     

Lifetime productivity of dairy cows in smallholder farming systems of the Central highlands of Kenya

Evaluation of lifetime productivity is sensible to target interventions for improving productivity of smallholder dairy systems in the highlands of East Africa, because cows are normally not disposed of based on productive reasons. Feeding strategies and involuntary culling may have long-term effects on productive (and therefore economic) performance of dairy systems. Because of the temporal scale needed to evaluate lifetime productivity, experimentation with feedstuffs in single lactations is not enough to assess improvements in productivity. A dynamic modelling approach was used to explore the effect of feeding strategies on the lifetime productivity of dairy cattle. We used LIVSIM (LIVestock SIMulator), an individual-based, dynamic model in which performance depends on genetic potential of the breed and feeding. We tested the model for the highlands of Central Kenya, and simulated individual animals throughout their lifetime using scenarios with different diets based on common feedstuffs used in these systems (Napier grass, maize stover and dairy concentrates), with and without imposing random mortality on different age classes. The simulations showed that it is possible to maximise lifetime productivity by supplementing concentrates to meet the nutrient requirements of cattle during lactation, and during early development to reduce age at first calving and extend productive life. Avoiding undernutrition during the dry period by supplementing the diet with 0.5 kg of concentrates per day helped to increase productivity and productive life, but in practice farmers may not perceive the immediate economic benefits because the results of this practice are manifested through a cumulative, long-term effect. Survival analyses indicated that unsupplemented diets prolong calving intervals and therefore, reduce lifetime productivity. The simulations with imposed random mortality showed a reduction of 43% to 65% in all productivity indicators. Milk production may be increased on average by 1400 kg per lactation by supplementing the diet with 5 kg of concentrates during early lactation and 1 kg during late lactation, although the optimal supplementation may change according to milk and concentrate prices. Reducing involuntary culling must be included as a key goal when designing interventions to improve productivity and sustainability of smallholder dairy systems, because increasing lifetime productivity may have a larger impact on smallholders’ income than interventions targeted to only improving daily milk yields through feeding strategies.     

Effects of heather and oat supplementation on gastrointestinal nematode infections and performance of grazing Cashmere goats

This work aimed to evaluate the effects of tannin-containing heather (Calluna vulgaris, Erica spp.) and energy (oats, Avena sativa) supplementation, combined or not, on feed intake, gastrointestinal nematode infections and performance of goats grazing mountain grasslands. Two successive experiments were established across one grazing season on four paddocks. The first (late April to early August, Period 1) involved two treatments, i.e., supplementation with heather (+H) vs. non-supplementation (−H), each randomly allocated to two paddocks. The second (mid-August to mid-November, Period 2) consisted on four treatments in a 2 × 2 factorial design, i.e., supplementation with heather and oats (+H+O), only heather (+H−O), only oats (−H+O), and no supplementation (−H−O). Results from Period 1 indicated that faecal nematode egg counts (FEC) were lower in +H goats (50% less in August), achieving more favourable live weight (LW) and body condition changes than −H goats. Total dry matter intake (DMI) in June was similar between treatments, with heather accounting for 0.21 of +H goat diets. Kids FEC and LW gains were not affected by heather supplementation. In Period 2, both heather and oat supplementation reduced FEC (45 and 61%, respectively) and improved goat performance, without an interaction between both factors. Total DMI in October was higher in +H+O compared to other treatments (48 vs. 30 g DM kg LW^−0.75 d⁻¹; P < 0.01). Rumen ammonia concentration was lower (P < 0.001) in +H than in −H goats, and in +O than in −O goats, whereas that of volatile fatty acids (VFA) was not affected by treatments, though the molar proportions of some VFA were modified. It is concluded that the combination of both supplements (tannins and energy) contributes to reduce gastrointestinal nematode parasitism and increases goat performance, allowing a lower dependence on conventional chemotherapy.     

Characterization of semi-extensive goat production systems in southern Spain

This study attempts to describe the semi-extensive goat farming sector in Andalusia (south of Spain) and to establish characteristics. Eighty-nine goat farmers were surveyed in three areas of this region. The survey examined all aspects of the systems, from socio-economy to management. A multivariate analysis (multiple correspondence and cluster) was used to determine the different farm characteristics. Most of the goat farms studied are single-worker or family managed. The farmers lack training and are elderly, so that continuity of the activity is not assured, although newcomers are usually young. All the farms have some area in ownership, although the farms most specialized in dairy goat products are the smallest in both ownership and total area. The roads are generally in good condition, except on farms with little land, situated in areas of the sierra. Machine-milking installations, closely related to the presence of infrastructures and of goats with a dairy tendency, are generally lacking, (this aspect is improving day by day). Artificial nursing is less generalized than machine-milking. Farms specializing in milk production, whose main activity is dairy goat farming, have dairy specialized breed or crossbred (milk and meat) goats. Feeding depends largely on grazing, with little area being cultivated to produce feed for the goats. Little distinction is made for the production level. Olive or acorn tree branches (Quercus ilex spp.) are used as feedstuff, depending on the types of tree predominating in the area. Five farm types were established, the differences depending on 14 variables of socio-economic aspects, level of production, infrastructure and installations, and feeding. Generated information from this study entails an advance into knowledge of goat farming systems in the Mediterranean area (where little information is generated). The relevance of this study is important since Andalusia has 40% of goats in Spain that produce more than half of the total goat milk in the country, which points out the socio-economical importance for most depressed areas in the region. This work supposes previous steps for improving the semi-extensive goat farming sector. From a methodological point of view, the discussion on variable types and utility establishes farm type characteristics.     

Effects of grass silage harvesting time and level of concentrate supplementation on nutrient digestibility and dairy goat performance

The effect of harvesting time (HT) of timothy-dominated grass silage and level of concentrate on the chemical composition of silage, and on feed intake and milk production by Norwegian dairy goats, were evaluated. The silages were prepared from the primary growth at three stages of maturity: very early (HT 1), early (HT 2) and normal (HT 3). The silages were fed ad libitum to 18 goats of the Norwegian dairy goat breed in early lactation and supplemented with a low (LC; 0.6 kg per goat daily) or normal (NC; 1.2 kg per goat daily) level of concentrate. The experiment was conducted as a cyclic changeover design with four periods of 28 days using three blocks of goats according to their initial body condition (poor, medium or high body condition). Silages contained 771, 696 and 619 g digestible organic matter per kg dry matter in silage (D-value) for HT 1, 2 and 3, respectively. Postponing the harvesting time decreased (P<0.001) silage dry matter intake (DMI) and silage DMI per kg body weight (BW). Increased concentrate allowance decreased silage DMI, with substitution rates (decrease in silage DMI when concentrate dry matter intake is increased, kg/kg) of 0.43, 0.21 and 0.27 at HT 1, HT 2 and HT 3, respectively. Milk yield and yields of milk constituents decreased (P<0.001) with delayed harvesting time and thus reflected the changes in silage D-value. Milk free fatty acids (FFA) concentration was not affected by dietary treatments. The efficiency of nutrient utilization was best when LC was fed and increased with postponed harvesting time. The higher energy efficiency of the HT 3 LC fed goats indicates that these goats canalized a higher proportion of energy intake to milk production, compared to goats fed NC and earlier harvested silage. Marginal ECM production response to increased net energy lactation (NEL) intake were higher when intake was increased due to higher silage digestibility (0.14 kg ECM/MJ NEL) compared with increased NEL intake due to increased concentrate level (0.12 kg ECM/MJ NEL). Improving silage quality by earlier harvesting time resulted in higher feed intake and milk yield than obtained by the same increase in NEL intake by concentrate supplementation.     

Changes in heathland vegetation under goat grazing: effects of breed and stocking rate

Questions: How are heathland vegetation dynamics affected by different goat grazing management? Location: Cantabrian heathlands in Illano, Asturias, northern Spain. Methods: During 4 years, vegetation dynamics (structural composition, canopy height and floristic diversity) were studied under three goat grazing treatments with three replicates: high stocking rate (11.7 goats ha^?1) with a local Celtiberic breed, and high (15 goats ha^?1) and low (6.7 goats ha^?1) stocking rates with a commercial Cashmere breed. Results: The relative cover of woody plants, particularly heather species, decreased more while herbaceous cover increased more under local Celtiberic than under Cashmere breed grazing. Within Cashmere treatments, the cover and height of live shrubs decreased more and the herbaceous cover increased more under high than under low stocking rate. Redundancy analysis showed a significant effect of treatment × year interaction on floristic composition. Greater species richness was recorded under local goat grazing, but Shannon diversity index fell in the fourth year on these plots because of dominance by two grass species. Conclusions: Local Celtiberic goat grazing at such a high stocking rate (11.7 goats ha^?1) hinders the development of sustainable systems on these heathlands, both in environmental and productive terms, owing to the limitations in soil fertility. Nevertheless, Celtiberic goats could be useful for controlling excessive shrub encroachment and reducing fire hazard. Cashmere goat grazing at high stocking rate promoted the highest Shannon diversity by generating a better balance between woody and herbaceous plants, while shrub dominance was not altered under the low stocking rate.     

Genetic and phenotypic parameters of body weight in West African Dwarf goat and Djallonké sheep

The International Trypanotolerance Centre's small ruminant breeding programme was initiated in 1995. The aim was to increase the efficiency of meat production and the trypanotolerance of the animals (sheep and goat). To achieve that goal, selection was based on estimated breeding values for daily weight gain from 4 to 12 months of age measured on trypanotolerance challenge. The purpose of this study was to estimate genetic parameters for growth traits and to evaluate genetic trends in West African Dwarf goat and Djallonké sheep resulting from the breeding programme under a low input production environment. Data for West African Dwarf goat and Djallonké sheep included birth weight (BW), weaning weight (W120), yearling weight (W360), pre-weaning (GR0–4) and post-weaning (GR4–12) growth rate. The data were analysed using an animal model that accounted for fixed effects of sex, year of birth, season of birth, parity of the dam, type of birth and the interaction year by season of birth. Estimates of heritability for BW, W120, W360, GR0–4 and GR4–12 were 0.5, 0.43, 0.30, 0.32 and 0.11 for goats and 0.39, 0.54, 0.21, 0.54 and 0.23 for sheep, respectively. The genetic correlation between BW and W120 was high for goats (0.74) and moderate for sheep (0.47). Genetic correlations between W120 and GR4–12 were high (0.92) for goats and moderate (0.49) for sheep. Between GR0–4 and BW the correlation was positive but low for sheep (0.26) and moderate for goats (0.60). Positive trends were found in mean estimated breeding values for animals born in the period 1995–2002 which demonstrated the effectiveness of the implemented breeding programs.     

复合微量元素缓释丸对放牧反刍动物Cu、Co、Se营养价值的研究

从放牧生态环境大群的大别山黄牛和英山白山羊中选择年龄,体重相近的２０头牛和２０头羊,各随机分为两组,每组１０头,雌、雄均匀配,以复合微量元素缓释丸为试验材料,、每Ⅰ组投丸为试验组,每Ⅱ组不投丸为对照组,牛的两组每组以５头补料,５头不补料,试验期１３５ｄ。羊的两组均不补料,为全放牧方式,试验期６０ｄ,试验结束对羊Ⅰ、Ⅱ组各随机抽取３头屠宰,取样测定肝、肾、脾、肌肉、心、血和瘤胃内容物测定Ｃｕ、Ｃｏ和     

Livestock and feed water productivity in the mixed crop-livestock system

Recently with limited information from intensified grain-based farming systems in developed countries, livestock production is challenged as being huge consumer of freshwater. The smallholder mixed crop-livestock (MCL) system which is predominant in developing countries like Ethiopia, is maintained with considerable contributions of crop residues (CR) to livestock feeding. Inclusion of CR is expected to reduce the water requirement for feed production resulting improvement in livestock water productivity (LWP). This study was conducted to determine feed water productivity (FWP) and LWP in the MCL system. A multistage sampling procedure was followed to select farmers from different wealth status. Wealth status dictated by ownership of key farm resources such as size of cropland and livestock influenced the magnitude of livestock outputs, FWP and LWP. Significant difference in feed collected, freshwater evapotranspired, livestock outputs and water productivity (WP) were observed between wealth groups, where wealthier are relatively more advantaged. Water productivity of CR and grazing land (GL) analyzed separately showed contrasting differences where better-off gained more on CR, whereas vice versa on GL. These counterbalancing of variations may justify the non-significant difference in total FWP between wealth groups. Despite observed differences, low WP on GL indicates the need of interventions at all levels. The variation in WP of CR is attributed to availability of production factors which restrained the capacity of poor farmers most. A linear relationship between the proportion of CR in livestock feed and FWP was evident, but the relationship with LWP was not likely linear. As CR are inherently low in digestibility and nutritive values which have an effect on feed conversion into valuable livestock products and services, increasing share of CR beyond an optimum level is not a viable option to bring improvements in livestock productivity as expressed in terms of LWP. Ensuring land security, installing proper grazing management, improved forage seed supply and application of soil and water conservation are expected to enhance WP on GL. Given the relationship of production factors with crop biomass and associated WP, interventions targeted to improve provision of inputs, credit, extension and training support due emphasis to the poor would increase CR yield and reduce part of water use for feed production. Optimizing feed value of CR with treatment and supplementation, following water efficient forage production methods and maintenance of healthy productive animals are expected to amplify the benefits from livestock and eventually improve LWP.     

The responses of two ecotypes of Nigerian West African Dwarf goat to experimental infections with Trypanosoma brucei and Haemonchus contortus

The West African Dwarf (WAD) goat from the humid zone of Nigeria is known for its trypanotolerance as well as for its resistance and resilience to Haemonchus contortus (haemonchotolerance). Another ecotype of WAD goat with a larger body size is found in the drier savanna zone of the country. We tested the hypothesis that the latter is less trypanotolerant, and less haemonchotolerant than the former ecotype because they have been less exposed to these infections and because of the likelihood of introgression of alleles for parasite susceptibility into the latter from neighbouring parasite-susceptible Sahelian genotypes. Two controlled experiments were carried out. In the first, we compared the responses in 8–9 month old kids of both ecotypes to subcutaneous infection with 5 × 10⁶ Trypanosoma brucei. Infection in both ecotypes was characterised by (i) prepatent periods of 3 days; (ii) a modest peak parasitaemia 4–5 days post infection (pi), followed by rapid clearance of parasites from the blood to microscopically undetectable levels from D11 or D12 until the end of the experiment on D30 pi; (iii) a sharp but transient drop in PCV following peak parasitaemia, with no other clinical evidence of anaemia; and (iv) normal growth and a small but weakly significant change in body temperature. In a second experiment we infected groups of goats of both ecotypes with 6000 L3 of H. contortus. This infection also produced no significant changes in the PCV and body weight of the goats. Only a small percentage of the inoculum was recovered from both ecotypes at necropsy on D18 pi (Mean % recovery ± SE = 3.29 ± 0.61 for humid zone and 6.83 ± 2.72 for savanna goats) and there was no significant difference in their worm burdens. On the basis of these results we reject our hypothesis and conclude that the savanna WAD ecotype exhibits comparable, strong degrees of trypanotolerance and haemonchotolerance to its humid zone counterpart.     

Mixed grazing systems of goats with cattle in tropical conditions: an alternative to improving animal production in the pastureq

Mixed grazing systems combining sheep and cattle have shown better growth performance for one or both species. This observation has been attributed to their complementary feeding behaviour and the reduced host infection by gastrointestinal nematodes. Less attention has been paid to mixed grazing systems combining goats and cattle. Here, continuously grazing goats mixed with cattle (M) were compared with control goats reared alone (C) under tropical conditions. The comparison was conducted with gastrointestinal nematode-infected (I) and non-infected (nI) goats. Thus, the four treatments were cattle with gastrointestinal nematode-infected goats (MI), gastrointestinal nematode-infected goats alone (CI), cattle with non-infected goats (MnI) and non-infected goats (CnI). Average daily gain (ADG, g/day) and grass production were measured for the four groups of animals (six goats and two heifers treated with MI or MnI) grazing for 3 months on 4 subplots. Monthly measurements were performed over 5-day periods. This pattern was replicated in space for a second set of four subplots and in time for six successive cohorts of animals (bands 1 to 6). The ADG of goats in mixed grazing conditions was higher than controls irrespective of the infection status (32.6 v. 18.4 g/day for MI v. CI; 44.2 v. 33.5 g/day for MnI v. CnI). Concomitantly, the average biomass was lower for mixed grazing animals compared with controls (174 v. 170 for MI and MnI; 235 v. 208 for CI and CnI, respectively), suggesting better use of the sward. For daily BW gain (g/kg DM), mixed grazing also yielded better results than the control (1.88 v. 0.52 g BW/kg DM per day for MI v. CI; 2.08 v. 1.47 g BW/kg DM per day for MnI and CnI). Mixed grazing of goats and heifers offers a promising alternative for increasing goat and overall animal production as well as improving the management of pastures.     

Preferences for sheep or goats in Indonesia

This paper aims to explore farmers’ preferences for sheep or goats based on feeding practices, animal and flock performances and economic benefits of sheep and goats in different agro-ecological zones in Central Java, Indonesia. In total, 150 smallholder farmers were selected from three agro-ecological zones: the lowlands, the middle zone, and the uplands. Feeding and performance parameters were estimated through weekly farm visits and farm records, from September 2001 to August 2003. In the lowlands, small ruminants were fed mainly with field grass and crop residues, whereas in the middle zone and uplands feeds fed were mainly field grass and leaves. Sheep were given more opportunities to graze than goats, however, grazing was not a major component in the diets. In the lowlands and the middle zone the differences in feed intakes, ADG and reproductive performances between sheep and goats were small. In all zones, does had significantly larger litters than ewes. In the uplands, goats had a significantly higher DMI, grew slightly faster, and had a higher weaning rate than sheep. Consequently, in the uplands, the total economic benefits from goat flocks were 25% higher than from sheep flocks. The major differences in agro-ecological conditions that affect the choice for sheep or goats were the availability of cassava peels in the lowlands, favouring a choice for sheep, and the abundance of leaves in the middle zone and uplands, which favours keeping goats. The promotion of goats by the government, the family tradition of keeping sheep or goats, the preference for sacrificing sheep for religious festivities, and the high initial investment needed to buy goat breeding stock could be other important motives to keep sheep or goats. Sheep fattening based on rice bran supplementation could be a feasible innovation in the lowlands. In the middle zone and uplands goat breeding could make a positive contribution to rural livelihoods.     

The Boer goat. II. Growth, nutrient requirements, carcass and meat quality

Growth rates of Boer goats were generally lower than sheep and, under favorable nutritional conditions, weight gains of more than 200 g per day were obtained, against values of up to 176 g per day under extensive subtropical conditions. Lactation and pregnancy had a marked effect on ME intake, and the latter had an improved feed conversion ratio (6.06 kg/kg) in comparison to that of virgin does (10.96 kg/kg). Below 6% crude protein in the diet, feed intake is reduced and has negative effects on birth weights, growth and milk production. Little information is available on mineral requirements of goats. The carcass of Boer goats is generally leaner, less compact and has different carcass proportions than sheep. The relatively high collagen contents with lower solubility of Boer goat meat, has meant that the eating quality has been regarded as inferior to that of lamb and mutton. Breeding holds the key to improving tenderness of goat meat; different slaughtering techniques can be used as well. Boer goats have high potential as meat animals when yielding three kid crops in 2 years and when fed to gain more than 200 g/day.     

Adaptive responses at the whole lactation scale of Baladi dairy goats according to feed supply and level of body reserves in agro-pastoral feeding system

Two diets were tested on Baladi lactating goats during mid-lactation in order to determine their adaptive capacities facing feed restrictions: a low nutritive value pasture (LP) and a high nutritive value pasture (HP). During early lactation on natural pastures, goats’ body condition (BCS) degraded, as initially fat goats lost more weight (BW) and were subject to a greater body reserves mobilization (BCS and NEFA) than lean ones. An intense compensation for all goats followed their transfer to the HP whereas the mobilization continued in LP, but only for fat goats. The lean goats managed to maintain their body condition by increasing their feed intake. When moved to mixed agricultural pastures at late lactation, all goats showed a full reconstitution of body reserves, particularly intense for those coming from LP, showing their strong capacities to recover their body reserves at this period. In parallel, milk production decreased for all goats on natural pastures, as the milk fat and milk proteins content. After transfer to HP, the high lactation rebound (+36%) showed the good reactivity of the Baladi goat in response to a feed improvement. Another rebound appeared in groups coming from LP after being transferred to a better feeding condition. However, during the reproduction phase, the milk yields decrease showing the highest priority given to the body reserves recovery.     

Resource use efficiency in urban and peri-urban sheep, goat and cattle enterprises

Urban livestock husbandry receives growing attention given the increasing urban demand for livestock products. At the same time, little is known about the resource use efficiency in urban livestock enterprises and eventual negative externalities. In livestock production, feeds are an important resource whose nutrients are transformed into products (meat and milk) to generate financial return to the producer. The lack of knowledge on nutrient supply through feed might lead to oversupply with severe environmental impacts. In Niamey, a typical West African city and capital of the Republic of Niger, urban livestock production is constrained by feed scarcity, especially during the dry season. Here, the issue of resource use efficiency was studied in 13 representative and differently managed sheep/goat and cattle enterprises characterized by high and low feed inputs, respectively, during a period of 28 months. Nitrogen (N), phosphorus (P) and potassium (K) inflows into each farm through livestock feeds and outflows through manure were determined using a semi-structured questionnaire; interviews were accompanied by regular weighing of feed supplied and dung produced. Live weight gain (LWG) and efficiency of conversion of total feed dry matter offered (kg TDMO/kg LWG) were computed along with nutrient balances (NBs) per metabolic body mass (kg0.75). NBs (per kg0.75/day) in the high-input (HI) sheep/goat enterprises were +1762.4 mg N, +127.2 mg P and +1363.5 mg K and were significantly greater (P < 0.05) than those in low-input (LI) units (+69.1 mg N, -98.3 mg P and +16.5 mg K). In HI cattle enterprises, daily balances averaged +454.1 mg N, +40.1 mg P and +341.8 mg K compared to +34.4 mg N, -9.0 mg P and +68.3 mg K (P > 0.05) in LI cattle systems. All systems were characterized by poor conversion efficiencies of offered feed, which ranged from 13.5 to 46.1 kg TDMO/kg LWG in cattle and from 15.7 to 43.4 kg TDMO/kg LWG in sheep/goats. LWG in HI sheep/goats was 53 g/day in the rainy season, 86 g/day in the hot dry season and 104 g/day in the cool dry season, while HI cattle lost 79 g/day in the hot dry season and gained 121 g/day and 92 g/day in the cool dry and rainy seasons, respectively. The data indicate that there is nutrient wasting and scope for improvement of feeding strategies in Niamey's livestock enterprises, which might also decrease nutrient losses to the urban environment.     

An individual-based model simulating goat response variability and long-term herd performance

Finding ways of increasing the efficiency of production systems is a key issue of sustainability. System efficiency is based on long-term individual efficiency, which is highly variable and management driven. To study the effects of management on herd and individual efficiency, we developed the model simulation of goat herd management (SIGHMA). This dynamic model is individual-based and represents the interactions between technical operations (relative to replacement, reproduction and feeding) and individual biological processes (performance dynamics based on energy partitioning and production potential). It simulates outputs at both herd and goat levels over 20 years. A farmer's production project (i.e. a targeted milk production pattern) is represented by configuring the herd into female groups reflecting the organisation of kidding periods. Each group is managed by discrete events applying decision rules to simulate the carrying out of technical operations. The animal level is represented by a set of individual goat models. Each model simulates a goat's biological dynamics through its productive life. It integrates the variability of biological responses driven by genetic scaling parameters (milk production potential and mature body weight), by the regulations of energy partitioning among physiological functions and by responses to diet energy defined by the feeding strategy. A sensitivity analysis shows that herd efficiency was mainly affected by feeding management and to a lesser extent by the herd production potential. The same effects were observed on herd milk feed costs with an even lower difference between production potential and feeding management. SIGHMA was used in a virtual experiment to observe the effects of feeding strategies on herd and individual performances. We found that overfeeding led to a herd production increase and a feed cost decrease. However, this apparent increase in efficiency at the herd level (as feed cost decreased) was related to goats that had directed energy towards body reserves. Such a process is not efficient as far as feed conversion is concerned. The underfeeding strategy led to production decrease and to a slight feed cost decrease. This apparent increase in efficiency was related to goats that had mobilised their reserves to sustain production. Our results highlight the interest of using SIGHMA to study the underlying processes affecting herd performance and analyse the role of individual variability regarding herd response to management. It opens perspectives to further quantify the link between individual variability, herd performance and management and thus further our understanding of livestock farming systems.     

Converting multi-trait breeding objectives into operative selection indexes to ensure genetic gains in low-input sheep and goat breeding programmes

Small ruminant breeding programmes in low-input production systems are best organised at the community level. Participant farmers have to agree on goal traits and their relative importance. When BLUP breeding values of goal traits are not available in time, appropriate selection indexes can be used to aid visual selection. Taking Ethiopian Abergelle goat and Bonga sheep community-based breeding programmes (CBBPs) as an example, breeding objective functions were defined and selection indexes were constructed and evaluated. Breeding goals for Abergelle goats included early sale weight, survival and milk production. Breeding goals for Bonga included the number of offspring born, sale weight and survival. Economic weights of objective traits can be used in several ways depending on measured traits and the reliability of their genetic parameters. Selection indexes included combinations of objective traits measured on candidates and their dams and situations when Abergelle communities prefer to restrict genetic changes in number of offspring born or adult weight and when Bonga communities prefer to restrict changes in adult weight. Genetic and economic gains were evaluated as well as sensitivity to feed cost assumptions and to repeated dam records. After independent culling on preponderant traits such as coat colour and horn/tail type, sires in Abergelle goat community breeding programmes should be selected on indexes including at least own early live weight and their dams average milk production records. Sires for Bonga sheep programmes should be selected on own early live weight and desirably also on their dam’s number of offspring born. Sensitivity to feed cost assumptions was negligible but repeated measurements of dam records improved index accuracies considerably. Restricting genetic changes in number of offspring born or adult weight is not recommended.     

Effects of an experimental Trypanosoma congolense infection on the reproductive performance of West African Dwarf goats

Thirty-six West African Dwarf (WAD) goats were used to assess the effects of an experimental Trypanosoma congolense infection on their reproductive system. Estrous cycles were synchronised and when confirmed pregnant (n = 31), the does were randomly allocated into control and trypanosome-infected groups. After infection, the animals were carefully observed till parturition. Trypanosome infection caused an increase of rectal temperature, a significant drop in PCV (infected: 23.3 +/- 0.3%; control: 28.5 +/- 0.4%; P < 0.0001) and abortions in 27.8% of the infected does. Kids born from infected does had a lower birth weight than kids born from control goats (0.9 +/- 0.1 kg versus 1.6 +/- 0.1 kg; P < 0.0001). Eight out of 13 kids (61.5%) that were born alive from infected does died during their first week of life. Plasma pregnancy-associated glycoprotein (PAG) and progesterone concentrations were lower in the infected animals than in the controls. In general, PAG concentration in does which aborted dropped before abortion. Our results revealed that artificial T. congolense infection affected reproductive performance of WAD goats with abortions, premature births and perinatal losses being observed. Neither transplacental transmission of T. congolense nor histopathological lesions of the placenta could be demonstrated.