Behaviour of goats, sheep and cattle on natural pasture in the sub-humid zone of West Africa

The behaviour of sheep, goats and cattle on a shrub and tree savannah in the sub-humid zone of West Africa was studied during the dry (February to May), rainy (June to September) and cool season (October to January). Two mature females per animal species were followed by two observers during 3 days per month and behaviour activities were recorded every 15 min of the daily grazing time. When browsing, the plant name, plant part and plant height reached during prehension were recorded. The distance travelled and the grazing circuits were recorded with a step counter and a Geographic Position System device. The knowledge of farmers concerning appreciated browse species relative to the browse species consumed by animals in the area was also investigated.

During the dry season sheep, goats and cattle spent around 25% of their time browsing and 20%, 16% and 31%, respectively, of their time grazing. During the cool season, goats (17%) browsed more than sheep (7%) and cattle (5%) (P < 0.05). During the rainy season, sheep browsed 20% of the time while cattle spent only 7% of their time browsing, while goats were tied, with no opportunity for browsing. Browsing leaves was the most important part of the browsing activity. During the cool season, browsing height was the same (1.0 m) for cattle and goats, but lower for sheep (0.6 m) (P < 0.05). In the dry and cool season, sheep and goats walked shorter distances than cattle.

The plant species with the highest frequency of consumption were Acacia dudgeoni Craib, Ficus gnaphalocarpa (Miq.) A. Rich, Dioscorea togoensis Knuth, Cordia myxa L., and Manguifera indica L. for sheep and goats and Afzelia africana Sm., Kaya senegalensis (Desv.) A. Juss, Pterocarpus erinaceus Poir. and Dicrostachys cinerea (L.) Wight and Arn. for cattle. Species with a high frequency of citation by farmers were A. africana (92%), K. senegalensis (88%), P. erinaceus (86%), Faidherbia albida A. Chevalier (80%), A. dudgeoni (70%) and F. gnaphalocarpa (69%).

In conclusion, browse species make an important contribution to the diet of ruminant animals in the sub-humid zone and farmers are familiar with the species consumed by ruminant animals.     

The effects of PPR on the reproductive health of Black Bengal goats and the possible role played by oxidative stress

Outbreaks of Peste des petits ruminants (PPR) viral disease in Black Bengal goats were investigated from the middle Indo-Gangetic Plains of India. Clinical profile of PPR-affected flocks was recorded from four different outbreak sites of the region. The PPR outbreak was diagnosed serologically using commercially available sandwich ELISA kit. Relatively, low mortality rate (mean 26.75%) for PPR outbreak was recorded due to the endemic status of the disease. To understand the role of oxidative stress in PPR virus pathogenesis, various oxidant and antioxidant parameters in goats infected with PPR were estimated and compared with the uninfected/healthy goats of the same flock. The measured high level of pro-oxidant malondialdehyde (MDA) obtained from lipid peroxidation along with lower levels of anti-oxidants viz. superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) in PPR-affected Black Bengal goats suggests oxidative stress as one of the mechanism of pathogenesis of PPR virus. In addition, the correlation of oxidative stress due to PPR and the resulting reproductive disorders in the female goats were evaluated. The abortion in pregnant does observed during PPR outbreak was proportional to debility and oxidative stress manifested during PPR infection. The reproductive performance of recovered female goats in the period of 18 months of monitoring was significantly compromised in terms of kidding and twinning frequency. The mortality rate in kids born from PPR-recovered goats was significantly higher compared to those from health goats in the first 9 months post-recovery. From the present study, it may be concluded that together with the PPR virus, infection in goats and the resulting oxidative stress play a vital role for abortion and reduced post-reproductive performance in Black Bengal female goat.     

Economics of Prophylaxis against Peste des Petits Ruminants and Gastrointestinal Helminthosis in Small Ruminants in North Cameroon

Data on reproduction and mortality were collected over one year from 5100 sheep and 13 300 goats in treated and control flocks. The treated animals received vaccination against peste des petits ruminants (PPR) and anthelmintics twice a year. Productivity parameters (fecundity and mortality rates) obtained with and without prophylaxis were fitted into a benefit–cost economic analysis model and run for project lifespans varying from one to five years. At a 7% discount rate, the overall benefits for a project lifespan of five years were estimated as over 15 million FCFA and 11 million FCFA for sheep and goats, respectively. The benefit–cost ratio ranged from 2.26 to 3.27 in goats and 3.01 to 4.23 in sheep, depending on the project lifespan. It was concluded that PPR and gastrointestinal helminthosis are important causes of economic losses in small ruminants in Cameroon. A national or even a regional vaccination campaign against PPR and strategic anthelmintic treatment of small ruminants are recommended.     

Pathological and immunohistochemical study of experimental peste des petits ruminants virus infection in goats

Peste des petits ruminants (PPR) is an emerging, economically important viral disease of goats and sheep in the Indian subcontinent. In the present investigation, 15 hill goats were experimentally infected with 2 ml of 10% splenic suspension of a virulent isolate of PPR virus (PPR/Izatnagar/94) that had caused heavy mortality (>75%) in goats during 1994 outbreaks in northern India. More than 86% (13 of 15) animals died between 9 and 13 days post inoculation at the height of temperature or when temperatures were declining. Necropsy findings included congestion of gastrointestinal tract (GIT), nasal sinuses, consolidation of antero-ventral lobes of lungs, engorged spleen, and occasionally oedematous lymph nodes. Histopathological examination of major organs of GIT revealed degeneration and necrosis of labial mucosa, severe mucosal and submucosal congestion, degeneration and necrosis of intestinal epithelium and lymphoid cell depletion from Peyer's patches along with presence of syncytia at times. Lungs showed broncho-interstitial changes and presence of intracytoplasmic and intranuclear eosinophilic inclusions in alveolar macrophages and syncytial cells. These changes in lungs were frequently complicated with serofibrinous pneumonia (57%, eight of 14). Lymphocytolysis and occasional syncytia formation were evident in the lymphoid tissues. Immunohistochemical (IHC) findings included presence of PPR virus antigen in the labial, intestinal, and bronchiolar epithelial cells, pneumocytes, macrophages and syncytial cells in lungs, and lymphoid (intact and necrotic) and reticular cells in lymphoid organs. The findings of the study indicated the highly virulent nature of the PPR virus isolate (PPR/Izatnagar/94), causing 100% mortality and characteristic pathological changes in the target organs such as lungs, intestines and lymphoid tissues. The results of the IHC study suggested that indirect immunoperoxidase could be an alternative method in the absence of more sophisticated methods of laboratory diagnosis of PPR virus infection in goats.     

Sero-epidemiology of peste des petits ruminants (PPR) in Pakistan

A sero survey was conducted during 2005-2006 to estimate the sero prevalence of PPR in the small ruminant population of Pakistan. A total of 2798 samples were collected including goats (1979) and sheep (819) from villages in 27 randomly selected districts. These were tested by cELISA for PPRV and true prevalence estimates were calculated by Rogan and Gladen estimator. Overall, 1273 (45.5%) were found positive; 980 (49.5%) of 1979 samples from goats and 293 (35.8%) of 819 serum samples from sheep were positive. The true sero-prevalence of PPR was estimated to be 48.5% (95% CI, 46.6-50.3), and 52.9% (95% CI, 50.7-55.1) and 37.7 (95% CI, 34.4-41.0) for goats and sheep, respectively. PPR virus is widely distributed all across Pakistan and has become an endemic infection of small ruminants. Since it is one of the leading causes of morbidity and mortality in small ruminants, it poses a serious threat to food security and the rural economy in Pakistan.     

小反刍兽疫的诊断与综合防控措施

小反刍兽疫是由小反刍兽疫病毒引起的一种急性、亚急性传染性疾病,主要感染绵羊、山羊及一些野生小反刍动物,发病率和死亡率均较高,给广大农牧民和养殖场造成巨大的经济损失。因此,对该病的诊断及综合防控措施进行概述,以期为该病的防控提供参考。     

Graphical approaches to support the analysis of linear-multilevel models of lamb pre-weaning growth in Kolda (Senegal)

Linear-multilevel models (LMM) are mixed-effects models in which several levels of grouping may be specified (village, herd, animal, …). This study highlighted the usefulness of graphical methods in their analysis through: (1) the choice of the fixed and random effects and their structure, (2) the assessment of goodness-of-fit and (3) distributional assumptions for random effects and residuals.

An LMM was developed to study the effect of ewe deworming with morantel on lamb pre-weaning growth in a field experiment involving 182 lambs in 45 herds and 10 villages in Kolda, Senegal. Growth was described as a quadratic polynomial of age. Other covariates were sex, litter-size and treatment. The choice of fixed and random effects relied on three graphs: (1) a trellis display of mean live-weight vs. age, to select main effects and interactions (fixed effects); (2) a trellis display of individual growth curves, to decide which growth-curve terms should be included as random effects and (3) a scatter plot of parameters of lamb-specific regressions (live-weight vs. quadratic polynomial of age) to choose the random-effects covariance structure.

Age, litter-size, age×litter-size, litter-size×treatment and age×litter-size×treatment were selected graphically as fixed effects and were significant (p<0.05) in subsequent statistical models. The selection of random-effect structures was guided by graphical assessment and comparison of the Akaike’s information criterion for different models. The final random-effects selected included no random effect at the village level but intercept, age and squared-age at the herd and lamb levels. The structure of the random-effects variance–covariance matrices were blocked-diagonal at the herd level and unstructured at the lamb level. An order-1 autoregressive structure was retained to account for serial correlations of residuals. Smaller residual variance at 90 days than at younger ages was modeled with a dummy variable taking a value of 1 at 90 days and 0 elsewhere.

Ewe-deworming with morantel during the rainy season lead to higher lamb live-weights (probably related to a better ewe-nutrition and -health status). A positive correlation was demonstrated between early weight and growth rate at the population level (with important lamb and herd-level random deviations). The persistence of this correlation at older ages should be checked to determine whether early weights are good predictors of mature weights and ewe-reproductive lifetime performance.     

Seasonal Prevalence of Gastrointestinal] nematodes of goats in Pernambuco state, Brazil

During each of 36 1-month periods from April 1979 to March 1982, 3–4 goats selected from typical farms were necropsied and examined for gastrointestinal nematodes. The goats were male, 12 months old, born on the farm and raised without any anthelmintic application. At the beginning of each month, from April 1981 to March 1982, three 12-month-old male goats shown to be free of gastrointestinal nematodes after anthelmintic treatment were grazedwith a flock of naturally infected goats (tracer goats). At the end of each month, these goats were placed on a cementfloored pen and were maintained there for 4 weeks prior to necropsy and examination for gastrointestinal nem nematodes.

Every goat examined was found to be parasitized by more than one species of nematode. Haemonchus contortus, Strongyloides papillosus and Oesophagostomum columbianum were the most prevalent nematodes found. Total worm burdens present in the farm animals were highest during late rainy/early dry season (March-June) and lowest in mid-rainy season (January-February). The acquisition of nematodes by tracer goats occurred mainly from mid-rainy to early dry season (January-June).     

西藏绒山羊WNT4和HOXC13基因对绒毛纤维直径性状的遗传效应分析

试验旨在探索WNT4和HOXC13基因多态性及其对西藏绒山羊绒毛纤维直径性状的影响，寻找与西藏绒山羊绒毛纤维直径性状相关的分子标记。以380只1岁西藏绒山羊群体为研究对象，利用混池DNA直接测序法检测WNT4和HOXC13基因的SNP，利用飞行时间质谱技术对SNP分型，利用SAS 9.1软件中最小二乘方差模型对SNP位点与绒毛平均纤维直径、纤维直径标准差、纤维直径变异系数进行关联分析。结果表明，WNT4基因第3外显子区域检测到2个SNPs位点（SNP1和SNP2），HOXC13基因第2外显子区域检测到2个SNPs位点（SNP3和SNP4），均处于中度多态（0.25 < PIC < 0.50）。χ²检验表明，群体中WNT4基因的SNP1和SNP2位点均处于Hardy-Weinberg不平衡状态（P < 0.05）。关联分析结果表明，4个SNPs位点均与平均纤维直径呈极显著相关（P < 0.01），SNP2和SNP3与纤维直径标准差呈极显著相关（P < 0.01），SNP2与纤维直径变异系数呈极显著相关（P < 0.01）。综上，WNT4和HOXC13基因对西藏绒山羊绒毛纤维直径有显著影响，可以尝试将其SNPs位点作为影响西藏绒山羊绒毛纤维直径的分子标记之一，为超细型西藏绒山羊选育工作提供理论依据。     

Age variations in the prevalence of sarcocystosis in sheep and goats from northern and central Jordan

Awassi sheep and mountain goats slaughtered in northern and central Jordan were examined for Sarcocystis cysts by post-mortem examination, trichinoscopy of muscle samples taken from esophagi and diaphragms and serologically by indirect hemagglutination (IHA) during the period June 1986–May 1988. Macrosarcocysts were found in 11.3% (70/620) of sheep and 11.7% (46/393) of goats aged over 1 year old. Microsarcocysts were found in 50.1% (1185/2693) of the sheep diaphragm samples and 56.4% (711/1261) of the same organs of goats. The prevalences were lower in the esophageal muscles (26.4%, 348 of 1319 and 25.1%, 97 of 386) than the diaphragmal muscles (29.0%, 383 of 1319 and 34.2%, 132 of 386) in the younger age groups (less than 7 months) of sheep and goats, respectively. The prevalences in both the esophagus and the diaphragm increased with age. The seroprevalences of anti-Sarcocystis antibodies in sheep and goats were significantly higher (P < 0.05) than the prevalence of Sarcocystis cysts detected by trichinoscopy. The seroprevalence of sarcocystosis increased with age in sheep and goats.     

Pathogenicity of attenuated peste des petits ruminants virus in sheep and goats

Progressive loss of virulence for goat kids was noticed when peste des petits ruminants (PPR) virus was passaged in Vero cells. While goats inoculated with the 60th passage suffered from the clinical PPR disease and mortality, goats inoculated with the 80th passage did not show any sign of the disease. If the progressive loss of virulence of the virus with passage continues, it will not be long before a homologous PPR vaccine will be obtained at the National Veterinary Institute, Vom.     

Prevalence and mortality rate of peste des petitis ruminant (ppr): possible association with abortion in goat

Present study was designed to investigate the prevalence and mortality (%) caused by Peste des Petitis Ruminant (PPR) and its possible association with abortion in goat flocks at different areas of Pakistan. A total of 140 animals were samples in the population of 650 which was having 185 deaths (Mortality rate = 28 %) from three different regions of the country. There were 58 abortions in the 140 pregnant goats of above said population One hundred & ten (110) serum samples from diseased, recovered and apparently healthy animals were tested for the presence of PPR antibodies by competitive ELISA (c ELISA). Eighty-four (84) animals were positive for PPR antibodies whereas in apparently healthy adult goats in the same flock, no PPR antibodies were detected. Twenty-four (24) tissue samples collected from the dead animals and six samples from aborted fetus were tested for the presence of PPR antigen by Immuno-capture ELISA (Ic ELISA). Nineteen (19) out of thirty (30) organ samples mainly from lung, spleen, lymph node were found positive for PPR antigen but negative from lungs of aborted fetus. There was a high rate of abortions (28–45 %) in each of the outbreak and it was highest in the outbreak of Golra Sharif, Islamabad (No. = 21 in total population of 100). As the serum samples from the aborted dams were found positive for PPR antibodies so the study provides the possible association of mortality and prevalence of PPR disease with high rate of abortions in goat.     

Canine intestinal helminths in Finland: prevalence, risk factors and endoparasite control practices

In this survey, the prevalence of canine gastrointestinal helminths in Finland was investigated by coprological examination (n = 541) and possible risk factors for helminth infections in dogs were analysed. In addition, the dog owners (n = 296) completed a questionnaire about use of anthelmintics, sources of information about parasites and antiparasitic treatments and reasons for choosing the drugs.

The prevalence of gastrointestinal helminths was 5.9%. Eggs from four different species were identified in the faecal samples. Toxocara canis eggs were present in 17 dogs (3.1%), Uncinaria stenocephala eggs in 14 dogs (2.6%) and Diphyllobothrium latum eggs in 2 dogs (0.4%). Moreover, one sample contained eggs of Trichuris vulpis (0.2%). Kennel housing and visits abroad were identified as risk factors for T. canis and U. stenocephala infections.

Most dogs (86.0%) received anthelmintic treatment at least once a year. Hunting dogs were dewormed least; one-third was treated less than once a year. Approximately, half of the owners occasionally changed the anthelmintic used. The most important trait of the anthelmintic was its broad spectrum, fenbendazole being the most commonly chosen. Veterinarians, dog magazines and dog breeders were the predominant sources of information concerning parasites and deworming strategies.     

努比亚山羊LMCD1基因生物信息学分析、真核表达载体的构建及表达

【目的】 扩增努比亚山羊LIM结构域基因1（LIM domain gene 1,LMCD1）并进行生物信息学分析,构建真核表达载体并检测LMCD1基因的表达情况,为研究努比亚山羊LMCD1基因功能及探究LMCD1基因在山羊骨骼肌肉发育中的作用提供依据。【方法】 从努比亚山羊背最长肌组织中提取总RNA,应用RT-PCR方法扩增LMCD1基因CDS区序列,并进行生物信息学分析;将LMCD1基因以同源重组的方式连接pEGFP-N1载体,经酶切、测序鉴定后重组阳性质粒命名为pEGFP-N1-LMCD1;将pEGFP-N1-LMCD1重组质粒转染至山羊骨骼肌卫星细胞,通过实时荧光定量PCR检测努比亚山羊LMCD1基因的表达情况。【结果】 努比亚山羊LMCD1基因CDS区序列全长1 092 bp,编码363个氨基酸。LMCD1蛋白分子式为C₁₇₇₅H₂₈₁₈N₅₀₈O₅₃₃S₂₉,分子质量为40.73 ku。努比亚山羊LMCD1基因CDS区序列与山羊相似性最高（99.8%）,与斑马鱼相似性最低（55.4%）,与其他物种的相似性在87.0%~98.8%之间。LMCD1蛋白无信号肽,不存在跨膜结构域,为亲水性蛋白。通过构建努比亚山羊pEGFP-N1-LMCD1真核表达载体并转染至骨骼肌卫星细胞,过表达LMCD1基因,产生绿色荧光信号。【结论】 试验成功扩增LMCD1基因CDS区序列,构建了pEGFP-N1-LMCD1真核表达载体,并分析了生物学功能,为后续开展LMCD1基因在山羊骨骼肌肉发育中的机制研究提供了理论基础。     

Peste des petitis ruminants morbillivirus infection in lambs and young goats at Qassim region, Saudi Arabia

An outbreak of peste des petits ruminants (PPR) in lambs and young goats of Najdi breed of sheep and goats occurred during winter 2005 at Qassim region of central Saudi Arabia. The PPR infection was confirmed by demonstration of antibodies against the virus in the serum of clinically-ill young sheep and goats using competitive ELISA test. Clinical examination of infected animals showed fever, salivation, lacrimation, mucopurulent nasal discharge, difficult breathing and diarrhoea. The disease was particularly severe in the goats. Morbidity was about 20% and mortality was less than 3 percent. Autopsy showed necrotic and ulcerative lesions in the mouth, stomach and intestine. Mesenteric lymph nodes were swollen and congested. The lungs were patchy pneumonic mostly at the diaphragmatic and apical lobes. Liver and kidney lesions were seen in goats only and both organs were congested and necrotic. Histopathological examination revealed necrotic inflammation in the gastrointestinal tract. Intracytoplasmic viral inclusions were seen in the enterocytes of goats. Lung sections showed bronchopneumonia and syncytial and giant cells. The bronchial epithelium of goats had intracytoplasmic viral inclusions. Extensive coagulation necrosis, fatty degeneration and presence of intracytoplasmic viral inclusions were seen in hepatocytes and syncytial cells were evident in biliary epithelium of goats. Congestion, coagulation necrosis and syncytial cells were seen in the renal tubular epithelium of goats only. In a survey to determine the magnitude of the outbreak, PPR antibodies were evidenced in 363/996 (36.6%) sheep and 530/962 (55.1%) goats.     

Association of polymorphism in the alpha (1,2) fucosyltransferase gene with growth performance in two Western pig breeds in Taiwan

The mutation at 307 bp (M307) of the alpha (1,2) fucosyltransferase gene has been proposed as being a marker for selection of E. coli F18 adhesion-resistant pigs. Nonetheless, exactly how this mutation affects pigs' growth performance remains unclear. This study investigated genotypic frequencies and the effect of M307 and the ryanodine receptor (RYR1) on the growth performance of two major Western pig breeds in Taiwan. In total, 1510 (1024 Duroc and 486 Landrace) boars were performance tested using segregated early weaning entrance. The genotypes of M307 and RYR1 were determined by polymerase chain reaction-based restriction fragment length polymorphism. The performance traits included average daily gain, the feed conversion ratio, backfat thickness, and age at 110 kg of body weight. The statistical model included starting age, test season, genotype of M307, genotype of RYR1, and two- and three-way interactions. The data were analyzed within breeds. Consequently, the genotypic frequencies of the AA genotype in M307 were 0.06 and 0.06, and of the GG genotype were 0.53 and 0.64 in Duroc and Landrace pigs, respectively. The genotypic frequencies of the NN genotype in RYR1 were 0.75 and 0.99, and of the nn genotype were 0.01 and 0.00 in Duroc and Landrace pigs, respectively. There was no significant effect of the M307 genotype on the growth performance in either Duroc or Landrace breeds. However, the RYR1 significantly influenced the average daily gain and age at 110 kg of body weight of Duroc pigs. The results suggest that selection of the favorable AA genotype at M307 for E. coli F18 adhesion resistance may not affect the growth performance traits in Duroc and Landrace pigs. However, the effect of the RYR1 on growth performance should be monitored during selection.     

Risk factors for intramammary infections and relationship with somatic-cell counts in Italian dairy goats

Routine examination of milk was performed on five herds of lactating goats in northern Italy as part of a milk quality-monitoring program in the year 2000. As part of the study, aseptic samples of foremilk were collected monthly from both half udders during the entire lactation for 305 goats, resulting in a total of 4571 samples. The samples were tested with cytological and bacteriological analyses to evaluate the relationship between mammary infections and somatic-cell count (SCC; Fossomatic (TM) method). Prevalence of intramammary infection (IMI) was 40.2% (n = 1837) of all udder-half samples examined. The most-prevalent mastitis agents were coagulase-negative Staphylococci (CNS), 80% (n = 1474 udder-half samples); within this group, Staphylococcus epidermidis was the most-prevalent species (38%). Other prevalence were Staphylococcus aureus 6% (n = 112 udder-half samples) and environmental pathogens 14% of infected udder-half samples (n = 251) with a diverse mixture of species, none of which had a frequency of >4%. Enterococcus faecalis was the most-frequently isolated among this group. Neither Salmonella spp. nor Listeria monocytogenes were detected. The risk (sample level) of infection differed across herds, parities, and stage of lactation according to results from logistic multiple regression. Infection was more common among goats in third and fourth parities and during the later stages of lactation. Of the 2734 samples from uninfected udder halves, the mean log₂ SCC was 3.9 cell/ml; of the 1837 bacteriological positive samples, the mean log₂ SCC was 5.6 cell/ml. According to results from a linear mixed model, concentrations of somatic cells tended to increase with increasing age and days in milk and with the presence of bacteria. Infection with S. aureus was associated with the highest SCS.     

Comparison of grazing behaviour, dietary overlap and performance in non-lactating domestic ruminants grazing on marginal heathland areas

During the years 2000–2001, 7 non-lactating beef cows, 40 ewes and 40 does were managed in mixed grazing on a natural heathland vegetation plot (22 ha) with 20% improved pasture (perennial ryegrass) on a hill (1000 m a.s.l.) experimental farm located in the NW of Spain. Samples of faeces and vegetation components were collected monthly to estimate diet selection, using the alkane markers, and diet overlapping level. Animals were weighed monthly to quantify live weight changes and performance of the three livestock species during different periods (spring, summer, autumn, winter) of the grazing season.

The percentage of shrubs in the diet was significantly higher in the small ruminants (ranging between 36% and 85%) than in cows (less than 25%) in any period. Gorse (Ulex gallii) and heather (Erica spp., Calluna) percentages were always significantly higher in does than in ewes, except in autumn for heather. Herbaceous component (namely grasses) was higher in cattle (75–99%) than in small ruminants (15–64%). The lowest mean dietary overlap was found between cattle and goats (50.4%), with large differences during the grazing season, ranging between 20% and 70%.

The three animal species increased their live weight in the first grazing period (spring), when the mean sward height on the improved area was higher than 6.0 cm. However, when the sward height was lower than 3.5 cm (summer–winter), cows lost weight (− 437 g/day) while ewes and goats were still able to increase their weight (29 and 5 g/day, respectively).

Therefore, it seems that small ruminants, mainly sheep, are more suitable than cattle from the vegetation utilization and animal performance points of view, as cows were unable to maintain live weight when the preferred grass availability decreases. Goats were the species that included the highest proportion of heathland vegetation components in the diet, especially gorse, although their performance was significantly lower than in sheep. In consequence, small ruminant production systems could be more sustainable than cattle. The results indicate that mixed grazing of sheep and goats could be appropriate in these vegetation communities, allowing the development of sustainable systems, in which animal performance and the efficiency of resource use are maximized.     

Relationships between N'Dama cow body condition score and production performance under an extensive range management system in Southern Senegal: calf weight gain, milk production, probability of pregnancy, and juvenile mortality

This study aimed to determine the relationships between N'Dama cows body condition score (BCS) and (i) calf growth and the milk collected; and (ii) the probabilities of pregnancy and juvenile mortality. Animals from 10 herds ranging from 20 to 210 animals in herd size were followed monthly in an extensive range management system in Southern Senegal between 1993 and 1998. For daily weight gains and milk collected, linear mixed-effects models were fitted between calving and 6 months postpartum. Cow lactation was included as random effect, with an unstructured variance-covariance matrix. Calving season, parity, herd size, and calving BCS were the fixed effects. For the probabilities of pregnancy and juvenile mortality, survival models for grouped data were fitted on a monthly scale. The model selection was based on the Akaike information criteria. In large herds, calving BCS had little effect on milk production. In small herds, calves born to cows scoring ≥2.5 points at calving grew quicker and their dam were more milked. The relative difference in milk production between thin and fat cows averaged 23%. The relative gain was higher in the cool dry season than in the other seasons, and for primiparous than for multiparous cows. Except during the hot dry season, the probability of pregnancy was twice as high for cows scoring ≥2.5 points the two previous months than for other cows. The BCS had no effect on calf survival until 1 year of age in large herds. In small herds, calves born to thin cows at calving showed a survival at 1 year more than five points lower than calves born to fatter cows. The threshold of 2.5 points on a five-point scale is pertinent to describe the production performance of N'Dama cows in such a breeding context.