Bernard Faye

The use of multilevel models to evaluate sources of variation in reproductive performance in dairy cattle in Reunion Island.

Sources of variation in measures of reproductive performance in dairy cattle were evaluated using data collected from 3207 lactations in 1570 cows in 50 herds from five geographic regions of Reunion Island (located off the east coast of Madagascar). Three continuously distributed reproductive parameters (intervals from calving-to-conception, calving-to-first-service and first-service-to-conception) were considered, along with one Binomial outcome (first-service-conception risk). Multilevel models which take into account the hierarchical nature of the data were used to fit all models. For the overall measure of calving-to-conception interval, 86% of the variation resided at the lactation level with only 7, 6 and 2% at the cow, herd and regional levels, respectively. The proportion of variance at the herd and cow levels were slightly higher for the calving-to-first-service interval (12 and 9%, respectively) - but for the other two parameters (first-service-conception risk and first-service-to-conception interval), >90% of the variation resided at the lactation level. For the three continuous dependent variables, comparison of results between models based on log-transformed data and Box-Cox-transformed data suggested that minor departures from the assumption of normality did not have a substantial effect on the variance estimates. For the Binomial dependent variable, five different estimation procedures (penalised quasi-likelihood, Markov-Chain Monte Carlo, parametric and non-parametric bootstrap estimates and maximum-likelihood) yielded substantially different results for the estimate of the cow-level variance.

Environmental factors associated with lameness in dairy cattle

An epidemiological survey of the incidence of different foot diseases causing lameness was undertaken on 80 French dairy farms between 1979 and 1980. A total of 29.5 cases of lesions per 100 cows was recorded in that period, which represents a higher incidence that of clinical mastitis (20.37). Data concerning the incidence of foot lesions, farm structures, herd management system, feeding and soil characteristics were analysed using the ξ2 test of independence and one-way analysis of variance. Results showed that a high incidence of infectious and metabolic foot disorders was associated with loose housing, feeding based on maize silage, absence of a footbath, foot trimming and mineral supplementation. A relationship was also observed between articular lesions and grass-silage feeding. Tied-housed cows fed hay were less affected. Regular hoof trimming at pasture and a long time spent checking the animals were found to have a positive effect on foot health. A low incidence of foot disorders was also associated with a larger variety in dietary components. A high incidence of lameness was reported in large herds kept on rough floors.

Associations between health disorders of French dairy cows and early and late culling within the lactation.

Data from an observational study, carried out during a 4.5 year period (1986–1990), were used to quantify the effects of health disorders on the risk of culling. The study population consisted of 47 commercial Holstein dairy herds from western France, comprising 4123 cows. Logistic regression was used to assess the relationships between health disorders and early and late culling. Fourteen main health disorders with clinical signs and one subclinical disease were studied: abortion, periparturient accident, calving provided with assistance, digestive disorders, ketosis, locomotor disorders, mastitis, metritis, milk fever, cystic ovaries, respiratory disorders, retained placenta, teat injuries, non-traumatic udder disorders and status with respect to milk somatic cell count. Adjustments were made for year, month of calving, parity, breeding value for milk, best of the two first milk production records and reproductive performance. The possible effects of interactions among variables were also studied. The herd effect was taken into account using random effect models. Non-traumatic udder disorders, teat injuries, milk fever and the occurrence of both ketosis and assistance at calving were significantly associated with an increased risk of being early culled (odds ratios (OR) ranging from 1.6 to 10.3). Early and late abortion, late metritis, poor peproductive performance, retained placenta, non-traumatic udder disorders within 45 days post-partum and mastitis occurring in the first 3 months of the lactation were positively associated with a late culling (OR ranging from 1.2 to 6.6). Cows with lower breeding value for milk and higher parities were high risk groups for culling. A lower level of milk production and occurrence of both reproductive disorders and poor reproductive performance were risk factors for late culling.

Trace-elements status in camels. A review.

Data relating to trace-elements status in camels is scarce, from both a clinical and biochemical point of view. Clinical deficiency or toxicity has rarely been described in this species. However, there is a some evidence that camels are sensitive to trace element disorders in the same way as other ruminants. For example, copper deficiency in camels has been reported in East Africa. Normal plasma level is comparable to cattle (70–120 mg/100 mL). Camels appear to maintain zinc levels at a lower value than other domestic ruminants (<60μg/100 mL). Iron metabolism is more active in the liver than in the spleen. Data concerning manganese levels are possibly unreliable. Some cases of selenium deficiency (white muscle disease) have been reported. No data are available for cobalt status in camels. Finally, camels appear to be more sensitive to iodine deficiency than the other domestic ruminants.

The influence of high dietary protein, energy and mineral intake on deficient young camel (Camelus dromedarius)—II. Changes in mineral status☆

1. Mangrove Avicennia marina is poor in some trace elements such as copper, zinc and manganese. In a trial we used 32 young camels divided into four groups. 2. Groups 1 and 3 were supplemented with copper and zinc in drinking water after 1 month of mangrove feeding. 3. Groups 2 and 3 received concentrate rich in protein and energy. The supplementation was stopped after 2 months. 4. All the camels were deficient in trace elements at the beginning of mineral supplementation. 5. The plasma concentration of copper increased significantly up to normal levels (less than 70 micrograms/100 ml) in energy protein supplemented groups, but the quantity supplied (100 mg of copper sulphate/day) was not sufficient to maintain this level after the end of supplementation. 6. The original zinc deficiency was too severe to observe a significant effect of the mineral supplementation. 7. Calcium, magnesium and phosphorus levels were improved during the supplementation period in protein-energy supplemented groups. 8. A high interaction between mineral absorption and quality of the diet was observed. A well-balanced diet seems essential to avoid deficient mineral status.

Interrelationships between herd management practices and udder health status using canonical correspondence analysis

The relationships between the herd-level distribution of udder health measures (traumatic, physical, functional and congestive udder disorders, clinical mastitis and somatic cell counts (SCC) greater than 400 x 10(3) ml-1) and farm (general hygiene, milking practices and housing system) and aggregated individual characteristics were studied by canonical correspondence analysis (CCA). This is a correspondence-analysis technique in which the axes representing disease patterns are expressed as linear combinations of potentially explanatory variables. These main axes can be drawn so that the distribution of diseases for combinations of the main-explanatory managerial variables can be visualized. The type of quarantine for newcomers, type of animal housing, presence of shelter at pasture, use of udder towel before milking, milk production and loss of body condition after calving, were strongly correlated with udder health status. Mastitis and physical udder disorders were associated with the combination of no introduction of replacement heifers and low loss of body condition after calving. Congestive disorders were more common on farms when no quarantine for newcomers was combined with high loss of body condition after calving. Higher clinical and subclinical mastitis incidence risks were associated with the combination of no udder towel, loose housing with high animal density and high milk production. In most cases, clinical mastitis and high SCC were explained by the same covariates but with contrasting levels of those covariates.

Tuareg ethnoveterinary treatments of camel diseases in Agadez area (Niger)

For generations, nomadic herders have been learning to manage herd health, particularly in dromedaries because of their great value. Owing to the unavailability of veterinary services, camel herders in remote areas have been developing their own pharmacopoeia and veterinary techniques. The bleeding of sick animals is a common treatment, as Tuareg herders believe that ‘tainted blood’ (izni) is the cause of many conditions. Several surgical techniques are also used, such as excision of calcified sublingual cord. The remedies mentioned in this survey are derived from Maerua crassifolia, Boscia senegalensis, Acacia raddiana, Cucumis prophetarum, Calotropis procera, Ricinus communis, Citrullus colocynthis, green tea, millet, tobacco and onions. Artificial elements are also used for treatment of animals: Powders collected from batteries, various haircare or skincare creams, crushed glass, insecticides or motor oil belong to their pharmacopoeia. This broadmindedness allows the introduction of modern veterinary medicine. Factors such as the lack of real production objectives constitute limits to this progress, however.

Interrelationships between health status and farm management system in French dairy herds

Abstract The notion of pathological associations has led researchers to establish farm ‘health profiles’, in the knowledge that a certain number of health disorders on stock seem to be correlated. In this study (part of an eco-pathological survey of 83 dairy farms representative of the range of dairy farm types to be found in France), five health profiles are described, allowing classification of the farms according to incidence levels of infectious diseases of the foot, uterus and teat (Profile 3), incidence of calving disorders (Profiles 2 and 4) and low disease incidence in general (Profiles 1 and 5). The farms were also analysed in terms of farm structure data, providing a classification into three dairy farm classes defined as traditional, intensive and intermediate. Crossing these three farm types against the five health profiles reveals a concordance between traditional farms and low-pathology health profiles, between intensive farms and a high incidence of infectious disease, and between intermediate farms and calving disorders. This concordance suggests that some production systems should be regarded as high risk, with a higher risk where the farmer has insufficient mastery of the techniques required for good herd management.

Camel meat and meat products

Camel meat has many benefits as a meat product. It has low fat content and is highly nutritious, and has potential to be used to combat hyperacidity, hypertension, pneumonia and respiratory disease. This book reviews up-to-date literature on camel meat and meat products, carcass and meat quality characteristics, muscle structure, post-mortem analysis and the nutritive value to humans. A comparatively small component of global meat consumption, camel meat has the potential to undergo an explosion of production worldwide, and currently farming for camel meat in Asia, Africa, Latin America and Australia is undergoing significant expansion. The potential of camel meat in helping to meet projected world food shortages, and being sustainably farmed, is also explored by the editors.

A comparison of dairy cattle systems in an irrigated perimeter and in a suburban region: case study from Morocco.

Multivariate analyses were used to compare dairy production practices and their consequences on milk yield and profitability in cattle farms from two representative regions of Morocco. A regular follow-up of 118 farms (48 in the Rabat-Salé suburban belt and 70 in the Gharb irrigated perimeter) was undertaken to obtain accurate data. Results show significant differences between the two regions. Intensive milk production was more frequent in the suburban zone (more concentrates and better annual milk yield per cow). When conducting a “within-region” principal components analysis, farms’ discrimination appeared to take into account all management variables (feeding, cattle sales, profitability), with no reference to farms’ structural parameters (arable land and number of cattle). A typology of farms was then established using cluster analysis, with 4 distinct groups, namely: a) concentrates wasters, b) farms with a relatively important milk yield per cow, c) deficit dairy farms and d) beef oriented farms. The last group included almost exclusively farms from the irrigated perimeter (5 out of 7). These results indicate that dairy production promotion in Morocco requires more than just the intensification of forage production, but should focus also on improving management practices. The extension of complete and balanced dairy rations is urgently needed to enhance milk yield and profitability.