Weekly milk samples from ten lactating she camels (Camelus dromedarius) were analyzed regularly for 11 months after parturition. The main values for all samples were 2.54 ± 0.72g/100g fat matter, 3.07 ± 0.30g/100g protein, 4.21 ± 0.37g/100g lactose and 0.76 ± 0.10g/100g ash. Fat content decreased from 3.41% at the first week to 2.29% at 36th week post-partum with rising at the end to 2.95% while protein decreased from 3.44% at week 1 to 2.79% at the end of lactation, and lactose from 4.48% to 3.90%. Ash increased from 0.72% to 0.82% then decreased down to 0.71%. Regarding seasonal variation, maximum level of fat was observed in January (3.46%) and minimum at summer time (2.29% in July). Protein content was maximum in February (3.32%) and minimum in October (2.76%). For lactose, the maximum mean value was 4.38% in February and the minimum in September (3.83%). The ash content was quite variable in January then stable all over the year. All components were highly positively correlated, except between fat and ash content which was not significant. No significant effect of parity, gestation length, calf body weight at birth or adult weight on all milk content. The average total milk production was 1207 L for 11 months range between 875 and 1616 L. The correlation between milk production and milk components are significantly negative.

A total of 22 dairy dromedary camels under intensive conditions in late lactation (275±24 days) were used to study the relationship between external and internal udder morphology and machine milking performances. Measurements of udder and teat morphology were obtained immediately before milking and in duplicate. Individual milk yield, lag time and total milking time were recorded during milking, and milk samples were collected and analyzed for milk composition thereafter. Cisternal and alveolar milk volumes and composition were evaluated at 9 h milking interval. Results revealed that dairy camels had well developed udders and milk veins, with medium sized teats. On average, milk yield as well as milk fat and protein contents were 4.80±0.50 L d-1, 2.61±0.16% and 3.08±0.05%, respectively. The low fat values observed indicated incomplete milk letdown during machine milking. Lag time, and total milking time were 3.0±0.3, and 120.0±8.9s, on average, respectively. Positive correlations (p<0.05) were observed between milk yield and udder depth (r=0.37), distance between teats (r=0.57) and milk vein diameter (r=0.28), while a negative correlation was found with udder height (r=-0.25, p<0.05). Cisternal milk accounted for 11% of the total udder milk. Positive correlations were observed between total milk yield and volume of alveolar milk (r=0.98; p<0.001) as well as with volume of cisternal milk (r=0.63, p<0.05). Despite the low udder milk storage capacity observed in dairy camels, our study concluded that the evaluated dromedary sample had adequate udder morphology for machine milking. Finally, positive relationships were detected between milk yield and udder morphology traits of dairy camels.

Weekly milk records of 47 she-camels in a multibreed dairy camel herd were collected for over a period of 5 years. A total of 72 lactation curves were defined, and relationships with parity, calving season, lactation length, milk production level, following lactations, and dam weight were analyzed. Overall mean values were milk yield up to 12 months, 1,970 ± 790 l; lactation length, 12.5 months; persistency, 94.7 %; weekly peak yield, 50.7 l; monthly peak yield, 220 ± 90 l; and the number of weeks to reach peak yield, 28. The highest productivity was recorded in summer with a weekly mean of 48.2 ± 19.4 l, compared with 34.1 ± 16.3 l in winter. The highest average yield recorded was for camels at sixth parity, whereas the highest weekly peak was at eighth parity, and highest persistency at fifth parity. Camels that calved during the cold months (November to February) were most productives, with the highest persistency, peak yield, and longest lactation length. Four types of curves were identified corresponding to different parities and milk yield levels. Based on these data, specific models for camels are proposed.

By-products from olive culture provided to camel could modify the fatty acid composition of its milk. The present experiment involving ten lactating shecamels divided in two groups aimed to evaluate the effect of enriched diet with crude olive cake on the milk production, milk fat excretion and fatty acid composition. The control group received diet including alfalfa, barley and concentrate. In the treated group, barley was partially substitute by olive cake (3 kg.day?1 as fed) for more than 3 months. There was no negative or positive impact on milk production, the fat and protein content in milk. However, a significant increase of total quantity of fat and protein excreted in milk was observed in treated group. Some changes were observed in fatty acid composition with a decrease of medium-chain fatty acids (C15:0 iso, C15:0, C16:0 iso, C17:1) but also vaccenic acid (C18:1?-7). At reverse an increase of palmitic (C16:0) and ?-linolenic acid (C18:3?-6) was observed after 3 months of olive cake distribution. As for other ruminants, it is possible to modulate the fatty acid composition of camel milk by the diet, but further trials for longer period and highest quantity of olive cake have to be implemented in camel. (Résumé d'auteur

In order to determine the effect of some factors, as different levels of energy and protein, milking interval, lactation stage, and lactation rank on she-camel performance after weaning of camel-calves, 20 lactating shecamels were divided into four groups, 5 animals each, according to age and weight at last parturition. Groups had randomly allocated to one of four treatments diets. Group A received diet with 13% Crude Protein (CP) and 2.4 MCal Metabolisable Energy (ME). Group B received diet with 13% CP and 3.0 MCal ME. Group C and D received diet with 15% CP and 2.4, 3.0 MCal ME respectively. Diets contain 35/65 (roughage/concentrate, respectively). After 14 days of adaptation period, individual feed offered and orts had been recorded, daily and continued up to entire experimental period of 10 months. Milk yield was recorded two milking time from three consecutive days. The results show that diet (B) gave higher milk yield (MY), Fat Corrected Milk (FCM), Energy Corrected Milk (ECM) and Feed Conversion Ratio (FCR) 8.32, 11.77, 7.47, and 1.38 respectively. Diet (A) has higher fat % content when comparing with the other diets. Treatment did not affect milk composition except on fat and ash percentage. Milk secretion rate for 10 hours milking interval "evening milking" was higher comparing with 14 hours milking interval "morning milking" 397, 353 g/h respectively. Maximum MY, FCM and ECM were at mid lactation. In late lactation MY, FCM, ECM decreased. Higher milk productivity was at 3rd and 6th season of lactation.

Reproductive traits and calving weight were assessed in Saudi camels, and non-genetic factors influencing them were studied using data collected at Al Jouf centre from 1987 to 2009. Age at first conception, age at first calving, open period, calving interval, gestation length and weight at calving of camels averaged 42.3 months, 54.8 months, 10.6 months, 22.6 months, 377.5 days and 591.9 kg, respectively. A mixed model including the camel as a random effect was used to assess the effect of environmental effects on the traits studied. Age at first conception and age at first calving were affected by camel's birth year. Open period and calving interval were not affected by parity or year of calving. However, camels that calved from October to February had a calving interval of 2.5 months higher than those that calved from March to September. Gestation length was affected by season and year of calving but not by parity or sex of calf. Camels calving from March to September had a gestation length 6.6 days shorter than those calving from October to February. Weight at calving was affected by parity and year of calving but not by season of calving. It was concluded that an improvement in camel reproductive traits is possible both through improving management systems and utilisation of controlled breeding techniques.

No abstract

Selenium deficiency is widely described in livestock from the Arabian Peninsula, notably in the camel, and selenium supplementation is based on cattle or horse requirements, usually with sodium selenite product. In order to test the effect of organic Se supplementation vs inorganic Se, 24 pregnant camels were subjected to 3 treatment groups starting one month before delivery (control without Se, non-organic bolus, organic Se). Blood, milk and feces samples were collected from one month before delivery to 3 months of lactation. At delivery, the organic group had a significant higher Se concentration (P < 0.01) in serum (8.21± 1.38 lg/100 mL) and in colostrum (7.27 ±2.89 lg/100 mL) than in inorganic group (3.90 ±0.68 and 3.72 ±0.71, respectively) and than in control group (5.45 ± 2.38 and 2.70 ± 0.66, respectively). In calf serum, the Se concentration was significantly higher (P < 0.001) in the two supplemented groups (6.32 ± 2.81 and 5.99 ± 3.31 lg/100 mL in organic and inorganic groups, respectively) than in control (3.42 ±1.41 lg/100 mL). The Se in mother serum decreased after parturition but was highly correlated to Se serum in calf and to Se fecal excretion. Se in milk was lower than in colostrum in all groups (P < 0.01). Treatments had no significant effect on somatic cell count. This study revealed that organic supplementation in camel appeared more efficient. (Résumé d'auteur