Effect of local diets on nutritional and sensory quality of meat of indigenous goats in Tunisian arid regions.

The valorization of natural resources in small ruminants feeding can reduce the cost of feed and produce good meat quality. The objective was to evaluate the effects of local feed resources on the physico-chemical aspects, the sensorial characteristics and the fatty acid profile of goat kid's meat. Twenty-six kids are divided in three groups (average body weight = 15.85 kg; age = 4 months). The groups received oat hay (group control C), dried olive leaves + dried Stipa tenacissima (group OL) or grass hay (group Ko). The animals were slaughtered after 90 days of experience, with an approximate final live weight of 18.5 kg. Total solids, pH, fat, crude protein, vitamin, cholesterol and fatty acid contents of meat were determined. The OL group had the highest ultimate pH (6.82 vs. 6.73); cooking loss, gross composition (total solids, protein and fat), cholesterol and colour coordinates (L, a* and b*) were similar among groups. The vitamin E, affected by diet, was higher in group OL than the other groups (3.71 mg/kg vs. 1.32 and 2.17 mg/kg, respectively, for C and Ko groups). Moreover, meat from this group showed the highest saturated fatty acid. Unsaturated fatty acids content was higher in the meat of C and Ko groups. On the other side, polyunsaturated fatty acid level was not affected by the diet treatment. The n6/n3 ratio was significantly affected by the diet; it was lower in meat of groups Ko and OL (3.17 and 3.38 respectively). The feeding effect on sensory quality of meat was not significant.

Effects of vacuum level and pulsation rate on milk ejection and milk flow traits in Tunisian dairy camels (Camelus dromedarius).

This work aims to compare the effects of milking at two vacuum levels (38 and 48 kPa) and three pulsation rates (60, 90, and 120 cpm) on milk production and milk flow characteristics. Six multiparous Maghrebi camels in late lactation and once daily milked were used. The best combination of setting for camel's milking was high vacuum and low pulsation rate (48 kPa/60 cpm). Milk yield and average and peak milk flow rate were the highest, while milking time was the shortest using this combination of setting (3.05 ± 0.30 kg, 1.52 ± 0.21 kg/min, 2.52 ± 0.21 kg/min, and 3.32 ± 0.31 min, respectively). Lower vacuum level lengthened milking time by more than 100 % and was not sufficient to extract milk correctly (1.69 to 2.48 times less milk yield harvested), suggesting a negative interaction with the stimulatory effect of pulsation. Higher pulsation rates did not better stimulate the camels and induced more bimodality and lower milk flow rates. Animal characteristics and liner/claw design affect machine milking and further investigations must be carried out to verify their effects and to study long-term effect of high vacuum level on udder health and teat condition.

First description of milk flow traits in Tunisian dairy dromedary camels under an intensive farming system.

In order to evaluate milking ability in dromedary camels, 124 milk flow curves were registered during morning milking of 20 dairy Maghrebi dromedary camels. Animals were in lactations 1-8, were 6-19 years old and were 4-15 months of their current lactation. Milk flow curves were recorded using an electronic milk flow meter (Lactocorder®). Milk flow curves were classified in three typical patterns: type 1 represents curves with one high and short peak of milk flow; type 2 represents curves with a moderate mean milk flow rate during a large plateau phase; and type 3 represents curves with lower mean milk flow rate and a relatively longer milking duration. The ratio of the different milk flow patterns in the population evaluated was 40:38:22% for types 1, 2 and 3, respectively. The highest milk yield per milking, average and peak milk flow were observed in camels with type 1 curves (4·24 kg, 1·49 and 3·54 kg/min, respectively) followed by type 2 animals (3·30 kg, 1·12 and 2·12 kg/min, respectively) and lastly type 3 curves (2·34 kg, 0·65 and 1·23 kg/min, respectively). This study confirmed that a major proportion of dromedary camels have a suitable machine milking ability. Nevertheless, our results suggest that pre-stimulation and improving the milking process may improve milking efficiency and guarantee a more complete and rapid emptying of the udder.