1Département de Biotechnologie Animale, Institut Supérieur de Biotechnologie de Beja, Université de Jendouba, Tunisie.
2 Environmental Biomonitoring Laboratory (LR01/ ES14); Faculty of Sciences of Bizerte - University of Carthage Tunisia.
Abstract - The objective of this work was to evaluate the productive and morphological changes of the udders of local-crossbreed cows (Brune de l’Atlas x Frisonne) in Tunisia. A total of 10 multiparous cows milked twice a day using portable machine milking were used. Milk production, physical-chemical composition of milk, and somatic cell count were collected for 4 months. Evaluations of the external morphology of udder as well as posterior and anterior teat were performed before evening milking. Time of udder preparation (T1), time between the end of udder preparation and cluster attachment (T2), and total machine milking time (T3) were performed. Average milk flow rate was calculated and residual milk was determined after oxytocin injection. Milk production varies significantly by recording month with a peak production level in April (10.2 ± 0.84 l/d). The content on milk fat; protein; lactose and total dry matter were 3.7; 2.9; 4.8 and 12.2%, respectively. The average somatic cell count was 256.000 cells / ml. The values of T1, T2 and T3 were 1.52 min; 2.05 min and 5.35 min, respectively. Residual milk represents 19.4% of total milk production. Udder measurement shows that the local-crossbreed cow was characterized by a more or less developed udder with teats a little thick and long. In addition, a positive correlation was observed between milk production and length as well as circumference of the udder. It is concluded that the local breed-cross cow in Tunisia has an interesting productive potential. Improved milking management can significantly increase the productive potential of this breed.