Evaluation of the productive and reproductive performance of Holstein dairy cows reared in a warm Tunisian (Mediterranean) climate.

This work consists in studying the productive and reproductive performance of Holstein dairy cows (n=77) reared an intensive production system a Mediterranean climate, as well factors their variations. Meteorological data collected between 2017 2020 for region Beja, North-West Tunisia, revealed that average monthly values ​​of ambient temperature (Ta), relative humidity (HR) temperature-humidity index (THI), are respectively 19.97 ±1.24°C, 73.69±3.42%, 66±1.74. During 3 years study, were exposed to hot summer season which began Jun (THI= 76) persisted until September (THI =77). On average, milk at 305 days lactation, fat (MG) protein (MP) content, somatic cell count (SCC) 5782 ± 358 Kg, 3.36 1.65%, 3.12 0.42% 489 x 103 cells/ml. Several significantly (P < 0.05) affect production. Indeed, highest is observed during year 2020. When THI increases, drop greater (-0.18kg/d, per point). Multiparous produce more than primiparous cows, with higher yields peak lactation (30.0 kg/d) lower persistence coefficient (95.6%). Cows calved winter produced (+22%; P<0.05) summer. The interval calving first insemination (IV-IA1), fertilizing (IV-IAF) (IVV) 87.4 28.2 days, 134 71 425 ±75 respectively. success rate 1st (TRIA1) three or insemination, number inseminations conception 29.1±18.5%, 9.7±5.5% 2.11±1.6. In conclusion, control breeding conduct, particular heat detection technique, essential improve productivity cow raised Tunisian climate.