Periódicos Brasileiros em Medicina Veterinária e Zootecnia

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Machine milking impact on dairy cows physiological adjustments: an observational approach according to different breed

Fazio, EsterinaMedica, PietroCravana, CristinaFerlazzo, Adriana

Background: Machine milking can induce both physical and psychological stimuli, with physiological adjustments, including adrenocortical, haematochemical and haematological changes, particularly in dairy farms. The purpose of the present study was to evaluate the physiological patterns of cortisol responses and total protein and haematocrit changes in pregnant dairy cows before and after morning and early afternoon machine milking, by taking into account the effect of different milking times and breed.Materials, Methods & Results: This was a comparative and observational study on the adaptive responses of circulating cortisol concentrations, total protein and haematocrit values to machine milking evaluated in 36 healthy multiparous lactating dairy cows, 5.2 ± 2.54 years of age, at the 4th-5th month of pregnancy, stabled in stall. The animals were divided in three groups according to different breed (group A: 10 Holstein Friesian dairy cows; group B: 10 Swedish Red dairy cows; group C: 16 crossbred (Friesian-cross) dairy cows and were submitted to machine milking 2 times daily at 06:30 a.m. and at 03:30 p.m. Blood samples were collected via the coccygeal vessels in the tail, in the morning: in baseline conditions (before milking) at 06:00 a.m., and after milking at 07:00 a.m.; and in the early afternoon: in baseline conditions, at 03:00 a.m., and after milking at 04:00 p.m. for two consecutive days. One-way RM ANOVA showed significant effects of the machine milking on the cortisol (F=29.66 and F=11.50; P < 0.001), total protein (F=27.24 and F=30.34; P < 0.001) and haematocrit (F=19.44 and F=13.50; P < 0.01) changes in Holstein Friesian dairy cows, both at morning and at afternoon.[...](AU)

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