Comparación del estado de salud de la ubre y la calidad sanitaria de la leche de vacas ordeñadas manual o mecánicamente Comparison of udder health and sanitary quality in bulk tank milk from cows manually or mechanically milked

The objective of this study was to compare udder health and milk quality in a bulk tank in two groups of cows of small herds. The first with 14 cows milked manually (G 1 ) and the second with 21 machine milked cows (G 2 ). Adequate milking practices were applied and controlled in both groups. The study was carried out for five weeks in a herd located in a dry tropical region of Mexico. Prevalence and incidence of subclinical mastitis was studied by clinical examination and by the California mastitis test in each gland. The milk’s sanitary quality was studied by bacteriological analysis and by determination of acidity of the milk. In G 1 , the mean prevalence rate of subclinical mastitis was 57%, incidence rate was 29 per one hundred weeks-cow (8 of 27), and prevalence rate of clinical mastitis was 7%. In G 2, the prevalence rate was 33%, incidence rate of subclinical and clinical mastitis were 10 per one hundred weeks-cow (7 of 70) and 0.96 per one hundred weeks-cow (1 of 104), respectively; thus udder health was better in G 2 than in G 1 (P 0.05). Coliform counts for G 1 and G 2 were: 421 ± 286 and 144 ± 180 CFU/ml, respectively; bacterial load being 2.9 times higher in G 1 than in G 2 (P 0.05). It is concluded that udder health and sanitary quality of milk obtained by mechanical milking were better than in cows that were manually milked.