Prácticas de manejo en explotaciones de ganado vacuno lechero y su influencia en la calidad de la leche

Abstract

Consumers are choosing to buy healthy dairy products from farms that meet hygiene and animal welfare requirements. Good hygienic practice guides have been developed to help farmers manage their farms in accordance with these requirements. The work carried out in this thesis was designed to verify whether the implementation of the management practices proposed in the 2005 INLAC Guide for Dairy Cattle on dairy farms provides an assurance of the hygienic quality of the milk obtained. Audits were carried out, using the Guide as a reference, in 148 dairy cattle farms in Galicia, after which they were classified according to the points obtained and divided into four groups from lowest to highest score. It was found that the sections of the INLAC 2005 Guide referring to water quality, management of medicines and veterinary treatments, the configuration of the milking and dairy premises and their materials, and milking and milk cooling equipment were decisive in this evaluation, as they showed the greatest differences in points between the groups of farms studied. The farms with the lowest scores had 18% higher somatic cell counts, 88% higher bacterial counts and 5.52 times more inhibitor positives in tank milk than those with the highest scores. At each of the visits, a water sample was taken to check the microbiological quality of the water and its relation to the bacteriology in tank milk. The results indicated that the vast majority used untreated own well water and that there was a well-identified geographical area with a 5.5 times higher relative risk of faecal streptococci in water. While it was shown that those farms with water microbiology problems managed to keep milk bacteriology within legal limits, farms with poor water quality belonged to the group with the lowest scores in the audits to verify compliance with the 2005 INLAC Guide, with the worst milk hygiene quality indices. Finally, the impact of maintaining external certification of the INLAC Guide by an accredited body was studied in the 13 farms that had this certification, all of which were in the group with the highest scores.