Relatório do estágio pré-profissional na exploração agrícola do établissement public local d'enseignement et de formation professionnelle agricole (Eplefpa) de Saint Joseph : influência do número de lactação na produtividade e qualidade do leite das vacas holandesas e suas cruzas com Pardo suíço

Abstract

This report describes the activities developed during the internship in animal production carried out on Réunion Island, France, at the Établissement Public Local d'Enseignement et de Formation Professionnelle Agricole farm. The internship consisted of directly monitoring the management routines in the swine, goat, broiler, and dairy cow sectors, encompassing management, feeding, health, hygiene, reproduction, and production monitoring activities. Practical participation in field routines allowed for the consolidation of essential technical skills for professional practice. During the internship, a study was developed on the effects of lactation number and breed on milk production and quality. Production records of 26 cows distributed across four lactation numbers were analyzed using a two-way ANOVA (breed × lactation number) followed by Tukey's test (p<0.05). Average daily production ranged from 22.6 to 32.2 kg/day in Holstein cows and from 21.0 to 30.4 kg/day in crossbred cows, with a significant effect of lactation number (p=0.013). The third lactation showed the highest values ​​(32.2 kg/day Holstein; 30.4 kg/day F1), followed by the second and first lactations, representing increases of more than 40% compared to the initial lactations. Protein levels ranged from 3.11% to 3.46% in Holstein cows and from 3.24% to 3.34% in crossbred cows, while fat levels ranged from 3.14% to 3.80% and from 3.52% to 3.92%, respectively, with no significant effect of lactation number (p>0.05). However, a significant effect of breed on fat content was observed (p=0.033), with higher values ​​in crossbred cows (3.84±0.34%) compared to Holstein cows (3.56±0.32%). Somatic cell count (lnCCS) remained between 11.7 and 13.4 in Holstein cows and 10.5 and 12.1 in crosses, with no significant differences between lactation numbers or breeds (p>0.05). It is concluded that the number of lactations is determinant for productivity, peaking in the third lactation, and that the Holstein × Brown Swiss cross improves fat content without compromising production. The adoption of good management practices and crossbreeding strategies constitutes a promising alternative for the sustainability of intensive systems in tropical regions. (TRADUÇAO NOSSA)