Levantamento sobre a nutrição proteica de vacas em lactação com nutricionistas brasileiros

Abstract

Protein plays a multifactorial role in the nutrition of dairy cows, being necessary to meet various physiological and metabolic demands, ensuring an adequate supply so that animals achieve better health and performance responses. The objective of this study was to describe the practices adopted by Brazilian nutritionists regarding the protein nutrition of lactating cows.The research was conducted through an online questionnaire on the Google Forms platform, consisting of 36 questions directed at nutritionists working on dairy farms in Brazil. Descriptive statistics were performed for all numerical variables. Open-ended questions were summarized and grouped into categories based on content similarity. The responses were counted using the "COUNTIF" function in Excel. A cluster analysis was performed according to the cows' production level, generating three analysis groups.A total of 56 nutritionists responded to the questionnaire between June and October 2024, covering 3,008 clients and an average of 83 lactating cows per farm across 17 Brazilian states, with an average milk production of 27.8 kg/cow/day. The NASEM (2021) model was described as the primary tool used by nutritionists in diet formulation for lactating cows.Nutritionists reported several challenges in balancing protein in animal diets, with the main ones being high costs and the lack of diversity in protein ingredients. Crude protein was described as the primary metric for protein balancing by 25% of respondents. Most nutritionists reported changes in their protein recommendations for lactating cows over the past three years.Additionally, bulk tank milk urea nitrogen was described as the main tool used by nutritionists to assess protein adequacy in dairy cow diets. Conventional soybean meal was mentioned by all nutritionists as a commonly included ingredient in lactating cow diets, and the main criterion for ingredient selection was the cost per unit of crude protein.Furthermore, many nutritionists expressed concerns about the future regulation of nitrogen excretion by dairy farms. However, many nutritionists still do not adopt the NASEM 2021 model for diet formulation, and despite changes in protein recommendations, they continue to use outdated metrics for protein balancing.