RESUMO: Os objetivos deste estudo foram descrever as práticas de manejo usadas em granjas leiteiras no sul do Brasil e compreender as percepções e atitudes dos agricultores acerca destas práticas. Granjas (n=135), localizadas nos 32 municípios do norte do Rio Grande do Sul (Alto Uruguai Gaúcho), foram visitadas e caracterizadas em relação a todas as práticas de manejo da bezerra através de inspeção e entrevistas com os agricultores. Em outro momento, foram realizadas 25 entrevistas em profundidade para entender as percepções e atitudes dos agricultores acerca destas práticas e a sua potencial influência sobre o bem-estar e desempenho das bezerras. A maioria dos entrevistados percebia o manejo da bezerra como de importância marginal para a atividade. Em geral, os agricultores não perceberam o bem-estar animal como relevante e as práticas de manejo adotadas eram baseadas em fatores práticos e econômicos. Estas conclusões são consistentes com as práticas usadas pelos mesmos agricultores, muitas das quais representam fatores de risco para o bem-estar, crescimento e sobrevivência das bezerras. Sete fatores, (autorresponsibilidade, ambição econômica, assistência técnica, sucessão familiar, vivências, especialização e comprometimento familiar) aparentaram influenciar as percepções, atitudes e escolhas dos agricultores acerca das práticas de manejo que afetam o bem-estar e desempenho das bezerras. Estes fatores devem ser considerados na concepção de programas que visam melhorar o manejo da bezerra leiteira.

ABSTRACT: This study aimed to describe the management practices used in dairy farms in the south of Brazil, and to understand farmers’ perceptions and attitudes regarding these practices. Farms (n=135) located in all 32 of the municipalities in the northern region of Rio Grande do Sul (Alto Uruguai Gaúcho), Brazil were characterized regarding all calf management practices during a farm visit where farms were inspected and farmers interviewed. In a second visit, 25 in depth interviews were done to understand farmers’ attitudes and perceptions towards these practices and potential influence on calves’ welfare and performance. Management of lactating calves was perceived by most of the interviewees as of marginal importance for dairy activity. In general farmers did not perceive animal welfare as relevant, and most chose management practices mainly based on practical, productive and economic factors. These conclusions are consistent with management practices used by farmers, many of which represent risk factors for low calves’ survival, growth and welfare. Seven factors (self-responsibility, economic ambition, technical assistance, family succession, urban experiences, specialization and family commitment) appeared to influence farmers’ perceptions, attitudes and choices regarding husbandry practices that affect the welfare and performance of calves, which may be considered when designing programs aiming to improve dairy calf management.

Feed shortages are relatively frequent in subtropical pasture-based dairy production systems. The effect of feed restriction on milk yield and physical-chemical traits was evaluated in this study. The experiment was carried out in Brazil's south region. Treatments consisted of control and restricted diet. Six multiparous and six primiparous cows, with 499 ± 47.20 kg body weight (BW), at mid-lactation (188 ± 124 days in milk), producing 19.35 ± 4.10 kg of milk were assigned to two groups, balanced for parity, each group receiving a different sequence of the dietary treatments for 56 days, in a crossover design. Diet nominated as control included 8 kg DM 100 kg BW-1 of Bermuda grass var. Tifton pasture (Cynodon dactylon (L.) Pers.), 5.00 kg of concentrate and 2.50 kg of Tifton hay per day. The restriction diet consisted of 50 % of the quantity offered in the control diet. Milk production and physicochemical composition were evaluated. Feed restriction reduced milk production by 40 %, body condition score by 5 %, milk magnesium by 14.3 %, lactose by 1.7 %, titratable acidity by 10 % and stability to the ethanol test by 9 % and it tended to increase (7 %) milk potassium content. No changes were found for the remaining characteristics. Since feed restriction is quite frequent in Brazil's extensive dairy production systems, our concern is that besides decreased milk production, changes can occur in the physiochemical attributes of the milk, mainly a reduction in the stability to the ethanol test, which may increase the volume of milk rejected by the industry.

O objetivo deste trabalho é apresentar os principais resultados da pesquisa sobre o leite instável não ácido ou LINA. A proporção de amostras de leite com estabilidade térmica, abaixo do mínimo exigido pela indústria brasileira, configura um sério problema, com uma ocorrência mais elevada durante os períodos de carência alimentar. Trata-se de um problema multifatorial, cujos fatores intervenientes são relacionados à execução do teste (concentração do álcool), ao manejo (alimentação, clima, relação homem-animal), ao animal (suscetibilidade ao estresse, potencial produtivo, estádio da lactação, sanidade, problemas digestivos e metabólicos, frações da caseína), entre outros. Existem dúvidas quanto à capacidade do teste do álcool em estimar a estabilidade térmica do leite. A indústria necessita de um teste rápido, de baixo custo e que realmente identifique o leite adequado ao processamento térmico. O manejo correto dos animais, aliado ao uso de parâmetros realistas de execução do teste do álcool, pode contribuir para melhorar a estabilidade do leite.

This paper aimed to present the main results about the unstable non acid milk (LINA). The proportion of milk samples with thermal stability below the Brazilian dairy industry standard is a serious problem, with highest occurrence at short food supply periods. It is a multi factorial problem, which causing factors are related to test execution (ethanol concentration used), to management (feeding, climate, human-animal relation), to animal (stress susceptibility, productive potential, lactation stage, sanitary condition, digestive and metabolic disorders), among others. There are doubts to the accuracy and precision of the alcohol test to detect stability problems. Dairy industry needs a fast, low price and easy test, but that can identify milk suitable to thermal processing. An adequate animal's management besides realistic parameters of milk test might contribute to improve milk stability.