Dry matter intake and milk yield of cows grazing Xaraés palisadegrass under different management strategies

This study aimed to evaluate the intake and milk yield of crossbred cows (Holstein x Zebu), under two management strategies, based on 95% light interception and fixed days. Eight lactating cows with body weight of 466 kg (± 35 kg) and lactation stage of 137 days (± 107 days) were used, four animals were assigned to each treatment. Dry matter intake was estimated indirectly, using neutral detergent insoluble fiber as internal indicator and chromium oxide as external indicator. This was a completely randomized design, with four replications, two grazing strategies and three days of occupation. The animals under light management showed dry matter intake on the first day (11.42 kg) similar to the second day (9.57 kg), and this was similar to the third day (7.06 kg), but the intake on the first day was greater than on the third day. On the fixed days, intake did not differ between the first and second day (12.05 and 11.47 kg, respectively), and intake of the third day (6.70 kg) was lower than in the first two days. The dry matter intake in relation to the body weight of the animals presented similar results to the dry matter intake of forage in kilos, which can be explained by the small difference in weight between the mean of the groups. The individual milk yield showed a similar behavior among the grazing strategies for the days of occupation, which increased from the first to the second day (12.49 to 13.88 kg) and decreased from the second to the third day (12.20 kg). Grazing management strategies did not promote differences in the performance traits of lactating cows. The day of grazing during the period of occupation can be decisive for intake and production.(AU)

Dry matter intake and milk yield of cows grazing Xaraés palisadegrass under different management strategies

This study aimed to evaluate the intake and milk yield of crossbred cows (Holstein x Zebu), under two management strategies, based on 95% light interception and fixed days. Eight lactating cows with body weight of 466 kg (± 35 kg) and lactation stage of 137 days (± 107 days) were used, four animals were assigned to each treatment. Dry matter intake was estimated indirectly, using neutral detergent insoluble fiber as internal indicator and chromium oxide as external indicator. This was a completely randomized design, with four replications, two grazing strategies and three days of occupation. The animals under light management showed dry matter intake on the first day (11.42 kg) similar to the second day (9.57 kg), and this was similar to the third day (7.06 kg), but the intake on the first day was greater than on the third day. On the fixed days, intake did not differ between the first and second day (12.05 and 11.47 kg, respectively), and intake of the third day (6.70 kg) was lower than in the first two days. The dry matter intake in relation to the body weight of the animals presented similar results to the dry matter intake of forage in kilos, which can be explained by the small difference in weight between the mean of the groups. The individual milk yield showed a similar behavior among the grazing strategies for the days of occupation, which increased from the first to the second day (12.49 to 13.88 kg) and decreased from the second to the third day (12.20 kg). Grazing management strategies did not promote differences in the performance traits of lactating cows. The day of grazing during the period of occupation can be decisive for intake and production.

INFLUÊNCIA DE UM PROCESSO ARTIFICIAL DE INDUÇÃO DE LACTAÇÃO NA SAÚDE DAS VACAS

Protocolos hormonais de indução artificial de lactação constituem uma alternativa para reduzir perdas econômicas decorrentes de baixos índices reprodutivos. Objetivou-se neste estudo avaliar o efeito da indução artificial de lactação na saúde das vacas, por meio dos exames físico e complementares (hemograma e bioquímica sérica). As vacas foram submetidas ao protocolo de 21 dias de tratamento com aplicações de benzoato de estradiol, progesterona, cloprostenol, dexametasona e somatotropina bovina recombinante. Foi realizado exame físico e coleta de amostras sanguíneas semanalmente. Os animais responderam ao protocolo e apresentaram-se clinicamente saudáveis. No dia vinte e um, todos os animais apresentaram leucograma de estresse, devido à dexametasona. Os valores da enzima sérica aspartato amino transferase estiveram elevados nos momentos dia sete e dia quatorze devido à aplicação excessiva de medicação intramuscular, fosfatase alcalina e gama glutamiltransferase apresentaram valores crescentes, não caracterizando hepatopatia. Os animais mantiveram escore de condição corporal, níveis normais de colesterol, superiores de triglicerídeos, e tendência de redução do beta hidroxibutirato (BHBA). O protocolo foi eficiente ao ser implantado em vacas leiteiras mestiças e os medicamentos utilizados não interferiram na saúde dos animais.

Hormonal protocols lactation artificial induction are an alternative to reduce economic losses due to low reproductive rates. There are no studies with clinical evaluation of the animals submitted to the protocols. The objective of this study was to evaluate the effect of lactation artificial induction on the health of the animals, through the physical and complementary exams (hemogram and serum biochemistry). 12 cows were submitted to a 21-day treatment protocol with estradiol benzoate, progesterone, cloprostenol, dexamethasone and recombinant bovine somatotropin. Physical examination and blood sampling were performed weekly. The animals responded to the protocol and were clinically healthy. In D21, all animals showed stress leukogram due to dexamethasone. The AST serum enzyme values were elevated at moments D7 and D14 due to the excessive application of intramuscular medication, AF and GGT presented increasing values, not characterizing liver disease. The animals maintained body condition score, normal cholesterol levels, higher triglycerides, and a tendency to reduce beta hydroxybutyrate (BHBA). The protocol was efficient when it was implanted in crossbred dairy cows and the drugs used did not interfere in the animals health, allowing the pregnancy and the gestation of them.