Produção e composição química do leite, consumo e digestibilidade de forragens tropicais manejadas em sistema de lotação intermitente

Abstract

RESUMO -Os objetivos neste trabalho foram comparar a composição química, a digestibilidade in vitro da matéria seca (DIVMS), as frações lâminas foliares e bainhas-colmos e a disponibilidade de forragem e avaliar a produção e composição do leite, o peso vivo, o escore corporal e o consumo de matéria seca de forrageiras tropicais. As forrageiras avaliadas foram capim-tanzânia (Panicum maximum Jacq.), grama-estrela (Cynodon nlemfuensis Vanderyst) e capimmarandu (Brachiaria brizantha Staf). As pastagens foram adubadas com nitrogênio (200 kg/ha.ano), K 2 O e P 2 O 5 (50 kg/ha.ano) e manejadas em sistema de lotação intermitente com três dias de ocupação de piquete e dois intervalos de desfolha: janeiro e fevereiro com 24 dias e março, abril e maio com 30 dias. Foram utilizadas 24 vacas em delineamento de blocos ao acaso, com oito vacas por tratamento. As lâminas foliares da grama-estrela tinham em média 18,5% de PB e as bainhas-colmos, 79,9% de fibra em detergente neutro (FDN), valores superiores aos obtidos nas demais forrageiras.A grama-estela também apresentou maior teor de FDN (72,8%) e lignina (7,1%) na forragem disponível. A digestibilidade in vitro da matéria seca do capim-marandu (64,%) foi superior à da grama-estrela (59,4%). Nos capins-tanzânia e marandu, as produções de leite foram de 9,8, valor superior ao de 8,4 kg/vaca.dia da grama-estrela. O teor de proteína do leite das vacas manejadas no capim-tanzânia (2,9%) foi superior ao obtido com grama-estrela (2,8%), mas os teores de gordura e sólidos totais do leite, o escore corporal, o peso vivo e o consumo de matéria seca não diferiram entre as forrageiras avaliadas. A grama-estrela teve maior porcentagem das frações fibrosas, menor DIVMS e menor produção de leite em comparação aos capins-tanzânia e marandu. days. There were 24 cows, eight per treatment. A complete randomized block design was used. The stargrass leaves had 18.5% crude protein (CP) and 79.9% neutral detergent fiber (NDF) on the stems, respectively, which were higher than the other grasses. Stargrass also had higher NDF (72.8%) and lignin (7.1%) in hand plucked samples. The marandu in vitro dry matter digestibility (IVDMD) (64%) was higher than that of stargrass (59.4%). The treatments were different for milk yield and the mean (9.8) for tanzania and marandu grasses were higher than the 8.4 kg/cow.day for stargrass. Milk protein of cows managed on tanzania grass (2.9%) was higher than that of (2.8%) of stargrass. There was no treatment difference for milk fat, total solids, body condition, body weight and feed intake. Stargrass had higher NDF and lignin, however lower IVDMD and milk yield in relation to tanzania and marandu grasses.

Production and quality of milk from Mantiqueira dairy cows feeding on Mombasa grass pasture and receiving different sources of roughage supplementation

“…The average fat content (32.0 g/kg of milk) obtained in the spring-summer period was lower than that reported by Porto et al (2009), who evaluated Holstein × Zebu grazing cows on Tanzania grass pasture supplemented with 2 kg/cow/day of concentrate (38.0 g/kg of milk). However, it is noteworthy that the fat content in milk is more related to genetic factors than to the diet.…”

“…The low stocking rate described can be explained by maintenance fertilization performed annually (500 kg of NPK fertilizer 20-05-20). Porto et al (2009) evaluated Holstein × Zebu cows, managed in Tanzania grass pasture, during summer-autumn period, and obtained average daily milk production of 9.8 kg per cow, supplying 2 kg/cow/day of concentrate. This production level is lower than those observed in the present study, and can be related to the stocking rate obtained by the authors, which was 4.0 cows/ha, against 3.1 and 3.4 cows/ha observed in both years of evaluation in the present research, and also to the ecotype of the animals.…”

Production, Forage Quality, and Performance of Holstein Cows under Intermittent Grazing on Tifton 85

“…The fat levels were higher during the fall and summer (P < 0.05), with a mean of 4.08% (Table 2), a value slightly higher than the 3.8% observed by Porto et al (2009). The NDF levels are directly related to the amount of fat in milk, considering that the degradation of fiber in the rumen produces acetate, which is the primary precursor for the synthesis of milk fat (Bargo et al, 2003;Porto et al, 2009).…”

“…The NDF levels are directly related to the amount of fat in milk, considering that the degradation of fiber in the rumen produces acetate, which is the primary precursor for the synthesis of milk fat (Bargo et al, 2003;Porto et al, 2009). …”

Evaluation of sheep fed on multinutritional blocks with garlic extract

“…The relation leaf x stem and the distribution of leaves in the forage are factors that exert influence in the selective process of consumption (PORTO et al, 2009), since the green parts of the plant are the most nutritious and hence preferred by the animals ( VAN SOEST, 1994). The averages of different letters in the same line indicate significant (P < 0.05) using Tukey test.…”