Milk yield and composition, feed intake and stocking rate of crossbread cows in tropical grasses managed in a rotational grazing system

Abstract

RESUMO -Objetivou-se com este trabalho avaliar a produção e composição química do leite, o consumo de matéria seca e a taxa de lotação em pastagens de capim-tanzânia (Panicum maximum Jacq. cv. Tanzânia), grama-estrela (Cynodon nlemfuensis Vanderyst cv. Estrela-Africana) e capim-marandu (Brachiaria brizantha Stapf cv. Marandu). As gramíneas foram manejadas sob regime de lotação rotacionada com vacas mestiças Holandês × Zebu, com 30 dias de intervalo de desfolha e três dias de ocupação do piquete e foram adubadas com 1.000 kg/ha/ano da fórmula 20:05:20 (NPK), parcelada em três vezes durante a época das chuvas. O delineamento experimental foi em blocos ao acaso com três fatores em estudo e duas repetições. Foram utilizadas quatro vacas por piquete e, quando necessário, foram acrescentados animais reguladores objetivando obter oferta de massa seca de forragem verde de 7% do peso vivo. Os animais receberam individualmente 2 kg/dia de concentrado no período experimental. A produção de leite não diferiu entre as três gramíneas, com valores de 9,1; 9,1 e 8,7 kg/vaca/dia para as pastagens de capim-tanzânia, grama-estrela e capim-marandu, respectivamente. Da mesma forma, não houve efeito da gramínea na composição química do leite. A taxa de lotação foi semelhante entre as três gramíneas, com os valores de 4,6; 4,5 e 5,0 UA/ha para o capim-tanzânia, a grama-estrela e o capim-marandu. Maior consumo de matéria seca foi observado no capim-tanzânia com 2,6% do PV, enquanto a grama-estrela (2,3%) e o capim-marandu (2,4%) não diferiram entre si. O maior consumo de matéria seca na pastagem de capim-tanzânia não refletiu na produção de leite por animal. A produção e composição química do leite e a taxa de lotação sao similares entre as gramíneas avaliadas. Palavras-chave: Brachiaria brizantha, Cynodon nlemfuensis, Panicum maximum, vacas mestiças Milk yield and composition, feed intake and stocking rate of crossbread cows in tropical grasses managed in a rotational grazing systemABSTRACT -The objective of this study was to evaluate milk yield and composition, dry matter intake, and stocking rate in pastures with tanzania grass (Panicum maximum cv. Tanzânia), star grass (Cynodon nlemfuensis cv. EstrelaAfricana), and marandu grass (Brachiaria brizantha cv. Marandu). The grasses were managed in a rotational grazing system with Holstein × Zebu crossbreed cows, with a 30-day resting period and three days of paddock occupation. The pastures were fertilized with 1,000 kg/ha/year using the 20:05:20 (NPK) formula, split in three applications during the rainy season. It was used a complete random block experimental design with three factors being studied and two replications. In the experiment, four cows/paddock were used and, when it was necessary, regulator animals were added in order to obtain a supply of 7% body weight green forage dry matter. The animals were individually fed concentrate at 2 kg/day during the experimental period. Milk yield did not differ among the three grasses, with values of 9.1; 9.1; and 8.7 kg/cow/day for pastures...

Milk fatty acid profile of Holstein x Gyr cows on 'Marandu' grass pasture under different grazing strategies

“…For the contents of CP and IVDMD of the pasture, there was effect of the treatments and grazing cycle, and of the interaction between them ( Table 2). The values of IVDMD are considered close to the 60 and 65.8% reported by Porto et al (2009) and Fukumoto et al (2010), in 'Marandu' pastures managed in a rotational grazing system under intermittent stocking, with pasture rest periods of 30 days, whereas the CP levels were higher than the values of 9.4 and 10% obtained in these same two studies. The higher level of CPobserved in the pasture under variable rest periods in the third cycle (Table 2) -, associated with the higher estimated DM intake from the pasture, culminated in the higher CP intake observed in this treatment and grazing cycle (Table 3).…”

“…For pasture DM intake, expressed in kilogram per cow per day and percentage of body weight (% BW), there was a difference between treatments only in the third cycle, with higher values obtained for the variable rest period, in comparison to the fixed one. The estimated consumption of 3.04% BW (Table 3) was the highest one in the present study, and can be considered high, when compared with the 2.4 and 2.9% BW obtained by Porto et al (2009) and Fukumoto et al (2010), in lactating Holstein x Gyr cows receiving 2 kg per day (1) Means followed by equal letters, uppercase in the columns and lowercase in the rows, do not differ at 5% probability by the LSMeans test of SAS software (SAS Institute, Inc., Cary, NC, USA).…”

Milk production and ingestive behavior of cows grazing on Marandu and Mulato II pastures under rotational stocking

“…Mombaça), ranging from 10.8 to 14.1 kg cow −1 day −1 (Hack et al, 2007). The values obtained in the present experiment are higher than those described by Fukumoto et al (2010), who obtained mean milk yields of 8.7, 9.1, and 9.1 kg cow −1 day −1 for Marandu, Tanzania (Panicum maximum Jacq. cv.…”

Influence of breeds genetic composition on the quality of milk from primiparous cows

“…Lactose results similar to those obtained in the present study (4.42%), were found by Botaro et al (2011) in a study aimed at evaluating the composition and protein fraction of milk from commercial herds in the state of São Paulo, while Fukumoto et al (2010) reported an average of 4.2% lactose when assessing milk production and composition, dry matter intake and stocking rate in tropical grass pasture managed under rotational grazing system.…”