Performance and digestive characteristics in dairy cattle maintained under grazing regime and supplemented with linseed.

Linseed is characterized by the rich unsaturated fatty acids and slow release of oil in the rumen. The objective of the present study was to evaluate the intake, rumen degradability, and digestibility of dairy cattle maintained under grazing regime and supplemented with linseed. Twelve Girolando (¾ Holstein × ¼ Gir) cows with a mean age of 5.2 ± 1.9 years and body weight of 583.9 ± 67.6 kg were used. The cows were maintained in a rotational grazing system on the mombaça grass (Panicum maximum) and divided into 2 experimental groups. The CONTR (n = 6) group received only the base diet (pasture) and the LINS group (n = 6) received pasture plus linseed. Initially, a fifteen-day adaptation period was established to stabilize the desired consumption amount. After this period, the animals received 800 g of linseed for 126 d. The ruminal degradability was evaluated using 2 males with a cannula in the rumen, and they were provided the same experimental diet. The measured dry matter production of pasture did not show differences during the experimental period. The intake of crude protein and ethereal extract was higher, whereas neutral detergent fiber content was lower in the cows supplemented with linseed. However, this did not alter the weight gain and digestibility coefficients, except the digestibility coefficient of the ethereal extract. At the ruminal level, linseed showed low effective and potential degradability with negative effect on grass degradability.Título em português: Desempenho e características digestivas em bovinos leiteiros mantidos em regime de pastoreio suplementados com linhaça