The effects of incorporating small quantities of straw in grass/grass silage‐based diets for dairy cows

Abstract

Two studies were conducted to examine the effects of incorporating small quantities of straw in the diets of dairy cows. In Experiment 1, forty Holstein Friesian dairy cows were used in a 2 × 4 factorial design experiment, with factors examined consisting of two parities (primiparous and multiparous animals) and four levels of straw inclusion in the diet (0, 0·08, 0·16 and 0·24 of forage dry matter). The basal forage offered in this study was grass silage, and the primiparous and multiparous animals were supplemented with 9·0 and 11·0 kg concentrate d–1 respectively. In Experiment 2, forty‐eight Holstein Friesian dairy cows were used in a 2 × 3 factorial design experiment, with factors examined consisting of two basal forage types (grass silage and zero‐grazed grass) and three levels of straw inclusion (0, 1·0 and 2·0 kg d–1). All animals were offered 7·0 kg d–1 of a concentrate supplement. Both experiments were partially balanced changeover designs, consisting of two, 4‐week periods. In Experiment 1, the total dry‐matter intake followed a significant quadratic relationship (P < 0·05), increasing with low levels of straw inclusion and decreasing at higher levels of inclusion. With increasing levels of straw inclusion, there was a linear decline in milk yield (P < 0·001) and milk protein concentration (P < 0·05), but milk fat concentration was unaffected (P > 0·05). In Experiment 2, the effect of straw inclusion on total dry‐matter intake was quadratic (P < 0·001), with intakes being maximum at the 1·0‐kg level of straw inclusion. Milk yield exhibited a linear decrease (P < 0·001) with increasing level of straw inclusion. Milk fat concentration was lowest at the 1·0 kg rate of straw inclusion (P < 0·05), but milk protein concentration was unaffected by straw inclusion. There were no significant interactions between basal forage type and level of straw inclusion for any of the variables examined (P > 0·05). Despite small increases in total dry‐matter intake at a low level of straw inclusion, there was no evidence that straw inclusion improved either nutrient utilization or animal performance. The reduction in milk yield observed with straw inclusion reflects, to a large extent, a reduction in metabolizable energy intake.

Effects of Dietary Substitution of Alfalfa Silage with Virginia Fanpetals Silage in Lactating Polish Holstein Friesian Dairy Cows

“…The decrease in the DM utilization rate may have been the result of introducing a small amount of straw to the groups. Similarly, in studies by Ferris et al [ 40 ], the inclusion of a small amount of straw in the diets of dairy cows resulted in an increase DM intake while lowering feed conversion. The intake of digestible NDF in the experimental groups was ca.…”

Energy evaluation of fresh grass in the diets of lactating dairy cows

“…A high OM content will probably result in a high DOM value. As a high DOM content is correlated with a relatively low CF content [R 2 = 0.201 (P < 0.05) in the 80-90% grass diet group], altered rumen fermentation may occur, resulting in negative effects on ruminaI digestive efficiency (Mertens, 1997;Ferris et al, 2000). Furthermore, in grass digestible CP accounts for much of total DOM, and although correlations between discrepancy and digestible CP were not observed, a N surplus probably did occur.…”

Adding straw to a total mixed ration and the method of straw inclusion affects production and eating behaviour of lactating dairy cows

“…By stimulating chewing and rumination, effective fibre should promote a more stable rumen by preventing large variations in rumen pH that can occur when cows consume high levels of readily fermentable carbohydrate (Beauchemin et al, 2008). Whilst the concept of including limited amounts of straw in milking rations is accepted as being nutritionally sound, there is limited scientific proof available (Ferris et al, 2000). Further to this, chop length of the straw as well as the amount included in the ration may be crucial if expected benefits are to be achieved without compromising production or feed efficiency.…”