Effect of Replacing Corn Silage with Annual Ryegrass Silage on Nutrient Digestibility, Intake, and Milk Yield for Lactating Dairy Cows

Abstract

Twenty Holstein cows were used in an 8-wk randomized block design study to determine the effects of replacing corn silage with ryegrass silage on nutrient intake, apparent digestion, milk yield, and milk composition. The 8-wk trial consisted of a 2-wk preliminary period followed by a 6-wk collection period. Experimental diets were formulated to provide 55.5% of the total dry matter (DM) as forage. Ryegrass silage was substituted for 0, 35, 65, and 100% of DM provided by corn silage. Dietary concentrations of neutral detergent fiber (NDF) and acid detergent fiber (ADF) increased as ryegrass silage replaced corn silage. Intake of DM and crude protein (CP) was similar for all treatments, but intake of NDF and ADF increased linearly as ryegrass silage replaced corn silage. Apparent digestibility of DM declined linearly, whereas digestibility of CP increased linearly as ryegrass silage replaced corn silage. Apparent digestibility of NDF and ADF was highest for the diets in which ryegrass or corn silages provided all of the forage, resulting in a quadratic response. Dry matter intake was not different among treatments. Yield of milk, fat, and protein increased as ryegrass silage replaced corn silage. No differences were observed for body weight change, body condition score, and serum urea nitrogen concentration, but serum glucose concentration increased with increasing dietary proportion of ryegrass silage. These results indicate that substituting ryegrass silage for a portion or all of the corn silage in diets fed to lactating dairy cows can improve yield of milk and components.

Effect of silage type and concentrate level on conjugated linoleic acids, trans-C18:1 isomers and fat content in milk from dairy cows

“…On the ontrary to our results, feeding maize compared with grass silage is not always associated with significant reductions in milk fat percentage [22,23]. The different results can probably be ascribed to variations in chemical composition of maize silages especially in NDF and starch content, and physical characteristics such as particle size of the silages may also be important in terms of development of milk fat depression [9] together with the overall composition and amount of PUFA in the total mixed rations.…”

Nitrogen efficiency in contrasting dairy production systems

“…However, the chemical composition of grass silage can vary considerably depending on N application rates, maturity at harvest and weather conditions (McDonald et al, 2002). For example, CP contents of grass silage in literature ranged from 100 g kg/dry matter (DM) (Bernard et al, 2002) to 190 g kg/DM (Cooke et al, 2008), consistent with the range of CP for 3200 grass silage samples analysed for dairy farms in Ireland (Kavanagh (2011), personal communication). This variation in the chemical composition of grass silage can result in an inconsistent dry matter intake (DMI), poor milk production and consequently, a poor ENU by the lactating dairy cow (Burke et al, 2007).…”

Silage from maize (Zea mays), annual ryegrass (Lolium multiflorum) or their mixture in the dry season feeding of grazing dairy cows in small-scale dairy production systems in the Highlands of Mexico

“…The chemical composition of the MIX silage which was made from the same forage used for the MS treatment but with the third cut of the ARG crop did not show values in between the MS and the ARG silages according to their proportion in the final product (approximately at a ratio of 2 to 1); as reported by Bernard et al (2002) where the mixed silages had chemical values in-between the maize and annual ryegrass silages used in their experiment.…”

“…However, a limiting factor for grass silage is the low content of soluble carbohydrates. There are reports that mixtures of maize and grass silage increase milk yields and milk component yields (Bernard et al 2002).…”