Replacing alfalfa hay with dry corn gluten feed and Chinese wild rye grass: Effects on rumen fermentation, rumen microbial protein synthesis, and lactation performance in lactating dairy cows

Abstract

This experiment was conducted to investigate nutrient digestibility, rumen microbial protein synthesis, and lactation performance when a portion of alfalfa was replaced with combinations of dry corn gluten feed (DCGF) and Chinese wild rye grass in the diet of lactating cows. Six multiparous and 3 primiparous Chinese Holsteins were arranged in a replicated 3 × 3 Latin square experiment for 21-d periods. The animals were fed 1 of 3 treatment diets during each period: (1) 0% DCGF (0DCGF); (2) 6.5% DCGF (7DCGF); and (3) 11% DCGF (11DCGF). Diets were isonitrogenous, and a portion of alfalfa hay was replaced with DCGF and Chinese wild rye grass, with similar concentrate mixtures and corn silage contents. The dry matter intake was greater for 11DCGF (21.9 kg/d) than for 0DCGF (20.7 kg/d) or 7DCGF (21.2 kg/d). The treatment diets did not result in difference in milk production, fat and lactose concentration, or yield. Compared with 0DCGF, the ration containing 11% DCGF improved the milk protein concentration. Dry matter and neutral detergent fiber digestibility was greater for 7DCGF (62.7% and 45.6%) and 11DCGF (63.1% and 47.2%) than for 0DCGF (59.4% and 42.3%), and the nitrogen digestibility was similar for the 3 treatments. The concentration of rumen volatile fatty acids was higher in cows fed the 11DCGF diet than in those fed the 0DCGF diet, with no difference between the 7DCGF and 11DCGF diets. The estimated microbial crude protein yield was greater for the 11DCGF diet (1985.1 g/d) than for the 0DCGF diet (1745.0 g/d), with no difference between the 0DCGF and 7DCGF diets. Thus, it appears that feeding DCGF and Chinese wild rye grass in combination can effectively replace a portion of alfalfa hay in the rations of lactating dairy cows.

Replacing alfalfa hay with dry corn gluten feed alters eating behavior, nutrient digestibility, and performance of lactating dairy cows

“…These changes decreased the acetate-to-propionate ratio with increasing levels of DCGF in agreement with previous reports (Biricik et al 2007;Sullivan et al 2012). In our current experiment, molar proportions of butyrate declined linearly consistent with the findings reported by Hao et al (2017). Molar proportions of valerate increased as DCGF replaced AH reflecting the higher dietary CP content and digestibility consistent with previous reports (Mullins et al 2010;Sullivan et al 2012).…”

“…The linear increase in DMI as DCGF replaced AH is consistent with previous studies (Kononoff et al 2003;Mullins et al 2010;Sullivan et al 2012;Hao et al 2017). In contrast, Biricik et al (2007) did not report any change in DMI as DCGF increased in the diet.…”

“…Previous studies have reported decreased ruminal pH with increasing proportions of CGF (Biricik et al 2007;Mullins et al 2010) unless peNDF was maintained. Hao et al (2017) did not observe a decrease in ruminal pH as CGF increased, but these researchers fed Chinese wild ryegrass to maintain peNDF. Long-particles from forage are fermented more slowly reducing the potential decline in ruminal pH compared with diets with smaller particles (Mullins et al 2010).…”

“…Few studies have examined replacement of only the forage portion of the diet with CGF. Hao et al (2017) reported linear increases in DMI and MY with no changes in feed efficiency when alfalfa hay (AH) was replaced by 6.5 or 11% DCGF, but these researchers fed Chinese wild ryegrass to maintain adequate physically effective neutral detergent fibre (peNDF) concentrations.…”

“…Replacing forage with NFFS reduces dietary peNDF that would be expected to reduce chewing activity and saliva secretion to buffer VFA production lowering rumen pH (Bradford and Mullins 2012). The effects of replacing forage other than corn silage with DCGF on eating behaviour have not been thoroughly examined as most researchers either maintained !29.6% forage (Schroeder 2003) or added other effective fibre sources to maintain peNDF (Rezac et al 2012;Hao et al 2017). Previous researchers have reported negative effects on dietary peNDF when forage was replaced with NFFS (Bradford and Mullins 2012) that could potentially reduce rumination activity (Mertens 1997), fibre digestibilty and perfornance (Allen 1997).…”