Supplementation of dried distillers grains with solubles to beef cows consuming low-quality forage during late gestation and early lactation1

Abstract

Three experiments were conducted to evaluate supplementation of dried distillers grains with solubles (DGS) to spring-calving beef cows (n = 120; 541 kg of initial BW; 5.1 initial BCS) consuming low-quality forage during late gestation and early lactation. Supplemental treatments included (DM basis) 1) 0.77 kg/d DGS (DGSL); 2) 1.54 kg/d DGS (DGSI); 3) 2.31 kg/d DGS (DGSH); 4) 1.54 kg/d of a blend of 49% wheat middlings and 51% cottonseed meal (POS); and 5) 0.23 kg/d of a cottonseed hull-based pellet (NEG). Feeding rate and CP intake were similar for DGSI and POS. In Exp. 1, cows were individually fed 3 d/wk until calving and 4 d/wk during lactation; total supplementation period was 119 d, encompassing 106 d of gestation and 13 d of lactation. Tall-grass prairie hay (5.6% CP, 50% TDN, 73% NDF; DM basis) was fed for ad libitum intake throughout the supplementation period. Change in cow BW and BCS during gestation was similar for DGSI and POS (-5.0 kg, P = 0.61 and -0.13, P = 0.25, respectively) and linearly increased with increasing DGS level (P < 0.01). Likewise, during the 119-d supplementation period, BW and BCS change were similar for DGSI and POS (-72 kg, P = 0.22 and -0.60, P = 0.10) and increased linearly with respect to increasing DGS (P < 0.01). The percentage of cows exhibiting luteal activity at the beginning of breeding season (56%, P = 0.31), AI conception rate (57%, P = 0.62), or pregnancy rate at weaning (88%, P = 0.74) were not influenced by supplementation. In Exp. 2, 30 cows from a separate herd were used to evaluate the effect of DGS on hay intake and digestion. Supplementation improved all digestibility measures compared with NEG. Hay intake was not influenced by DGS (P > 0.10); digestibility of NDF, ADF, CP, and fat linearly increased with increasing DGS. In Exp. 3, milk production and composition were determined for cows (n = 16/treatment) of similar days postpartum from Exp. 1. Daily milk production was not influenced by supplementation (6.3 kg/d, P = 0.25). Milk fat (2.1%) and lactose (5.0%) were not different (P > 0.10). Milk protein linearly increased as DGS increased (P < 0.05) and was greater for DGSI compared with POS. Similar cow performance was achieved when cows were fed DGS at the same rate and level of CP as a traditional cottonseed meal-based supplement. Increasing amounts of DGS did not negatively influence forage intake or diet digestibility.

Feeding dried distillers grains with solubles to lactating beef cows: impact of excess protein and fat on cow performance, milk production and pre-weaning progeny growth

“…Increased MUN is an indication of excess dietary protein and/or decreased ruminal microbial synthesis. Increased MUN due to DDGS feeding in the present experiment, as well as other studies (Gunn et al, 2014;Winterholler et al, 2012), is likely caused by excess dietary protein, however elevated MUN could be a result of the decreased rumen degradable protein (RDP) content and/or the increased fat content of DDGS-based diets, as supplemental fat can have a negative effect on fiber digestion and can decrease microbial protein production (Coppock and Wilks, 1991). However, although formulated RDP content of the DDGS diet in the current study was lower compared with the CON diet, the RDP content of the DDGS diet still exceeded NRC (1996) recommendations.…”

“…Cows fed DDGS had a greater percentage of milk fat on day 68 PP (P < 0.001), but not on day 116 PP (P = 0.34). Recent reports (Winterholler et al, 2012;Gunn et al, 2014) have indicated that milk fat in beef cows may be as low as 1.4% to 1.7%, however, it is possible that milk fat values in the present experiment were considerably lesser than expected because of incomplete emptying of the quarter at sampling. Nevertheless, it has been reported that within milking variation in milk components and fatty acids is low to none (Larsen et al, 2012;Rico et al, 2014).…”

“…However, Shike et al (2009) reported a decrease in milk production and concomitant increase in BW when multiparous and primiparous cows were limit-fed a 55% DDGS diet at an energy concentration isocaloric with a control diet containing 57% corn gluten feed. In contrast, Winterholler et al (2012) observed a tendency for increased milk production in multiparous and primiparous beef cows with increased supplementation of DDGS.…”

“…Radunz et al (2010) observed no change in milk protein when DDGS was fed at 4.1 kg/day. Winterholler et al (2012) observed an increase in milk protein percentage and MUN as the amount of DDGS supplementation increased up to 4 kg/day. Increased MUN is an indication of excess dietary protein and/or decreased ruminal microbial synthesis.…”

“…However, dietary treatment had no effect on total solids (P ⩾ 0.88) or lactose (P ⩾ 0.28) on either day. Radunz et al (2010) and Shike et al (2009) observed no effect of DDGS on milk fat percentage, whereas Winterholler et al (2012) and Gunn et al (2014) reported that DDGS decreased milk fat percentage. Different responses in milk fat production among DDGS supplementation studies may be related to the type of forage or basal diets fed.…”