Effects of starch content of calf starter on growth and rumen pH in Holstein calves during the weaning transition

Abstract

The objective of this study was to evaluate the effects of substituting high fiber byproducts for dry ground corn in calf starter on growth and rumen pH during the weaning transition. Holstein bull calves were raised on an intensified nursing program using milk replacer containing 26% CP and 18% fat. Calves were fed a texturized calf starter containing either dry ground corn at 18.8% of dry matter (DM; CRN), beet pulp replacing dry ground corn at 10.2% dietary DM (BP), or triticale dried distillers grains with solubles replacing dry ground corn and high-protein feedstuffs at 18.6% of dietary DM (DDGS) in the pellet; treatment calf starters differed only in the pellet portion. Starch concentrations of CRN, BP, and DDGS were 35.3, 33.4, and 31.4%, respectively. After a calf consumed 2.50 kg of starter for 3 consecutive days, a small ruminant rumen pH data logger was inserted orally and rumen pH was measured continuously for 4d. Calves were then killed and rumen fluid was sampled to determine volatile fatty acid profile. No difference was found in overall average daily gain or growth rates of hip height, withers height, and heart girth. During the weaning transition, rate of increase in calf starter intake was greater for calves fed DDGS compared with those fed CRN (87.7 vs. 77.5 g/d), but lower for calves fed BP compared with CRN (68.1 vs. 77.5 g/d). The area under pH 5.8 (470 vs. 295 min × pH/d) or pH 5.2 (72.7 vs. 16.4 min × pH/d) was greater for calves fed DDGS than those fed CRN. Rumen pH profile was not affected by BP treatment compared with CRN, but calves fed BP tended to have greater water intake than those fed CRN (6.6 vs. 5.8 L/d). Volatile fatty acid profile was not affected by treatment with the exception of molar proportion of butyrate, which tended to be lower for calves fed BP compared with those fed CRN (15.0 vs. 16.6%). Hay intake was positively correlated to mean rumen pH for calves used in this study (r=0.48). Decreasing dietary starch concentration did not mitigate rumen acidosis in calves during weaning transition, and low rumen pH did not adversely affect growth during the weaning transition.

Partial replacement of triticale for corn grain in starter diet and its effects on performance, structural growth and blood metabolites of Holstein calves

“…The observation that calves fed triticale had greater height at wither and hip (Figure 1) tend to contrast with the results of a similar study by Laarman et al (2012), who reported no significant difference in wither height, hip height or heart girth for calves fed a starter diet containing triticale dried distillers grains (with solubles) as compared with calves fed a starter diet containing corn.…”

“…The discrepancy between the two studies is likely related to the difference in the dietary inclusion rate: in the present study, triticale was included up to 32% of diet DM. However, triticale dried distillers grains was fed at 18.5% by Laarman et al (2012), which is much closer to the T16 diet in the present study (i.e. 25% of corn replaced by triticale in the diet).…”

“…The fermentability of triticale, Moeinoddini, Alikhani, Ahmadi, Ghorbani and Rezamand however, was not measured in the current experiment and warrants further investigation. Laarman et al (2012) reported no significant difference in ADG for calves fed a diet containing triticale dried distillers grains (with solubles) as compared with that for calves fed a control diet containing corn. The discrepancy between the two studies is likely related to the difference in the dietary inclusion rate: in the present study, triticale was included up to 32% of diet DM.…”

“…Smith et al (1994) reported greater DMI for steers fed diets containing a mix of triticale and corn when compared with steers fed diet containing triticale only. Laarman et al (2012) reported a greater rate of increase in starter DMI for diet containing triticale dried distillers grains (with solubles) as compared with control diet containing corn. This difference might be explained by the inclusion of alfalfa (3.1% starter DM) in starter diet in the study of Laarman et al (2012).…”

“…Laarman et al (2012) reported a greater rate of increase in starter DMI for diet containing triticale dried distillers grains (with solubles) as compared with control diet containing corn. This difference might be explained by the inclusion of alfalfa (3.1% starter DM) in starter diet in the study of Laarman et al (2012). Forage can stimulate starter DMI and act as a buffer when calves consume high starch levels from starter grains (Castells et al, 2012;Montoro et al, 2013;Hosseini et al, 2016).…”