Utilization of roughages and concentrates relative to that of milk replacer increases strongly with age in veal calves

Abstract

We aimed to investigate the feeding values of milk replacer (MR), roughage, and concentrates for veal calves in a paired-gain setting, thus avoiding any prior assumptions in feeding values and major differences in nutrient intakes. One hundred sixty male Holstein-Friesian calves at 2 wk of age and 45 ± 0.2 kg of body weight (BW) were included in the experiment. Calves were allocated to pens (5 calves per pen) and pens were randomly assigned to 1 of 4 solid feed (SF) levels: SF1, SF2, SF3, or SF4, respectively, and to 1 of 2 roughage-to-concentrate (R:C) ratios: 20:80 or 50:50. An adaptation period from wk 1 to 10 preceded the experimental period (wk 11 to 27). Total dry matter (DM) intake from SF was targeted to reach 20, 100, 180, and 260 kg of DM for SF1 to SF4, respectively, during the 16-wk experimental period, and increased with preplanned, equal weekly increments. Roughage was composed of 50% corn silage and 50% chopped wheat straw based on DM. The quantity of MR provided was adjusted every 2 wk based on BW to achieve similar targeted rates of carcass gain across treatments. The reduction in MR provided (in kg of DM) to realize equal rates of carcass gain with inclusion of SF (in kg of DM) differed between the R:C ratio of 50:50 (0.41 kg of MR/kg of SF) and the R:C ratio of 20:80 (0.52 kg of MR/kg of SF). As carcass gain unintentionally increased with SF intake, the paired-gain objective was not fully achieved. When adjusted for realized rates of carcass gain, calves fed an R:C ratio of 20:80 still required 10% less MR than calves fed an R:C ratio of 50:50 for equal rates of carcass gain, indicating that the utilization of SF for gain increased with concentrate inclusion. Averaged for the 16-wk experimental period, the feeding value of MR relative to that of concentrates and roughages was close to that predicted based on their respective digestible energy contents. Nevertheless, the feeding value of SF relative to that of MR increased substantially with age. Therefore, additivity in feeding values of these ration components cannot be assumed. The results of the current study may contribute to the development of new concepts for formulation of veal calf diets with substantial amounts of SF.

Invited review: Abomasal damage in veal calves

“…The only findings in favor of the overloading theory are 3 articles providing some indirect evidence: Veissier et al (1998) found that group-housed calves that (probably) drank their MR meal faster had more pyloric lesions than individually housed calves that (probably) drank their MR slower; and Bähler et al (2010) and Welchman and Baust (1987) found that the heaviest calves, hence possibly dominant, faster-drinking calves, developed the most pyloric (but not fundic) lesions. Two articles opposing the overloading theory are Berends et al (2014), who found that decreasing milk meal size while simultaneously increasing the concentrate part of the diet caused worse damage (experimental study), and Brscic et al (2011), who found that calves receiving relatively low amounts of MR had a higher risk for lesions (risk assessment study).…”

“…In some cases, the stress-induced lesions of monogastrics resemble the ulcers found in the calf fundus (Welchman and Baust, 1987). Therefore, many authors have noted that stress may be a predisposing or even causal factor for ulceration in calves as well (Tulleners and Hamilton, 1980;Lourens et al, 1985;Wiepkema, 1985;Welchman and Baust, 1987;Wiepkema et al, 1987;Breukink et al, 1989;Mills et al, 1990;Lallès and Toullec, 1998;Stokka and Perino, 2000;Ahmed et al, 2002;Constable et al, 2005;Marshall, 2009;Van Immerseel et al, 2010;Sasaki et al, 2012;Valgaeren et al, 2013;Webb et al, 2013;Berends et al, 2014;Çatik et al, 2015). Proposed pathways through which stress could cause abomasal damage have a common starting point, whose involvement has been demonstrated only in rats.…”

Effects of solid feed level and roughage-to-concentrate ratio on ruminal drinking and passage kinetics of milk replacer, concentrates, and roughage in veal calves

“…The calves in the current study were selected from another experiment, which has been described by Berends et al (2014). In short, roughage was composed of 50% corn silage (Table 2) and 50% chopped (3 ± 2 cm) wheat straw (Table 2) on a DM basis.…”

Symposium review: Macronutrient metabolism in the growing calf

“…Notably, the total-tract digestibility of NDF increased significantly with BW from 46 at 108 kg of BW to 56% at 164 kg of BW. This increase in digestion efficiency with age or BW was later also demonstrated by Berends et al (2014a).…”