Nutritional carryover effects of the previous plane of nutrition of crossbred Angus steers affects freshwater intake, animal performance, and water and feed efficiency.

Abstract

This study evaluated how the backgrounding diet can affect water intake, animal performance and water and feed efficiency of steers fed finishing diets based on grains or forages. Twenty-four crossbred Angus steers (298 ± 10.2 kg) were fed during backgrounding either a moderate (MP, n = 12; triticale hay only, 9.1%crude protein [CP], 1.07 Mcal/kg net energy available for maintenance [NEm], and 0.52 Mcal/kg net energy available for gain [NEg]) or high plane of nutrition (HP, n = 12; 85% alfalfa hay and 15% beardless wheat hay, 12.62%CP, 1.23 Mcal/kg NEm, and 0.66 Mcal/kg NEg) during the background phase (85 d). After this period, steers were assigned to two finishing phase groups containing half of the animals from each backgrounding diets. During the finishing phase, animals were fed either a forage-based (Alfalfa hay; CP: 20.8% DM, NEm: 1.47 Mcal/kg, NEg: 0.88 Mcal/kg) or a grain-based diet (80% whole corn and 20% wheat hay; CP: 10.6% DM, NEm: 1.96 Mcal/kg, NEg: 1.31 Mcal/kg). There was no interaction between the effects of the previous plane of nutrition [(moderate (MP) or high (HP)] and finishing diets (forage or grain-fed) on any of the variables studied (P > 0.05). Animals backgrounded on MP were lighter and had a lower DMI when compared with HP (P < 0.01). However, no differences were observed on the drinking water intake (DWI) between MP and HP (P > 0.05). HP animals were more efficient in gross water efficiency (P < 0.01), but less efficient on residual feed intake (P < 0.05), compared to MP animals. During the finishing phase, forage fed animals had a greater DMI and DWI compared with grain-fed animals (P < 0.01), however, no differences were observed on the final BW (P > 0.05). Grain-fed animals were more efficient for water and feed intake and had a greater marbling score (P < 0.01) compared to forage-fed. Animals fed on HP and finished in a grain-fed diet had the least DWI (P < 0.05) and greatest body condition score (P < 0.05), marbling score (P < 0.01) and rib depth (P < 0.05). In the first 20 d of the finishing period, the previous plane affected the variables ADG, DMI, CPi, and DWI (as kg DMI and CP) in the finishing plane. Altogether, our results highlight the individual effects of backgrounding and finishing systems on DWI and the efficiency of finishing animals, as well as the importance of providing adequate nutrition during the earlier stages of life.