The Effects of Age at Weaning and Length of Lipid Supplementation on Growth, Metabolites, and Marbling of Young Steers

Abstract

The objective of this study was to determine how weaning age, days on supplements, and lipid supplementation affected the growth and marbling deposition of steers. Steers from a single sire were early weaned (n = 24) at 150 ± 11 days of age or traditionally weaned (n = 24) at 210 ± 11 days of age. Steers were assigned to control (n = 12/weaning group) or an isocaloric, isonitrogenous rumen by-pass lipid (RBL, n = 12/weaning group) for either 45 (n = 6/treatment) or 90 (n=6/treatment) days then harvested. Steer body weight (BW) was recorded on days −14 and −7, then BW and blood samples were collected on days 0, 22, 45, 66, and 90. The right rib section of each animal was collected for proximate analysis. Longissimus dorsi from RBL steers had increased lipids compared with control steers (3.6 ± 0.2 vs. 2.4 ± 0.2% on a wet basis; p < 0.0001). Steers fed for 90 days had greater (p = 0.02) concentrations of Longissimus dorsi lipid (3.3 ± 0.2%) than those fed for 45 days (2.7 ± 0.2%). There was a weaning age by treatment by days on feed interaction for intramuscular adipocyte diameter (p = 0.02) in which early weaned RBL fed for 90 days steers had an increased adipocyte diameter compared to the early weaned control fed for 90 and early weaned fed for 45 days steers with all other treatment groups as intermediates. Supplementation of RBL increased concentrations of C18:2, C20:4, and total fatty acids on days 45 and 90 (p ≤ 0.05). Data show that RBL supplementation increased the marbling content of the Longissimus dorsi. Furthermore, a longer period of supplementation resulted in increased adipose diameter.

Impacts of Nutritional Management During Early Postnatal Life on Long-Term Physiological and Productive Responses of Beef Cattle

“…Hence, these authors concluded that CSSO supplementation to EW steers enhanced early adipocyte hyperplasia and differentiation (Mangrum et al, 2016). Accordingly, Tipton et al (2020) also reported increased adipocyte hyperplasia in intramuscular adipose tissue of EW steers supplemented with CSSO for 90 days, evidenced by decreased adipocyte diameter. The same result was not evident in traditionally weaned steers provided the same supplementation, indicating that providing CSSO supplementation earlier in life may result in a greater number of undifferentiated stem cells driven toward adipogenic confirmation and differentiation (Tipton et al, 2020).…”

Evaluating the Rumen Degradation of Novel Protected Gelatin Capsules Containing Fish Oil Fed to Lactating Dairy Cows

“…Serum was then collected into separate tubes and stored at −20 °C until analysis. Duplicate 1 mL serum aliquots from all steers were lyophilized (HarvestRight, North Salt Lake, UT, USA) and then transmethylated according to Tipton et al [ 19 ]. An internal standard, methyl tricosanoic (C23:0), was incorporated into each sample during methylation.…”

Molecular and Cellular Mechanisms of Intramuscular Fat Development and Growth in Cattle

“…It is currently believed that early weaning, especially when combined with supplemental feeding, can enhance IMF deposition. Tipton and colleagues found that early weaning at around 150 days of age combined with isonitrogenous rumen bypass lipid supplementation significantly increased the IMF content in Angus steers, without negatively affecting the dressing percentage, when compared to traditional weaning at around 210 days of age [ 87 ]. Angus–Wagyu crossbred heifers subjected to early weaning (142 days of age) and a high-concentrate diet showed greater IMF deposition and weight gain compared to heifers weaned at 180 days and grown on pasture for 16 months before entering the feedlot [ 88 ].…”