Effect of Dietary Calcium Propionate Inclusion Period on the Growth Performance, Carcass Characteristics, and Meat Quality of Feedlot Ram Lambs

The objective was to determine the effect of calcium propionate (CaPr) inclusion in the diet, at different periods on the growth performance, carcass characteristics, and meat quality of finishing lambs. Thirty-six Dorper x Katahdin crossbred male lambs (39.1 +/- 0.44 kg BW) were housed in individual pens during a 42 d feeding period and assigned to four treatments (n = 9) consisting of CaPr administered at a dose of 10 g/lamb/d for 0 (control), 14, 28, or 42 d before slaughter. Final BW (FBW), average daily gain (ADG), dry matter intake (DMI), and ADG:DMI ratio increased quadratically (p < 0.05) by CaPr supplementation, being optimal at an estimated inclusion period of 25 d for FBW and ADG, 15 d for DMI, and 28 d for ADG:DMI ratio. Hot carcass weight (HCW), cold carcass weight (CCW), and dressing were quadratically improved (p < 0.05) at an estimated inclusion period of 24 d for HCW and CCW, and 20 d for dressing. The increased inclusion period (42 d) augmented fat thickness (linear effect, p < 0.05). At 28 d of CaPr supplementation, maximal response (quadratic effect, p < 0.05) was estimated in the empty body weight at 28 d, forequarter at 26 d, and neck at 24 d, but a longer inclusion period (42 d) increases the weight of leg and rack and reduced the proportion of loin as a percentage of CCW (linear effect, p < 0.05). In conclusion, dietary CaPr can be included for a period of 24 to 28 d to improve growth performance and carcass weight, without affecting organ mass or meat quality.