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Replacing dietary carbohydrate with calcium salts of fatty acids and the effects to finishing lamb feedlot performance and carcass characteristics




Seabrook, Jill L., author
Peel, R. Kraig, advisor
Callan, Robert J., committee member
Engle, Terry E., committee member

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The objective of this study was to investigate the performance and physiological effects imposed on finishing lamb (n = 60, BW x= 41.6 ± 1.4 kg) feedlot performance and carcass characteristics by replacing dietary carbohydrate with calcium salts of fatty acids (CSF A). Upon arrival, lambs were weighed on 2 consecutive d and randomly assigned to 1 of 4 dietary concentrations of CSF A. Treatments included 1) 0% CSF A (Control); 2) 4% CFSA; 3) 7% CSFA and 4) 11% CSFA on a DM basis. Diets were formulated to be isoenergetic (TDN basis) and isonitrogenous (DIP and UIP) and consisted of 75% concentrate, and 25% roughage ( com silage). Ration TDN was kept similar between treatments; rations with less com had a higher concentration of CSF A-pellet. Intake was controlled to balance TDN per kilogram of BW across treatments; all treatments met 2006 NRC requirements for growing lambs [18]. Lambs were weighed and bled every 14 ± 2 d. Blood samples were analyzed for glucose, lactate and insulin concentrations. On d 61, lambs were transported and slaughtered at a commercial abattoir. Hot carcass weight (HCW) was determined at the time of slaughter, and longissimus muscle (LM), liver and subcutaneous adipose tissue samples were collected at slaughter and snap-frozen for later analysis of FA composition. Longissimus muscle area (LMA) and back fat (BF) carcass measurements were determined after 48 h storage at 0°C chill. There was a treatment by time interaction for overall ADG (P = 0.01). Lambs receiving 11 % CSFA had lower ADG, lighter HCW (P < 0.001) and smaller LMA (P < 0.01) than all other treatments. Control lambs had greater (P < 0.05) BF than lambs receiving 11 % CSF A, but had similar BF to lambs receiving 4 and 7% CSF A. There was no treatment effect on dressing percentage. There was a treatment by time interaction observed for blood glucose (P = 0.02); lambs fed the control diet had a tendency to have higher blood glucose concentrations. Blood insulin values were not different (P = 0.36) between treatments, and insulin to glucose ratios were similar among treatments. Overall blood lactate levels had a tendency to be lower as dietary CSF A concentration increased, although not significantly (P = 0.11). Fatty acid profiles for LM, liver and subcutaneous adipose were similar across treatments. Overall, the data suggest that CSF A can be used to replace a carbohydrate source such as com; at rates up to 7% DMI before performance is negatively affected.


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Sheep -- Feeding and feeds
Calcium salts
Lamb (Meat) -- Quality


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