A comparative study on growth, feed intake, and serum vitamin and mineral concentrations in Western white-faced rams with and without limb deformities.

Angular limb deformities (ALD) have historically affected a portion of ram lambs enrolled in central performance tests. The condition results in varying degrees of abnormal ossification in long bones and can impact animal welfare and performance under extensive rangeland conditions. The objectives of this experiment were to compare growth rate, feed intake, and serum 25-hydroxyvitamin D [25(OH)D], and mineral element concentrations of rams affected and unaffected with ALD. In total, 108 ram lambs were enrolled in a central performance test and a subset of 25 were selected for the present study (191 ± 25 d of age; n = 12 ALD, n = 13 non-affected). Body weight (BW) and serum were collected on d 0, 28, 56, 83, and 112 of the test. Serum concentrations of 25(OH)D, macrominerals (Ca, Cl, K, Mg, Na, P, and S), and microminerals (Co, Cr, Cu, Fe, Mn, Mo, and Se) were quantified. Traits were analyzed as repeated measures with fixed effects of ALD status, sampling timepoint, and their interaction. The ALD status × sampling timepoint interaction was significant (P < 0.05) for serum 25(OH)D and Mg concentrations. Rams with ALD had greater serum 25(OH)D concentration at d 83 (45.0 ± 1.31 vs. 39.2 ± 1.25 ng/ml; P < 0.01) and 112 (52.5 ± 1.63 vs. 44.8 ± 1.29 ng/ml; P < 0.001) and greater Mg concentration at d 112 (32.0 ± 2.90 vs. 22.5 ± 2.14 mg/L; P ≤ 0.01). Rams with ALD had greater serum Cl (3672 ± 38.8 vs. 3500 ± 38.3 mg/L; P < 0.001) and lower serum Cu (1.55 ± 0.07 vs. 1.77 ± 0.07; P = 0.04) than non-affected rams. However, BW, average daily gain, feed intake, feed conversion rate, and serum concentration of all other mineral were similar elements (P ≥ 0.06) between ALD and non-affected rams. While ALD and non-affected rams differed in key serum vitamin and mineral element concentrations, it is a multifaceted disorder in which perinatal, endocrine, genetic, and nutritional conditions need to be researched to fully understand the etiology and mitigate its incidence.