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

Authors: LAVERELL, DYLAN - University Of Wyoming; Murphy Jr, Thomas; ENGLE, TERRY - Colorado State University; SMYLIE, JACOB - University Of Wyoming; KERSH, AARON - University Of Wyoming; JACOB, SARAH - Michigan State University; STEWART, WHITNEY - University Of Wyoming

Submitted to: Translational Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/19/2025
Publication Date: 5/22/2025
Citation: Laverell, D.M., Murphy, T.W., Engle, T.E., Smylie, J.M., Kersh, A.J., Jacob, S.I., Stewart, W.C. 2025. A comparative study on growth, feed intake, and serum vitamin and mineral concentrations in Western white-faced rams with and without limb deformities. Translational Animal Science. 9. Article txaf069. https://doi.org/10.1093/tas/txaf069.
DOI: https://doi.org/10.1093/tas/txaf069

Interpretive Summary: Angular limb deformities (ALD) have historically affected 3-18% of Western white-faced ram lambs enrolled in central performance tests in the Northern Great Plains. Osteochondrosis, the underlying pathology of ALD, occurs from thickening of cartilage on the elbow joint, and the forelimbs of ALD affected animals appear either "bowed out" or "bowed in" (i.e., “knocked kneed”). Therefore, ALD contributes to severe limitations in mobility that can negatively impact animal welfare and performance under most management conditions. The suspected nutritional drivers of developmental ALD may be more significant in extensively managed systems where sheep are more likely to experience macro- and micro-nutrient deficiencies. Historical challenges with ALD in Western white-faced rams, combined with limited published data on growth and nutritional factors merits additional investigation into the causes of ALD. The objective of this research was to quantify differences in growth rate, feed intake, and Vitamin D and mineral element concentrations of rams affected and unaffected with ALD. Rams with ALD had greater serum Vitamin D and magnesium concentration within certain time points of the experiment. Across the entire experiment, ALD rams had greater serum chloride and lower serum copper than non-affected rams. However, growth rate, feed intake, feed conversion rate, and serum concentration of all other mineral elements were similar between ALD and non-affected rams. While ALD and non-affected rams differed in key serum vitamin and mineral element concentrations, ALD is a multifaceted disease that is likely influenced by the environment, diet, genetics, and their interactions and further research is necessary to mitigate its impacts.

Technical Abstract: 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. A total of 25 ram lambs (191 ± 25 d of age; n = 12 ALD, n = 13 non-affected) enrolled in a central performance test were evaluated. 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 x 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 /= 0.06) 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.