Sheep Industry News August 2025

tests were largely unchanged, emphasizing that fleece quality can be maintained as other traits change. Ram Test Research Discoveries and Collaborations Feed Intake and wool quality Feed costs are widely considered to be the largest variable cost associated with sheep production. However, measuring individual feed intake in large settings was impractical until relatively recently. The University of Wyoming was one of the first institutions to implement Vytelle (formerly GrowSafe) electronic feeders for use in sheep (Figure 2) . These feeders re cord individual daily feed intake and enable other traits such as feed efficiency and feeding behavior to be evaluated. Residual feed intake (RFI) measures how much more or less feed an animal ate than expected for its size and growth. Therefore, RFI can be used to identify animals who more efficiently convert feed into gain. Data from white-faced rams on the 2009 – 2011 Wyoming tests found that RFI was not cor related with carcass, growth, or fleece traits. This suggests that

selection for improved RFI might not negatively impact other traits. While the cost of an electronic feeder is prohibitive for most, enrolling in a central ram performance test allows pro ducers to have access to this and other valuable data. Wool Quality Rams are shorn at the beginning and end of the testing period to evaluate wool traits. Before off-test shearing, staple length is measured across the body and a belly wool score is assigned by a trained evaluator (1 = no belly wool, 2 = belly wool less than one-third of the side, 3 = over one-third side to over one-half side). Greasy fleece weights are captured, and fleeces are individually cored to objectively quantify yield and fiber diameter. Notably, central performance tests are the only current program to provide clean fleece weight—a measure of actual marketable wool—which is critical for improving wool profitability. The University of Idaho, in collaboration with the University of Wyoming and North Dakota State University-Hettinger Re search Extension Center (NDSU), evaluated wool characteris tics using data collected at both the Wyoming and NDSU tests. One of the most important findings quantified the relationship between belly wool and fiber diameter. It was observed that rams with a belly wool score of 3 (high) had finer fiber diam eter than rams with a belly wool score of 1 (low). This is a great example of how genetic progress in one trait (lower fiber diam eter) can negatively impact another trait (increased belly wool) if left unchecked. Additionally, several genomic regions were found to be associated with wool quality and could be useful in marker assisted selection programs. Limb deformities also known as “bent leg” Angular limb deformities (ALD), also known as bent leg, have historically impacted 3% to 18% of rams enrolled in the Wyoming and NDSU tests. This phenomenon, which can result in the inward or outward bowing on one or both front legs (Figure 3) tends to be observed more frequently in fine-wooled rams. The obvious leg deformity impairs ram mobility and therefore necessitates culling, oftentimes at a reduced market value. Bent leg occurs during the developmental phase, mean ing we cannot visually tell at birth whether a ram will have the condition later. However, little is known about biological or husbandry factors associated with ALD because large contem porary groups of developing rams under uniform environmen tal conditions are rarely available for study. Through collaborations with the University of Idaho and NDSU, research in Rambouillet rams identified three genes as sociated with increased ALD risk, with certain genetic variants making rams up to 4.8 times more likely to develop the condi-

Figure 2. A lamb eating from a Vytelle (formally GrowSafe) electronic feeder, enabling individual feed intake to be calculated.

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