Sheep GEMS Update: Lambing assistance and udder health scores

Authors: LEWIS, RONALD - UNIVERSITY OF NEBRASKA; Murphy, Thomas - Tom; Freking, Bradley - Brad; Burke, Joan

Submitted to: Eastern Alliance for Production Katahdins Newsletter
Publication Type: Popular Publication
Publication Acceptance Date: 12/23/2023
Publication Date: 1/3/2024
Citation: Lewis, R., Murphy, T., Freking, B., Burke, J. 2024. Sheep GEMS Update: Lambing assistance and udder health scores. Eastern Alliance for Production Katahdins Newsletter. Winter 2023 Newsletter. p. 10-11.

Interpretive Summary:

Technical Abstract: Katahdin sheep are being raised in flocks across the U.S. that differ in climate and management. Breeding for climatic resilience and robustness across these environments is key to ensuring success. Two aspects of fitness are lamb survival and udder health. In Sheep GEMS, in collaboration with seventeen NSIP Katahdin breeders and three USDA ARS facilities with Katahdin flocks, we are exploring measurements that provide insights on genetic merit for fitness. Lambing assistance, which affects survival, is being evaluated in two ways. The first is based on whether the ewe herself required assistance. When observed to lamb, ewes are being scored as not requiring assistance or, if assistance was required, due to management (to benefit the shepherd), moderate lambing difficulty, or severe lambing difficulty. Complete lambing information is available on 880 Katahdin ewes from one lambing season in Sheep GEMS so far with intriguing preliminary results. Over half (55%) of the ewes were monitored at lambing time, with most (72%) not requiring any assistance. Where assistance was provided to benefit the ewe (rather than the shepherd), in nearly all cases she only needed moderate assistance. Severe lambing difficulty was rare. Also, ewes with twin, as compared to single and triplet, litters typically required less assistance. If an ewe was provided with assistance, her lambs were assigned their own lambing assistance code. Several of those codes relate to abnormal presentation such as one or two legs back, head back, back legs first, and breech. When moderate assistance was needed, it was almost always due to an abnormal presentation. Udder health is being evaluated by assigning a 1-to-9-point score to the depth of the udder and to the placement of the teats. For udder depth, a score of 1 is an udder that hangs close to the ground while a score of 9 is an udder up close to the abdomen wall; a score of 5 is an udder hanging down to the ewe’s hocks. For teat placement, a score of 1 coincides with teats pointing straight down (toward the ground) while a score of 9 coincides with teats pointing straight out to the side; a score of 5 are teats pointing outward at a 45-degree angle. Based on anecdotal evidence, an udder depth score of 7 and a teat placement score of 5 are thought to be ideal as they are associated with lower risks of mastitis and heavier weaning weights. Based on records from the one lambing season, udder depth scores decreased from 8 to 6 as ewes aged from 1 to 6 years of age and older. Teat placement scores, however, were typically 5 across ages. With the ‘best’ scores intermediate rather than extreme (i.e., 1 or 9), coupled with the age trend for udder depth, selection to improve udder health will be challenging. Overcoming that challenge by defining pragmatic ways to incorporate udder health into the breeding program is an aim of Sheep GEMS. These results are preliminary with much more to do. For instance, we need to consider the impact of lambing assistance and udder health scores on ewes’ lifetime performance and longevity, and on lambs’ survival and weaning weights. Those evaluations depend on engagement by Katahdin breeders in Sheep GEMS providing us with high quality data. We look forward to continuing to work with you. Acknowledgements. We thank the many U.S. sheep associations, including the Eastern Alliance for Production Katahdins, the Katahdin Hair Sheep International, the National Sheep Improvement Program, and Katahdin sheep producers, for their contributions to this research. This work is supported by the Organic Agriculture Research and Extension Initiative (grant no. 2016-51300-25723/project accession no. 1010329), and by the Agriculture and Food Research Initiative Competitive Grant (grant no. 2022-67015-36073/project accession no. 1027785), from the USDA National Institute of Food and Agriculture. Any