Use of a Visual Scoring System to Assess External Udder Conformation and Its Relationship to Colostrum Quality and Lamb Growth Rates

Abstract

In sheep raised for meat production, the relationship between external udder conformation, colostrum quality, and lamb growth rates has not received much attention. We hypothesized that ewes with a more desirable udder conformation at lambing would have greater colostrum quality and greater growth rates in lambs. Fifty Suffolk ewes were used in this study. Within 6–8 h of parturition, colostrum samples from both halves of the udder were collected and visual scoring of the udder was conducted. Colostrum quality was measured for total proteins using both optical and Brix refractometers. On day 2, day 45, and day 60 after parturition, lamb weights were recorded, and udder conformation measurements were repeated. A visual scoring system evaluating udder floor (scale 1–4), udder depth (scale 1–9), teat placement (scale 1–9), teat/mammary lesions (present or absent), and the presence of wool (present or absent) was used to assess the external udder conformation. Normal udder parameters included udder depth scores of 5 or 6; udder floor scores of 1 or 2; teat placement scores of 4, 5, or 6; and the absence of teat/mammary lesions and wool. All ewes not meeting normal parameters were considered to have an abnormal udder. The data were analyzed using the GLM procedure. Mean total colostrum protein was greater (p = 0.03) in ewes displaying a ‘normal’ udder conformation compared with those with an ‘abnormal’ conformation (14.82 ± 0.5 and 13.31 ± 0.3 mg/dL, respectively). Mean Brix values were also greater (p = 0.03) for ewes with a ‘normal’ udder compared to an abnormal udder confirmation (21.70 ± 0.8 and 19.54 ± 0.5, respectively). On day 2 after parturition, the mean lamb body weight was not different between ewes with ‘normal’ and abnormal udders (5.38 ± 0.26 vs. 5.46 ± 0.15). No differences (p > 0.05) in lamb weights were detected between ewes with normal and abnormal udder conformations on day 45 and 60 after parturition. These data provide evidence of greater colostrum total protein values and greater Brix values present in ewes with a ‘normal’ udder conformation. There were no differences in the weights of lambs born to ewes with normal or abnormal udder conformations.