Morphometric measurements in lambs as a basis for future mapping studies

Eck, Kim; Kunz, Elisabeth; Mendel, Christian; Luhken, Gesine und Medugorac, Ivica (2019): Morphometric measurements in lambs as a basis for future mapping studies. In: Small Ruminant Research, Bd. 181: S. 57-64

Abstract

Tail docking in young lambs of long-tailed breeds has become a regular practice worldwide, but nowadays animal welfare also plays an increasingly important role in society. Consequently, a genetic solution to breed for a shorter tail is needed, especially in long-tailed breeds like Merino, one of the most important and most numerous sheep breeds worldwide. A serious genetic analysis of the natural diversity in tail length should consider the autocorrelation of tail length and individual body size. This study aimed to compare different morphometric measurements and their suitability as a correction factor for individual body size and to identify an optimal time point for phenotyping of the main and correlated traits. For this purpose, a total of 88 Merinolandschaf lambs, the most common German Merino variety, were measured weekly during their first eight weeks of life. Besides absolute tail length itself, the following morphometric traits where phenotyped: body weight, withers height, back height, length of the body measured with a rule, length of the body measured with a measuring tape, length of the metacarpus, length of the femur and length from the anus to the hock. Additionally, the length of the tail was scored according to the Ovicap scoring scheme, gender and litter were identified and the tail wound in lambs that had to be docked due to injuries was examined. A high correlation (0.854) between initial tail length and the length at weaning confirmed that predictions about the development of tail length from data at birth should be possible. For correcting tail length for individual body size, withers height and body weight in five-week-old lambs proved most suitable. Withers height and body weight were selected for their high coefficient of determination in the linear model, their high correlation with tail length and the good retest reliability. The advantages of phenotyping and genotyping five-week-old lambs are easier handling compared to adult sheep, the ability to detect phenocopies produced by docking in case of tail injuries, a high coefficient of determination in the linear regression model and a good retest reliability at this time point.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Tiermedizin
• Themengebiete: 600 Technik, Medizin, angewandte Wissenschaften > 610 Medizin und Gesundheit
• ISSN: 0921-4488
• Sprache: Englisch