Author
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SCHALLES, ROBERT - KANSAS STATE UNIVERSITY |
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Cundiff, Larry |
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Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 1/28/1999 Publication Date: N/A Citation: N/A Interpretive Summary: After the introduction of some Continental breeds of cattle into the US during the 1960's and 70's, a congenital condition commonly referred to as "rat-tail" was reported when those breeds were crossed with cattle with black coat color (e.g., Angus or Holstein). The condition is characterized by short, curly, malformed, sometimes sparse hair and lack of normal tail switch development. The condition is very rare or nonexistent in purebreds but occurs in crosses, indicating that at least two loci are involved in its inheritance. Some markets discriminate against these animals, which decreases their economic value. The objective of this study were to determine 1) the effect of the rat-tail condition on calf performance and 2) the mode of inheritance of the syndrome. The performance of 43 rat-tail calves was compared to that of 570 non-rat-tail calves of the same breeding and contemporary groups. All rat-tail calves were sired by Simmental bulls sand were from cows with various percentages of Angus breeding. The rat-tai condition had no effect on birth weight, weaning weight, or gain from birth to weaning. However, the rat-tail calves had significantly lower rates of gain from weaning to yearling (during the winter months) than the non-rat-tail calves, resulting in a 19 kg lighter yearling weight. In a second study, Angus-Simmental F1 males and females with the rat-tail condition were mated to produce 64 F2 offspring that were used to determine the mode of inheritance of this syndrome. Analysis showed that the rat- tail syndrome is controlled by interacting genes at two loci. Cattle that express the syndrome must have at least one dominant gene for black color and be heterozygous at the other locus involved. Technical Abstract: A form of congenital hypotrichosis, commonly known as the rat-tail syndrome, occurs in a small percentage of calves produced by crossing some Continental breeds cattle with breeds that are black in color. These calves are characterized by short, curly, malformed, sometimes sparse hair and a lack of normal tail switch development. The performance of 43 rat- tail calves was compared to that of 570 non-rat-tail calves of the same breeding and contemporary groups. All rat-tail calves were sired by Simmental bulls and were from cows with various percentages of Angus breeding. The rat-tail condition had no effect on birth weight, weaning weight, or gain from birth to weaning. However, the rat-tail calves had significantly lower rates of gain from weaning to yearling (during the winter months) than the non-rat-tail calves, resulting in a 19 kg lighter yearling weight. The gains of steers from yearling to slaughter were not significantly different, but the rat-tail steers were 36 kg lighter (P=.01 and 13 days older (P=.15) at slaughter than the non-rat-tail steers. In a second study, Angus-Simmental F1 males and females with the rat-tail condition were mated to produce 64 F2 offspring that were used to determine the mode of inheritance of this syndrome. Analysis showed that the rat- tail syndrome is controlled by interacting genes at two loci. Cattle that express the syndrome must have at least one dominant gene for black color and be heterozygous at the other locus involved. |
