Genome-based test for left-sided abomasal displacement in German Holsteins.
Abomasal displacement is an economically important and heritable disease in dairy cows. Heritability (heritability) for left-sided abomasal displacement has been estimated to range from 12% to 53% in the threshold model (Wolf et al., 2001a, Hamann et al., 2004, Ricken et al., 2004). The first case report of abomasal displacement dates back to 1898, but only since the 1950s - since the increased breeding away from the old dual-purpose breeds to pure dairy breeds - the occurrence of this disease has been reported more frequently. The abomasum may be displaced to the left or right side of the abdomen. Left-sided abomasal displacement is by far the most common form, accounting for 85-95% of cases (Constable et al. 1992). In Holstein cows, abomasal displacement has been studied particularly intensively. The prevalence for left-sided abomasal displacement ranged from 1.2% to 2.6% in German Holsteins (Wolf et al. 2001, Hamann et al. 2004), and as high as 5.5% in US Holsteins (Detilleux et al. 1997). Left abomasal displacement usually occurs shortly before calving and up to eight weeks after calving. Because abomasal displacement massively affects general condition, feed intake, and metabolism, major economic problems are also associated with this disease. For example, according to Detilleux et al. (1997), milk yield is reduced by 557 kg in the first 60 days after left abomasal displacement compared to healthy cows. Geishauser et al (1998) studied milk, fat and protein yield in lactation of diseased cows compared with control animals. They found a reduction of 316 kg in milk yield and a 12 kg reduction in fat and 10 kg reduction in protein in milk. Similar values were found by Ricken (2003) with a 386 kg reduction in milk yield and 12.7 and 13.5 kg reductions in fat and protein, respectively. In the studies of Wolf et al. (2001), the milk quantity in lactation with abomasal displacement was even reduced by 1016 kg compared to grain troll animals. Fat quantity and protein quantity were reduced here by 41 kg and 36 kg, respectively. On average, between 37.9% and 47.7% of all cows suffering from left abomasal displacement leave the farm within one year after the disease (Ricken et al., 2005, Wolf et al., 2001a). This falls under the umbrella term "other reasons" in the causes of departure. Left abomasal displacement is usually treated surgically, with the abomasum degassed and connected to the abdominal wall in the correct position.
Due to the high heritability, the genetic background of left-sided abomasal displacement was investigated at the Institute of Animal Breeding and Inheritance Research. For this purpose, highly associated genomic regions for left-sided abomasal displacement were identified based on extensive sampling from the entire German Holstein population. These provide the basis for a new genome-based test for left-sided abomasal displacement. This genomic test allows identification of hereditary disposition for left-sided abomasal displacement with 80% confidence (r2). Testing of insemination bulls can thus significantly reduce the risk of left-sided abomasal displacement in their daughters. To perform the test, an EDTA blood sample of 5 ml or three semen straws are required.
Constable, P. D., G. Y. Miller, G. F. Hoffsis, B. L. Hull, and D. M. Rings. 1992. Risk factors for abomasal volvulus and left abomasal displacement in cattle. Am. J. Vet. Res. 53:1184-1192.
Hamann, H., V. Wolf, H. Scholz and O. Distl. 2004. Relationships between lactational incidence of displaced abomasum and milk production traits in German Holstein cows. J. Vet. Med. A. 51:203–208.
Detilleux, J. C., Y. T. Gröhn, S. W. Eicker, and R. L. Quaas. 1997. Effects of left displaced abomasum on test day milk yields of Holstein cows. J. Dairy Sci. 80:121-126.
Geishauser, T., M. Shoukri, D. Kelton, and K. Leslie. 1998. Analysis of survivorship after displaced abomasum is diagnosed in dairy cows. J. Dairy Sci. 81:2346-2353.
Hamann, H., V. Wolf, H. Scholz, and O. Distl. 2004. Relationships between lactational incidence of displaced abomasum and milk production traits in German Holstein cows. J. Vet. Med. A. Physiol. Pathol. Clin. Med. 51:203-208.
Ricken, M. 2003. Labmagenverlagerung beim Rind: Analyse von genetischen Faktoren und ökonomischen Auswirkungen auf die Milchproduktion. Dissertation, Tierärztliche Hochschule Hannover.
Ricken, M., H. Hamann, H. Scholz, and O. Distl. 2004. [Genetic analysis of the prevalence for abomasal displacement and its relation to milk performance traits in German Holstein cows]. Dtsch. tierärztl. Wschr. 111:366-370.
Wolf, V., H. Hamann, H. Scholz, and O. Distl. 2001a. [Influences on the occurrence of abomasal displacements in German Holstein cows]. Dtsch. tierärztl. Wschr. 108:403-408.
Wolf, V., H. Hamann, H. Scholz, and O. Distl. 2001b. [Systematic influences on the development of abomasal displacements in German Holstein cows]. Züchtungskunde 73:257-265.