REPRODUCTION MANAGEMENT IN THE GERMAN THOROUGBRED

BREEDING INDUSTRY

H. Merkt,1 E. Klug, 2 and W. J/3chle 3

In the animal industry, expenses conceming management of reproduction are highest in the business of horse breeding and particularly Thoroughbred breeding. Hence, efforts to improve fertility in the equine industry go back far in time. In Germany, first steps to establish a systematic approach to this goal were already taken in 1935, with the publication of Gt4idelines for the Control of Reproductive Diseases in the Thoroughbred Industry (Richtlinien zur Bek'~mpfung der Aufzuchtkrankbeiten in der Vollblutzucht). After World War II, the GermanAssociation of Thoroughbred Breeders (Direktorium fttr Vollblutzucht und Rennen) contracted Professor Richard G6tze from the Hannover School of Veterinary Medicine, a co-author of the Guidelines, to assist in the breed's restoration. The war and its aftermath had caused the loss of many horses and had left the rest of the breed in poor condition. As the most important measure, G6tze introducedin 1947 the so-called "Autumn Examination" (AE), in the course of which all stallions and mares used in Thoroughbred reproduction are examined annually by experts from the regional Schools of Veterinary Medicine. This is scheduled during September, long enough after the last breeding season to get the final results from last season's breeding and well in time before the next season to address animals with reproductive problems. 1

At admission to the AE, each stal- lion and each mare receives a special index card, with two copies, on which

Author's addresses: 1Institute for Reproduction Medicine; 2Hospital for Horses, School of Veterinary Medicine, Hannover, Germany; 3WJ Assoc., Inc. Denville, NJ 07834, USA.

examination results, treatments and their results are recorded. The original stays with the mare or stallion, one copy stays in the expert's file, and another copy is entered into the association's files. Every year during AE, this index card is updated by the regional expert and contains in concentrated form the whole reproductive history of the animal.

With this system in place, within three years the fertility rate (i.e. pregnancy rates in September) increased from 54% in 1947 to more than 70% in 1949 and later occasionally even to 80% and more (Fig. 2).

The breeding commission (Zucht-

Figure 1. Exposure of pregnant mares to a hovering helicopter. Overflights with two different kinds of military aircraft were used to study effects on pregnant mares. No adverse effects could be recorded.

kommission) of the breeder's association was so impressed with these early results, that in the early 1960s the AE became obligatory for the entire German Thoroughbred industry. In order to guarantee objectivity, the AE is financed by the association and not by the animal owners.

During AE, all stallions undergo an external clinical examination. The

Figure 2. Pregnancy rate at the Autumn Examinations since 1947.

70

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55

50 . . . . . . . . . . . . . . . . . . . . . . . . .

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822 JOURNAL OF EQUINE VETERINARY SCIENCE

N of mares baden mares

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3 S 7 9 fl f3 15 17 19 21 Age of mares, in years

Figure 3. Total number (N) of mares (- o -) and % of barren mares ( - �9 based on 7773 mares/years and age in 8 breeding years (Peckedrath 1985).

pregnancy rate of the mares they had covered during the last season is computed by considering only those mares which had a fair chance to become pregnant. If a stallion's pregnancy rate is lower than 70%, a detailed examination is initiated, including a spemaiogram.

All mares are clinically examined. Mares not pregnant are more thoroughly examined, which includes the taking of genital tract swabs, endometr ia l

smears and, if warranted, biopsies of the endometrium. If indicated, the expert provides recommendations for the mare's treatment to the local veterinarian who is always invited to share in the AE. In addition, the outcome of last year's pregnancy is recorded.

During the breeding season, reproduc- tive management, making diagnosis and prescribing treatments, lies in the hands of the local veterinarian. He/she will contact

the regional expert if help with problem cases is needed.

Pregnancy rates and age of mares Over the last 5 decades, with the

exception of one year, pregnancy rates did not drop under 70%. There are reasons for higher conception rates in some years. It is recognized that fertility is decreasing with increasing age of the mare (Fig. 3). Therefore, the majority of the brood mares are between the ages of 4 and 13 years.At a higher age, fertility drops steeply. This situation, as shown in Fig. 3, is skewed by the fact that after the age of 13 years about 10% of the mares are removed from breeding due to persistent infertility. Yet, breeders are particularly interested in breeding older dams whose previous offspring's have performed well. It is the veterinarian's task to assist the breeder in this effort. Hence, often considerable

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Volume 20, Number 12, 2000 823