–1RYHPEHU 201, Brno, Czech Republic Evaluating the descendants of stallions from the Cor de la Bryère line in Czech Warmblood breeding Zuzana Kubikova, Iva Jiskrova, Barbora Kubistova Department of Animal Breeding Mendel University in Brno Zemedelska 1, 613 00 Brno CZECH REPUBLIC [email protected] Abstract: The main aim of this study was to evaluate the influence of the stallion Cor de la Bryère’s line in Czech Warmblood breeding. The significance of this breeding line was evaluated by performing a comparison of the body measurements of descendants by the most important stallions permitted to act as stud horses within Czech Warmblood breeding. The specific observed attributes for evaluating the quality of the stallions were the values of descendants’ basic body measurements, i.e. stick height at withers, tape height at withers, chest circumference and cannon bone circumference. A total of seven breeding stallions were compared, three of which were Holsteiners, three Hanoverians and one a Czech Warmblood. The comparison group consisted of 347 descendants of the Czech Warmblood breed by the sires Calanthano, Carlos, Carol, Cartouche, Catango Z, Comero and Chazar. A high statistically conclusive influence of the sire was only established for cannon bone circumference. With the other body measurements, the influence of the sire was not proven. When evaluating individual years according to cannon bone circumference, the best group was judged to be descendants born in the year 1994. Furthermore, it was determined that on average both sexes of the descendants of this line meet the breed standard for the Czech Warmblood in terms of cannon bone circumference. Another factor evaluated was stick height at withers, which, like cannon bone circumference, is subject to the breed standard for the Czech Warmblood. In this case it was not possible to statistically demonstrate the effect of the observed factors. In view of the importance of this body measurement, the maximum, minimum and average values were evaluated, and on this basis it can be said that for stallions from the Cor de la Bryère line, breeders should select mares with a smaller body frame but a thick cannon bone. Key Words: stallion, offspring, Czech Warmblood, Holsteiner, Hanoverian INTRODUCTION History of the stallion Cor de la Bryère Cor de la Bryère was the son of the Thoroughbred stallion Rantzau, who played an active role in French sport horse breeding. Rantzau was the leading stud horse for dressage, showjumping and event horses in France between 1971 and 1973. His bloodline produced countless outstanding sport and stud horses (Muller 2018). Štěrba (2018) writes that in 1971 it was necessary to find a stud horse for Holsteiner breeding that would positively influence the jumping technique and rideability of his offspring, as these had been adversely affected by the massive use of the Thoroughbred. At that time the French stud was enjoying great successes, and so the board of the Holsteiner stud decided to lease a stallion of French breeding and thereby discovered the three-year-old stallion - rather immature but exuding quality - by the Thoroughbred Rantzau out of Quenotte by Lurioso. The French were not keen on him, did not include him in the breeding programme and advised his breeder to have him gelded. The main asset Cor de la Bryère brought to sport horse breeding was an unprecedented jumping style and action of the front legs. Each year he produced first-class horses for all equestrian disciplines. Some of the greatest include Contrast, followed by Corlandus (silver medal in dressage at the 1988 Olympic Games) and numerous showjumping champions such as Caletto I, Colando I, Corrado I, Cheyenne, Cera, Cordalmé Z, Cor d´Almé Z, Corland, Cash and many more. 108 –1RYHPEHU 201, Brno, Czech Republic His grandchildren have also been very successful, such as the Olympic champion Classic Touch, the world champion Fein Cera, Coriano, Calvaro Z, Careful, Operette la Silla, Cayon, Cabrio and Clinton (Muller 2018). Verband der Züchter des Holsteiner Pferdes (2016) writes that Cor de la Bryère became another pillar of Holsteiner breeding after the stud horse Langraf. Along with the line of Ladykiller XX, the “Corde” line has therefore been one of the strongest lines in establishing modern sport horse breeding. According to Kirsan (2017), at the time of Cor de la Bryère’s transfer to Holstein, including the Selle Français breed in Thoroughbred breeding was quite unprecedented. The Selle Français breed as a whole was not viewed positively at that time – not even in its homeland, much less abroad. However, this opinion was transformed by the legendary stallion Cor de la Bryère. The “Corde” line has also had an influence on Czech Warmblood breeding, where according to Dušek et al. (2011) the relatively short period of improvement and the number of breeds used has affected the variability of the conformation. Consequently, breeders’ efforts are now directed towards the greatest possible homogenization of conformation and consolidation of the breed. MATERIAL AND METHODS The underlying database was created on the basis of data obtained from the website of the Association of Czech Warmblood Breeders. Seven stud horses from the Cor de la Bryère line were selected and the relevant data on the stud horses and their offspring were collected. The database contains a total of 347 descendants, and the following data were recorded for each of them: name, year of birth, body measurements stick height at withers (SWH), tape height at withers (TWH), chest circumference (ChC) and cannon bone circumference (CBC) and information about the sire. Table 1 Distribution of descendants into groups according to the year of birth Number Year of birth 1 1994 2 1995 3 1996 4 1997 5 1999 6 2000 7 2001 8 2002 9 2003 10 2004 11 2005 12 2006 13 2007 14 2008 15 2009 16 2010 17 2011 18 2012 19 Other 109 –1RYHPEHU 201, Brno, Czech Republic Table 2 Distribution of stud horses into groups Number Stallion 1 2772 Calanthano 2 2800 Carlos 3 410 Carol 4 2726 Cartouche 5 814 Catango Z 6 411 Comero Table 3 Distribution of horses into groups by sex Number Sex 1 Mare 2 Stallion 3 Gelding Model equation: yijk = μ + pi + qj + rk +eijk where: yijk is the observed effect (KVP, KVH, OH, Ohol) μ is the total average of the set pi is the fixed effect of the i-th group of sires (i = 1,…, 7) qj is the fixed effect of the j-th year of birth (j = 1,…, 22) rk is the fixed effect of the k-th sex (k = 1,2,3) eijk is the random effect Based on the results from the general linear model, the differences between values were established by subsequent testing according to Tukey-B. The test was conducted at a significance level of P ≤ 0.05. The database of descendants was created in the programme Microsoft Office Excel 2010. The data acquired were then statistically processed using a GLM linear model in the statistical programme UNISTAT 6.5. The underlying database for evaluating the general linear model contains seven stud horses and their 347 descendants. Each stud horse was assigned an internal identification number from 1 to 7 solely for our purposes. The influence of the sire, year of birth and sex on the values of the basic body measurements was observed. The descendants’ years of birth were also given a number, with item number 19 (other) encapsulating descendants born in the years 1993, 1998, 2013 and 2016, which had to be amalgamated because of their low numbers. Likewise, it was necessary to number sex distribution, this time from 1 to 3. RESULTS AND DISCUSSION Evaluation by the GLM model revealed statistical conclusiveness of the observed influences for only one basic body measurement – cannon bone circumference. This confirmed that the transfer of sires’ phenotypic traits to offspring exhibits a degree of heritability, but according to these results it is primarily bone mass. The influence of the year of birth emerged as statistically inconclusive for the attributes SWH, TWH and ChC. In the case of CBC, however, this influence exhibited high statistical conclusiveness. This result can be explained by the fact that in one of the years more descendants with an above-average cannon bone circumference were born. Cannon bone circumference is an important breed attribute subject to the standards for the Czech Warmblood. That is why the values of this measurement are extremely important, since 110 –1RYHPEHU 201, Brno, Czech Republic they indicate the strength of the skeleton, which is highly desirable. Especially at present, it is essential that stud horses with the ability to pass on a strong skeleton to their descendants are included in breeding, because the influence of a large variety of different breeds in Czech Warmblood breeding has resulted in it becoming lighter, which is highly undesirable for breeding. The evaluation of sex within CBC again revealed a highly statistically conclusive influence. It can therefore be stated that the importance of monitoring this attribute was confirmed and statistically proven. The breed standard for Czech Warmblood breeding gives the threshold for cannon bone circumference as 19.5−22 for mares and 21−22.5 for stallions. Table 4 Comparison of results of the stud horses according to CBC of descendants by Tukey-B testing Stud horse No. of descendants Average CBC 2772 Calanthano 31 20.35 2667 Chazar 9 20.48 410 Carol 91 20.57 411 Comero 59 20.77 814 Catango Z 118 20.78 2726 Cartouche 36 20.96 2800 Carlos 3 21.17 This table shows that the highest average values for the cannon bone circumference measurement are achieved by descendants of the stud horse 2800 Carlos.