Results of the biological test of simmental bulls in central Serbia

Abstract

Exceptionally important aspect in cattle production, from the aspect of production and economy, is ensuring normal and regular fertility. Every cattle breeder wants to have high-yielding animals which at the same time have good fertility. In proper cattle breeding this means that from each cow during single year one healthy calf is obtained. Use of artificial insemination has enabled that one breeding male is used as sire for several tens of thousands of progeny, however, there is always the risk that sires could be carriers of lethal and semi-lethal genes, which can cause huge losses of calves. In order to bring these undesirable occurrences to a minimum, so called bilogical test is included in the breeding and selection activities, i.e. bulls are tested through their progeny for presence of difficult calving (dystocia) abd calf losses caused by genetic anomalies. In Republic of Serbia, this test is carried out on ehtire Simmental population in an exchange of data produced by primary breeding organizations. Per each tested bull, it is necessary to have data on minimum 50 randomly selected calves. Calves are examined visually 65 days after the birth, at the latest. In the present study, the results of the biological testing of 35 Simmental bulls, sires of total 3572 calves on the territory of Central Serbia, in the period 2008-2009, are used. The effect of sires on parameters of biological test were studied: body mass of calves at birth, calf score and calving score. Also, bulls were ranked based on said parameters, male/female calves ratio and percentage of twins and still-born calves for each bull individually were determined. After the rank of bulls was established, the correlation between the rank and studied fertility traits was determined. Correlations were expressed using the Spearman coefficient. Research results show that the effect of bulls was very high p lt 0,001 on all three parameters of the biological test, and also that the percentage of still born calves for all bulls was within limits, with the exception of bulls Zahlo (HB 1497) and Woz (HB 1433) where it was above 5.

Izuzetno važan aspekt u govedarskoj proizvodnji, gledano sa proizvodnog i ekonomskog stanovišta je obezbeđivanje normalne i redovne plodnosti. Svaki odgajivač goveda želi da ima grla koja su visoko proizvodna i istovremeno poseduju dobru plodnost. Za pravilno odgajivanje goveda to znači da se od svake krave u toku godine dobije po jedno zdravo tele. Upotreba veštačkog osemenjavanja omogućila je da jedan priplodnjak bude otac nekoliko desetina hiljada potomaka. Međutim, uvek postoji rizik da su očevi nosioci letalnih i semiletalnih gena, što može prouzrokovati velike gubitke teladi. Da bi se ove nepoželjne pojave svele na najmanju moguću meru u odgajivački i selekcijski rad uključeno je ispitivanje bikova po potomstvu na teška teljenja i gubitke teladi izazvane genetskim anomalijama, tzv. biološki test. Ovaj test se u Republici Srbiji vrši jedinstveno za čitavu populaciju simentalske rase, razmenom podataka između odgajivačkih organizacija. Po svakom biku koji se testira, neophodno je imati podatke za najmanje 50 slučajno odabrane teladi. Vizualni pregled teladi se obavlja najkasnije do 65 dana, od datuma rođenja teleta. U ovom istraživanju korišćeni su rezultati biološkog testa 35 bikova simentalske rase koji su bili očevi ukupno 3572 teladi na teritoriji centralne Srbije u periodu 2008. i 2009. godine. U radu je ispitivan uticaj očeva na parametre biološkog testa: telesnu masu teladi po rođenju, ocenu teleta i ocenu toka teljenja. Takođe je izvršeno rangiranje bikova na ove parametre, kao i utvrđivanje odnosa muške i ženske teladi, procenat bližnjenja kao i procenat mrtvorođene teladi za svakog bika posebno. Nakon utvrđenog ranga bikova izvršena je korelacija ranga ispitivanih osobina plodnosti. Korelacije su iskazane Spirmanovim koeficijentom. Rezultati istraživanja pokazali su da je uticaj bikova izuzetno visok p lt 0,001 na sva tri parametra u biološkom testu, kao i da je procenat mrtvorođene teladi kod svih bikova u dozvoljenim granica, osim bikova Zahlo (HB 1497) i Woz (HB 1433) gde je iznosio preko 5.