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Sexual behaviour of bulls in natural breeding
GOUBEJOVÁ, Jaroslava
The aim of this thesis was to capture basic categories of behaviour and sexual behaviour of bulls in natural breeding, acquire and evaluate data from behavioural observations. The observations were realized in the village Obora u Tachova and were focused on a pedigree bull of a breed called Limousine (ZLI 796) and a herd of 26 breeding-cows, crossbreed beef cattle which are reared in the system of cows without market production of milk. The observations were made during the period from March 2013 till March 2014. The pedigree bull was in the herd of cows classified year-round. Monitoring with subsequent recording from the observations was performed whenever there was a breeding-cow in the herd and was discovered by a regular inspection of the herd observer. The snapshot method was used for the observations with the length of an interval of 5 minutes. From the ethological observation it emerged that the category of lying influences sexual behaviour of the bull towards to a breeding-cow the most. The value decreased from 15.97%, which was recorded in case of no breeding-cow in the herd, to 11.87 % in case of one breeding-cow in the herd and, if there were more breeding-cows the value fell to 2,51 %. For the category called movement, the value increased from 12.50 % to 16.03 % in case of one breeding-cow and when there were more breeding-cows, the value increased to 22.17 %. Sexual behaviour of the bull has only a low effect on feed intake, which was always held on the level of 47 % and the category called stall which was in case of no breeding-cow and one breeding-cow 24 %. For more breeding-cows the values increased to 27%. It was found out that the length of a movement extends at the expense of lying. The number of failed attempts to copulate the bull with one breeding-cow decreased from 17.91 experiments to 12.22 experiments with two or three breeding-cows. In case of successful copulations, the value increased from the original 5.73 copulations with one breeding-cow in the herd to 6.56 copulations with the average number of successful copulations 3.11 per one copulation. The highest intensity of copulation passed off in the morning between 8 a.m. to 10 a.m., the second peak occurred around 5 p. m. in the afternoon. The success rate of the bull in the herd of the breeding-cows, where there was only one breeding-cow, was 81.82 %. The success rate of the bull in the herd of breeding-cows, where there were two or three breeding-cows, was 72.73 %. The total fertility of the bull reached to 91.30 %.
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