ENGLISH VERSION

ZESZYT 331

Marek Sapuła
Influence of Małopolski horses’ nervous excitability on their performance traits

The aim of the study was to analyse the level of nervous irritability and processes of memorization  in mares and stallions of Małopolski breed based on the scores of excitability test and maze test considering their use traits (length and frequency of gain in step and trot, speed of movement, reproductive indices of mares and stallions, scores of stallions’ performance test in training stations and value of heart rate measured during conducted tests). Nervous irritability and mental processes of studied horses were evaluated according to Budzyński’s methods.

In the present study the influence of the breeding centres (Studs, Herds of Stallions), sex of horses (mares, stallions), breeding maternal lines (mothers) and sire lines (fathers) and sire breeds was considered.

Moreover individual indices of breeding value of studied mares and stallions and mothers of stallions and mares, and also fathers of studied stallions and mares  were calculated (BLUP method) considering the scores in the excitability test and the movement indices. It was tried to evaluate coefficients of heritability (h2) for behavioural reactions of studied horses in the excitability test and maze test and movement indices by REML method.
The scores were based on the experiments conducted in the years 1995–2005. The study included 765 horses of Małopolski breed (547 stud mares used in the Studs and 218 stallions registered in the Herds of Stallions).

It seems to be important to include assessment of Małopolski horses in the tests of nervous balance into the breeding goal. The significant influence of breeding centre and sex of studied horses on the quality of behavioural responses in the excitability test and mental processes in the maze was found. Higher mares’ predispositions  to more functional perception and memorization of many environmental stimuli, better learning ability in comparison with  stallions were stated. The stallions have shown lower nervous irritability compared with mares. Highly significant dependences between the scores in the excitability test and heart rate value measured during the tests in studied mares and stallions were found. Lower heart rate level during the tests in quiet horses was found.

It was showed that level of nervous irritability of studied horses was significantly correlated with value of assessed movement indices. Longer step and higher speed of movement was characteristic for the horses with higher level of nervous balance. Considerable dependency between point assessment of the excitability test and scores of the maze test was stated. Quiet horses have shown better ability of quick memorization of the way in the maze in comparison with irritable ones.

Significant dependency between value of use traits in horses assessed during performance test and their mental features was found. The highest scores in the performance test were obtained by medium-irritable and quiet stallions.

The best indices of reproduction (foal index, fertility) were found in mares classified as quiet ones. The lowest rate of pregnancy lost (abortions, resorptions, stillborns) also was found in the quiet mares. During mating period the highest number of mares was covered by stallions classified as quiet ones.

The study showed that the highest nervous balance was characteristic for both, daughters and sons, originating form Purebred Arabian and Thoroughbred stallions. The best scores in the maze test were received by daughters and sons of Thoroughbred stallions.

Calculated indices of breeding value can be useful as one of the selection criterion in relation to nervous balance.