[The effect of preventative carazolol treatment on stress reactions in boars during semen collection]

The effect of the beta adrenoceptor blocking agent carazolol on heart and circulatory system, on blood values of the acid-base-equilibrium and on plasma enzymes such as creatine-kinase (CK) and aspartate-amino-transferase (ASAT) was investigated in four clinical healthy boars of the German Landrace and four boars of the Piétrain race before, during and after ejaculation at the phantom. The heart rate during semen collection increased less with treatment than it did without it. The relative diastolic time during exertion was prolonged by carazolol in those boars, which also without pharmacological influence had a very short relative diastolic time. By carazolol injection the systolic blood pressure could be decreased most in those boars, which without treatment had the highest rise of systolic blood pressure during semen collection. Furthermore it was shown, that the highest lactate values, which were found in some boars of the Piétrain race, were reduced most by the influence of carazolol. The blood values of the acid-base-equilibrium were highly negative correlated with the lactate values and changed according to them. The enzyme activities (CK and ASAT) 24 h after semen collection were not influenced by carazolol. Individual differences from boar to boar were evident in all examined parameters and were independent of the effects of carazolol treatment.