The influence of manner of sustenance on luteinizing hormone concentration in dogs

Abstract

The evaluation of the status of luteinizing hormone (LH) in the peripheral blood of dogs plays an important role in precise estrus detection. The measurement of the luteinizing hormone concentration in the peripheral blood is a reliable and exact method used for determining the optimal time for mating. The peak of luteinizing hormone (LH) is a key endocrinological occurrence in the estrus cycle that starts (provokes) ovulation and thereby determines the fertile period. Dogs (females) typically have two estrus cycles per year, in spring and autumn. The elevated seasonal activity during February-May might be induced, among other things, by the environmental factors that stimulate the hypothalamic–hypophyseal–ovarian axis. There are a number of evidences testifying to the fact that adenohypophysis secretion is affected by external or exteroceptive stimuli through the nervous system. This study included a total of 30 dogs (females) in the region of Tuzla whose blood samples were collected in spring for evaluation of the luteinizing hormone (LH) concentration. The dogs (females) were divided into three groups depending on the manner of sustenance: a) group A (dogs living exclusively in a home environment); b) group B (dogs living in a shelter environment); c) group C (stray dogs). LH concentration ranged from 0. 312 ng/ml to 0.871ng/ml during spring. No statistically significant differences were found in LH concentrations between groups A and B (p=0. 1202), groups A and C during spring (p=0.5444), nor between group B and group C dogs during spring (p=0.2888). Based on the evaluated luteinizing hormone concentration, our study suggests that spring is the time of the year when all (female) dogs, irrespective of the manner of sustenance, become reproductively active. This study showed the (female) dog reproductive behaviour to be caused by internal and external factors such as photoperiod, temperature, ambient conditions, nourishment, the change of seasons, etc. These results play an important role in estimating estrus in (female) dogs and observing all relevant factors that are crucial to maintaining the reproductive potential of (female) dogs.