Veterinarija ir Zootechnika

This study aimed to study the effect of oreganum on forced molting in laying Japanese quails to improve the physiological performance and restore the reproductive capacity of females. A total of 120 female Japanese quails (Coturnix coturnix Japonica) aged 18 weeks were divided randomly into six groups: group A – pre-molting from weeks 18 to 19; group B – supplemented with oregostim at a dose of 0.3 mL\1000 mL; group C (molting from weeks 20 to 22) – fed a restricted diet; group D – fed a limited diet with oregostim at the same dose and post-molting from week 23 to week 37; group E – fed a basal diet; and group F – fed a basal diet and treated by oregostim. The results showed that the molting group caused a significant reduction in the weight of body and ovary in group C and group D, while the weights were restored in group E and group F relative to other groups. Besides, there was a significant decrease of WBCs and RBCs count in group C and group D with a significant elevation in group E and group F compared with group A and group B. The percentage of egg production and large follicle number in group C and group D decreased significantly compared with group A and group B, while they restored to normal values in group E and group F compared with group A and group B and showed a significant increase as compared with group C and group D, respectively. We concluded from this study that oregostim does not have adverse effects on the molting period. Thus, the standard diet supplemented with oregostim was considered as a better molting technique.

The purpose of this review is to examine the scientific literature on the effects of heat stress on some physiological, productive and reproductive parameters in dairy cows. The article analyzes the scientific papers in which the influence of heat stress and its impact on some indicators is studied. As a result of the review, it became clear that heat stress has an impact on the studied indicators, but there are no clear criteria at which values of temperature-humidity index (THI) this effect is registered. The relationship between heat stress, productivity, successive lactation and physiological and reproductive parameters in dairy cows is still controversial. This poses a challenge, through research, to solve the problems in regards to high temperature and animal welfare and productivity for specific climatic conditions.