نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه علوم دامی، دانشکده علوم دامی، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، گرگان، ایران
2 گروه علوم دامی، دانشکده علوم دامی و شیلات، دانشگاه علوم کشاورزی و منابع طبیعی ساری، ساری، ایران
3 گروه علوم دامی، دانشکده کشاورزی، دانشگاه شیراز، شیراز، ایران
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
This research was conducted to evaluate the effect of the cold period on female Chukar partridges and its impact on reproductive traits and hematological parameters. A total of 104 adult breeding partridges were used in this study. The experimental treatments included a control group (without cold exposure) and a cold-exposed group. The research was carried out over 3 weeks in a completely randomized design with five repetitions in the control group and five repetitions in the cold-exposed group. The evaluation of reproductive parameters was performed at the end of the period, and the evaluation of hematological parameters was conducted once a week in three phases. The results of the analysis of reproductive indices showed that the cold period did not significantly differ in terms of egg production rate, fertility rate, and hatching rate compared to the control group (P>0.05). The heterophil-to-lymphocyte ratio significantly increased in different phases of the winter period compared to the control group (P<0.05). The total plasma protein, albumin, globulin, and hemoglobin levels after cold exposure in different blood sampling phases showed a significant increase compared to the control group (P<0.05). The findings of this study showed that cold exposure had a stimulating effect on the immune response, leading to a decrease in lymphocyte count and an increase in heterophil count. It is suggested that cold exposure may enhance immune responses and reduce egg production rates in Chukar partridges, possibly resulting in reproductive performance disorders.
کلیدواژه‌ها [English]
Extended Abstract
Exposure to cold is widely recognized as a significant stressor for avian species, affecting both reproductive performance and physiological parameters. Prolonged exposure to low ambient temperatures, commonly referred to as cold exposure, has profound effects on various physiological processes, particularly reproductive performance and immune responses. Therefore, the present study aims to investigate the impact of cold exposure on reproductive performance, hematological parameters, and the heterophil to lymphocyte ratio in female Chukar partridges. By subjecting female Chukar partridges to a controlled cold exposure regimen and comparing them with a control group reared under optimal thermal conditions, the specific effects of cold exposure on these parameters can be carefully evaluated. This research endeavor contributes to an enhanced understanding of the reproductive physiology and adaptive responses exhibited by Chukar partridges in cold environmental conditions. The study was conducted over a three-week duration, utilizing a total of 104 partridges (78 females and 26 males, ratio 2:1) randomly selected from the partridge population at the Faculty of Agriculture's animal husbandry farm in Shiraz University. The partridges were assigned to two groups using a completely random design: 1) a control group reared at a standard temperature range of 22-17°C, and 2) a temperature treatment group exposed to 10°C. Both groups underwent five repetitions, each consisting of eight partridges. The assignment of partridges to individual cages was also randomized, ensuring unbiased allocation. Reproductive parameters were evaluated upon completion of the study. Fertility rates were determined by assessing the number of suitable eggs for incubation, serving as a measure of fertile eggs. Ratios of hatched chicks to total incubated eggs were employed to calculate chick fertility rates and total fertility rates. Blood parameter evaluations were conducted weekly across three distinct phases. Statistical analysis revealed no significant differences (P>0.05) between the mean fertility rate, total chicken fertility rate, and individual chicken fertility rate of the experimental group and the control group. However, the findings elucidate that exposure to cold conditions leads to a reduction in lymphocyte count, an elevation in heterophil count, and an increased heterophil to lymphocyte ratio in female Chukar partridges. Furthermore, levels of hemoglobin, protein, albumin, and plasma globulin were observed to exceed those of the control group (P>0.05). These observed alterations likely serve as adaptive mechanisms that enable birds to endure the challenging conditions posed by prolonged cold stress. While the results suggest that female Chukar partridges can thrive in cold weather without impairments to reproductive morphology following exposure to cold stress, it is evident that the prolonged duration of cold stress may negatively affect immune function and egg production rates, thereby potentially hindering long-term reproductive success and disease resistance. As such, it is imperative that future studies in this field adopt a more comprehensive approach to gain a precise understanding of these phenomena.
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