جستجوی مقالات مرتبط با کلیدواژه "estrus synchronization" در نشریات گروه "علوم دام"

The aim of the current study was to improve the reproductive performance and birth weight of lambs using vitamin E and selenium (Ese) injection in estrus-synchronized Moghani ewes. In this research, a total of 200 Moghani ewes were divided into two groups in a completely randomized design. In the control group, only estrus synchronization was performed, but the second group was received two intramuscular injections of Ese (5 ml) on the days of sponging and sponge removal. Synchronization of estrus was done by inserting intravaginal sponges for 14 days followed by 400 IU eCG at sponge withdrawal. Two days after sponge withdrawal, ewes were joined with fertile rams. Twenty ewes from each group were selected randomly and their blood was sampled. The first and second blood samplings were done before inserting intravaginal sponges and three weeks after ram exposure, respectively. Then, some blood plasma metabolites were determined. After parturition, reproductive traits were calculated in each group. According to the results, lambing rate, fecundity rate, lamb production efficiency and twinning rate were higher in Ese group (88, 111, 126.1, 21.6 respectively) compared to control (73, 84, 112.3, 12.3 respectively). The birth weight of lambs did not significantly differ between the groups. Glucose and cholesterol concentration of blood were significantly higher in group receiving Ese three weeks after mating. In conclusion Ese injection improved the reproduction performance in Moghani ewes.

Estrus synchronization is a valuable management tool that has been employed in enhancing reproductive efficiency in ewes. Synchronization of estrus and ovulation for fixed-time artificial insemination in sheep is mostly based on the insertion of intravaginal devices containing either progesterone CIDR (Controlled Internal Drug Release) inserts or progestagens (sponges impregnated with fluorogestone acetate (FGA) or medroxyprogesterone acetate (MAP)). Intravaginal sponges are usually inserted over periods of 12 to 14 day and used together with eCG, particularly out of season, administered at the time of sponge withdrawal or 48 hours prior to sponge removal. It has now been indicated that shortening the duration of progesterone treatment with intravaginal instruments, while being effective in inducing estrus and ovulation, reduces the incidence of vaginal infections and consequently improves fertility. On the other hands, it has been reported that pregnancy rates of progestagen-synchronized ewes were lower during anestrus than during the breeding season. Therefore, this study was conducted to investigate the reproductive performance of indigenous ewes in Khanmirza city with short-term and long-term estrous synchronization programs accompanied by eCG during breeding and anestrous season. Moreover, efficacy of estradiol injection instead of gonadotropin during short-term progesterone treatment was evaluated in both seasons. The experiment was performed at two periods, during the breeding and the anestrus seasons on 2 different groups of 400 ewes. During each season, ewes (2 to 5 years of age and average body weight of 45±2.5 kg) were allocated to 4 groups of 100, in the way that each experimental group contained an equal number of ewes of a particular age. Experimental groups were: Control (without any synchronization program), Short term-estradiol group (ewes received 12 days progesterone treatment and intramuscular injection of 1mg estradiol benzoate at the time of sponge removal), Short term-eCG group (ewes received 12 days progesterone treatment and intramuscular injection of 400 IU eCG at the time of sponge removal) and Long term-eCG group (ewes received 14 days progesterone treatment and intramuscular injection of 400 IU eCG at the time of sponge removal). The progesterone treatment consisted on a vaginal sponge which contained 60 mg Medroxyprogesterone Acetate. Then, the ewes were placed in pens and one healthy ram was introduced for every 5 ewes, in order to detect heat and mating. Estrus signs were detected and recorded every hour for 5 days. The percentages of ewes that showed overt signs of estrus during a period of five days (estrus rate), estrus onset (the time elapsed between sponge removal and the first accepted mating) and pregnancy rate (The number of ewes without showing signs of estrous after 42 days of mating/total number of ewes×100) were recorded. Fecundity and prolificacy rate was calculated based on the number of lambs born. Lambs were monitored for 30 days after birth and deaths among them during this period were recorded against the ewes which were their mothers, and the survival rate was determined. The multiple birth rate was calculated by combining the twin and triplet birth rates. The results showed that reducing the duration of treatment with progesterone sponge in both trial period (autumn and spring) led to a significant reduction in estrus rate (P ≤ 0.05), but had no significant effect on other reproductive parameters (P > 0.05). Regardless of the season, injection of estradiol instead of eCG on sponge removal day, while increasing the estrus rate of ewes, led to a sharp increase in the rate of return to estrus (P ≤ 0.05) and caused decreases in the percentage of pregnant ewes, percentage of parturition ewes and lambing rate (P ≥ 0.05). In the breeding season, the mortality rate of lambs born from progesterone-synchronized ewes decreased and fecundity increased numerically compared to the corresponding group in breeding season group. Lack of possible effect of the anestrus season during synchronization programs on estrous rate and fertility of ewes can be attributed to optimal nutritional conditions of ewes in this season. Short term progesterone treatment (12 day) as well as injection of estradiol benzoate instead of eCG is not recommended to synchronize the estrous of ewes during both reproductive and anestrus seasons. In other words, short-term progesterone treatment (12 days) was not effective to synchronize estrus in breeding and anestrous sheep which can be attributed to follicular dynamics.

The aim of the present study was to compare sponge and cider with two different brands in estrous synchronicity, vaginal health and off-breeding performance in Moghani ewes. For this purpose, 120 ewes of Moghani breed were selected and randomly divided into four experimental groups. Ewes in the first and second groups, using sponge Sponjavet and CIDER Eazi breed (as valid and common brands) for 12 days, respectively, and the third and fourth groups, respectively, using sponge Fluorojest and CIDER Progest (as New brands made jointly by Iran and China) were treated for 12 days. Ewes in all groups received 400 IU units of eCG at the time of sponge and cider harvest. The rate of vaginal mucosal discharge and adhesion in sponge was higher than cider (P< 0.01). However, there was no significant difference between reproduction and progesterone concentrations between CIDER and sponge as well as brands of these two tools.Therefore, due to lower price and similar efficiency, Sponge Fluorojest and CIDER Progest can be considered as an appropriate alternative to common commercial sponge and CIDER..

Reproduction is directly affected by various management related factors. Manipulation of these factors can cause changes in reproductive performance. The reproductive performance is considered as the most important factor in determining the profitability of ruminant breeding. Estrous synchronization and supper ovulation are considered as the two valuable management tools used to increase the efficiency of reproduction in small ruminants and seasonal breeder animals, thanks to the use of hormonal therapies The control and manipulation of the sheep reproduction has been the objective of scientists around the world for many years. Identifying the appropriate foreign and indigenous breeds to improve reproductive performance is an essential requirement for self-sufficiency of sheep products. Intensive lamb production systems involve the obtention of more than one lambing per ewe per year. Accelerated lambing systems require the implementation of two, three or even five breeding periods at different times of the year. The purpose of this study was to investigate the effects of using CIDR and PMSG as an appropriate method of concomitant with artificial insemination of imported ewes and comparing them with native Iranian ewes on reproductive performance. 

 The experiment was conducted at the Research Unit Farm of the Light Livestock Breeding Center of the Water and Soil Conservation Company, located in the southern Khorasan province, Iran. 180 ewes with average weight of 50 ± 1.5 kg were divided into 6 groups of 30 rats based on internal and external breeds including: 1- Romanov group 2- Sharouleh group 3- Suffolk 4- Baluchi 5- Mogani group 6- Afshari were selected. Estral synchronization was performed in spring with CIDR. Ewes after CIDR (14 day) extraction and PMSG injection as soon as the signs of estrus were observed, the ewes were isolated from the others and artificially inseminated with fresh sperm using the transcortical method. Ultrasonography examination was performed by an ultrasound device (6 MHz linear probe, ECM model, France). The nutrition program with software (SRNS) version was adjusted based on the pregnancy diet. Investigation of the number of graafian follicles (follicles larger than 4 mm), was examined simultaneously with CIDR removal and estrus observation. Then, in each experiment parameters such as the time of estrus initiation (hour), rate of return to estrus, parturition rate, rate of multiple births, number of lambs and rate of lambing were evaluated.  

There were no difference between the experimental groups in terms of estrus symptoms. Results showed that Ovarian ultrasound at day 10 postoperatively showed that the number of lutein in foreign races was higher than other races and significant statistical differences were observed (p<0.05). The results of the present study showed that the mean daily body weight change of ewes was affected by experimental groups (p<0.05). Ovulation in most ewes, depending on the breed, occurs at a fixed time in relation to the onset of estrus. The breed of ewe could be one of the factors influencing the time of ovulation. Results Ovulation rate, Pregnancy rate, stillbirth rate, was significant difference in fertility rate and twinning rates between the groups (P <0.05). The highest ovulation rate (100%), pregnancy rate (100%), The fertility rate (160%) and Twinning rates (66%) belonged to the Romanov group and statistical differences were observed (p<0.05). Variability between results could be attributed to different protocols, management systems, nutritional status or physiological status resulting from diverse experimental conditions. Furthermore, these variable results may indicate that breed, timing of treatment or doses used in these treatments produce critical effects on fertility rate and embryo survival. 

In general, the use of some new technologies such as estrous cycle control and the use of hormones was effective in this study and increased the average production of lambs per ewe mixed in the herd. Significant differences between Romanov ewes in pregnancy rate, lambing rate and twinning with other breeds indicate the high genetic capacity of this breed of sheep in the success of reproductive performance. Due to low productivity of Iranian breeds compared to foreign breeds, it can be suggested that foreign sheep be used to improve breeding efficiency of Iranian sheep for breeding.

Ghezel is an Iranian medium-sized and fat-tailed sheep breed and is native in the East and West Azarbaijan provinces. Ghezel sheep plays an important role in supplying meat and milk in the region of Azerbaijan (Ghasemi-Panahi et al. 2016). Also, an important source of farmer's income is lambs production (Nabavi et al. 2015). Therefore, one of the prospects for improving the region's production is improving reproductive performance of sheep flocks. In order to suggest a proper approach to improve reproductive performance, there should be a comprehensive information from the livestock farms of these two provinces. Therefore, the present study was conducted with the aim of evaluating reproductive performance of Ghezel ewes in a couple of sheep farms in the East and West Azarbaijan provinces.

After designing questionnaire in this study, 30 Ghezel sheep flocks were randomly selected from different regions of East and West Azarbaijan provinces (15 flocks in each province). Then, livestock farmers of the region were interviewed using questionnaire and information on reproductive performance of flocks were collected including: pregnancy rate, multiparty, lambs' birth weight, age at the first parturition, weaning age, lambs weaning weight, number of unfertile and fertile ewes, flock surface area, farmers' education, and etc. The flocks were divided into four flock sizes. The breeding systems were also studied based on the three groups of nomadic, rural, and industrial breeding systems. The results of the questionnaires were reported as percentages (for classified data) and mean ± SD (for other data). Also, correlation coefficients between important traits were calculated using Spearman’s rank-order correlation of SAS 9.2 (2008) software.

Based on the results of this experiment, 87% of the breeding systems of two provinces were rural. Other reproductive indexes of two provinces included 65% lambing rate, 79% pregnancy rate, 24% ewes' fecundity rate, 20% estrus synchronization usage, 5% flock mortality rate, 9% ewe's infertility rate, 0.1 ram to ewe ratio, and 17 months of age for ewes at the first mating. Seifi et al. (2014), with evaluating Ghezel and Afshari sheep breeds, reported low reproductive performance in these two breeds. Khodayi-Motlagh et al. (2014) reported low knowledge of farmers about the methods of estrus synchronization. However, a number of studies reported an extraordinary improvement in the reproductive performance of Ghezel ewes using different methods of estrus synchronization or using flushing rations (Najafi et al. 2014; Ghasemi-Panahi et al. 2016; Hasani Dash Tapeh et al. 2017; Ahmadzadeh et al. 2018). Therefore, it seems that improving knowledge and skill of farmers about estrus synchronization methods and/or proper rationing can improve reproductive performance of Ghezel sheep in the region. According to the correlation results, there was a negative correlation between the breeding system and the flock size (correlation coefficient: -0.6) and between the flock size and estrus synchronization usage (correlation coefficient: -0.51), (P<0.05). These results indicated that the breeding system has been changed into the nomadic system in the larger breeding flocks and there is a less interest in the use of new methods of estrus synchronization in this kind of breeding system. Also, results indicated a significantly negative correlation (correlation coefficient: -0.42) between ram to ewe ratio and lambing rate (P <0.05). So, regardless of the role of rams on flock fertility, asymmetrical increase in ram to ewe ratio causes a negative impact on lambing rate by reducing the ewe population (which are the animals whom produce lambs). The results showed a significant positive correlation (P <0.05) between lambing rate and the age of ewes at the first mating (correlation coefficient: 0.54) and also the age of ewes at the first delivery (correlation coefficient: 0.66). These positive correlations indicate poor rearing condition of young ewes and are consistent with the general believe of farmers, which they breed ewes at the second year (age 16-18 months) to obtain optimum fertility rate. Results showed a negative correlation between the age of ewes at the first mating and birth weight of lamb (correlation coefficient: -0.60), while indicating a positive correlation between the age of ewes at the first mating and age of weaned lambs (correlation coefficient was 0.49), (P <0.05). These results can be explained by higher fecundity rate in older ewes, which reduces lamb birth weight, while it increases weaning age of lambs. The negative correlation (correlation coefficient: -0.41) between weaning age of lambs and estrus synchronization use (P <0.05) can be due to the fact that lambs from the synchronized ewes born and weaned at the same time and then, reared under better nutritional and management conditions.

The overall results of the present study showed low reproductive performance in the Ghezel sheep flocks of East and West Azarbaijan provinces due to the low use of estrus synchronization methods and poor management. Therefore, it seems that by informing the farmers about the new methods of estrus synchronization, raising their level of knowledge in this field, ration training, and management of synchronized animals can improve reproductive performance and increase profitability in the region.

Estrus synchronization is an important technique in management of reproductive function in ewes. The objective of this study was to evaluate the effect of using combination of PMSG and GnRH hormones on estrus synchronization during the breeding season in Farahani ewes. Forty mature Farahani ewes, weighting 48.97±0.55 kg, BCS 3.04±0.3, were used in this study. The experimental ewes were synchronized using CIDR for a period of 10 days and injected 2 ml PGF2α at day 0 and these ewes randomly assigned to four groups. The control group (group 1; n=10) did not receive any treatment. Ewes in group 2 were injected with 150 IU PMSG and 1 ml Buserellin acetate after CIDR removal. The group 3 ewes injected with 100 IU PMSG and 2 ml Buserellin acetate after CIDR removal. The group 4 of ewes were injected with 300 IU PMSG and 0.5 ml Buserellin acetate after CIDR removal. Estrus detected after CIDR removal, then, the ewes were mated with Farahani rams. After parturition, the reproductive parameters of ewes were recorded. The estrus rate was constant in all groups. The lamb weight in group 4 was significantly different (P>0.05) compared with other groups. Pregnancy rate was not significantly meaningful among treatments. The lowest glucose and progesteron concentration was achieved in group 4 that was significantly different (P > 0.05) compared to other groups. The data of birth weight also didn’t show significant differences (P>0.05) between the treatment groups. There was no significant difference in abortion and stillbirths between treatments (P˃0.05). The results showed that the combination of two PMSG and GnRH hormones in the estrus synchronization program could increase the lambing rate up to 0.7.

To evaluate the reproductive performance of Markhoz does in an accelerated kid production system (three kiddings in two years) and to compare with a conventional kid production system, 90 mature does in Sanandaj Breeding Station were monitored into three groups: 1-twice mating a year with hormone (CIDR and injection of 400-IU PMSG); 2- Twice mating a year without hormone; 3- Conventional system, once a year (control group). Data on pregnancy rate, twinning or prolificacy rate, litter size, fecundity rate, born kid crop and weaned kid crop and viability rate were calculated and analysis was performed with GLM process using SAS software. The parturition rate and fecundity rate of does in the experimental (1,2) and control groups was 2, 1.77 and 1.66, and respectively 3.43, 2.7 and 2.17 during the 24 months that had a significant difference (P<0.05). Born Kid Crop and Weaned Kid Crop and weaning rate during 24 months in treatment 1 was significantly more than the treatment 2 and control (P<0.05). Average of Born Kid Crop and Weaned Kid Crop per doe in the experimental groups and control was 2.95, 2.62 and 1.39 kg respectively, and 10, 8.01 and 7.67 kg respectively, that the differences between three treatment were significant (P<0.05). The Net income of the implementation of reproductive treatments and three kiddings in two years was more than control treatment.

The objective of this study was to investigate the effects of feeding sources of carbohydrates with different fermentation rate on reproduction performance of Moghani grazing ewes. Sixty Moghani ewes were allocated randomly to four nutritional groups as follows 1) without supplement feeding (control), 2) feeding 300 g barley grain per day, 3) feeding 300 g corn grain per day and 4) feeding 300 g concentrate mix containing ground barley grain and starch powder with 1 to 1 ratio from d 7 to d 14 of synchronization program. Estrus synchronization was done using CIDR for 14 days. At CIDR removal, the ewes in each group were received 400 IU PMSG intramuscularly and after 24 h, they were inseminated with frozen Romanov semen. There were no significant differences between experimental treatments for fecundity, prolificacy and twinning rate. Feeding carbohydrate sources increased blood glucose concentration (P=0.0567) and decreased urea concentration (P=0.0073) after 7 days feeding in compare to the control group. However, there were not significant differences between carbohydrate sources. The results of present study showed that feeding different carbohydrate sources as short term nutrition during estrus synchronization could have positive effects on energy metabolism of animals.

This study was evaluated the pregnancy rates of fixed time artificial insemination after synchronization of follicular wave Ovsynch CIDR and Co-synch CIDR protocols compared with artificial insemination after estrus detection in select synch protocol.
In this study, 42 cyclic buffaloes, uncertain stage of the estrous cycle, were randomly assigned into 3 groups. 1) Ovsynch CIDR (n = 14), administration of GnRH at days 0 and 9, PGF2α at day 7 and insertion CIDR from days 0 to 7. Buffaloes of this group were inseminated 16 h after the second GnRH administration. 2) Co-synch CIDR (n = 14), insertion the CIDR and administration of GnRH at day 0, administration the PGF2a at day 7 with remove the CIDR, and day 9 with second administration of GnRH, artificial insemination was performed.3) Select synch CIDR (n = 14), hormone treatments of this group were similar to two other groups. But, there was not the second injection of GnRH and artificial insemination was performed after estrus detection during 3 days.
The pregnancy rates of Ovsynch CIDR (28.57± 12.53%), Co-synch CIDR (50 ±13.87%) and Select synch CIDR (28.57 ±12.53%) had not significantly difference.
In summary, it can be concluded that Co-synch CIDR protocol due to non-significantly higher pregnancy rate is more effective method, when compared with other protocols. and non-necessary to estrus detection as well as low labor.

The objective of the present study is to investigate the morphological characteristics of follicular wave in synchronized cycle in compare to the normal estrous cycle in dairy cattle. Ten Holstein dairy cows were randomly selected from the University of Tehran dairy herd and assigned in 2 groups (n=5). The animals in treatment group were synchronized with 2 intramuscular injections of prostaglandin F2α 14 days apart. Ovarian ultrasonography (B mode; Pie medical، Falco 100، 8 MHz) was done daily in control group between 2 consequently estrus and in treatment group after first PG injection until estrus following second PG injection. The data analyzed using SAS. T-test was used to investigate the statistical difference between morphological characteristics of follicular wave. The result showed that there were no significant differences between the size of dominant follicle (F1)، the largest subordinate follicle (F2)، mean large size of subordinate follicles، mean size of F1 (mm) at deviation، mean number of days from emergence of the follicular wave to deviation، mean number of follicles in the waves، mean age of follicles، day of emergence of the follicular wave، age of dominant follicle in synchronized cycle and normal estrous cycle (P> 0. 05). In conclusion، the results showed that there were not significant differences between morphological characteristics of follicular wave in normal estrous cycle versus synchronized cycle.

This experiment were conducted to evaluate the efficacy of intravaginal sponge pessary (fluorogestone acetate; 40mg) to induce a synchronized estrus in lactating ewes and reproductive performance (fertility and fecundity) in out of breeding season in suburb of urmia. For this purpose 182 lactating ewes at around of 3-4 months of post partum were selected. Females were randomly divided into two groups considering their age and post partum period. Group1 (n =101) received an intravaginal sponge (40 mg fluorogeston acetate; Chrono-gest، intervet، Holland) for 14 days and with an injection of 500 i. u PMSG (Folligon، intervet، Holland) at the removal of sponges. Females in group 2 (n = 81) did not received further treatment and were considered as control. At the time of removal progesterone، the appearance of vaginal discharge was investigated. Twelve hours after termination of treatment، fertile ram was used to detected estrus and mating. Estrus response also fertility and lambing rates on the base of labor information in all females were analyzed with using of chi-square test. In group one 14 ewes had abnormal vaginal discharge at the time of removal. Estrus response، fertility and lambing rate for treatment group were 76، 45. 5 and 64. 6 percent; respectively (p<0. 05). Estrus was detected only 9. 8 percent of females in control group (p<0. 01). The prolificacy rate for treatment group was 1. 4 (p>0. 05). These results revealed that using of fluorogestone acetate (40 mg) for 14 days with together of PMSG (500 i. u) can be used with acceptable fertility rate in out of breeding season in lactating ewes around of urmia.