جستجوی مقالات مرتبط با کلیدواژه « همزمان سازی فحلی » در نشریات گروه « دامپزشکی »

Estrus synchronization is a valuable tool in ewe reproductive management.

This study was performed to evaluate the efficiency and determine the best time of eCG injection in short-term synchronization program based on GnRH-PGF 2α in Shal ewes during the breeding season.

One hundred and sixty non-pregnant Shal ewes, aged 2-6 years old were selected and randomly stratified to four equal groups. 25µg Alarelin acetate (GnRH analogue) and 75µg D-cloprostenol (PGF 2α analogue) were injected to all ewes, on days 0 and 5, respectively. The first group (control) did not receive any other treatment. Groups 2 to 4 received 400 IU of eCG, 48 hours before, 24 hours before and concurrent with PGF2α, respectively. Ewes were exposed to fertile rams during 96 hours post PGF2α injection. Blood serum progesterone concentrations were measured just before PGF2α injection and 10 days later.

No difference was observed in the first serum progesterone evaluation among experimental groups (P>0.05). However, progesterone had significantly higher concentrations 10 days after PGF 2α injection in groups 2 and 3 in comparison with groups 1 and 4 (P<0.05). Simultaneous use of eCG with PGF2α led to a higher estrus response in comparison with other groups (P<0.05). During the first day after PGF2α, a higher percentage of ewes in group 2 and 3 exhibited estrus compared with groups 1 and 4 (P<0.05). Conversely, estrus expression was higher 24-48 hours after prostaglandin injection in groups 1 and 4 than the other two (P<0.05). Thus, the interval to estrus was earlier in group 2 and 3 than groups 1 and 4 (P<0.05). No significant differences were detected in terms of conception rate, lambing rate, prolificacy and fecundity among study groups (P>0.05).

Use of eCG in different times (48 and 24 hours before and concurrent with PGF2α) in short-term synchronization program based on GnRH-PGF2α during the breeding season can be effective on estrus indices. Regarding the diversity of sheep's masses in Iran, it seems that acceptable results may be achieved when eCG is used concurrently with PGF2α in short-term protocol.

The objective of this study was to evaluate the best period of progesterone treatment and the time of eCG injection during estrous synchronization in nonbreeding season in Mahabadi does. During nonbreeding season, 103 Mahabadi does, weighing 57.5±0.45 Kg, 2-4 years old, were used in the trail. These does randomly assigned to 6 groups. The control group (n=10) exposed to Mahabadi bucks without any treatments. The group C9-e7of does (n=26) were synchronized using CIDR for a period of 9 days and injected 300 IU eCG at day 7. In groups C17-e15 (n=16) and C17-e17 (n=16), CIDR inserted for 17 days and eCG injected at days 15 and 17, respectively. The groups C19-e17 (n=17) and C19-e19 (n=18) synchronized by CIDR for 19 days and received 300 IU eCG at days 17 and 19, respectively. Estrus detected one day after CIDR removal, then, the does were mated with Mahabadi bucks. The reproductive parameters were analyzed by ProcGenmod using SAS 9.1. The highest mating, kidding and fecundity rates were obtained in group C17-e17 and the highest estrus detection rate and litter size were achieved in group C19-e17 that were significantly higher than control group (P0.05). In all reproductive parameters measured, there were not significantly differences (P>0.05) between C9-e7 group and the other treatment groups of does. Furthermore, the short treatment period of progesterone insertion using in group C9-e7 compared with the other groups, will suggest that this group could be recommended for estrous synchronization program in nonbreeding season of Mahabadi does.

The objective of this study was to compare the conception rate in dairy lactating Holstein cows to fixed timedartificial insemination among Ovsynch and Ovsynch plus CIDR protocols. One-hundred-and-eighty two Holsteincows with parity ranging from 1 to 4 and post partum period of ≥ 60 days at unknown stages of estrus cycle wererandomly assigned to two treatment groups. Females in the control group (Ovsynch; n = 92) underwent a standardOvsynch protocol (GnRH analogue on Day 0, PGF2alpha analogue on Day 7 and GnRH analogue on Day 9),with timed-AI on Day 10, approximately 18-20 h after the second GnRH treatment. Cows in the Ovsynch + CIDRgroup (n = 90) received a standard Ovsynch protocol plus a CIDR for 7 days (starting on Day 0) were inseminated at the same time using frozen semen. The animals being studied were under nutritional and environmentalconditions and experiment was carried out in different herds with the definite numbers. Pregnancy diagnosis ofanimals under experiment and insemination were performed 45 days later after insemination via rectal touching.The conception rate tended to be greater in the Ovsynch + CIDR group (64.4%, P < 0.05) than in the Ovsynchgroup (46.7%). These results revealed that a CIDR-based protocols for timed-AI improved conception rate in earlypostpartum suckled cows relative to the Ovsynch protocol. Treatment with a CIDR may prevent early maturationof follicles observed in non-pregnant cows treated with the Ovsynch protocol, by maintaining elevated blood progesterone concentrations until PGF2alpha treatment

The objective of this study was to evaluate three methods of estrous synchronization, viz. controlled internal drug releasing device (CIDR), intravaginal sponges impregnated with fluogestone acetate (FGA), and cloprostenol (Estrumate; an analogue of prostaglandin F2α) in Nadooshani goats of Yazd province, Iran. The estrous synchronized does (n = 30 to 33 per treatment), after heat detection, were artificially inseminated (once) with diluted semen of fertile bucks. Pregnancy was determined by measuring blood serum progesterone levels on day 21 after insemination, followed by ultrasonography at mid-gestation. No significant difference was observed for the interval between the end of the synchronization protocol and the standing heat amongst treatments (range: 23 to 35 hrs). There was no significant difference in the interval between the time of standing heat and insemination among treatments (range: 15 to 27 hrs). Blood serum progesterone levels (overall mean: 4.80 ± 0.41 ng/ml; SEM), litter size (overall mean: 1.32 ± 0.05; SEM), non-return rate to estrus and the kidding rate were not significantly affected by the synchronization methods. Serum progesterone levels were significantly lower (P<0.01) in does that returned to estrus after artificial insemination (AI). Prolificacy and fecundity were not significantly affected by the synchronization methods; however, cloprostenol method was found to be more convenient and economical under the conditions of this experiment.