scholarly journals Effects of gonadotropin-releasing hormone administration or a controlled internal drug-releasing insert after timed artificial insemination on pregnancy rates of dairy cows

2016 ◽  
Vol 17 (4) ◽  
pp. 577 ◽  
Author(s):  
Jae Kwan Jeong ◽  
In Soo Choi ◽  
Hyun Gu Kang ◽  
Tai Young Hur ◽  
Ill Hwa Kim
Keyword(s):  
Dairy Cows ◽  
Artificial Insemination ◽  
Gonadotropin Releasing Hormone ◽  
Pregnancy Rates ◽  
Releasing Hormone ◽  
Hormone Administration ◽  
Timed Artificial Insemination

Estrous synchronization and fertility of cross-bred dairy cows using prostaglandin F2α and gonadotropin releasing hormone

2021 ◽  
pp. 171-175
Author(s):  
Abubakr O. Ismail ◽  
◽  
Erneo B. Ochi ◽  
Ambrose S. Jubara ◽  
Bakri Ahmed A/Rahim ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Artificial Insemination ◽  
Prostaglandin F2α ◽  
Fixed Time ◽  
Gonadotropin Releasing Hormone ◽  
Pregnancy Rates ◽  
Releasing Hormone ◽  
Treatment Groups ◽  
Estrous Synchronization ◽  
Descriptive Statistical Analysis

A comparative hormonal study of prostaglandin, gonadotropin releasing hormone and their combination was conducted on 30 randomly selected cross-bred dairy cows of SEMEX project for artificial insemination in Hillat Kuku, Khartoum North, Sudan. The study attempts to determine the response of the animals to hormonal induction and synchronization of estrous as well as fertility following fixed time artificial insemination. Three treatment groups of 10 cows each were undertaken. Groups 1, 2 and 3 involved administration of prostaglandin F2α (PGF2α), gonadotropin releasing hormone (GnRH) and a combination of PGF2α + GnRH, respectively. Descriptive statistical analysis was performed. The results revealed that all the three protocols induced and synchronized estrous were almost synchronous in all the treated groups. However, protocol 3 revealed a significantly (p<0.05) better result of 70% pregnancy rate compared to other two protocols that equally provided 50% pregnancy rates. The study resolves that protocol 3 be highly recommended to change the mindset of farmers about the spread of reproductive technology in Sudan. Protocols 1 and 2 provided acceptable pregnancy rates that can be enhanced with the improvement of management.

scholarly journals Estrus expression and pregnancy rates in heifers primiparous and multiparous Nelore cows subjected to timed artificial insemination with strategic use of gonadotropin-releasing hormone

2021 ◽  
Vol 42 (6supl2) ◽  
pp. 3825-3836
Author(s):  
Denis Vinicius Bonato ◽  
◽  
Luigi Carrer Filho ◽  
Eriko Silva Santos ◽  
Murilo Rezende Figueira ◽  
...  
Keyword(s):  
Logistic Regression ◽  
Regression Model ◽  
Artificial Insemination ◽  
Logistic Regression Model ◽  
Gonadotropin Releasing Hormone ◽  
Pregnancy Rates ◽  
Releasing Hormone ◽  
Sacrococcygeal Region ◽  
Timed Artificial Insemination

We evaluated the effects of nulliparous, primiparous, and multiparous conditions on the estrus and pregnancy rates in females that did not show estrus but were treated with gonadotropin-releasing hormone (GnRH) at the time of timed artificial insemination (TAI). Nelore females (n = 531) were allocated according to the following categories: nulliparous (n = 144), primiparous (n = 132), and multiparous (n = 255). The animals received a conventional TAI protocol, and estrus expression was identified by the absence of paint in the sacrococcygeal region on the day of TAI. Females that did not show estrus were treated with 10 μg of GnRH together with insemination. The rates of estrus and pregnancy were analyzed using a logistic regression model (P < 0.05). The estrus expression was lower (P = 0.006) in the primiparous (61.36%) group than in the nulliparous (76.39%) and multiparous (75.69%) groups. Similar pregnancy rates were observed in females that showed estrus (nulliparous 84.54%, primiparous 86.42%, and multiparous 80.31%; P = 0.39) and in females that did not show estrus and received GnRH (nulliparous 41.18%, primiparous 56.86%, and multiparous 58.06%; P = 0.24). The total pregnancy rates were also similar (P = 0.98) among the categories (nulliparous 74.3%, primiparous 75.0%, and multiparous 74.9%). The primiparous females had a lower rate of estrus, and the pregnancy rates were similar among the categories that received GnRH.

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