Effects of equine chorionic gonadotropin on reproductive performance in anestrous mink.

This research study is about the impact of equine chorionic gonadotropin (eCG) on the reproductive performance of anestrous mink (those not experiencing estrus or ‘heat’). The study’s results demonstrate that eCG can significantly enhance the reproductive performance of these mink, and by extension, it could potentially be used to manage and treat anestrous mink during the natural breeding season.

Objective of the Research

• The primary aim of the research was to determine whether equine chorionic gonadotropin (eCG) and human chorionic gonadotropin (hCG) can induce estrus in anestrous mink. The incidence of anestrous mink during the regular breeding season can be as high as 5%, which can inhibit successful breeding.

Methodology of the Research

• For the research, 75 female anestrous minks that failed to show signs of estrus during the March breeding season were selected. These minks, kept under standard ranch conditions, were then randomly assigned to different treatment groups.
• The minks received treatment doses twice – on the 16th and 18th of March. Treatments included saline, 25, 50, or 100 IU of eCG and a combination of 50 IU of eCG on March 16 and 50 IU of eCG plus 100 IU of hCG on March 18.
• Beginning from March 22, pairs of male and female minks were formed for the breeding process.

Findings of the Research

• The study found that none of the mink treated with saline were successful in mating. This was contrasted by the minks that received eCG, where the introduction of this substance improved their reproductive performance significantly.
• Between 47% to 100% of the minks treated with eCG mated, and between 33% to 80% of them gave birth. Furthermore, the average litter size per whelping female increased markedly, ranging from 2.6 to 4.0 kits.
• The research also noted increased reproductive efficiency with rising eCG doses, which was not further enhanced by the addition of hCG.

Implications of the Research

• The results imply that eCG could have a potential application in treating anestrous mink during the breeding season, improving their reproductive performance even when they fail to demonstrate estrus naturally.