Feed intake, body weight, body condition score, musculation, and immunocompetence in aged mares given equine somatotropin.

This study investigated the effects of equine somatotropin (eST) on aged mares, focusing on feed intake, body weight, body condition score and immune response. The results showed no change in feed intake, body weight, or fat cover, but the eST-treated mares developed better muscle definition and experienced an increase in the number of certain types of white blood cells, indicating potential benefits to the mares’ health and wellbeing.

Objectives and Methodology

• The primary aim of this study was to examine whether the administration of equine somatotropin (eST) in aged (20 to 26 years old) mares would lead to changes in their feed intake, body weight, body condition score (largely based on fat cover), and immune response (immunocompetence).
• A total of 16 mares were involved in the experiment, and they were given different dosages of eST – 0, 6.25, or 12.5 mg per day.
• The researchers’ methods included monitoring and evaluation of the mares’ body conditions, feed intake, and various blood cell count measures for a period of 6 weeks during the eST injection period.

Findings

• No significant differences were observed in terms of dry matter intake, body weight, or body condition scores during the 6-week eST treatment period across the different groups.
• However, an improvement in muscle definition was noted in the eST-treated mares, as gauged by photographs taken before and after the treatment.
• In terms of immunocompetence, an increase in total circulating leukocytes (white blood cells) was recorded in both eST-treated groups. This increase was particularly attributable to a rise in granulocytes (a type of white blood cell).
• There were no changes observed in lymphocyte numbers or granulocyte oxidative burst activity.
• Another important finding was that while lymphocyte proliferative responses to various substances (phytohemagglutinin, pokeweed mitogen, lipopolysaccharide) remained unchanged during the treatment, there was a twofold increase in lymphocyte proliferation in response to phytohemagglutinin and pokeweed mitogen, observed two weeks post eST treatment.

Conclusion and Implications

• The study concludes that administration of eST to aged mares does not lead to significant changes in common health markers such as feed intake or body weight. However, it did result in increased muscle definition and certain white blood cell counts, suggesting possible benefits to the health and wellbeing of the mares.
• This suggests that eST supplementation may be beneficial for the general health and physical functionality of aged mares.