Technologies for the control of fat and lean deposition in livestock.
Authors: Sillence M N
Journal: Veterinary journal (London, England : 1997)
Summary
# Editorial Summary: Technologies for Controlling Fat and Lean Deposition in Livestock Improving the lean-to-fat ratio in livestock production carries substantial economic and environmental benefits—enhanced feed conversion efficiency, reduced nitrogenous waste excretion, and lower production costs—yet the EU's 15-year ban on hormonal growth promoters (HGPs) has created a significant challenge in achieving these outcomes through universally acceptable means. Sillence's 2004 review synthesises the landscape of emerging technologies, examining both established pharmacological approaches licensed in countries such as Australia and the United States (bovine growth hormone, porcine and equine growth hormone, and ractopamine) alongside experimental strategies including genetic selection markers, natural feed additives (betaine, chromium, and conjugated linoleic acid), and immunological "production vaccines" that manipulate the neuro-endocrine system. Notably, combining beta-agonists with growth hormone, which upregulates beta-adrenoceptor sensitivity, demonstrates exceptional improvements in carcass composition and feed efficiency, whilst targeting myostatin and leptin—hormones governing body composition—offers potential for sustained alterations in lean:fat ratios through genetic approaches. Despite these advances, none of the alternatives currently matches the efficacy and reliability of exogenous HGPs, meaning practitioners in regions with HGP restrictions face a pragmatic gap between theoretical promise and practical application. For equine professionals in particular, the limited development of equine-specific growth hormone applications relative to other species underscores the need for continued research into tailored nutritional, genetic selection, and endocrinological strategies that balance production efficiency with regulatory compliance and consumer acceptance.
Read the full abstract on PubMed
Practical Takeaways
- •For equine practitioners: Growth hormone and beta-agonists may have application in equine production, but regulatory status and consumer acceptance vary significantly by region and must be verified before use
- •Genetic selection using molecular markers offers a sustainable, non-pharmaceutical approach to improving body composition that avoids regulatory and consumer acceptance issues associated with exogenous treatments
- •Natural feed additives show promise but require specific conditions for efficacy; practitioners should base supplementation decisions on evidence for their particular production goals rather than assuming universal benefit
Key Findings
- •Combined use of beta-agonists with growth hormone produces outstanding improvements in carcass composition and feed efficiency by upregulating beta-adrenoceptors
- •Leptin, adiponectin and myostatin discovered through study of genetically obese and double-muscled animals offer potential for manipulating body composition across livestock species
- •Genetic selection enhanced by polymorphic gene markers (thyroglobulin, callipyge gene) and feed additives (betaine, chromium, conjugated linoleic acid) can improve fat:lean ratio under specific circumstances
- •Production vaccines using auto-immune responses to neutralise growth-limiting factors or prolong anabolic hormone half-life remain less efficacious and reliable than exogenous hormonal growth promoters