Border Leicester Rams Into Action

Lynton Arney and David Kleemann Inverbrackie Border Leicester Stud - Meat & Livestock Australia, SARDI

Type: Research Paper
Knowledge level: Advanced

Farm Table says:

Interesting study but further studies are required on a larger number of ewes and rams to confirm that melatonin treatment of BL rams has an impact on litter size and whether ewes become pregnant earlier.

What is the problem?

First cross ewe producers using Border Leicester (BL) rams have sometimes experienced low and variable lambing results when joining BL rams to Merino ewes in the spring.

Seven clients from Inverbrackie BL stud proposed that seasonality might be an issue and examined if treatment of rams with melatonin, on one property in each of two years, might be a remedy.

What did the research involve?

The experimental design employed was constrained to a valid comparison of melatonin treatments (melatonin, no melatonin) but not age of ram (young, mature).

BL rams were treated with melatonin in each of two years (2014, 2015) in both young and mature rams at a Central site on a commercial property of one of the PDS members.

Less intensive studies were performed on Satellite sites of other  Producer Demonstration Site (PDS) members in each of the two years. An intensive study was also conducted on Turretfield Research Centre in the second year.

What were the key findings?

  • treatment of young BL rams increased pregnancy rate in year two but not in year one
  • litter size was not significantly increased by melatonin treatment of young BL rams
  • treatment of mature BL rams did not increase either pregnancy rate or litter size
  • a higher proportion of ewes became pregnant earlier for the melatonin treated rams. This effect was significant  for young rams in both years but was significant for mature rams in one year only
  • scrotal circumference was increased by melatonin treatment in both age groups of ram and in both years
  • melatonin increased scrotal circumference of treated rams before mating however after mating scrotal circumference was smaller  than the untreated rams. This effect was independent of ram age
  • libido tests indicated melatonin increased  ram performance at one location but not at another
  • the amount of time exogenous melatonin levels persisted varied with ram
  • there was indirect evidence from ram activity data collected on PDS properties that melatonin may have improved libido in young rams enabling them to compete with their older counterparts
  • most PDS members recognised the value of treating young BL rams with melatonin but were more reserved about using the technology in mature rams

Final comment

The main benefit of the technology when used in young BL rams is that between year variability of pregnancy rate is reduced.

Further studies are required on a larger number of flocks to confirm that melatonin treatment of BL rams has an impact on litter size and that a higher proportion of ewes become pregnant earlier.

 

2017 - Australia - Lynton Arney and David Kleemann Inverbrackie Border Leicester Stud - Meat & Livestock Australia, SARDI
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