Flocks possessing sheep rated five star as per the Sheep Ireland €uro-Star genetic indices have the potential to deliver an additional €18 net profit per ewe compared to flocks with one-star animals.
The findings are part of a recent study undertaken by Teagasc using production data collected on 7,644 commercially recorded animals to investigate the value of selecting five-star animals on either the terminal or replacement index over selecting one-star animals.
The findings showed that selecting five-star animals resulted in a higher average litter size, lower lamb mortality and higher-performing lambs that reach slaughter weight quicker.
The five-star flock sold more lambs per ewe and at an earlier age, with the combined benefits equating to these ewes delivering €18 net profit more per head.
On a 100-ewe flock this translates to an additional €1,800 net profit on the farm’s bottom line.
Lower GHG emissions
Furthermore, the finding show the five-star flock also produced 7% lower greenhouse gas emissions per unit of output (kilo of carcase weight) compared to the one-star flock.
Teagasc concludes the results clearly show the benefit of consistently selecting high-star-rated rams, with many additional benefits now also being realised in terms of animal health.
A glimpse in to the future of liver fluke control
Sheep farmers could have new technologies at their disposal in the near future which would revolutionise their efforts in combating liver fluke infestation. Research conducted by Teagasc and the Molecular Parasitology laboratory at the National University of Ireland (NUI) Galway has seen the development of a laboratory diagnostic test that can detect the presence of liver fluke infection as early as four weeks post-infection in sheep.
This means that there is the potential to detect liver fluke at an important stage of its life cycle, with acute and sub-acute fluke infections having the potential to cause serious damage at certain times of the year. Identifying the presence of liver fluke at this stage also allows for targeted treatment before fluke reach the adult stage and eggs start to be shed on pasture.
The test works via immunodiagnostic methods. These methods work by detecting antibodies or antigens circulating in the blood or found in faeces, with the particular test for liver fluke capable of detecting immature stages of infection.
A paper outlining the technology states that the next step in advancing the technology is to develop a simple process for testing animals.
The aim here is to develop a handheld, pen-side, lateral flow test for liver fluke.
This would work on the basis of a sample containing a small quantity of blood being collected from sheep, with the lateral flow tests allowing rapid on-site detection of infection.
Liver fluke vaccine
Exciting work is also taking place between Teagasc and the Molecular Parasitology laboratory at NUI Galway in developing a vaccine capable of preventing liver fluke infection in sheep.
Any breakthrough in developing an effective vaccine would be hugely advantageous not only in the direct treatment of animals but also in preventing egg shedding on to vegetation and breaking the liver fluke cycle.
A number of vaccines are currently being tested utilising a variety of proteins found in liver fluke. The research update paper states that the aim of using such proteins in a vaccine is to stimulate the sheep immune system to mount an effective immune response to kill the liver fluke parasite and limit any future infections. Testing of vaccines has recently taken place in trials at the Teagasc Mellows Campus in Athenry and the update reports that field trials of promising candidates are starting in the summer of 2022. In particular these field trials will assess how well the vaccine works when faced with day-to-day challenges sheep experience at pasture.
Ewe replacement cost equates to 25% lifetime lamb value output
Research has shown that at a national level, the cost of producing a replacement ewe, to join the flock at 19 months old to lamb down at two years old equates to 25% of the value of her lifetime lamb carcase output. With such significant costs attributed to replacing the ewe flock, increasing her lifetime output can help dilute associated costs. The two major factors that influence the number of lambs reared per ewe lifetime are ewe prolificacy (ewe genotype) and the number of lamb crops produced (age at first lambing).
Trial work at Teagasc Athenry looked at age at first lambing (ewe lambs or hoggets) and ewe genotype (>75% Suffolk, Belclare x Suffolk and purebred Belclare) and followed these ewes throughout their productive lives to determine if there was any differences in survival and lamb output. Those mated as ewe lambs reared on average a lamb per ewe lamb joined, with a litter size of 1.44 for those scanned in lamb.
Many farmers avoid lambing ewe lambs as they feel it will have a negative effect on the production the following year. However, those that lambed as ewe lambs had a litter size of 1.77 lambs/ewe in the second year while those lambing for the first time as two-year-olds had a litter size of 1.78 lambs/ewe.
Lifetime performance averaged 4.1 lambings and 6.7 lambs reared for those lambed at one year old compared to 3.2 lambings and 5.3 lambs reared on average for those that lambed down for the first time as two-year-olds.
In order to have a 90% probability of rearing at least one lamb in the first year, ewe lambs need to be 63% to 72% of mature body weight at a minimum at the time of joining. This translates to a weight of 48.5kg for Belclare, 51kg for Belclare x Suffolk and 60kg for Suffolk at 7.5 months old.
Looking at ewe genotype, on average, the Belclare x Suffolk had a greater number of lambings, and reared 0.7 and 1.4 more lambs in her lifetime than the purebred Belclare and >75% Suffolk ewes respectively while also recording heavier weaning weights and fewer days to slaughter than the other ewe genotypes.