New Zealand genetics delivering the goods in Athenry

The Teagasc INZAC flock, consisting of 180 ewes, is entering into its second full year of production.

The flock is comprised of 120 Irish Suffolk and Texel ewes – split 50:50 between each breed – and a flock of 30 New Zealand Texel and 30 New Zealand Suffolk ewes.

Dr. Fiona McGovern gave pedigree sheep breeders a run through of the operation earlier today, as part of a Sheep Ireland industry meeting.

McGovern, a UCD graduate, said the trial was established to validate the Replacement Index and to compare the difference between Irish and New Zealand ewe genetics.

As part of the trial, she said, the performance of Irish one-star (‘low’) and five-star (‘elite’) ewes under the Replacement Index is being compared.

Although the trial is primarily focused on maternal traits, data on a number of terminal traits is also being collected due to the overlapping nature of both indices.

These include lamb birth, 60-day and weaning weights. The length of time it takes the ewes’ progeny to reach slaughter or ‘Days to Slaughter’ is also measured under the study.

A New Zealand Texel ewe and her lambs
A New Zealand Texel ewe and her lambs

About the INZAC flock

McGovern added that the first of the animals involved in the study were brought onto the farm in 2014. 2016 was the first full year of the trial.

Currently the ewes are being grazed as three separate groups. These include an ‘elite’ flock, consisting of 60 Irish Suffolk and Texel ewes – all of which are five-star rated on the Replacement Index.

The trial also features a ‘low’ flock, consisting of a mixture of 60 Irish Texel and Suffolk ewes. All of these ewes are rated as being one-star on the Replacement Index.

The third group – the New Zealand ewes – is also comprised of a mixture of Texel and Suffolk animals.

Five star Irish Texel and Suffolk sheep
Five-star Irish Texel and Suffolk sheep

Each of the groups are split 50:50 between Suffolk and Texel genetics.

The three groups are grazed on a 15ha platform, which is subdivided into a 5ha ‘farmlet’ for each individual group. Each farmlet carries 12 ewes/ha and receives 150kg of nitrogen/ha/year.

Traits measured:
  • Ewe longevity
  • Fertility
  • Lambing difficulty
  • Survival traits
  • Mothering ability
  • Milk yield
  • Lamb birth and growth rate
  • Ewe weight and Body Condition Score (BCS)
  • Health data

Better performance with New Zealand genetics

Early trial results show that the New Zealand flock had better performance in a number of areas, but it must be noted that the results presented are only from the first year of a four-year trial.

The trial results show that more New Zealand ewes held to the first service at breeding, while there was no significant difference between the ‘low’ and ‘elite’ ewe groups.

Looking at other key breeding metrics, there was no difference in the barren percentage, scan rate or lambing rate between the three ewe groups.

Some of the five star Texel and Suffolk ewes on the farm in Athenry
Some of the five-star Texel and Suffolk ewes on the farm in Athenry

However, the New Zealand flock did produce more lambs (number of lambs born) when compared to the Irish ‘low’ and ‘elite’ flocks, which had almost identical results.

Interestingly, the New Zealand group had less lambing difficulty (dystocia) than either of the two Irish flocks, which once again posted similar performance figures.

Source: Teagasc. Red letters denote significant differences.
Source: Teagasc. Red letters denote significant differences

From a production point of view, there was no difference between the birth, 40-day, weaning and drafting weights between the progeny of either group.

However, the lambs produced from the New Zealand and ‘elite’ flocks did reach slaughter weight earlier than the ‘low’ group.

The New Zealand and ‘elite’ lambs took 155 days and 164 days respectively, to reach slaughter weight – meaning that there was no significant difference between both groups. However, it took the ‘low’ lambs 178 days to come to slaughter.

McGovern added that the last of the ‘low’ lambs were sold off-farm in November and required concentrates to finish, while the last of the New Zealand lambs were drafted in September after 96% of these animals had received a grass-only diet.