SIL Flock 2629 - Nithdale Romneys

Nithdale Romneys genetic trends graph (July 2023) for New Zealand Maternal Worth (NZMW) + WormFEC + Meat + Dags. $13 per ewe ahead of the industry average (green line) and 200% faster rate of genetic gain. Nithdale Romneys are our base romney flock which we introduced the MyoMAX gene into in 2005. They average 81% romney/19% texel.
Nithdale Romneys Genetic Trend (July 2023) for NZMW + FEC + Meat + Dags + Wool

SIL Flock 452 - Wairaki Romneys

Wairaki Romneys genetic trends graph (July 2023) for New Zealand Maternal Worth (NZMW) + WormFEC + Meat + Wool + Dags. $12 per ewe ahead of the industry average (green line). Wairaki Romneys were purchased off Richard and Trudy Slee, Wairaki Station in 2014. We have maintained these as 100% Romney.
Wairaki Romneys Genetic Trend (July 2023) for NZMW + FEC + Meat + Dags + Wool

Current Breeding Objectives

Our goal is to breed a low cost maternal sheep that can handle a tough environment and maximise output of quality meat and wool.

- Low costs as in no drenching, no dagging, no assistance at lambing and recently breeding for FE tolerance.

- Maximising output of quality meat and wool - Our focus is still on production and performance including quality within a low cost system and challenging environment.

We have been selecting rams and ewes to retain based on structural soundness, good constitution and genetic merit. The genetic indexes we have been using are the New Zealand Maternal Worth index (NZMW) + WormFEC (DPF) + Meat (DPM) + Dags (DPD) produced from the weekly NZ Genetic Evaluation from Sheep Improvement Limited (SIL). Since 2014 we have started using the facial eczema tolerance index (DPX) in our selection decisions. Since 2021 we have started using the methane breeding value (PACCH4) also in our selection decisions. Traits recorded are: pregnancy scan and number of lambs born (in both mixed aged ewes and hoggets), survival (derived from pregnancy scan and lambs reared), weaning weight, live weight at 6 months, meat scanning (A, B & C measurements) in the ram lambs, CT meat scanning a percentage of ram lambs, faecal egg counts in the ram lambs, dag score, fleece weight at 12 months, GGT levels (FE tolerance), mating weights, condition score of ewes and methane production.

Worm Resistance

Over the last few years there has been an increasing awareness of drench resistance and the associated problems faced by sheep farmers. These problems are only going to get worse. Many vets are seeing drench reduction tests showing resistance to all 3 major drench families. There are even farms that have resistance to the two latest drench families: Zolvix and Startec.

There could also be a trend in overseas markets in time for product where anthelmintics have not been used.

We see breeding sheep for resistance to internal parasites as the long term solution to drench resistance and a dependence on animal health products. We have been part of the WormFEC program since 1992 and have made significant progress in reducing faecal egg counts. The Adult FEC BVs have reduced by nearly a half over that period of time. We don’t drench ewes, we have reduced the number of drenches our lambs are receiving and the age at which the lambs are showing an immunity to internal parasites is getting younger. Our ram lambs are left undrenched until sampled in mid February. We can’t throw away the drench gun yet but we are heading in the right direction. 

The graph opposite shows the genetic trend for the breeding value for reduced adult faecal egg count. We have achieved close to a 40% reduction in FEC over 25 years compared with an industry that hasn't changed. 

Drench Reduction Test

In February 2020 we did another drench reduction test on Nithdale and really happy with the results. Why are our results so good? I put that down to 3 things: 1. We have good quarantine practices in place. All stock coming on to the farm are drenched with at least a triple drench and left in the yards overnight. 2. We have reduced the amount of drenching in our stock. We don’t drench ewes, we only drench ewe lambs when they need it (based on a FEC test) and improved gains in growth rates means works lambs are gone quicker and aren’t drenched as much. 3. The biggest driver has been breeding sheep that are resistant to internal parasites over the last 29 years. This has enabled us to reduce the amount of drenching we do.

WormFEC Gold Group

The WormFEC Gold Group kicked off towards the end of 2018. There are 14 flocks in New Zealand which qualify for the WormFEC Gold Group which are leading the way in breeding sheep that are resistant to internal parasites including Nithdale Romneys. To qualify a flock needs to have a certain level of resistance measured by the flocks average DPF (Dual Purpose FEC Index), been testing for at least 8 years and testing a certain percentage of their ram lambs. The group’s aim is to promote the concept of genetic selection for parasite resistance as a sustainable, long term solution to worm challenges and drench resistance. The website has a lot of information on it so check it out:

MyoMAX Gene

Since 2005 there has been a gene test available for the MyoMAX gene, which is a major gene in the Texel breed responsible for 60% of the lean meat. The presence of the gene is either as a double or single copy or not present. Trials have shown that an animal with two copies of the gene has approximately 10% more lean meat on its carcass than an animal that has no copies. We began crossing some of our Romneys with Texels that had two copies of the gene when the gene test was first available in order to increase the meat yield in our Romneys. With each cross we are able to identify those sheep carrying the gene while crossing each generation back to the Romney. Our objective is to breed a sheep that is 80-95% Romney with two copies of the MyoMAX gene. In other words a sheep that effectively has all the traits we have been breeding for in the Romney and looks like a Romney with the meat traits of the Texels. More than half our ewes to date have at least one or two copies of the gene. To learn more about the MyoMAX gene, download the information sheet

Total Meat Yield of Nithdale lambs through the Alliance viascan 2005-2016 compared with the Southland Average 2007-2016

Whole Flock Genomics

Since 2017 we have been getting genomic information on all lambs tailed. Not only do we get parentage and information on major genes like MyoMAX, we also get genetic information for 35 traits based on the DNA of the animal. In the old genetic evaluation system, eBVs or estimated breeding values were generated from pedigree and performance information. Under the new 'Single Step' genetic evaluation, genomic information based on the DNA of the animal as well as the pedigree and performance information is run in one single genetic evaluation. If no genomic information is included (no gene testing done) then the results are based solely on eBVs. However if gene testing has been done then the genomic information is included and the accuracy of the BVs are much greater. This improves our selection decisions meaning that we make faster genetic gain. If we make faster genetic gain so do our clients.

DNA Parentage

Since 2012  we have been lambing the stud Romneys on the hill and determining the parentage of the lambs through DNA. Tissue samples are taken from lambs at tailing time and their DNA is matched to their sire and dam through the genomic parentage test. The accuracy is extremely good with each year's lambing getting a perfect match on 99.5% plus of the lambs tailed. The benefits of this is that we can lamb the ewes unassisted – reflecting what is happening on most farms in New Zealand and we get accurate parentage results which improves the accuracy of data on those animals.

Facial Eczema Tolerance

Due to the increasing risk of northern clients getting facial eczema (FE) and the possible spread south due to climate change we started selecting for FE tolerance in our Romneys in 2012. We sourced top FE tolerant sires from the North Island and in 2015 began testing rams at Nithdale with sporadesmin. One sire line we dosed at 0.5mg/kg with 5 ram hoggets showing nil liver damage. One ram Nithdale 2155/15 was used in the stud and in the Waikato in 2017 (ranked 15th on the June 2019 NZGE Maternal Worth with Facial Eczema list, click here to view). Genomics also gives us BVs for FE tolerance on our own rams at Nithdale.

Scrapie Resistance

Scrapie is a brain disease in sheep not found in New Zealand but is endemic in UK and parts of Europe. Even though we don't have the disease in New Zealand we can still determine the scrapie geneotype and therefore the scrapie resistance status of our sheep. With whole flock genomics we get the scrapie genotype on all our animals (Romneys and Suftex). While the percentage of ARR/ARR (Type 1 - Resistant) in our Suftex rams is only 8%, in our Romneys, 28% are ARR/ARR, so providing a really good selection from our maternal flock for clients in the UK that are wanting to import our genetics.

Reducing Methane Emissions in Sheep

With Climate Change Policy being set farmers will be required to reduce methane emissions from their farms. De-stocking is one way. Another way is to select for reduced methane emissions in sheep. With initial testing AgResearch has determined that: 1) there is genetic variation in methane emissions in sheep (up to 30% variation). 2) it is a heritable trait (h2 of about 0.20). 3) selecting for reduced methane does not negatively impact other productive traits. 4) gains of 1% reduction per year can be made. Back in 2014 Nithdale ewe hoggets were first involved in the methane testing as AgResearch developed the testing for this trait and since 2020 we have been testing a selection of ram lambs. In the 2021 mating we used PACCH4 BVs (BVs for methane emission) in our selection decisions on rams to use within the flock.
Testing Ewe Hoggets at Nithdale for Methane Emissions

Genetic Trends

Genetic trends show the amount of genetic gain in cents over time for a particular trait or index. The steepness of the graph indicates the rate of genetic gain - the steeper it is the faster the rate of gain. These genetic trends are based on the 2 July 2021 SIL genetic evaluation of all flocks on SIL (1335). The green line is the industry average. The dotted line is Nithdale (flock 2629).

To view Nithdale Romneys’ genetic trends click on the index or trait below:

Selection of 2th Rams Used 2016 – DPO (DPP+DPF) from NZGE (New Zealand Genetic Evaluation) - June 2019

Nithdale 1063/14 - Used by Nithdale and Waihora (Taupo) 2016. DPO 2921
Nithdale 1237/14 - Used by Nithdale, Paki-iti (Fielding) and Mount LInton Station 2016. Double MyoMAX. DPO 3332
Nithdale 2155/14 - Used by Nithdale and ARDG (Waikato) 2016. Sporodesmin dosed at 0.5mg/kg bodyweight with nil liver damage. DPO 2129, DPX 1591
Nithdale 192/14 - Single MyoMAX. DPO 2040

7 Beef + Lamb NZ Genetic Awards in 4 years

2012 - ACE Dual Purpose + WormFEC Flock

2013 - SIL ACE Trait Leader for Internal Parasite Resistance & SIL ACE Trait Leader for Reproduction

2014 - SIL ACE Trait Leader for Internal Parasite Resistance & SIL ACE Trait Leader for Reproduction

            (Runner up for Dual Purpose Overall)

2015 - SIL ACE Trait Leader for Internal Parasite Resistance & SIL ACE Trait Leader for Reproduction

2017 - Finalist SIL ACE Dual Purpose + WormFEC Flock

Links to ACE Reports

ACE stands for Advanced Central Evaluations – it is New Zealand’s national across flock and breed sheep evaluation to identify the best rams for economic traits. It is one of the best ways to identify top rams and top breeders across the country (across flocks and across breeds).To find out more visit the SIL website or download the latest ACE Reports in PDF format.