Friday, March 29, 2024

The tolerant cow

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Sacrificing some genetic value to breed facial eczema-tolerant dairy cows could be a better path to increasing milk production. Bay of Plenty farmer Richard Sisam told Sheryl Brown why he’s using genetics to tackle the disease.
Reading Time: 6 minutes

Many farmers are probably not feeding their cows enough to benefit from the milk production of their Breeding Worth (BW) potential, so there is an option to drop BW to include facial eczema (FE) tolerance, Bay of Plenty farmer Richard Sisam says.
While stock losses from FE in dairy cows are not high, production losses are an enigma, he says.
DairyNZ says for every three in 100 cows with clinical signs, 70% of the herd might have subclinical FE, which can decrease milk production by up to 50%.
That unseen subclinical disease could be doing irreversible liver damage, affecting long-term production, and the true impact on production is hard to equate, Richard says.
Whakatane farm consultant Tonya Greig agrees. Since she started her training in 1982, Tonya has been a consultant on the Sisam family operation. The crossbred herd is not going to produce 600kg milksolids because of the farms’ steep hills and low-input operation, she says.
To spend money chasing exceptional BW when cows are still not producing to their current BW is not the answer.
“I’ll take facial eczema tolerance any time over pushing BW and PW.”
Richard’s experience with breeding for FE tolerance in sheep is what motivated him to seek out FE-tolerance genetics in his dairy herd.
He switched to CRV Ambreed bulls five years ago when the company first offered the genetics and now has four age-groups of FE-tolerant dairy animals on the ground.
The Sisam family have farmed at Taneatua, 15 minutes south of Whakatane, for 100 years. The operation is owned by the wider Sisam family and run as a company with other outside shareholders.
The 3330ha effective property includes 827ha of milking platform split into four dairy units, with most of the income coming from bull beef run on the remaining land, which is also used as a dairy support block.
Richard is managing director of the property, also overseeing the dairy units, while brother Bruce supervises the sheep and beef operation, running 5500 ewes, 1600 hoggets and 2000 bulls.
The original sheep and beef business used to rear dairy heifers as another source of income, but got caught out in the depression in early 1930s with no buyers. They ended up milking the heifers themselves and continued dairy farming.
“We are accidental dairy farmers who quickly recognised the profitability of dairying,” Richard says.
They now have four dairy units milking 2080 cows.
Richard wants reduce the risk of FE to his dairy cattle because he’s seen firsthand the effects on sheep.
“It’s such an annoying disease and very hard to predict.
“Even with high resistance in your ewes there is attrition on their livers. Some of the sheep livers you couldn’t get a knife into, they’re just like a ball of rubber.”
In the dairy industry there is a lot more control for FE and zinc has been a success story, but building tolerance into genetics will be cheaper over time, he says.
In dairy cows, even if there are no clinical signs the animals could still be getting liver damage, affecting their potential. Exposure every year could be taking a toll and FE damage would still be accumulating in the cows’ system, Richard says.
Farmers should be thinking about the best future-proof option for FE control.
“Cows eating a lot of grass, you’re going to get hit.
“It’s not a big cost to breed FE-tolerance into your cows. It should be there in the background working away for free.”
Zinc dosing could be expensive, but the cost of FE-tolerant bulls is minimal. The cost is more in lost BW, but BW doesn’t hold a lot of value when cows are sick, Richard says.
“We all know sick cows don’t produce much and either don’t recover or take a while to recover.”
Farmers who didn’t fully commit to breeding FE-tolerant sheep 20 years ago never progressed and that is why he’s trying to be ahead of the game with dairy cows.
“I’m putting my money where my mouth is.”
In the 1980s the Sisam family farmed 12,000 ewes and would lose more than 1000 in a bad FE season. They introduced FE-tolerant genetics and now, farming 5500 ewes, will lose up to 50 lambs in a moderate FE-challenged season and have very few ewes showing signs of clinical FE.
“Always at the back of my mind was if you can do it with sheep, surely you can do it with cows so when CRV Ambreed offered the product, I supported it 100%.”
Even with FE-tolerant genetics there is still a need for zinc treatment.
“You’re still going to get that bell-shaped curve, but we’re trying to bring the line across to show more resistance.”
Richard has monitored the spore count onfarm closely in previous years, but it is a job that takes a dedicated person and you can still get it wrong, he says.
They now predominantly use the local vet spore forecast and try to be proactive with treatment.
They drench all R1 and R2 replacements with zinc bullets and put zinc through the water troughs on the milking platform.
“As soon as the spore counts go up, with our young cattle, we put a zinc capsule down them. We still get a little bit of clinical, but it doesn’t seem to last too long and they recover a lot quicker.”
Two of the farm dairies have in-dairy feed systems which aren’t being used, but will be an opportunity for zinc treatment in meal or mineral pellets in the future, Tonya says.
All cows are bred to CRV Ambreed FE-tolerant sires during five weeks of artificial breeding, including R2s. They aim for crossbreds, with anything Jersey going to Friesian and anything Friesian bred to Jersey. They keep it simple, Richard says.
After four weeks they use short gestation AI Hereford bulls, which makes it easy for staff to identify replacement calves. They have a three-week submission rate of 90%. They average a 7-10% empty rate, varying between the farms.
They aim for 600 replacements every year, which are grazed on the bull farm. They are always looking to improve their liveweight targets, which could be hindered with FE, Richard says.
The heifers are achieving good weights, with 80% averaging 420kg. The 20% Jersey crossbreds average 390kg and are run in a once a day herd on Dairy unit 3.
The dairy units are all slightly different though with their own challenges, but the herds all average 390-400kg MS/cow, Tonya says.
Dairy unit 1 is 90% flat sandy silt loam soil with lots of paspalum grass and is prone to floods in the valley, dairy unit 2 is 60-70% hard hill country, unit 3 is a mixture of hills and flat country. Dairy 4 is rolling country with about 20ha of flat country.
The farms operate between a DairyNZ System 2 up to a System 4 depending on the milk price. Cows are fed about 2kg palm kernel if it’s profitable or when necessary. They also typically feed maize silage through autumn and winter.
The unit farm managers have a healthy competition going on between them and average about the same production per cow, but they don’t just get what they want when they want it, Tonya says.
The dairy units share supplement and machinery depending on what is needed where.
All dairy units have a manager and a 2IC, with casual staff rotating between the units for relief milking, calf-rearing, weed spraying and other jobs.
The advantage of scale is they can rely on each other when necessary. When the last flood hit unit 1, 150 cows were walked 10km up to unit 4 to be milked and fed until the 50ha underwater recovered.
Most cows are wintered on their own units, but each unit gets 14ha of the sheep and beef block to winter 200 cows on for two weeks in May through to June.
With climate change and regular drought conditions, facial eczema is a growing issue for dairy farmers.
CRV Ambreed has a selection of FE-tolerant bulls, including Friesian, crossbred and Jersey, available for farmers to use to build resistance in their herd.
Ambreed has been working with AgResearch on the FE-tolerant genetics for a number of years, CRV Ambreed’s genetics strategist Phil Beatson says.
“We have had it in our sights for at least 10 years. We know there is a big cost that goes into the disease, as well as it being a wicked disease in terms of animal welfare – distressing both farmers and the general public.”
Currently farmers can mitigate FE successfully using zinc, but they need to consider how long it will be acceptable to do that, he says.
“Farmers need other strategies. We are really looking into the future and there’s a real need and a real place for a genetic solution.”
Ambreed select 50 of their progeny bull calves every year to challenge for FE-tolerance and the top dozen bulls are chosen.
Using the FE-tolerant sires, cows will typically breed offspring that are 25% less reactive to a facial eczema challenge compared with the average bull.
There has been a big uptake of the genetics by a few farmers, but there hasn’t been strong interest across the industry yet.
Phil says the two reasons farmers are slow to take up the new genetics are zinc supplement is still a relatively easy solution with cattle, and farmers don’t want to have to give up breeding values.
But the bulls with FE-tolerance still have very strong breeding indexes, Phil says.
Ambreed and AgResearch are applying for funding to investigate the economic impact of FE to farmers.
The loss to farmers is probably quite significant, and it will be important to get the story out to make them aware of the true cost, Phil says.
“It’s something I think we need to be proactive on and have this programme. Hopefully we will see more and more farmers seeing a need for it and use this product.”

FARM FACTS

  • Owner: Sisam and Sons
  • Managing director: Richard Sisam
  • Location: Taneatua, Whakatane
  • Area: 3330ha effective, milking platform: 827ha effective
  • Cows: 2080 crossbred, 2260 wintered
  • Production: 380kg MS/cow
  • Farm dairy: 3x 40-aside herringbones, 1x 54-bail rotary
  • Average BW: 91 (40% reliability)
  • Average PW: 114 (61% reliability)
  • Pasture eaten 2014-15: 10t DM/ha, including maize silage grown onfarm
  • Total supplement eaten: 2317t DM, including all supplement bought and made on dairy and beef blocks.
  • Effluent irrigation area: 136ha
  • Operating expenses: $4.15/kg MS
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