Case study: shift in sow culling strategy helps herd increase numbers weaned

Key performance figures

• Average numbers born alive 14.83
• Average numbers weaned 12.51
• Average sow age 3.6
• Farrowing rate 91%
• Current replacement rate (while transitioning to smaller herd) 40%
• Target longer-term replacement rate 50–55%

Gilt Watch

Reducing the average age of sows and adjusting the service routine are two of the factors that have contributed to the improved breeding herd performance so far, said Mr Hunt, who took part in our Gilt Watch programme – designed to help maximise return on investment in gilts and improve overall herd performance.

He has always looked to keep improving pig performance and financial viability over his four decades in pig farming, currently running around 450 indoor sows on a weekly farrowing system.

“Gilt Watch has really focused my mind and got me to think differently about performance figures and management. It’s not just about producing more piglets born alive,” Mr Hunt explained. “The changes we’ve made have helped to increase the number of pigs actually weaned per sow.”

As a gilt multiplication unit, the Hunts supply breeding gilts to PIC and take all other progeny through to finishing. They also process a small number of pigs through their own processing facility, retail and wholesale business.

The herd previously stood at 520 sows and the Hunts are in the process of reducing numbers, the end target being a herd of 420 highly productive sows. Current industry issues have galvanised that plan. They used to keep sows until they had had eight litters or more and now do not keep sows beyond their seventh litter; their target is to get to a point where sows have no more than five litters.

“Our average age at culling is currently about 6.5 litters and we’re on our way to making that six parities,” said Mr Hunt.

“And, after three parities, any sow weaning fewer than 30 piglets per year will be culled.”

Focus on pigs weaned

Mr Hunt started to export performance data into Excel grouped by litter/parity to analyse performance, rather than by their farrowing groups. This revealed that, after five parities, Mr Hunt’s sows were still giving birth to good numbers but numbers weaned were tailing off significantly. “Sows are now averaging nearer 12.5 weaned per litter instead of 10s and 11s.

“The average age of sows across the herd has reduced from 4.6 to 3.6 litters. I’ve now got it clear in my mind that, although the culling policy involves a higher turnover of sows, it results in another 500 pigs per year from the same number of sows based on our old herd profile, that’s a huge difference financially.”

“At the Gilt Watch meetings, Stephen Hall advocated a maximum of five litters and, although it took me a while to fully understand the reasoning, it certainly helped us see the benefits of reducing the age spread and tightening the parity profile.”

Mr Hunt used a fairly simple illustration to quantify the impact. “In a herd of 500 sows, if you take the average number of pigs produced by the 400 sows in parities one to five and compare it with the average number of pigs produced by the 100 sows in parities 6 and above you see a clear difference.

“Then, by removing those older sows and replacing them with younger ones, the herd now has 500 sows weaning those higher numbers.

“Gilt litters can be variable and, as they tend to be good for milk production, we’ve also made a point of fostering and loading up gilts, with many sows giving birth to 18 to 20 piglets,” Mr Hunt continued. “We don’t select any gilt with less than 14 teats and many now have 16. We aim for as many working teats as possible.”

Gilt management and selection

The Hunts aim is to sell 2,000 breeding gilts per year, but it has been nearer 1,300 in the past year, while 250 gilts go into their own herd as replacements. They have two separate sites, one with all the breeding and gilt production and the other for rearing and finishing slaughter pigs.

They depopulated and restocked in 2012 with a complete existing herd and now run predominantly Landrace sows producing a mixture of White Duroc and Large White crosses, along with pure lines of Landrace.

Key selection criteria for breeding gilts for sale and replacements are: good legs and a minimum of 14 working teats with an increasing number now having 18.

“We aim for service at 210 to 220 days, based on age and maturity rather than weight. All gilts are on a finisher ration until they reach 100 kg, then breeding gilts move onto a gilt rearer ration,” Mr Hunt explained. “Between 75% and 80% of animals we produce are going to be finisher pigs so we focus on growth rates primarily.”

“Finisher performance has improved with the White Duroc. They grow well and are more docile, achieving average growth rates of 850 to 900 kg and a 12mm probe.”

Health status is high, with the herd totally clean. The Hunts vaccinate against PMWS, and then any further vaccinations according to customers’ needs. They also vaccinate their own breeding herd against erysipelas and parvovirus.

Service routine

There was a period when Mr Hunt was concerned about returns in gilts, who were not coming into oestrus. While it is difficult to pinpoint exactly what has made the difference and enabled them to achieve the current 90% successful service rate, he highlights boar contact and a consistent routine as important factors.

“We’re achieving slightly better boar stimulation now as we’ve been able to improve boar contact times and quality though we still find it difficult to get boars completely away from the gilts, as they are in the same double-pitched building where they can still hear and smell them.

“We are also very consistent in our timing with Altresyn, keeping it at almost exactly the same time each day.”

Feeding

Sows are fed manually, twice a day, in the farrowing house with quantities tailored to each sow’s appetite. They have managed to increase feed intakes among gilts, feeding a high-specification lactation ration. Extra calcium is also provided as they identified a bone-depletion problem that previously caused problems with lameness post-weaning.

Three weeks before farrowing, the quantities of the dry sow ration are increased. Feed levels are then decreased when they go into the farrowing house and move to a lactation diet. “We also feed bran pre-farrowing for gut fill and to help smooth the passage of stools and hopefully reduce stillbirth,” Mr Hunt added.

Next steps

Along with the contraction of the breeding herd and increased piglet numbers they plan to increase finished weights. “As we’re not able to change the fixed cost base of the business, we need to produce more kilos of pork per sow, capitalising on the increased numbers weaned.

“Weights previously averaged 78–80 kg, before backlogs began last year, and I think they will need to average 85–90 kg in the longer term,” he continued. They have managed to cope with the additional 900 pigs they have had to keep on farm over the past 12 months by recommissioning an old fire-damaged building.

Mr Hunt is also considering ways to reduce energy costs, including reducing the temperature in the farrowing house by one or two degrees for the sows and covering the heat mat to maintain higher temperatures for the piglets.

Meanwhile, genetic developments will keep helping to improve performance, believes Mr Hunt.

To find out more about Gilt Watch, get in touch with Pat Loten or visit our Gilt Watch web page.