Where are gilts going?

Friday, January 20, 2023

Data can be used to determine where to look for the causes of animal losses.

By Emily Croft

Herd data is an important tool that can be used by producers to benchmark their herd, determine their strengths, and identify areas for improvement on their farm. Gilt retention is a topic of increasing interest where data can be used for management decisions, maximizing the potential of the females entering the herd. Identification of issues in gilt retention may also be used to examine other underlying problems.

There are currently many options for data management programs in the swine industry, but producers should also keep in mind that the interpretation and application of data is as important as collecting it.

New data from PigCHAMP, a leading data management software designed for the swine industry, is showing reduced gilt retention rates in recent years, noting higher culling and mortality rates.

Current recommendations suggest maintaining an average herd parity of 3.5 to optimize productivity from gilts. The data shared by PigCHAMP is showing that only 55 per cent of gilts entering the herd are retained to their third parity. Removal of females from the herd too young can limit the efficiency of the herd. Unsatisfactory gilt retention rates can also indicate other underlying problems in the herd.

"That's what we see too," shares Graeme McDermid, the production team lead at South West Vets in Stratford, Ont., regarding trends in gilt retention.

"Our goal is to get 75 per cent of gilts to their third parity. If we fall short of that, then we haven't realized all the economic potential that gilt would've brought."

Collecting and using data from software like PigCHAMP is an opportunity to determine why gilts are leaving the herd too early and where to look for a solution.

What is happening to gilt retention?

Jayne Jackson, product and sales manager with PigCHAMP, recently put together data from 1.36 million pigs on 279 U.S. farms from 2017 to 2020 to assess recent trends in gilt retention.

The collected data looked at gilts from the time of entry into the herd until their fourth parity. By the gilts' first farrowing, an average of 83 per cent of gilts remained, below the typical target of 85 to 90 per cent retention. By the second parity, only 66 per cent of gilts remained on average, whereas it is typically recommended that retention to the second parity is 75 per cent.

"We know majority of production occurs in parities three and four, and we aren't even getting animals there. Only 50 to 60 per cent of our herd is making it there," says Jackson.

Jackson took the PigCHAMP data further, looking into the break-down of reasons for culling and mortalities.

In the data set shared with Better Pork, death losses made up over half of removals from the herd. The number of mortalities increased with age. Death losses in each parity were consistently greater than five per cent, reaching over 10 per cent in parity three and later.

"We like to see under 10 per cent as an average, but five to 10 per cent is pretty common. If mortality rates are over 10 per cent, we have to dig in and try to understand what is going on," says McDermid.

If producers have records noting the cause of mortalities they can narrow their focus for management changes, allowing them to take control of their losses.

"There's an expectation in my mind that your decision to remove an animal off the farm should be your choice, not due to death. This is telling us it's not in our control," says Jackson.

The reasons identified for culling through the PigCHAMP data changed throughout increasing parities.

The rates of culling increased after third parity.

From the time of entry into the herd until the second parity the most common reasons for culling were no estrus, not pregnant, lame, or recycle, in that order.

Culling due to lameness increased with each parity and was the most common reason for culling by parity three. Thereafter, age became the greatest reason for culling.

"In my experience recently, especially with group pens and electronic sow feeders, gilts have small feet to carry a fair bit of weight," McDermid explains.

"Lameness is more visible in these pens. Staff are observing the pigs every day and are seeing cracked toes, broken dew claws, and other causes of lameness."

Reproductive reasons for culling are also important to understand. Pregnancy losses and delays can be costly. When reviewing culling data, farmers and their teams should look at other conditions that contribute to changes to estrus behaviour and pregnancy rate, such as body weight and body condition.

"The more recent focus on body weight at first breeding is really important. We are seeing recommendations from a lot of genetic suppliers to breed gilts around 140 kilograms, and wait until the second or third estrus cycle," says McDermid, noting that management at breeding can make a difference in gilt retention and reproductive success.

"A rule for the farms we work closely with is that they should use a weight tape. Without it, there's no confirmation of weight, and breeding times start to drift. The weight tape has been a really good tool."

After breeding and farrowing, some gilts may not be able to support their piglets as well as others. The toll on their body may further impact reproductive success.

"We have young sows nursing a lot of pigs, sometimes 14 or more piglets, and we need to make sure she has all the calories and feed she can eat to maintain condition. Not all of them are capable of supporting large litters. Producers might consider pulling pigs to relieve some of the load on her," says McDermid, explaining that body condition loss may play a role in reproductive problems.

"We don't want to lose too much condition. When the sow goes through weaning and moves back into the breeding barn, that's potentially where culling happens. She might be milked down and needs time to put condition back on.

"I think lameness also plays a role. If she's lame and sore, she's not focussed on a good heat and getting rebred."

Mortalities may present a greater challenge when using data to identify underlying causes.

Prior to parity one, sudden death was the most common cause of mortality reported, followed by lameness, and unknown causes. Moving forward, in parity one and two, the major causes of death were prolapse, sudden death, lameness, and unknown. Prolapse, sudden death, and lameness continued to be major causes of mortality as parities progressed.

PigCHAMP data also revealed that the majority of deaths occurred around 117 days after the last AI service, or immediately after farrowing. This timing aligns with prolapses leading to euthanasia but does not explain the large number of sudden or unknown deaths being observed.

Knowing that most of these unexpected deaths occur around farrowing gives the swine industry a focused timepoint to investigate. This is an opportunity for farm managers, staff, and their support teams to use data to get to the bottom of what is happening to gilt retention in their herd.

Using data to improve management

A major question that is brought about by the high prevalence of sudden or unknown deaths is how could record keeping be improved to better define what is happening at this time? Are the staff trained to know what to look for? Or is it a problem that cannot easily be observed?

McDermid suggests that the best way to get high quality records and catch problems early is to make sure the pigs are being observed frequently with daily walk throughs by staff. He says that staff should make sure they are getting all the pigs up to catch any potential injuries or illnesses early.

"A lot of loose housing and electronic sow feeder systems are good at showing when a feeding is missed, but if farmers are relying on that it's probably too late. They end up chasing the problem. It's important to act with a sense of urgency on every case," says McDermid.

Identifying problems early may be one way to create more accurate records while improving gilt retention long-term.

"We now know when it comes to mortalities, we have a place to look at. We have a clear window for timing," says PigCHAMP's Jackson.

"If we get the right people standing on the right farms looking at this, a team of vets, nutritionists, geneticists, the farm manager and the farm staff who do the work, we can get a clear understanding of expected processes."

Many operations have a strong team supporting their farm. This provides good opportunity for discussions of data collection and interpretation, trends and benchmarking, as well as staff training.

McDermid shares that interpretation and application of data in herd improvement is important to make the collection worth it.

"The data is there. It's just about being able to manipulate it to find out what it means," says McDermid. "We owe it to our farm staff, with all the work that goes into collection.

"We have to make it mean something. It creates a lot of good dialogue with farm staff and management."

The more teamwork, training, and structured record-keeping that occurs on a farm, the earlier gilt retention and its associated challenges can be improved.

"A lot of our labour force is learning on the job now with the labour shortage. Our expectations need to change, and we need to do a better job of communicating how things need to be done," says Jackson.

A good place for farms to start working using data for herd improvement is finding a software program, like PigCHAMP, and start discussing what data should be collected with their health team. BP