While many producers use pigs/ sow/year as the benchmark for success in the breeding herd, there is now much more focus on lifetime productivity, driven by concern about high culling and death rates.
I have discussed in the past the situation in Denmark, where sow death loss is around 15 per cent. In the U.S., PigChamp data for 329 farms from 2010 shows a figure of 9.5 per cent. The situation in Canada is likely somewhat better, although there is little data, with the 28 farms recording with PigChamp showing a figure of 9.3 per cent. In addition to death losses, culling rate is also far too high, which means that the average productive life of sows is very short.
The cost of these losses is a concern for producers and the industry as a whole. The fewer piglets a sow produces over her lifetime, the higher the cost per piglet, primarily because of the investment at the start of her time in the herd. The overhead cost of the replacement gilt and the feed it takes to get her to first farrowing has to be amortized over her productive life. If the sow produces an average of only four litters per lifetime rather than five, the overhead cost per piglet for that cost component is increased by 25 per cent.
The reasons why both death loss and culling rate has increased in many countries is complex. However, there seems no doubt that the greater nutritional and physical strain on the sow as a result of the increased productivity, especially in her early life, is a major factor. A recent study in Japan showed that gilts have an increased risk of mortality at the time of movement into the breeding herd as well as near the time of their first farrowing. It also indicated that the greatest risk period for sows is at farrowing and in the first one to two weeks after farrowing. Understanding the periods of greatest risk can help to identify the likely causes. For the gilt, many factors can impact stress and physical injury, such as inadequate space, poor access to feed, competition with pen mates, substandard health management routines and poor handling by the stockperson. A review of these areas is appropriate if losses of young females is a problem.
Better sow health
Today s extremely lean and highly productive sows are very vulnerable to deficiencies in nutrition, environment and management. The main reasons for culling are reproductive problems, lameness and physical injuries such as shoulder sores. Scientists at Iowa State University reckon that understanding and solving lameness challenges in pigs could save U.S. pork producers $23 million per year. They have just embarked on a four-year study of this issue with the aid of a $700,000 USDA grant. Currently, there are no science-based solutions to help producers solve lameness problems in pigs, says animal scientist Anna Johnson. The project s goal is to find tools that producers can use to measure pain mitigation, lameness and make practical recommendations that can be applied to manage the problem.
Lameness is the second-highest reason that sows leave the breeding herd early, Johnson notes. Problems during reproduction are rated as the No. 1 problem, but we think that lameness may be contributing to the reproduction problems. There are currently no approved drug treatments for pigs that are dealing with pain associated with lameness, she adds.
The sow s reduced fat cover makes her more susceptible to injury and shoulder sores may be a manifestation. The British Pig Executive (BPEX) has just published a leaflet on this topic which provides some useful guidance on how to avoid and treat the problem. It points out that the most likely time that sores develop is in the first two weeks after farrowing, due to the amount of time the sow spends lying on a hard floor. Thin sows are more prone to get sores due to their reduced fat cover. BPEX suggests that assessment of individual sows is done using a zero to four scale, and says that if a sow has a shoulder sore of degree three or four, euthanasia should be carried out to prevent unnecessary pain and suffering. Sows with a score of one or two can be treated in a recovery pen.
BPEX provides 10 top tips to prevent shoulder sores, the most important of these relating to the management of body condition. It suggests a target body condition score of 3.0-3.5 throughout the sow s reproductive cycle and advises routine condition scoring to monitor whether this is being achieved. The key is to ensure adequate intake during lactation to avoid loss of body weight and condition.
Attention to the flooring surface in the farrowing pen is also advised, so that the surface provides good grip without being abrasive. Also, if the width of farrowing crates is adjustable, BPEX suggests opening them to the widest position when sows enter the farrowing room, reducing the width at farrowing to minimize crushing and then opening them up again one to two days later. Sows will spend more time lying down when their movement is restricted.
It also advises that at risk sows are identified and given special attention. These include thin sows, sows that have previously had shoulder sores, lame sows or those with other foot or leg problems, sick sows and old sows.
The attention that is now being paid to sow productive lifetime is long overdue and research is starting to provide some answers to help improve this parameter. If an average of five litters per lifetime is not being achieved then some of the areas mentioned above are worth investigating.