Understanding & Addressing Sow Mortality

Monday, May 13, 2024

A Balanced and Sustainable Breeding Approach is Critical.

By Brent Devries & Afton Sawyer, for Hypor

Genetic improvement for sow prolificacy has been very successful. Unfortunately, sow survivability has inadvertently been decreasing. This has become a growing challenge in the global swine industry. Not only are there large economic impacts related to the loss of a productive sow, but herd performance, staff morale, animal welfare, and resources used for production are also negatively affected.

Underlying causes of sow mortality can be categorized as either infectious or non-infectious. Infectious causes can be reduced through a high health status via strict biosecurity protocols and proper individual animal care. Non-infectious causes, in which genetics can play a role, are primarily lameness, pelvic organ prolapse, and factors leading to sudden death. Sow mortality often involves multiple risk factors and various bacterial agents. Genetics and effective management strategies can help solve this challenge.

There are two high-risk periods of sow death during the production cycle. The highest occurs in the first 10 days postpartum, and the other in prepartum, right at the end of gestation. These two periods together are called the peripartum period. Most sudden deaths (53 per cent) and the increasing incidence of pelvic organ prolapses occur during this short period. Thus, the time shortly before, during, and after farrowing is critical.

Young sows (until Parity 3) are the main susceptible group, particularly P1 and P2, as they account for about 40 per cent of total sow mortality. This is unfortunate as it is commonly accepted by the industry that a sow needs to wean three litters to pay off her investment. These premature sow removals are costly and do not provide the opportunity for voluntary culling based on age or performance.

General management practices

Food, water, and air are undoubtedly three important pieces to raising healthy sows who will continue to provide multiple litters throughout their lifetime. Water has many important roles, such as temperature regulation, movement of nutrients into cells, removal of waste products, lubrication, and is part of almost every chemical reaction occurring within the body. Requirements for sows vary depending on stage of production, age, temperature, and diet. The amount consumed varies in literature, but it is advisable that water be supplied ad libitum. To deliver sows with enough fresh, cool, and clean water to optimize biological processes, drinkers should supply a minimum of 2.5 to three litres per minute.

Along with water, feed requirements can vary and may need to be adjusted. Regular checking of sows' body condition is a great way to ensure a sow is in the proper condition to maintain herself, her litter, and is well-suited for the next phase. Refer to Table 1 as a guideline for sows in the first phase of gestation (first 34 days).

Factors which can lead to pelvic organ prolapse are poor body condition, inadequate feed intake pre-farrowing, constipation, poor water quality, and farrowing assistance, among a few others. Therefore, routine monitoring of sow body condition, food, and water is essential. It is also important to move sows, ideally four to seven days before their natural due date, so there is enough time for acclimatization to the room's feed and watering system. Monitoring of the farrowing process will help with determining the need or type of farrowing assistance. At the time of farrowing, if assistance is necessary, the sleeving process should be clean, gentle, and not done in a systematic way.

As previously mentioned, lameness can account for over a quarter of sow death. While this can be influenced by genetics, nutrition, and selection, this can also occur from the environment. Simple adjustments and validation of ventilation and room settings can keep excess wetness out of pens or influence where manure is built up. Overall, this can help prevent sows from slipping and injuring themselves. Regular maintenance of pens and equipment can also prevent the possibility of injuries. An example of this is inspecting the bottoms of feed tubes in gestation stalls. These can deteriorate, leading to sharp edges, which can injure sows and cause infections or prevent them from eating normally.

The role of genetics

Historically, swine breeders have successfully identified and selected key sow conformation traits over many generations. This has been possible because most conformation traits have moderate heritability, although with some variation from less than 0.1 (little genetic influence) to more than 0.4 (substantial genetic influence). Structurally sound animals are more robust and can thus thrive in various housing systems over many parities.

The genetic impact on sow survivability is evident in an industry benchmark using standardized data. Commercial farms using one particular genetic line had a 22 per cent lower female death loss rates versus the industry average since 2017. Interestingly, this difference is not due to the longevity of the older sows, but rather in the early deaths of the more valuable young sows (see Fig. 2).

Even a one percentage point improvement in sow survivability can have a large economic impact. In-depth analysis at Iowa State University found such an increase translates to savings of $15.40 CAD/sow/year. This equates to $38,460/year on a 2500-head farm. Or, in other words, each dead sow costs $1,540. A similar cost of $1,340 CAD per dead sow was reported by Ron Ketchem in 2021. The primary underlying costs are loss of piglets, loss of cull sow value, and gilt replacement. Neither of these calculations considered two other costs associated with increased sow mortality as pointed out by Dr. John Deen: A higher proportion of P1 sows and removal of dead sows. P1 sows have poorer farrowing and nursing performance, and their progeny have poorer growth performance along with higher mortality. Secondly, physical removal of a dead sow is labour-intensive (especially from a stall) and can be emotionally wearing on the workers.

Our labour force is already stretched thin. So much so that proper individual animal care is being neglected and is contributing to the rise in sow mortality. This trend needs to reverse. Start by accurately recording the reasons for female death loss.

This will help identify the underlying key factors. From there, review your management practices and target areas to improve. Consider the genetic foundation of your herd. Is it appropriate for your current and future environment? A balanced and sustainable breeding approach is critical not only for economic reasons, but also for our social responsibility. BP

Hypor is the swine genetics brand of Hendrix Genetics, a leading multi-species breeding company headquartered in The Netherlands.