Parental Behaviour in Sows.

Parental behaviour in sows begins with prepartum nest-building behaviour, which mainly consists of rooting, pawing, and foraging, to achieve a structure for farrowing and to nurse and protect the offspring. A hormonal background is linked to the onset and cessation of nest-building behaviour. The ambient farrowing environment that can adequately address the needs for nest-building behaviour thus plays an important role in good parental behaviour of the sows during and after farrowing. In addition to these environmental factors, here we also discuss other well-known intrinsic factors, such as heredity, parental experience, and litter size, affecting parental behaviour of the sows for successful farrowing and lactating performance.

The differences in energy metabolism and redox status between sows with short and long farrowing duration.

Farrowing duration is a crucial factor affecting survival of piglets and health of sows, and is highly correlated with the incidence of stillbirth. The present study assessed the metabolic characteristics of sows with short farrowing duration (SFD) or long farrowing duration (LFD). A total of 20 Yorkshire sows were screened from 60 sows and were retrospectively allocated into SFD (211 min on average, n = 10) or LFD (388 min on average, n = 10) group. Parameters associated with energy metabolism and redox status were characterised. Results showed that sows at farrowing had decreased plasma concentrations of glucose, triglyceride, acetate, butyrate and total short-chain fatty acids (P < 0.05), but increased concentrations of lactic acid and propionate (P < 0.05), when compared with sows on day 107 of gestation. The SFD sows had shorter time from last meal until the onset of farrowing (P < 0.05) and tended to have less stillbirths (P = 0.08) and lower stillbirth rate (P = 0.07). For the blood metabolites, SFD sows at farrowing had higher concentration of plasma glucose (P < 0.05), but lower concentration of lactic acid (P < 0.05) than LFD sows. Besides, SFD sows tended to have higher plasma malondialdehyde concentration (P = 0.06) than LFD sows. Correlation analysis showed that farrowing duration was negatively correlated with plasma glucose concentration at onset of farrowing. In conclusion, our study strongly suggests that glucose is a key metabolite for energy metabolism of the uterus during farrowing. The farrowing process could be closely related to uterine energy expenditure, and sows with shorter farrowing duration could be resulting from the shorter time from last meal until the onset of farrowing, associated with a greater proportion of energy from glucose.

Coping with large litters: management effects on welfare and nursing capacity of the sow.

A number of management issues can be used as drivers for change in order to improve animal welfare and nursing capacity of the hyperprolific sow. Group housing of sows during gestation is a recommended practice from the perspective of animal welfare. Related health issues include reproductive health and the locomotor system. It appears that management of pregnant sows in groups is challenging for a producer and considerable skill is required. We explored the benefits and challenges of group housing, including feeding issues. Increasing litter size requires additional attention to the mammary gland and its ability to provide sufficient nursing for the growing litter. We discuss the fundamentals of mammary development and the specific challenges related to the hyperprolific sow. We also address challenges with the farrowing environment. It appears that the old-fashioned farrowing crate is not only outdated in terms of welfare from the public's perspective, but also fails to provide the environment that the sow needs to support her physiology of farrowing, nursing, and maternal behaviour. Studies from our group and others indicate that providing the sow with a loose housing system adequate in space and nesting material, along with reasonable chance for isolation, can be considered as fundamental for successful farrowing of the hyperprolific sow. It has also been shown that management strategies, such as split suckling and cross fostering, are necessary to ensure proper colostrum intake for all piglets born alive in a large litter. We thus conclude that welfare and nursing capacity of the sow can be improved by management. However, current megatrends such as the climate change may change sow management and force the industry to rethink goals of breeding and, for instance, breeding for better resilience may need to be included as goals for the future.