No abstract

Colostrum yield and composition of 40 Landrace3Large White sows were determined from the onset of parturition until 24 h post partum. Colostrum yield was calculated by adding individual piglets' colostrum intakes for each litter. Colostrum was assayed for prolactin, progesterone, oestradiol-17b, immunoglobulin G and its nutritional composition was determined. Piglets' individual colostrum intake averaged 300 6 7 g and sows' colostrum yield averaged 3.67 6 0.14 kg (minimum 1.91 kg, maximum 5.31 kg). Live weight and characteristics at birth (umbilical cord already ruptured, splayleg, difficulty to breathe) were the major factors influencing individual colostrum intake. Colostrum yield was not affected by litter size, tended to be influenced by parity (P 5 0.059) and was lower when farrowing was induced (P 5 0.017). On the other hand, no relationships were found between hormone concentrations in colostrum and colostrum yield. Mean piglet birth weight and litter weight variation at birth were related to colostrum yield (r 5 0.38; P 5 0.015 and r 5 20.34; P 5 0.030, respectively). These results suggest that determinism of colostrum yield depends, in part, on global vitality of the litter but seems to be, most probably, affected by the capacity of sows to produce enough colostrum for the whole litter. Further studies are needed to understand the endocrine regulation of colostrum secretion in sows.

Colostrum intake from birth to 24 h after the onset of parturition ( T 24 ) was estimated for 526 piglets from 40 litters. Plasma concentrations of immunoglobulin G (IgG), lactate, glucose and cortisol were determined at T 24 for six piglets per litter. Plasma IgG concentration was also assayed at weaning (28 days) on the same piglets. Rectal temperature was measured at T 24 on all piglets. Mortality was recorded until weaning and comparisons were made between piglets that died before weaning and those that were still alive at weaning. The piglets that died before weaning had lower birth weight, lower colostrum intake, lower weight gain between birth and T 24 , and had a lower rectal temperature, higher plasma cortisol concentration and lower plasma IgG and glucose concentrations at T 24 than piglets still alive at weaning. In addition, a higher proportion of piglets that died before weaning had difficulty taking their first breath after birth and were affected by splayleg. Considering all piglets, colostrum intake was positively related to rectal temperature and plasma glucose concentration and negatively related to plasma cortisol concentration at T 24 . Plasma IgG concentration at T 24 was explained by colostrum intake, IgG concentration in the ingested colostrum, birth weight and birth rank (P , 0.0001). Plasma IgG concentration at weaning was related to plasma IgG concentration at T 24 (r 5 0.54; P , 0.0001) and to colostrum intake (r 5 0.32; P , 0.0001). Finally, body weight was explained by colostrum intake, birth weight and age until 6 weeks of age (P , 0.0001). These results show that colostrum intake is the main determinant of piglet survival through provision of energy and immune protection and has potential long-term effects on piglet growth and immunity.

Lameness in sows has an economic impact on pig production and is a major welfare concern. The aim of the present project was to develop methods to evaluate and quantify lameness in breeding sows. Five methods to study lameness were compared between themselves and with visual gait scoring used as a reference: footprint analysis, kinematics, accelerometers, lying-tostanding transition and foot lesion observation. Fifty sows of various parities and stages of gestation were selected using visual gait scoring and distributed into three groups: lame (L), mildly lame (ML) and non-lame (NL). They were then tested using each method. Kinematics showed that L sows had a lower walking speed than NL sows (L: 0.83 6 0.04, NL: 0.96 6 0.03 m/s; P , 0.05), a shorter stride length than ML sows (L: 93.0 6 2.6, ML: 101.2 6 1.5 cm; P , 0.05) and a longer stance time than ML and NL sows (L: 0.83 6 0.03, ML: 0.70 6 0.03, NL: 0.69 6 0.02 s; P , 0.01). Accelerometer measurements revealed that L sows spent less time standing over a 24-h period (L: 6.3 6 1.3, ML: 13.7 6 2.4, NL: 14.5 6 2.4%; P , 0.01), lay down earlier after feeding (L: 33.4 6 4.6, ML: 41.7 6 3.1, NL: 48.6 6 2.9 min; P , 0.05) and tended to step more often during the hour following feeding (L: 10.1 6 2.0, ML: 6.1 6 0.5, NL: 5.4 6 0.4 step/min standing; P 5 0.06) than NL sows, with the ML sows having intermediate values. Visual observation of back posture showed that 64% of L sows had an arched back, compared with only 14% in NL sows (P 5 0.02). Finally, footprint analysis and observation of lying-to-standing transition and foot lesions were not successful in detecting significant differences between L, ML and NL sows. In conclusion, several quantitative variables obtained from kinematics and accelerometers proved to be successful in identifying reliable indicators of lameness in sows. Further work is needed to relate these indicators with causes of lameness and to develop methods that can be implemented on the farm.