Pre-weaning piglet mortality represents significant economic losses, and approximately half of this mortality occurs within the first 3 days after birth. Factors involved in postnatal mortality can also be associated with a poor growth performance until weaning. The aim of this study was to evaluate the effect of some variables measured right after birth on piglet survival during the first week of life and growth performance until weaning. Piglets included in the analysis (n=612) were born from 3 to 5 parity sows. Piglets were monitored for blood oxygen saturation (SatO2), heart rate (HR), blood glucose concentration, rectal temperature at birth (RT0 h) and at 24h after birth (RT24 h). Genetic line, birth following or not an obstetric intervention, birth order, sex, skin color, integrity of the umbilical cord, and time elapsed from birth until first attempts to stand were also recorded. Piglets were weighed at birth (BW), and at 7, 14 and 21 days after birth in order to evaluate their postnatal development. Cumulative mortality rates were 3.3%, 5.4% and 8.7% at 3, 7 and 21 days after birth, respectively. Body temperature at birth (RT0 h) did not affect (P>0.05) the survival nor the piglet growth performance. Piglets with cyanotic skin and those that took more than 5 min to stand showed higher chance of mortality (P<0.05) compared to normal skin piglets and to piglets which stood before 1 min, respectively. Piglets with broken umbilical cord had higher odds (P<0.05) of mortality up to 3 days after birth, respectively. Higher odds (P<0.05) of mortality up to 3 or 7 days were associated with later birth order (>9), low BW (<1275g), low (24-30 mg/dl) and high (45-162 mg/dl) blood glucose concentrations, or low RT24 h (<38.1°C). Piglets with BW<1545 g, low RT24 h (<38.6°C) and female piglets had higher odds of a low weight at weaning (P<0.05). Among the factors studied, cyanotic skin, delay for standing, broken umbilical cord, high birth order, low BW, low RT24 h, and both low and high blood glucose concentrations are indicators of a lower ability of piglets to survive during the first week after birth. The growth performance until weaning is compromised in piglets with a lower BW, a lower RT24 h and if they are female pigs.

a b s t r a c tCross-fostering is the transference of piglets to equalise litter size according to the birth weight. In many commercial farms piglets are usually grouped in litters with 100% adopted piglets. The aim of the experiment was to assess the behaviour of piglets during the suckling period as well as to assess their performance and mortality rate up to weaning in litters with different composition in terms of adopted and biological piglets. Three treatments were studied: 100B (100% biological piglets, n¼13), 50B50A (50% biological piglets and 50% adopted piglets, n¼ 13) and 100A (100% adopted piglets, n¼ 13). All litters were standardised to eleven piglets on average within 20.170.4 h (14.3-24.7 h) of birth. The behaviour of piglets was recorded during four consecutive sucklings for four days (days 1, 2, 4 and 6 after farrowing, considering day 1 as the cross-fostering day). The observations were performed at two time periods: TP1 (from release of piglets out of creep box until milk letdown) and TP2 (from the end of milk letdown up to 15 min later). Piglets were weighed at days 1, 4, 7, 10, 13 and 16. There were no differences (P40.05) among the treatments in the following behavioural variables: percentage of missed nursing episodes; number of fights for teats and percentage of piglets involved in fights at TP1; percentage of piglets vocalising at TP1 and at TP2; number of fights per piglet elsewhere in the cage and percentage of piglets involved in these fights; number of instances of playful behaviour per piglet and percentage of piglets involved in it. At TP2 of day 1, 100B piglets displayed a lower number (Po0.05) of fights for teat (0.9 vs. 1.6 vs. 1.4 for 100B, 100A and 50B50A, respectively) and tended to have a lower percentage (Po0.07) of piglets involved in these fights than 100A (49.6%, 67.2% and 64.9% for 100B, 100A and 50B50A, respectively). Nutritive nursing episodes (overall medians of 4.0, 3.0, 4.0 and 4.0 for days 1, 2, 4 and 6, respectively), survival rate (overall 97.2%) and average weight of piglets (1983 g, 2650 g, 3411 g, 4207 g and 5047 g for days 4, 7, 10, 13 and 16, respectively) were similar (P40.05) among treatments. Cross-fostering performed on average at 20 h after birth has no adverse effects on survival and growth performance of adopted piglets.

No abstract

Investigou-se o efeito da ordem de parto (OP) e da perda de peso durante a lactação no desempenho reprodutivo de 666 matrizes suínas. Foram formadas três classes de OP (OP1, OP2 e OP3-5) e duas classes de percentual de perda de peso (≤1% e >1%) durante a lactação. Foram avaliados: taxa de parto, intervalo desmame-estro (IDE) e tamanho da leitegada subsequente. Houve interação de OP versus perda de peso na taxa de parto das fêmeas (P<0,05). As fêmeas OP1 e OP2 tiveram maior chance (P<0,05) de não parir na classe >1% de perda de peso. A maior perda de peso não foi um fator de risco para não parir na condição OP3-5 (P>0,05). Não houve interação de OP versus perda de peso (P>0,05) para IDE e total de leitões nascidos. Fêmeas OP1 apresentaram IDE mais longo e menor tamanho da leitegada no parto subsequente (P<0,05) do que fêmeas OP2 e OP3-5. As perdas corporais na lactação não influenciaram o IDE (P>0,05), mas reduziram o tamanho da leitegada subsequente (P<0,05). Conclui-se que maior perda de peso na lactação resulta em aumento de falhas reprodutivas nas fêmeas mais jovens e reduz o tamanho da leitegada subsequente em todas as OP.

Lysine requirements for gain in maternal body reserves and piglet birth weight, during pregnancy, in contemporary prolific genotypes, are not well established. This study aimed to evaluate the effect of dietary lysine in late pregnancy on piglet birth weight, and on the gestational and lactational performance of gilts. Pregnant gilts were uniformly distributed into two groups and received, from 85 to 110 days of gestation, either of two lysine levels in their diet: Control group - 28g lysine/day (n=136), and Lysine group - 35g lysine/day (n=141). There were no effects (P>0.10) of supplemental lysine on body weight and backfat (BF) gain of females or on piglet birth weight. Gilts supplemented with lysine tended to have a lower percentage of stillbirths (P=0.077), reduced within-litter birth weight variation (P=0.094) and a lower percentage of piglets weighing less than 1100g (P=0.082) than in the Control group. During lactation, the performance of sows and litters was also evaluated in a subgroup of sows (n=26/group). There were no differences between the Control and Lysine groups (P>0.10) in voluntary feed intake, body reserve losses (weight and BF), weaning-to-estrus interval of the sows, and litter weaning weight. In conclusion, an increase in lysine (from 28 to 35g/day) in late gestation of gilts (85 to 110 days) tends to reduce the rate of stillbirths and to improve the uniformity of litter weight at birth, but does not affect the performance of females until farrowing or during subsequent lactation.