P. Langendijk

Intermittent Suckling Causes a Transient Increase in Cortisol That Does Not Appear to Compromise Selected Measures of Piglet Welfare and Stress.

Simple Summary This study assessed the effects intermittent suckling (IS) had on physiological and behavioral indices of piglets before and after weaning. Piglets were allocated to either a control treatment (conventional weaning) or an IS treatment (separation from the sow for 8 h per day starting the week before weaning). Apart from an initial peak in cortisol at the start of IS, piglets subjected to IS did not show physiological changes suggestive of a chronic stress response before and after weaning. The event of weaning still caused a decrease in growth rate and an increase in white blood cell parameters in both treatment groups. However, the IS piglets tended to gain more weight in the second half of the week after weaning. The results of this study suggest that short periods of separation (e.g., 8 h/day) do not appear to compromise piglet welfare over the peri-weaning period. Abstract This study tested the hypothesis that piglets subjected to intermittent suckling (IS) would show changes in physiological and behavioral indices indicative of compromised welfare in the peri-weaning period. A total of 21 primiparous sows and their litters were allocated to either a control treatment (n = 10) where piglets were weaned conventionally, or an IS treatment (n = 11) where piglets were separated daily from their sows for 8 h starting the week before weaning. Performance, physiological and behavioral measures were taken at various time points during the week before and after weaning. Plasma cortisol levels were higher (p = 0.01) in IS piglets 7 d before weaning. Regardless of treatment, the N:L ratio at 3 d and 7 d after weaning was higher (p < 0.05) than that at 1 d before weaning. The IS piglets ate more creep feed during lactation (p < 0.05), and there was a tendency for the IS piglets to gain more weight between 3 d and 7 d after weaning (p < 0.1). This study showed that, aside from an increase in cortisol at the start of IS, piglets subjected to IS did not display physiological or behavioral changes indicative of compromised welfare.

Intermittent suckling with or without co-mingling of non-littermate piglets before weaning improves piglet performance in the immediate post-weaning period when compared with conventional weaning

BackgroundIn this experiment, intermittent suckling (IS) with or without the co-mingling (CoM) of piglets was studied as a method to stimulate solid feed intake and reduce post-weaning stress.MethodsThree weaning regimes using 30 multiparous sows were compared: (1) conventional weaning (CW) (nu2009=u200910 litters), where piglets had continuous access to the sow until weaning (d 0, farrowingu2009=u2009d −25 relative to weaning); (2) intermittent suckling (IS) (nu2009=u200910 litters), where piglets were separated from the sow for 8xa0h/d starting at d −7 (relative to weaning); and (3) intermittent suckling with co-mingling (ISCo) (nu2009=u200910 litters) where IS started at d −7 and two litters were housed together during separation and then returned to their original sow. Ad libitum creep feed was available from d −17. At weaning pigs were housed in pens of 11 pigs, 27 pens in total. The ISCo treatment was divided in half to examine effects of different mixing strategies after weaning. Half of the ISCo litters were kept in familiar groups (ISCoF, familiar, nu2009=u20094) and the other half were mixed within treatment resulting in groups of unfamiliar pigs (ISCoNF, not familiar,xa0nxa0= 5), the same as IS (nu2009=u20099) and CW (nu2009=u20099) treatments.ResultsThe ISCo piglets ate more creep feed in the week before weaning (Pu2009<u20090.01), but also showed more aggressive and manipulative behaviour on first day of CoM compared with CW piglets (Pu2009<u20090.05). IS with or without CoM increased exploratory and play behaviour on the first day of treatment intervention (Pu2009<u20090.001) and increased sleeping behaviour on the last day of treatment intervention compared with CW (Pu2009<u20090.001). Mixing strategy at weaning had an effect on performance data with the highest growth and feed intake seen in ISCoF pigs 2 to 8xa0d after weaning (P <0.001). IS and ISCoNF pigs also grew faster and ate more than CW pigs 2 to 8 d after weaning (Pu2009<u20090.001). Post-weaning injury scores suggested reduced aggression in ISCo as evidenced by reduced redness (skin irritation) (Pu2009<u20090.05), and a tendency for ISCo to have less scratches than CW (Pu2009<u20090.1). The IS pigs slept the most and displayed less manipulative behaviours on the day of weaning and plasma haptoglobin levels remained low in IS pigs after weaning (Pu2009≤u20090.01).ConclusionsBoth intermittent suckling techniques improved production indices in the immediate post-weaning period. However, the addition of co-mingling before weaning in combination with grouping familiar pigs together after weaning improved performance in an additive manner.

Intermittent Suckling in Combination with an Older Weaning Age Improves Growth, Feed Intake and Aspects of Gastrointestinal Tract Carbohydrate Absorption in Pigs after Weaning.

Simple Summary The weaning of piglets involves abrupt changes that often cause reduced production and predisposition to gastrointestinal tract dysfunction. Increasing the weaning age or using gradual weaning are techniques that can improve post-weaning performance. In this study, it is shown that an older weaning age (day 35) in combination with intermittent suckling (daily separation of piglets from the sow for 8 h in the week before weaning) improved growth rate, feed intake and aspects of gastrointestinal tract carbohydrate absorption after weaning. However, intermittent suckling and weaning at 28 days did not seem to improve post-weaning performance in this study. Abstract This study tested the hypothesis that intermittent suckling (IS) with or without an older weaning age would improve post-weaning gastrointestinal tract (GIT) carbohydrate absorptive capacity in pigs while reducing post-weaning stress and aspects of the inflammatory response. Three weaning regimes using primiparous sows were compared: (1) conventional weaning (CW28) (n = 22), where piglets were weaned conventionally at day 28; (2) IS28 (n = 21), where IS started at day 21 until weaning at day 28; and (3) IS35 (n = 21), where IS started at day 28 until weaning at day 35. Sugar absorption tests (10% mannitol or 10% galactose) were used to measure GIT absorptive capacity. All measured parameters were compared in relation to weaning across treatments (i.e., different physiological ages were compared). The IS35 pigs grew fastest in the 12 days after weaning (p < 0.01) and had the highest solid feed intake before and after weaning (p < 0.05). Irrespective of treatment, pre-weaning mannitol levels were higher than post-weaning levels (p < 0.01), whereas post-weaning galactose levels were highest in IS35 pigs (p < 0.01). Cytokine data did not show any treatment effects. In conclusion, these data suggest that IS in combination with an older weaning age (day 35) improved post-weaning adaptation as evidenced by improvements in performance measures and galactose absorption. However, IS28 did not improve post-weaning performance.

Allopregnanolone and social stress: regulation of the stress response in early pregnancy in pigs

Abstract This experiment investigated whether allopregnanolone, a neurosteroid metabolite from progesterone, modulates the stress response during early pregnancy. Twenty-five nulliparous sows (Sus scrofa) were allocated to one of three treatments: pregnant, ovariectomized or ovariectomized administered daily intravenously with alfaxalone as a synthetic allopregnanolone analog. On days 5, 12 and 19 of pregnancy, all sows were subjected to social stress by submitting them individually to a resident-intruder test, acting as the intruder. Blood samples were collected to analyze plasma progesterone, allopregnanolone, cortisol and adrenocorticotropic hormone (ACTH) concentrations. On day 26, 10 sows across the three treatments were subjected to a dexamethasone suppression test followed by a corticotrophin-releasing hormone administration to test the functionality of their hypothalamo-pituitary-adrenal (HPA) axis through cortisol release. Pregnant sows returned more rapidly to baseline cortisol concentrations following the resident-intruder test (pu2009=u20090.006). However, there were no other differences in cortisol or ACTH concentrations according to treatment or day, or to the HPA responsivity test on day 26. Allopregnanolone concentration in pregnant sows was higher than in ovariectomized sows (pu2009<u20090.001), but stable during the first third of pregnancy. Allopregnanolone concentration was correlated with longer resident-intruder test duration (pregnant: ru2009=u20090.66, pu2009=u20090.0003; ovariectomized: ru2009=u20090.47, pu2009=u20090.03), reflecting lower aggressiveness, and with progesterone concentration (ru2009=u20090.25, pu2009=u20090.03). Alfaxalone administration raised plasma allopregnanolone concentration in alfaxalone-administered sows but resulted in little behavioral and physiological effects. These findings did not support the hypothesis that the stress response of the female pig changes in the first third of pregnancy. Allopregnanolone was associated with lower aggression in social encounters.

Lactational oestrus and reproductive performance following a delayed limited nursing schedule in primiparous sows

With conventional lactation management, sows only conceive after weaning. However, intermittent suckling (IS) enables follicle growth and ovulation during lactation by reducing the suckling-induced inhibition of gonadotrophins. The current study evaluated IS regimes initiated at Day 21 or Day 28 post farrowing compared to conventional weaning on Day 28, in primiparous sows. Sows (Large White and Large White x Landrace) were randomly allocated to Control (C28; nxa0=xa044), IS21 (nxa0=xa029) and IS28 (nxa0=xa034) treatments at Day 20. Sows in IS21 and IS28 were subjected to intermittent suckling from Day 21 or Day 28 post farrowing. During IS, sows were separated from their piglets for 8xa0h daily, then weaned 7xa0d later at Day 28 and Day 35 respectively, whereas piglets in the C28 treatment had continuous access to sows until weaning at Day 28. Percentage of IS sows that showed oestrus during lactation was 59% (16/27) in IS21 and 72% (21/29) in IS28 (Pxa0>xa00.05). Cumulatively over the lactation and 7xa0d post-weaning period, 93% of IS21, 85% of IS28 and 93% (31/33) of C28 sows showed oestrus (Pxa0>xa00.05). Pregnancy rate at Day 30 post mating, for sows that were mated during lactation was 93% (15/16) in IS21 and 95% (20/21) in IS28, whereas C28 sows had a 96% (30/31) pregnancy rate (Pxa0>xa00.05). No difference was found in the time of oestrus relative to weaning (C28) or onset of IS (IS21 and IS28) (Pxa0>xa00.05). The IS sows that did not ovulate before weaning all showed oestrus within 7 days from weaning, and the weaning to oestrus interval was similar to control sows (Pxa0>xa00.05). However, for all IS sows (across IS treatments) that showed lactational ovulation, LH secretion pattern at onset of IS was different (Pxa0<xa00.05) from the sows that did not ovulate in lactation. Plasma progesterone concentration tended to be lower in the IS21 treatment (Pxa0<xa00.10) compared to the C28 sows at 4xa0d after ovulation. The subsequent litter size was not affected by treatments although numerically lower for IS21 (Pxa0>xa00.05). The present study showed that in modern primiparous sows, lactational oestrus can be induced and pregnancy can be maintained at a similar rate and producing comparable subsequent litter sizes to conventionally weaned sows when IS commenced at four weeks post farrowing. However, when IS commences at three weeks post farrowing, this may affect the percentage of sows showing oestrus in lactation and may potentially influence subsequent litter size.

Human chorionic gonadotrophin in early gestation induces growth of estrogenic ovarian follicles and improves primiparous sow fertility during summer

Reduced summer farrowing rates may be due to inadequate corpora luteal (CL) support. Porcine CL become dependent on LH from 12 d of pregnancy and the embryonic estrogen signal for maternal recognition of pregnancy (MRP) is initiated at about 11-12 d after insemination. We hypothesised that injection of the LH analogue human chorionic gonadotropin (hCG) would induce growth of estrogenic follicles and, by mimicking the signal for MRP and stimulating progesterone secretion, increase primiparous sow fertility. In Experiment 1, during a 28 d lactation 53 mixed parity sows were full-fed either throughout lactation (n=16) or until 18 d and then feed restricted during the last 10 d of lactation (n=36). At 12 d after mating restrict-fed sows were injected with 1000IU hCG (n=17) or were not injected (n=19); the full-fed sows acted as non-treated positive controls. Transrectal ovarian ultrasound exams were performed on days 12, 16, 20, 24, and 28; blood samples were obtained on days 12, 14, and 15 for estradiol and progesterone assay. For Experiment 2, during the summer months primiparous sows received 1000IU hCG 12 d after mating (n=28) or were non-injected controls (n=27). Pregnancy status was determined at 28 d and sows allowed to go to term to determine farrowing rates and litter sizes. In Experiment 1, injection of hCG increased (P<0.001) follicle diameter and serum concentrations of estradiol (P<0.01) and progesterone (P<0.05). There were no effects of lactation feeding level on wean-estrus interval, farrowing rate or subsequent litter size. In Experiment 2, hCG injection was associated with a higher pregnancy rate (P<0.05) and farrowing rate (P<0.08). There was no effect on litter size. These data confirm that hCG stimulates growth of estrogenic follicles and CL function, and improves primiparous sow fertility during the summer months.

Embryonic survival at day 9, 21 and 35 of pregnancy in intact and unilaterally oviduct ligated multiparous sows.

To investigate the effect of uterine space on timing of embryonic mortality, multiparous sows were left intact (CTR; n=42) or subjected to unilateral oviduct ligation (LIG; n=23), after their first post wean oestrus. Intact sows were killed at day 9 (n=10), day 21 (n=15), or day 35 (n=17), and LIG sows were killed at day 21 (n=11) or day 35 (n=12) of gestation. At day 9, 92% of ovulations were represented by an embryo. At day 21, embryonic mortality was 24% and was not altered by increasing uterine space. At day 35, space per embryo was twice as large in LIG sows (30±3 v. 16±0.8 cm), and implantation length tended to be larger (19.0±1.2 v. 15.5±1.3 cm). Between day 21 and day 35, CTR sows lost another 8% to 14% of their embryos, whereas LIG sows lost none. Embryos tended to be heavier (4.9±0.2 v. 4.3±0.3 g) in LIG sows. In conclusion, embryonic loss in multiparous sows is 24% by day 21 and is not related to space, whereas after day 21 limited space causes additional 8% to 14% embryonic mortality in intact sows only.

The Course of Parturition Affects Piglet Condition at Birth and Survival and Growth through the Nursery Phase

Simple Summary In this study, data were collected on the condition in which piglets were born, and this was related to their position in the birth order, and to the progress of parturition. The objective of the study was to find out if these observations were related to performance in early life, up to 10 weeks. It appeared that the later the piglets were born in a litter, the higher the risk of being stillborn, and this was aggravated in sows that took a relatively long time to give birth to their litter. In the first few piglets in a litter, risk of stillbirth was only 2%, whereas this increased to 17% in piglets born 13th in the litter or later. Similarly, birth order affected the condition of the liveborn piglets, with blood values such as pH being evident of suboptimal oxygenation in piglets born later. These blood values were predictive of neonatal behaviour such as colostrum intake, but also for neonatal survival and growth during suckling and even to 10 weeks of life. These data are the first in piglets to emphasise the impact of condition at birth on survival and growth until the end of the nursery phase. Abstract The aim of this study was to relate the course of parturition to the condition of piglets at birth, based on umbilical cord blood acid-base values, and relate the condition at birth to neonatal survival and performance up to 10 weeks of life. Data were collected from 37 spontaneous unassisted parturitions, and neonatal performance was based on observations of 516 piglets. Stillbirth rate increased from 2% in the first piglets, to 17% in piglets born 13th in the litter or later. This was aggravated in sows with longer than average stage II of parturition. Umbilical cord blood values also reflected the effect of birth order, with pH decreasing and lactate increasing in the course of parturition. Interestingly, sows that had a long expulsion stage of parturition also took longer to give birth to the first four piglets (r = 0.74), suggesting that sows with complicated parturition were already experiencing problems at the start of expulsion of piglets. Piglets with signs of asphyxia, based on umbilical blood lactate higher than 4.46 mmol/L, were slower to start suckling, had a higher risk of neonatal mortality, and had a slower growth rate over the first 10 weeks of life.

Temporary undernutrition during early gestation, corpora lutea morphometrics, ovarian progesterone secretion and embryo survival in gilts

The present study reports effects of severe undernutrition on luteal function and pregnancy in pigs. Gilts were inseminated and either fasted on Day 10 and 11 after conception (n=11) or fully fed throughout (n=10). Fasting did not affect LH or progesterone pulsatile secretion pattern on Day 11 in samples taken from blood vessels draining an ovary. Ultrasonographic measurements of the size of the corpora lutea did not show any effect of fasting either. However, fasted gilts had 10 to 30% lower systemic progesterone from Day 12 through Day 15 after conception (P<0.05). All gilts farrowed, but fasted gilts had fewer born piglets than fully fed gilts (8.8±0.8 vs 10.9±0.5 respectively; P<0.05). In conclusion, fasting during embryo elongation can compromise embryonic survival by affecting ovarian function in the days after fasting, without having an immediate effect on LH secretion and progesterone output by the ovaries.