Post-weaning Reproductive Performance Research Articles

Characterization of plasma metabolites at late gestation and lactation in early parity sows on production and post-weaning reproductive performance1

Lactation is a very energy demanding period for sows. The current study provides a better understanding of the biochemical response of first- (n = 246) or second-parity (n = 127) sows during late gestation through lactation and assesses relationships with piglet production and dam reproductive performance. Plasma samples were collected from first- or second-parity dams at late gestation (110 d gestation [d110G]), d 1 post-farrowing (d1PF), and weaning (WN) then analyzed for various stress and protein metabolism compounds, including; creatine, creatine phosphokinase (CPK) activity, creatinine, urea nitrogen, albumin, and lactate. Litter performance was measured as number of piglets nursed and piglet ADG. Post-weaning reproductive performance was assessed by measuring weaning-to-estrus interval (WEI) and subsequent ovulation rate collected at time of harvest. Plasma creatine and CPK activity increased (P < 0.05) between d110G and d1PF. Plasma creatinine decreased (P < 0.05) from d110G through WN in first-parity dams, but remained similar between d110G and d1PF before declining (P < 0.05) at WN in second-parity dams. Plasma urea nitrogen increased (P < 0.05) over the course of the study and was negatively (P < 0.05) associated with piglet ADG at d110G and d1PF and with ovulation rate at d110G (P < 0.05). Similarly, plasma albumin increased (P < 0.05) in first-parity dams over the course of the study, whereas it plateaued (P < 0.05) at d1PF and remained similar (P > 0.10) through WN in second-parity dams. First-parity dams had less (P < 0.05) plasma lactate at d110G than at d1PF or WN. However, second-parity dams had increased (P < 0.05) plasma lactate at d110G and d1PF, then decreased (P < 0.05) levels at WN. Plasma lactate at WN was positively (P < 0.05) associated with WEI in first-parity dams, but negatively (P < 0.05) related to WEI at d1PF in second-parity dams. Plasma lactate levels at all time points were positively (P < 0.05) associated with ovulation rate in second-parity dams. The biochemical profile of these dams differed by parity and merits further investigations into these differences to identify methods to improve physiological response to lactation for improved animal welfare, production, and reproductive performance.

063 Effects of betaine and heat stress on lactation and post-weaning reproductive performance on sows

063 Effects of betaine and heat stress on lactation and post-weaning reproductive performance on sows

Elevating glucose and insulin secretion by carbohydrate formulation diets in late lactation to improve post-weaning fertility in primiparous sows.

Primiparous (P1) sows commonly lose excessive body reserves to meet energy requirements for maintenance and milk production during lactation, and consequently, post-weaning reproductive performance may be compromised. The present studies determined whether ad libitum feeding a glucogenic carbohydrate diet (CHO) during late lactation could stimulate insulin and glucose secretion (experiment 1) and improve subsequent litter size (experiment 2). For experiment 1, 15 P1 sows, and for experiment 2, 99 P1 sows (198.5±2.7kg) were allocated randomly according to suckled litter size (≥10 piglets), either to a CHO diet (14.3 MJ DE/kg, 19.8% crude protein) or a standard lactation diet (control; 14.2 DE MJ/kg, 19.5% crude protein) at 8days before weaning. The CHO diet aimed to provide glucogenic content (extruded wheat, dextrose and sugar) as energy sources instead of fat sources without changing total dietary energy. Pre-prandial plasma glucose and insulin concentrations were not influenced by treatments. However, post-prandial plasma glucose and insulin concentrations and their peaks were both higher (p<.05) compared to the control treatment. Body weight loss during lactation was relatively low at 3%-4% for both treatments and did not differ between control and CHO treatments (-7.6 ± 1.6 vs -5.4 ± 1.2kg; p>.05). Second litter size was not influenced by diet (p>.05), but the weaning-to-mating interval was shorter in CHO sows (p<.05). This study demonstrates that providing an enriched CHO diet in late lactation did influence post-weaning follicle growth but did not improve subsequent litter size. This may be due to the primiparous sows in this study not experiencing severe negative energy balance and there was no second litter syndrome in this farm which limited the ability of diet to improve sow fertility.

Measurements of body composition during late gestation and lactation in first and second parity sows and its relationship to piglet production and post-weaning reproductive performance

The objective of this study was to characterize multiple body condition traits in a white crossbred composite population of first- and second-parity sows and, determine if these traits relate to litter production and reproductive parameters. Differences between parity or time were determined using a mixed model and reported as LSM±SE. As expected, parity 2 dams were heavier (P<0.0001; 202.5±1.57kg versus 174.1±1.35kg) than parity 1 dams. Of interest however, parity 2 dams lost more (P=0.0340) loin eye area from late gestation to weaning (−4.1±0.78cm2 versus −2.5±0.60cm2) but had a greater (P=0.0026) recovery in loin eye area from weaning to post-weaning (2.8±0.76cm2 versus 0.6±0.59cm2) versus primiparous females. However the period between weaning measurements and post-weaning measurements tended (P=0.0978) to favor parity 1 dams (16.0±0.35d) versus parity 2 dams (15.4±0.43d). Parity 2 dams also had a greater (P≤0.05) ovulation rate following weaning than parity 1 dams. Regression analyses indicated body weight of dams at several time points had a positive (P≤0.05) relationship to ovulation rate (range 0.03±0.012 to 0.05±0.013corpora luteakg−1). Piglet ADG was positively (P≤0.05) associated with dam body weight (range 0.30±0.103gkg−1 to 0.49±0.106gkg−1) and dam backfat thickness (range 0.93±0.363gmm−1 to 1.14±0.378gmm−1) regardless of parity. Regression analyses indicated interactions (P≤0.05) between parity and backfat thickness at weaning (−0.11±0.023pigletsmm−1) and post-weaning backfat thickness (−0.12±0.025pigletsmm−1) were negatively associated with number of nursed piglets weaned among parity 1 dams. Furthermore, loin eye area at weaning (−0.06±0.024pigletscm2 −1) and loss of loin eye area from late gestation to weaning (−0.05±0.020pigletscm2 −1) were negatively (P≤0.05) associated with number of nursed piglets weaned but were not influenced by parity in regression analyses. In conclusion, these data provide knowledge on differences in body composition before and after the lactation period in young dams under similar conditions. Of interest, second parity dams appear to have greater lean tissue elasticity versus primiparous females. Future studies will further refine the relationship among body composition in primiparous females and subsequent impact on sow longevity.

Lactational Performance for Improving Postweaning Reproductive Performance and Lifetime Performance on Swine Commercial Farms

We studied the associations of the weaning litter weight (WLWt) and number of pigs weaned (PW) with measurements of postweaning reproductive performance and examined the repeatability of WLWt, PW and average pig weight at weaning (PIGWt) on commercial swine farms. This study spanned 6 years and was conducted using 57,611 weaning records from 11,574 sows born in 1999 on 92 farms. Variance components analysis was used to determine the repeatability of measurements of lactational performance. Mixed-effects models were used to analyze the associations of measurements of lactational performance with farrowing rate and weaning-to-first-mating interval. The values for repeatability of WLWt, PIGWt and PW were 0.31, 0.34 and 0.17, respectively. No differences in weaning-to-first-mating intervals were found among the five PW groups (< or = 6, 7 to 8, 9 to 10, 11 and 12 to 14 pigs) or among the three WLWt groups (< or = 48.0, 48.0 to 69.0 and > or = 69.0 kg). Sows with 12 to 14 PW had farrowing rates similar to those with 9 to 11 PW. Sows with a WLWt > or = 69.0 kg had the highest farrowing rate (P<0.01). However, sows with 11 PW had an approximately 100 to 200 g lighter PIGWt than those with 4 to 10 PW (P<0.01). This study suggests that increased WLWt and PW do not impair postweaning reproductive performance, but instead decrease PIGWt.

A Field Study of the Associations between Behaviors and Reproductive Performance in Lactating Sows

The present study examined factors associated with suckling, eating and postural behaviors (standing, lying and sitting) and the relationships between sow behaviors and reproductive performance. A commercial farrowing-to-finish farm with approximately 300 female pigs was visited eight times for 3 years to record sow behaviors using time-lapse video recorders for 24 hr. The lactational and postweaning reproductive performances of each sow were recorded using a recording software system. Statistical models were built to investigate the factors associated with each behavior. Regression analyses were performed to determine the associations between behavior measurements and adjusted 21-day litter weights (A21d-Wt), weaning-to-first-mating intervals (WMI) and occurrence of >or= 2 dead piglets during lactation. The means of suckling intervals and frequency of postural changes of the 145 recorded sows were 47.5 +/- 0.59 min and 86.8 +/- 2.97, respectively. As parity increased from 1 to >or= 4, the suckling interval and total standing duration increased (P<0.05). The number of nursing piglets and observation days 4 to 21 of lactation were not associated with the suckling intervals. A longer duration of lactation was associated with a longer total standing duration and a higher frequency of postural changes (P<0.05). Shorter suckling intervals were associated with heavier A21d-Wt (P<0.05). Each change in postural behavior increased the likelihood of occurrence of >or= 2 dead piglets during lactation (P<0.05). No postural or suckling behaviors were associated with WMI. Eating behavior was not associated with any reproductive performance. In conclusion, sow behaviors during lactation were related to lactational performance but were not related to postweaning reproductive performance.

Effect of Season, Parity and Lactation on Reproductive Performance of Sows in a Tropical Humid Climate

The aim of this study was to analyze post-weaning reproductive performance of Large White sows in relation to season, parity and their lactation performance under tropical conditions in Guadeloupe (French West Indies, 16° Lat. N, 61° Long. W.). This work was based on data recorded in the experimental unit of INRA from January 1993 to December 2003. Two seasons were determined a posteriori from climatic parameters recorded continuously in a station close to the experimental unit. Mean ambient temperature was higher during the hot season than the warm season (26°C vs. 24°C) but relative humidity was comparable for both seasons (i.e. 87% on average). Season had a significant effect on all reproductive parameters analyzed. Primiparous sows weaned in the hot season had a higher probability of a prolonged weaning to estrus interval, WEI (odds ratio was 4.1; p 2.5, p<0.01) and a lower subsequent farrowing rate (-10%, p<0.01) were found for sows weaned in the hot season. A higher daily feed intake during lactation reduced the probability of a prolonged WEI (p<0.05). Body weight and average back-fat thickness at farrowing affected WEI and WCI (p<0.05), whereas body weight and average backfat thickness change in lactation did not. This study confirms the negative effects of the hot season on primiparous reproductive performance. It also indicates that lactation performance influences sow non-productive period.

Reproductive endocrinology and postweaning performance in the multiparous sow: Part 1. Influence of metabolic status during lactation

The metabolic status of the sow during lactation might influence reproductive endocrinology and the postweaning reproductive performance. With regard to the multiparous sow, previous studies addressing this topic are scarce and the results inconsistent. Blood samples were collected from 18 multiparous sows during lactation and after weaning for analysis of nonesterified fatty acids (NEFA), triglycerides, creatinine, urea progesterone, LH, and estradiol-17β. Based on the average preweaning NEFA levels the sows were divided into a “high” and a “low” catabolism group. The NEFA values were higher in the “high” group during each of the last 3 weeks of lactation. The levels of urea, creatinine and progesterone were similar (P>0.05) in the two groups throughout the study. Reproductive functions seemed equally inhibited during lactation in the two groups and there were no differences in postweaning reproductive performance. The results suggest that metabolic rate during lactation varies considerably between equally nourished multiparous sows but this has no influence on postweaning reproductive performance.

Effects of passive immunization using antibody against an α-inhibin peptide on follicle-stimulating hormone concentrations and litter size in sows

The objective of the experiment was to determine whether passive immunization against inhibin at weaning would increase FSH secretion and thereby influence postweaning reproductive performance in sows. Commercial Yorkshire sows (n = 173) were assigned within parity to 5 α-inhibin fragment antibody (α-IF-Ab) dosage groups: 0 (control), 3.25, 6.5, 13 and 26 RP-2 kU/kg α-IF-Ab. Antibody had been semipurified from ovine antisera raised against α-IF, a peptide that mimicked the N-terminal region of inhibin's α-subunit. A RP-2 U refers to a laboratory reference preparation. Sows were administered a single intramuscular injection of control solution or α-IF-Ab just before 21-d-old piglets were weaned. Blood samples were taken immediately before immunization and 24 h later. Sows were bred upon expression of estrus. Serum α-IF-Ab titers in sows 24 h following passive immunization increased (P < 0.001) with dosage. In control sows serum FSH concentrations decreased 24% by 24 h postweaning (P < 0.001). The decrease was diminished or prevented by α-IF-Ab treatment in a dose-responsive manner (P < 0.001). Most (167/173) sows were bred within 10 d postweaning, and wean-to-service intervals tended (P < 0.1 ) to be shorter in the 13 and 26 RP-2 kU/kg α-IF-Ab dosage groups. Farrowing rate was 72% (124/173) and was similar among sows in the α-IF-Ab dosage groups. Litter size, expressed as total or live piglets born per sow or per sow farrowed, was unchanged by α-IF-Ab treatment. Results demonstrate that 1) inhibin plays a key role in regulating FSH secretion at weaning, and 2) blocking the acute postweaning drop in FSH secretion has little if any effect on subsequent reproductive performance.

Factors influencing the postweaning reproductive performance of sows on commercial farms

The objective of this study was to investigate the effects of various factors, including lactational feed intake, on the reproductive performance of sows in commercial herds. The 4 measures of reproductive performance were weaning-to-first-service interval, weaning-to-conception interval, litter weight at weaning, and subsequent litter size. Parity, farrowing season, lactation length, farrowing-to-conception interval, litter size, and lactation feed intake were investigated as risk factors common to the 4 measures of post-weaning reproductive performance. Using 4 basic multiple regression models for each measure, the least-square means for sets of factors were compared using the GLM procedure of SAS. Parity 1 sows had the longest weaning-to-first-service interval and weaning-to-conception interval, and the lighter litter weight at weaning (P < 0.05) than mid-parity sows. Sows in Parities 2 to 5 had larger subsequent litter size (P < 0.05) than those in Parities 1 and ≥ 7. Sows farrowing in summer and spring had the longest and second longest weaning-to-conception interval (P < 0.05), respectively, while sows farrowing in summer had longer weaning-to-first-service interval than those that farrowed in spring (P < 0.05). Sows farrowing in summer produced the lightest litter weight at weaning (P < 0.05). No differences in subsequent litter sizes were found due to farrowing season (P > 0.10). As lactation length increased, weaning-to-first-service interval and weaning-to-conception interval decreased, and litter weaning weight increased. Longer lactation length and farrowing-to-conception interval were associated with larger subsequent litter size (P < 0.05). Litter size did not affect weaning-to-first-service interval or weaning-to-conception interval. Larger litter sizes were associated with heavier litter weight at weaning. Greater lactation feed intake improved the 4 measures of reproductive performance.

The effects of food level during lactation and early gestation on the reproductive performance of mature sows

AbstractSeventy-six Large White × Landrace sows from parities 2 to 6 were allocated to one of four treatments at day 110 of gestation on a parity and live-weight basis. The four treatments involved food levels of either 3 or 6 kg/day during a 28-day lactation followed by either 1·75 or 3·50 kg/day during the first 28 days of gestation. Litter size suckled was standardized at 10 piglets wherever possible. Live weight and backfat changes were monitored in all sows and litter growth and survival rates were recorded. Post weaning all sows were given daily boar contact and mated twice at the first observed oestrus. A single blood sample was collected from each sow at days 7, 14, 21 and 28 of gestation for determination of plasma progesterone concentration. Data on litter size and piglet birth weights were collected at the subsequent parturition. Sows low-fed during lactation lost significantly more live weight (31·2v.5·8 kg,P&amp;lt; 0·01) and P2 backfat (3·6v.1·9 mm,P&amp;lt; 0·05) in lactation than did high-fed sows. Underfeeding the lactating sow also significantly reduced the weaning weight of the litter (62·3v.68·7 kg for low-v.high-fed sows,P&amp;lt; 0·05), but did not significantly change either creep food intake by the litter or pre-weaning mortality rate. Parity 2 sows weaned significantly heavier piglets and litters than did sows from parities 3 to 6 (7·48 and 74·9 kgv.6·72 and 63·8 kg respectively,P&amp;lt; 0·01). Food level in lactation did not significantly influence the length of the rebreeding interval (6·3v.7·3 days for high-v.low-fed sows) and although there was a two-fold difference in the proportion of sows failing to exhibit oestrus post weaning (0·08v.0·16 for high-v.low-fed sows) this difference was also not significant. Lactation food level did not significantly influence either sow live-weight or backfat change in gestation, plasma progesterone concentrations during early gestation or subsequent litter size. However, sows low-fed in lactation did tend to produce fewer piglets in the subsequent litter (9·54v.10·75 piglets born alive for low- and high-fed sows respectively,P= 0·062). Post-weaning reproductive performance was significantly affected by sow live weight (P&amp;lt; 0·05) and backfat (P&amp;lt; 0·01) at parturition, and live weight (P&amp;lt; 0·01) and backfat (P&amp;lt; 0·05) at weaning, but not by changes in these parameters during lactation. Food level in early gestation did not significantly influence either plasma progesterone concentrations, the size of the subsequent litter (10·09v.20·29 piglets born alive for high- and low-fed sows respectively) or mean piglet birth weight (1·27v.2·22 kg for high- and low-fed sows respectively). It is concluded that (1) both lactation food level and parity may alter pre-weaning piglet growth, and (2) the effects of lactation food level on the subsequent reproductive performance of mature sows appear to be different from those seen in parity 1 sows.

Effect of feeding supplemental fat or lysine during the postweaning period on the reproductive performance of sows with low or high lactation body weight and fat losses

The effects of feeding supplemental fat or lysine during the postweaning period on breeding and subsequent reproductive performance were determined in two experiments of a 2 × 3 factorial design, using 168 Landrace × Yorkshire first-parity (exp. 1) and 180 Yorkshire second-parity (exp. 2) sows. At the end of lactation, they were divided into two groups: LWL (&lt; 14 kg) and HWL (&gt; 14 kg) based on 3 wk lactation weight loss. The three experimental diets fed during the postweaning period were: (1) control; a 12% gestation diet fed 2 kg d−1 (24.7 MJ DE, 9.4 g lysine d−1); (2) Fat; control diet plus animal fat to provide approximately 50% more daily energy intake (37.0 MJ DE d−1); and (3) Lysine; control diet plus lysine to provide approximately 50% more daily lysine intake (14.4 g d−1). After breeding, all sows were fed the control diet at 2 kg d−1, and they were killed at 30 d of gestation to evaluate their reproductive performance. High weight loss during the lactation period increased the incidence of anestrus and reduced the pregnancy rate in first-parity sows. Feeding supplemental fat was beneficial in increasing the proportion of sows in estrus within 7 d postweaning and the pregnancy rates of first-parity sows with high lactation weight loss. Supplemental fat also had a beneficial effect on ovulation rate, the number of normal embryos, fetal survival and the fetal weights, whereas supplemental lysine improved only fetal weights. Feeding supplemental fat or lysine improved only ovulation rate in second-parity sows with high lactation weight loss. The results indicated that feeding supplemental fat or lysine can improve the postweaning reproductive performance of sows that had high weight and fat losses during lactation. Key words: Sows, estrus, ovulation, embryo survival, fat, lysine

Metabolic and endocrine changes in the sow during lactation

During lactation sows are often unable to consume sufficient feed to meet their metabolic needs and they must mobilise their body reserves to compensate for the nutrient deficit. It is generally recognised that this loss of body weight and body condition may influence subsequent reproductive performance but it is unclear what endocrine signals link the nutritional and reproductive states of the sow. The present experiments were, therefore, designed in an attempt to understand how changes in the nutritional and metabolic status of the sow during lactation influences post-weaning reproductive performance.

Influence of follicular ablation during lactation on postweaning interval to estrus, ovulation rate, and endocrine function in sows

Duroc sows farrowed second litters in March and lactated 35 ± 2 days. At 36 hr before weaning, electrocautery of follicles ≥3 mm in diameter (n=8) or sham surgery (n=5) was performed to test the hypothesis that ablation of medium-sized follicles would prolong the duration of postweaning anestrus. Number of follicles and diameters at surgery were: 1.3 ± .6 (> 5 mm diameter), 26 ± 1 (3 to 5 mm) and > 20 (< 3 mm). Blood samples were collected at 15 min intervals for 3 hr beginning at −12, 0, 12, 60 and 96 hr from weaning. Interval to estrus was 3.4 ± .2 days in seven of eight cauterized sows and 3.6 ± .6 days for sham-surgery sows. The remaining cauterized sow was anestrus at slaughter, 40 days after weaning. Number of corpora lutea and pregnancy rate were 15.8 ± .6 and 92%, respectively, and were similar between sham-surgery and cauterized sows. Concentration of follicle stimulating hormone (FSH) at 12 hr before weaning was greater in sows subjected to electrocautery than for sham-surgery sows, but FSH values were similar at other sampling times. Concentrations of estradiol were similar at all times for both treatment groups. Luteinizing hormone (LH) was higher (P<.05) at 60 hr in cauterized sows because of the onset of the preovulatory LH surge in one sow. We conclude that destruction of medium-sized ovarian follicles before weaning did not influence postweaning reproductive performance.