Supplying sows energy on the expected day of farrowing improves farrowing kinetics and newborn piglet performance in the first 24 h after birth

The farrowing process is one of the most energy-demanding activities for the modern hyperprolific sow. This study evaluated the effects of supply of energy on the expected date of farrowing on the farrowing kinetics and piglets’ performance during the first 24 h after birth. A total of 80 sows were used. The sows and their respective litters were considered as the experimental unit. On the expected day of farrowing, the sows were allocated to one of the following groups: sows that did not have access to feed from farrowing induction until the end of the farrowing process (CON, n = 40); sows fed 500 g of energetic supplement, which consisted of 250 g of the basal lactation diet plus 250 g of cane sugar, 18 h after farrowing induction (SUP, n = 40). The farrowing duration, farrowing assistance, birth interval, number of total born, stillborn and mummified piglets were recorded for each sow. Piglets were weighed individually at birth and 24 h later. The interval from birth to first suckle was evaluated individually for each piglet in 16 randomly selected litters (eight litters per treatment group). Blood glucose concentrations of six sows were measured shortly after expulsion of the first piglet. Farrowing duration, farrowing assistance and stillborn rate tended to be greater (P = 0.06, P = 0.09 and P = 0.07, respectively) in sows from the CON group compared to sows from the SUP group. However, there was no difference (P > 0.05) between the groups for birth interval. Colostrum intake was greater (P < 0.05) for piglets from the SUP group compared to piglets from the CON group. Additionally, BW gain of the piglets suckling the SUP group was greater (P < 0.05) than those suckling the CON group at 24 h after birth. The blood glucose concentrations during the expulsive stage of farrowing were greater (P < 0.05) in the SUP group than for sows from the CON group. In conclusion, supplying modern hyperprolific sows energy on the expected day of farrowing is a valuable nutritional intervention to improve the farrowing kinetics and piglets’ performance in early life.     

Effects of l-carnitine in the distillers dried grains with solubles diet of sows on reproductive performance and antioxidant status of sows and their offspring

Distillers dried grains with solubles (DDGS) are highly susceptible to lipid oxidation because DDGS contain about 10% crude fat, which is largely composed of polyunsaturated fatty acids. l-carnitine serves an important function in fatty acids β-oxidation, and also has antioxidant properties. The objective of this study was to examine the effects of l-carnitine in the DDGS diet of gestating and lactating sows on reproductive performance, milk composition and antioxidant status of sows and their offspring. One hundred and twenty sows (Landrace×Large white, mean parity 4.2, initial BW 230 kg) were randomly allotted to 1 of 4 dietary treatments (n=30 sows/treatment). Treatments were arranged as a 2×2 factorial with two levels of dietary DDGS (0 v. 250 g/kg in gestating diets and 400 g/kg in lactating diets) and two levels of dietary l-carnitine (0 v. 100 mg/kg in gestating diets and 0 v. 200 mg/kg in lactating diets). Distillers dried grains with solubles had no significant effect on litter size but significantly reduced the birth weights and weaning weights of piglets (P<0.05). Distillers dried grains with solubles reduced the antioxidant enzyme activities (P<0.05) and increased the malondialdehyde level in the plasma of sows on day 60 of gestation (P=0.004) and day 14 of lactation (P=0.008). The compositions of colostrum and milk were not affected by inclusion of DDGS and dietary l-carnitine (P>0.05). Supplementing the diets with l-carnitine had no significant effect of total litter size (P>0.05) but increased the number of piglets born alive and piglets weaned, birth weight and weaning weight of piglets and litter weight at birth and weaning (P<0.05). l-carnitine supplementation also increased the concentration of l-carnitine in milk and l-carnitine status of piglets (P<0.05). The antioxidant enzyme activities of new born and weaning piglets were increased (P<0.05) by maternal dietary l-carnitine but this did not extend to finishing pigs. In conclusion, including DDGS in the sows diet could induce oxidative stress, which may be associated with the reduced individual birth and weaning weight of piglets. Dietary l-carnitine supplementation improved the antioxidant and l-carnitine status of sows, which may be associated with the improved reproduction and piglet performance and the antioxidant status of piglets at birth and weaning. There were no interactions between DDGS and l-carnitine.     

The behaviour and welfare of sows and piglets in farrowing crates or lactation pens

Temporary confinement during parturition and early postpartum may provide an intermediary step preceding loose housing that offers improvement in sow and piglet welfare. Three experiments were conducted to investigate the implications of replacing farrowing crates (FCs) with an alternative housing system from 3 days postpartum until weaning. In each experiment sows farrowed in FCs and were randomly allocated at day 3 of lactation to either a FC or a pen with increased floor space (lactation pen (LP)) until weaning. In experiment 1, piglet growth and sow and piglet skin injuries were recorded for 32 sows and 128 focal piglets in these litters. Behaviour around nursing and piglet behavioural time budgets were also recorded for 24 of these litters (96 focal piglets for time budgets). In experiment 2, measures of skin injury and behavioural time budgets were conducted on 28 sows and 112 focal piglets. The behavioural response of sows to piglet vocalisation (maternal responsiveness test (MRT)) was also assessed. In experiment 3, piglet mortality from day 3 of lactation until weaning was recorded in 672 litters over 12 months. While housing did not affect piglet weight gain in experiment 1, or piglet skin injuries in experiments 1 or 2, sows in both experiments sustained more injuries in LP than FC (experiment 1, 2.9 v. 1.4; experiment 2, 2.5 v. 0.8 lesions/sow; P<0.05). Sow–piglet interactions were more frequent in LP than FC at days 11 and 18 postpartum in both experiment 1 (day 11, 1.4% v. 1.2%; day 18, 1.7% v. 1.0% of observations; P=0.05) and 2 (day 11, 1.0% v. 0.3%; and at day 18 were 1.0% v. 0.6% of observations; P<0.01), and LP sows were more responsive in the MRT in experiment 2 (2 v. 0 median number of tests in which sows react, P<0.01). In experiment 1 piglets played more (0.7% v. 0.3% of observations, P=0.05) and manipulated others less (0.3% v. 0.7% of observations, P=0.04) in LP, but more piglets missed nursing bouts (0.2 v. 0.1 piglets/bout, P<0.01) compared with FC. There was no effect of housing on piglet mortality from day 3 of lactation until weaning in experiment 3 (0.63 and 0.64 deaths/litter for LP and FC, respectively, P>0.05). Thus, housing sows and litters in LP from day 3 of lactation minimises piglet mortality while improving maternal behaviour in sows and social behaviour in piglets.     

Responses to n-3 fatty acid (LCPUFA) supplementation of gestating gilts,and lactating and weaned sows

Feeding n-3 long-chain polyunsaturated fatty acids (LCPUFA) to gilts or sows has shown different responses to litter growth, pre-weaning mortality and subsequent reproductive performance of the sow. Two hypotheses were tested: (1) that feeding a marine oil-based supplement rich in protected n-3 LCPUFAs to gilts in established gestation would improve the growth performance of their litters; and (2) that continued feeding of the supplement during lactation and after weaning would offset the negative effects of lactational catabolism induced, using an established experimental model involving feed restriction of lactating primiparous sows. A total of 117 primiparous sows were pair-matched at day 60 of gestation by weight, and when possible, litter of origin, and were allocated to be either control sows (CON) fed standard gestation and lactation diets, or treated sows (LCPUFA) fed the standard diets supplemented with 84 g/day of a n-3 LCPUFA rich supplement, from day 60 of first gestation, through a 21-day lactation, and until euthanasia at day 30 of their second gestation. All sows were feed restricted during the last 7 days of lactation to induce catabolism, providing a background challenge against which to determine beneficial effects of n-3 LCPUFA supplementation on subsequent reproduction. In the absence of an effect on litter size or birth weight, n-3 LCPUFA tended to improve piglet BW gain from birth until 34 days after weaning (P = 0.06), while increasing pre-weaning mortality (P = 0.05). It did not affect energy utilization by the sow during lactation, thus not improving the catabolic state of the sows. Supplementation from weaning until day 30 of second gestation did not have an effect on embryonic weight, ovulation rate or early embryonic survival, but did increase corpora lutea (CL) weight (P = 0.001). Eicosapentaenoic acid and docosahexaenoic acid (DHA) levels were increased in sow serum and CL (P < 0.001), whereas only DHA levels increased in embryos (P < 0.01). In conclusion, feeding n-3 LCPUFA to gilts tended to improve litter growth, but did not have an effect on overall subsequent reproductive performance.     

Impact of feed restriction on the performance of highly prolific lactating sows and its effect on the subsequent lactation

A total of 50 mixed parity sows of a high-prolificacy genetic line were used to evaluate the impact of feed restriction during lactation on their production and reproductive performance and their performance in the subsequent lactation. From day 7 of lactation, sows were distributed according to a completely randomized experimental design into two treatments. In treatment 1, sows were fed 8.0 kg feed/day (control) and in treatment 2, sows were fed 4.0 kg/day. The same suckling pressure was maintained until weaning on day 28 of lactation. Average minimum and maximum temperatures measured during the experimental period were 32.1°C and 16.5°C, respectively. Control sows presented significantly higher feed intake (P<0.001) compared with the restricted sows (6.43 v. 4.14 kg/day, respectively). Treatments influenced BW and backfat thickness losses (P<0.001). Control sows lost less BW than the restricted-fed sows (7.8 v. 28.2 kg). Restricted-fed sows lost more backfat thickness than those in the control group (3.97 v. 2.07 mm; P<0.01). Restricted-fed sows tended (P<0.10) to be lighter at weaning compared with the control sows (211 v. 227 kg). The composition of BW loss was influenced by the treatments (P<0.001), as the restricted-fed sows lost more body protein, lipids and energy compared with the control sows (3.90 v. 0.98 kg, 11.78 v. 4.83 kg and 584 v. 224 MJ, respectively). Litter weight gain was greater (P<0.05) in control sows than in restricted-fed sows (2.70 v. 2.43 kg/day). Daily milk production was 19% higher (P<0.01) in the control sows compared with the restricted-fed sows (8.33 v. 6.99 kg/day). However, restricted-fed sows presented a higher (P<0.05) lactation efficiency than the sows of the control group (82.30% v. 72.93%). No differences were detected (P>0.10) in weaning-to-estrus interval and averaged 4.3 days. No effect of the treatment (P>0.10) was observed on any of the studied performance traits in the subsequent lactation, except for litter size at birth that tended (15.2 v. 14.1; P<0.10) to be lower for the restricted sows. In conclusion, the present study demonstrated that feed restriction during lactation leads to intense catabolism of the body tissues of sows, negatively affecting their milk production, and the litter weight gain and possibly number of piglets born in the next litter. On the other hand, restricted-fed sows are more efficient, producing more milk per amount of feed intake.     

Effects of dose and route of administration of genistein on isoflavone concentrations in post-weaned and gestating sows

Phytoestrogens could be a useful tool in swine husbandry practices because of their structural and functional similarities to estradiol. The goal of this study was to compare various routes and doses of administration of the phytoestrogen genistein in sows of two different physiological statuses. Circulating concentrations of isoflavones, estradiol and IGF-I were determined. In experiment 1, 65 sows were equally divided into the five following groups, between days 3 and 5 of the first or second estrous cycle post weaning: (1) controls (CTL); (2) 1 g of genistein fed daily (OR1); (3) 2 g of genistein fed daily (OR2); (4) two daily i.m. injections of 200 mg of genistein (IM400); and (5) two daily i.m. injections of 400 mg of genistein (IM800). Treatments were carried out for 10 days. In experiment 2, 10 sows were equally divided into two groups on day 90 of gestation, namely, controls (CTL) or 2 g of genistein fed daily for 10 days (OR2). In both trials, jugular blood samples were collected on days 1 (before treatment), 5 and 10 at 0730 h. In experiment 1, a blood sample was also collected at 1730 h on day 10 for CTL, IM400 and IM800 sows. In experiment 1, circulating concentrations of genistein on days 5 and 10 were greater in OR2, IM400 and IM800 than in CTL and OR1 group sows (P < 0.01). Daily dietary supplementation with 2 g of genistein resulted in blood concentrations that were similar to those in animals given daily two i.m. injections of 200 mg. Values of all isoflavones, except equol, which was not detectable, were greater in PM than in AM on day 10 (P < 0.01). In experiment 2, genistein concentrations were greater in OR2 compared with CTL on days 5 and 10 (P ⩽ 0.05). There was no difference in the genistein response to OR2 because of physiological status (i.e. weaned v. gestating, P > 0.1). Estradiol and IGF-I concentrations were not altered by any of the treatments (P > 0.1). Providing genistein either per os or via i.m. injections increased circulating concentrations of genistein in female swine within 5 days of the onset of treatment. The genistein response to i.m. injections of genistein was similar in weaned and late-pregnant sows, even though endogenous concentrations of estradiol differed. This response was specific in that estradiol, IGF-I and isoflavones other than genistein were not affected by treatments.     

Confinement of lactating sows in crates for 4 days after farrowing reduces piglet mortality

To reduce mortality among suckling piglets, lactating sows are traditionally housed in farrowing crates. Alternatively, lactating sows can be housed in farrowing pens where the sow is loose to ensure more behavioural freedom and consequently a better welfare for the sow, although under commercial conditions, farrowing pens have been associated with increased piglet mortality. Most suckling piglets that die do so within the first week of life, so potentially lactating sows do not have to be restrained during the entire lactation period. Therefore, the aim of the current study was to investigate whether confinement of the sow for a limited number of days after farrowing would affect piglet mortality. A total of 210 sows (Danish Landrace × Danish Yorkshire) were farrowed in specially designed swing-aside combination farrowing pens measuring 2.6 m × 1.8 m (combi-pen), where the sows could be kept loose or in a crate. The sows were either: (a) loose during the entire experimental period, (b) crated from days 0 to 4 postpartum, (c) crated from days 0 to 7 postpartum or (d) crated from introduction to the farrowing pen to day 7 postpartum. The sows and their subsequent litters were studied from introduction to the combi-pen ∼1 week before expected farrowing and until 10 days postpartum. Confinement period of the sow failed to affect the number of stillborn piglets; however, sows that were crated after farrowing had fewer live-born mortality deaths (P < 0.001) compared with the sows that were loose during the experimental period. The increased piglet mortality among the loose sows was because of higher mortality in the first 4 days after farrowing. In conclusion, the current study demonstrated that crating the sow for 4 days postpartum was sufficient to reduce piglet mortality.     

Monitoring blood plasma leptin and lactogenic hormones in pregnant sows

The mechanism of action of leptin in pregnant breeding sows, in which hyperphagia is managed through dietary strategies, is yet to be clarified. The aim of this study was to monitor leptin concentrations and their interactions with lactogenic hormones in Large White×Landrace breeding multiparous sows (n=15). All sows showed a normal body condition (mean body condition score: 2.96). Blood samples were collected the day after weaning the litters, at insemination, every 15 days up to day 45 of pregnancy and every 7 days from day 46 to farrowing. At delivery, the placenta was collected for the analysis of leptin and leptin receptor expressions. Plasma leptin levels increased from the end of mid gestation (day 72) and remained high until farrowing (P<0.05). As expected, plasma prolactin (PRL), low during most of pregnancy, increased during the 2 weeks before farrowing (P<0.05), whereas progesterone levels reached plateau at 30 days of gestation and decreased at farrowing (P<0.05). Cortisol levels peaked close to farrowing (P<0.05). Leptin was expressed in the placenta, where the receptor expression analysis showed the presence of the short form but not of the long form. A positive correlation was found between leptin and PRL concentrations during mid (r=0.430; P<0.001) and late (r=0.687; P<0.001) pregnancy, and with progesterone in early pregnancy (r=0.462; P<0.05). During late gestation, a positive correlation was observed between leptin and cortisol (r=0.585; P<0.001). Our results suggested that, in restrictively fed pregnant sows, the leptin levels increased from the end of mid pregnancy to delivery, confirming the presence of leptin resistance. We showed a correlation between leptin and lactogenic hormones during different stages of pregnancy in sows. Lactogenic hormones show pregnancy-specific changes in their secretion and all may become involved in modulating leptin signal.     

Eicosapentaenoic acid- and docosahexaenoic acid-rich fish oil in sow and piglet diets modifies blood oxylipins and immune indicators in both,sows and suckling piglets

Over the last decades, genetic selection has increased sows’ litter size. Consequently, there is a high proportion of piglets born with low weight which are vulnerable. Their viability may potentially be enhanced through early nutrition. The aim of the current study was to evaluate whether including a fish oil rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in the diets of the sow and piglets was able to increase concentrations of anti-inflammatory molecules in their blood. Thirty-six sows, in four consecutive batches, were randomly assigned to either a control diet with animal fat (15 g/kg in gestation and 30 g/kg in lactation) or an n-3 long-chain fatty acid (n-3 LCFA) diet from insemination until the end of lactation. From day 11 of lactation, piglets were also offered a diet containing 30 g/kg of animal fat or n-3 LCFA. To prepare the n-3 LCFA diet, 15 g/kg or 30 g/kg of animal fat in the control diet were replaced by an equivalent amount of solid fish oil for sows and piglets, respectively. All the sows were sampled for serum and plasma at day 108 of gestation and at weaning. Additionally, only for the first batch of sows, blood samples were also obtained at weaning from the two lightest (>800 g) and the two heaviest birth weight piglets in each litter. Serum fatty acids (FAs) were quantified by gas chromatography, plasma oxylipins by ultra-HPLC-MS and plasma immunoglobulins (Ig) and cytokines by ELISA. The n-3 LCFA diet increased the concentrations of n-3 FAs in gestating and lactating sows and in piglets (P < 0.001, P < 0.001 and P = 0.011, respectively), particularly EPA (P < 0.001, P < 0.001 and P < 0.001, respectively) and DHA (P < 0.001, P < 0.001 and P < 0.001, respectively), and also their oxygenated derivatives. In addition, fish oil increased plasma IgM in gestating and lactating sows (P = 0.014 and P = 0.008, respectively), interleukin (IL) 6 in sows at weaning (P = 0.012), and IL1β in piglets (P = 0.018). Birth BW of piglets, regardless of diet, slightly influenced some of the n-6-derived oxylipins. In conclusion, fish oil addition in diets increased the blood concentrations of n-3 FAs and their oxygenated derivatives, some of which have anti-inflammatory activity, in gestating and lactating sows and piglets, IgM in gestating and lactating sows, IL6 in lactating sows and IL1β in piglets.     

Treatment of lactating sows with the dopamine agonist Cabergoline: effects on LH and prolactin secretion and responses to challenges with naloxone and morphine

This study was conducted to examine the effects of chronic administration of a long-acting dopamine agonist, Cabergoline, on LH and prolactin secretion during lactation in the sow. The effect of the administration of the opioid antagonist naloxone and the agonist morphine in Cabergoline treated animals was also evaluated. In Part I of the experiment, 16 sows were treated as either CONT sows (n=4; control, no treatment); CAB sows (n=4; treated with Cabergoline from days 10 to 26 of lactation); CAB+NAL sows (n=4; received Cabergoline treatment and naloxone challenges); CAB+MORP sows (n=4; treated with Cabergoline and morphine challenges). Plasma LH and prolactin concentrations were measured in blood samples taken from all sows during 6-h periods at days 12, 19 and 26 of lactation. To extend the results at the most critical response period at day 26, another 11 sows were allocated in Part II to either Control (n=3), Cabergoline (n=4) or Cabergoline and morphine (n=4) treatments as for Part I, but the effect of treatments were only confirmed in a single period of sampling at day 26 of lactation. Cabergoline treatment alone increased (P<0.001) mean plasma LH concentrations at day 26 but not at days 12 and 16 of lactation. In contrast, naloxone challenges given in the presence of Cabergoline treatment increased (P<0.05) mean LH at days 12 and 19 of lactation but not at day 26. Morphine challenges in the presence of Cabergoline treatment decreased (P<0.05) mean LH concentrations only at day 26 of lactation, but did not completely reverse the effect of Cabergoline. No treatment differences in plasma oestradiol-17β were detected at any time. Plasma prolactin decreased (P<0.001) in response to treatment with Cabergoline but there were no additional effects of naloxone or morphine. These data provide evidence for the existence of dopaminergic and opioidergic regulation of LH secretion in lactation in the sow and the relative influence of these systems changes as lactation progresses. Furthermore, the data suggest that the stimulatory effect of Cabergoline treatment on LH secretion in late lactation may be mediated by its effects on an inhibitory opioidergic mechanism. Finally, the data provide conclusive proof that prolactin does not directly influence LH secretion or estrogenic activity of the ovary during lactation in the sow.     

Effects of different amounts and type of diet during weaning-to-estrus interval on reproductive performance of primiparous and multiparous sows

During weaning-to-estrus interval (WEI), the sows are usually fed with high feed level to improve the reproductive performance. However, the WEI has been reduced over the years which may reduce the impact of feed level on performance in the modern genetic lines. The aim of this study was to evaluate the effect of two feeding levels (moderate feeding level (MFL): 2.7 kg/day and high feeding level (HFL): 4.3 kg/day) and two diet types (gestation: 13.67 MJ/kg of metabolizable energy (ME) and 0.62% of standard ileal digestible lysine (SID Lys) and lactation: 14.34 MJ ME/kg and 1.20% of SID Lys) offered during the WEI on reproductive performance. In total, 19.0% of sows were excluded from the analysis due to feed intake below 75% (9.6% and 28.5% in MFL and HFL groups, respectively), remaining 254 primiparous and 806 multiparous sows. Follicular size and change in BW were measured in subsamples of 180 and 227 females, respectively. Data were analyzed considering the sow as the experimental unit. Feeding level, diet type, parity and their interactions were included as fixed effects, whereas the day of weaning was considered as a random effect. The feed intake of MFL and HFL groups averaged 2.5 ± 0.02 and 3.8 ± 0.02 kg/day, respectively. There was an interaction between feeding level and parity for daily feed intake. Within HFL, multiparous sows consumed 181 g/day more than primiparous sows (P < 0.01), but no difference was observed within MFL (P > 0.05). Both primiparous and multiparous sows lost proportionally less weight when fed HFL than MFL gestation diet during WEI. The percentage of weight loss was lower in HFL than in the MFL group in multiparous sows fed the lactation diet. The WEI was not affected by feeding level, diet type or its interaction (P > 0.05), but it was longer in primiparous than in multiparous sows (P = 0.001). There was no effect of feeding level, diet type, parity or their interactions on anestrus and farrowing rates. Multiparous sows showed greater follicular size, and greater numbers of total born and born alive piglets in the subsequent cycle than primiparous sows (P < 0.05). In conclusion, feeding weaned primiparous and multiparous sows with 4.3 kg/day of a gestation (58.78 MJ ME and 26.66 g SID Lys) or a lactation diet (61.66 MJ ME and 51.60 g SID Lys) does not improve follicular size and reproductive performance in the subsequent cycle.     

Effects of dietary enrichment with a marine oil-based n-3 LCPUFA supplement in sows with predicted birth weight phenotypes on birth litter quality and growth performance to weaning

The effects of a marine oil-based n-3 long-chain polyunsaturated fatty acid (mLCPUFA) supplement fed to the sow from weaning, through the rebreeding period, during gestation and until end of lactation on litter characteristics from birth until weaning were studied in sows with known litter birth weight phenotypes. It was hypothesized that low birth weight (LBW) litters would benefit more from mLCPUFA supplementation than high birth weight litters. A total of 163 sows (mean parity=4.9±0.9) were rebred after weaning. Sows were pair-matched by parity and litter average birth weight of the previous three litters. Within pairs, sows were allocated to be fed either standard corn/soyabean meal-based gestation and lactation diets (CON), or the same diets enriched with 0.5% of the mLCPUFA supplement at the expense of corn. Each litter between 9 and 16 total pigs born was classified as LBW or medium/high average birth weight (MHBW) litter and there was a significant correlation (P<0.001) between litter average birth weight of the current and previous litters within sows (r=0.49). Sow serum was harvested at day 113 of gestation for determination of immunoglobulin G (IgG) concentrations. The number of pigs born total and alive were lower (P=0.01) in mLCPUFA than CON sows, whereas the number of stillborn and mummified pigs were similar between treatments. Number of stillborns (trend) and mummies (P<0.01) were higher in LBW than MHBW litters. Tissue weights and brain : tissue weight ratios were similar between treatments, but LBW litters had decreased tissue weights and increased brain : tissue weight ratios compared with MHBW litters. Placental weight was lower (P=0.01) in LBW than MHBW litters, but was not different between treatments. Average and total litter weight at day 1 was similar between treatments. mLCPUFA increased weaning weight (P=0.08) and average daily gain (P<0.05) in MHBW litters, but not in LBW litters. Pre-weaning mortality was similar between treatments, but was higher (P<0.01) in LBW than MHBW litters. IgG concentration in sow serum was similar between treatments and litter birth weight categories. In conclusion, litter birth weight phenotype was repeatable within sows and LBW litters showed the benchmarks of intra-uterine growth retardation (lower placental weight and brain sparing effects). As maternal mLCPUFA supplementation decreased litter size overall, only improved litter growth rate until weaning in MHBW litters, and did not affect pre-weaning mortality, maternal mLCPUFA supplementation was not an effective strategy in our study for mitigating negative effects of a LBW litter phenotype.     

Exogenous genistein in late gestation: effects on fetal development and sow and piglet performance

Due to their functional similarity to estradiol, phytoestrogens could prove to be beneficial in late gestating sows. The goal of this study was to determine the impact of providing the phytoestrogen genistein during late pregnancy on the performance of sows and their litters. In total, 56 gilts were equally divided into the two following groups on day 90 of gestation: (1) controls (CTL); and (2) two daily i.m. injections of 220 mg of genistein (GEN). Treatments were carried out until farrowing. Jugular blood samples were collected from 16 gilts/treatment on days 89 and 110 of gestation, and on days 3 and 21 of lactation. Milk samples were also obtained from those sows on day 3 of lactation. A male piglet from 16 CTL and 15 GEN litters was slaughtered at 24 h postpartum and a blood sample was obtained. The liver, heart and visceral organs were weighed and the semitendinosus (ST) muscle was collected and carcass composition was determined. The treatment increased (P<0.05) the concentrations of genistein and daidzein in the plasma of gilts on day 110 of gestation and of genistein in the plasma of piglets at 24 h postpartum. It also increased IGF1 concentrations in gilts at the end of the treatment period (P<0.05). Genistein had no impact (P>0.1) on weight or backfat loss of sows during lactation, milk composition or weights of piglets. The pre-weaning mortality rate of piglets was very low (<7%), yet the odds ratio comparing CTL with GEN sows indicated almost twice as many chances of pre-weaning deaths occurring in litters from CTL than GEN sows. Weights of the piglet carcasses were similar for both treatments, as well as weights of the various organs and of the ST muscle (P>0.1). However, carcasses from GEN litters contained more fat than those from CTL litters (9.63% v. 8.34%, P<0.05). None of the biochemical properties of the ST muscle differed between groups (P>0.1). In conclusion, injecting gilts with 440 mg/day of genistein in late gestation increased IGF1 concentrations in gilts and carcass fat in neonatal piglets, but had minimal effect on muscle development of piglets at birth and on the performance of lactating sows and their litters.     

Effects of dietary menhaden oil on growth and reproduction in gilts farrowed by sows that consumed diets containing menhaden oil during gestation and lactation

In sows, n-3 fatty acids increase litter sizes, however, effects on gilt reproductive development have not been adequately studied. Moreover, not determined are effects of feeding n-3 fatty acids to sows on reproduction in offspring. The objective here was to determine effects of 4% dietary menhaden oil on growth and puberty in gilts farrowed by sows fed menhaden oil. Sows (n = 44) were assigned to: (1) control gestation and lactation diets, or (2) diets including menhaden oil. For primiparous sows only, total litter size and born alive were greater (P < 0.05) in females fed menhaden oil. Conversely, pigs from primiparous controls were heavier (P < 0.05) than pigs from primiparous sows fed menhaden oil (parity by diet interactions, P < 0.01). Diet did not affect (P > 0.20) other sow and litter characteristics. At weaning, 84 gilts from control- or menhaden oil sows were placed three gilts per pen and provided control diets or diets containing menhaden oil. Nursery and grow-finish feed intake and feed efficiency were similar (P > 0.21) for gilts from the different sows and weight gain was similar (P > 0.24) for gilts fed control or menhaden diets. Gilts fed menhaden oil tended to eat less in the nursery (1.18±0.08 kg v. 0.98±0.08 kg; P = 0.09) and overall (1.83±0.04 kg v. 1.72±0.04 kg; P = 0.06). Thus, overall feed to gain was greater (2.52±0.03 v. 2.33±0.03; P < 0.01) and nursery (2.12±0.04 v. 1.80±0.04; P = 0.10) and grow-finish (3.07±0.19 v. 2.58±0.19; P = 0.08) feed to gain tended to be greater, for control gilts. Age at puberty was greater (P = 0.02) for gilts from menhaden oil-fed sows (205.1±3.2 days) compared to gilts from controls (193.9±3.2 days) and tended to be greater (P = 0.09), for controls (203.5±3.2 days) compared to gilts fed menhaden oil (195.5±3.2 days). A tendency existed (P = 0.09) for greater follicular fluid in gilts fed menhaden oil, however, ovulation rate and ovarian, luteal and uterine weights were not affected by sow diet, gilt diet or the interaction (P > 0.23). Feeding gilts menhaden oil enhanced feed efficiency and hastened puberty onset. Gilts from sows consuming menhaden oil exhibited delayed puberty and retaining females from sows fed this feedstuff may be ill advised.     

Dietary L-arginine supplementation increased mammary gland vascularity of lactating sows

The present study aimed to evaluate the mechanisms modulated by dietary arginine supplementation to sows during lactation regarding antioxidant capacity and vascularization of mammary glands. At 109 days of gestation, animals were transferred to individual farrowing crates equipped with manual feeders and automatic drinker bowls. Environmental temperature and humidity inside the farrowing rooms were registered every 15 min. At farrowing, sows were assigned in a completely randomized design to a control diet (CON) or the CON diet supplemented with 1.0% L-arginine (ARG). A total of three gilts and two sows were fed the CON diet, whereas three gilts and three sows were fed ARG diets. Sows were fed a fixed amount of 6.0 kg/day, subdivided equally in four delivery times (0700, 1000, 1300 and 1600 h) for 21 days. At weaning, sows were slaughtered and mammary tissue samples and blood from the pudendal vein were collected. Data were analyzed considering each sow as an experimental unit. Differences were considered at P<0.05. L-arginine fed sows presented lower messenger RNA (mRNA) expression for prolactin receptor (P=0.002), angiopoietin1 (P=0.03) and receptor tyrosine kinase (P=0.01); higher mRNA expression for prostaglandin synthase 1 (P=0.01); a trend of decrease for glucocorticoid receptor (P=0.06) and IGF receptor 1 (P=0.07); and a trend (P=0.05) for an increased glutathione peroxidase mRNA expression. The angiopoietin2:angiopoietin1 mRNA ratio tended to increase (P=0.07) in ARG fed sows. L-arginine fed sows had greater (P=0.04) volumetric proportion of blood vessels and a trend of enhance (P=0.07) in the number of blood vessels per mm². These findings show that 1.0% ARG supplementation to sows activates proliferative mechanisms, may improve mammary tissues’ angiogenesis and tended to increase mRNA expression of genes that encode antioxidant enzymes in mammary gland of sows.     

The effect of varying duration of water restriction on drinking behaviour,welfare and production of lactating sows

Access to drinking water is essential for animal welfare, but it is unclear if temporary water restriction during the night represents a welfare problem. The aim of the present study was to investigate the effect of various durations of nightly restriction of water on thirst in loose housed lactating sows from day 10 to 28 of lactation. A total of 48 sows were deprived of water for either 0 h (n=12; control), 3 h (n=12; 0500 to 0800 h), 6 h (n=12; 0200 to 0800 h) or 12 h (n=12; 2000 to 0800 h). Control sows consumed 22% of their water intake during the night (2000 to 0800 h), whereas water consumption during this time was reduced to 13%, 7% and 0% in sows restricted for 3, 6 and 12 h. With increased duration of nightly water restriction a reduced latency to drink (26.8, 18.0, 5.3 and 6.7 min for 0, 3, 6 and 12 h sows; P<0.001) and an increased water intake during the 1^st hour after water became accessible (2.1, 3.4, 4.7 and 5.6 l for 0, 3, 6 and 12 h sows; P<0.001) was seen. During the last 30 min before water became accessible more sows deprived of water investigated (0%, 50%, 75%,and 50% of 0, 3, 6 and 12 h sows; P<0.01) or forcefully manipulated (0%, 17%, 50% and 33% of 0, 3, 6 and 12 h sows; P<0.05) the water trough, suggesting frustration and a negative experience of thirst. When all signs of imminent water access were provided, but access was delayed by 25 min, a tendency for more of the sows deprived of water for 6 and 12 h to interact forcefully with the water trough was seen (22%, 18%, 42% and 67% of 0, 3, 6 and 12 h sows; P=0.09). Duration of water restriction did not affect water consumption on a 24-h basis, nursing behaviour or performance. In conclusion, behavioural indicators of thirst increased with increasing duration of nightly water restriction in lactating sows.     

Effect of lysophospholipids in diets differing in fat contents on growth performance,nutrient digestibility,milk composition and litter performance of lactating sows

It is well known that energy plays an important role in sow growth and development. Increasing the utilization of lipids will be beneficial to sows. Emulsifiers are substances which stabilize mixtures and prevent oil and water from separating, thereby enhancing the digestion of lipids. This study was conducted to evaluate the effect of dietary emulsifier (lysophospholipids (LPL)) supplementation in diets differing in fat contents on growth performance, nutrient digestibility and milk composition in lactating sows, as well as performance and fecal score in piglets. A total of 32 multiparous sows (Landrace×Yorkshire) were used in a 21-day experiment. On day 110 of gestation, sows were weighed and moved into the farrowing facility, randomly assigned in a 2×2 factorial arrangement according to their BW with two levels of LPL (0 and 30 mg/kg) and two levels of fat (4.75% and 2.38% fat; 13.66 and 13.24 MJ/kg). BW loss and backfat thickness loss were decreased (P<0.05) by LPL supplementation. Backfat thickness at weaning was higher (P<0.05) in sows fed LPL supplementation diets. The apparent total tract digestibility of dry matter, nitrogen, gross energy and crude fat in sows fed LPL diets was increased (P<0.05) compared with those fed non-LPL diets. Sows fed the high-fat diets had higher (P<0.05) milk fat on day 10 and milk lactose on day 20 than those fed the low-fat diets. Milk fat and lactose concentrations in LPL supplementation treatments was increased (P<0.05) compared with non-LPL treatments on day 10 and day 20, respectively. Positive interaction effects (P<0.05) between fat and LPL were observed for milk fat concentration on day 10. In conclusion, LPL addition decreased BW loss and backfat thickness loss, improved nutrient digestibility and milk fat as well as milk lactose concentrations. In addition, there was a complementary positive effect of dietary fat and LPL supplementation on milk fat concentration in lactating sows.     

Review: Nutrient requirements of the modern high-producing lactating sow,with an emphasis on amino acid requirements

Sow productivity improvements continue to increase metabolic demands during lactation. During the peripartum period, energy requirements increase by 60%, and amino acid needs increase by 150%. As litter size has increased, research on peripartum sows has focused on increasing birth weight, shortening farrowing duration to reduce stillbirths and improving colostrum composition and yield. Dietary fibre can provide short-chain fatty acids to serve as an energy source for the uterus prior to farrowing; however, fat and glucose appear to be the main energy sources used by the uterus during farrowing. Colostrum immunoglobulin G concentration can be improved by increasing energy and amino acid availability prior to farrowing; however, the influence of nutrient intake on colostrum yield is unequivocal. As sows transition to the lactation period, nutrient requirements increase with milk production demands to support large, fast-growing litters. The adoption of automated feed delivery systems has increased feed supply and intake of lactating sows; however, sows still cannot consume enough feed to meet energy and amino acid requirements during lactation. Thus, sows typically catabolise body fat and protein to meet the needs for milk production. The addition of energy sources to lactation diets increases energy intake and energy output in milk, leading to a reduction in BW loss and an improvement in litter growth rate. The supply of dietary amino acids and CP close to the requirements improves milk protein output and reduces muscle protein mobilisation. The amino acid requirements of lactating sows are variable as a consequence of the dynamic body tissue mobilisation during lactation; however, lysine (Lys) is consistently the first-limiting amino acid. A regression equation using published data on Lys requirement of lactating sows predicted a requirement of 27 g/day of digestible Lys intake for each 1 kg of litter growth, and 13 g/day of Lys mobilisation from body protein reserves. Increases in dietary amino acids reduce protein catabolism, which historically leads to improvements in subsequent reproductive performance. Although the connection between lactation catabolism and subsequent reproduction remains a dogma, recent literature with high-producing sows is not as clear on this response. Many practical aspects of meeting the nutrient requirements of lactating sows have not changed. Sows with large litters should approach farrowing without excess fat reserves (e.g. <18 mm backfat thickness), be fed ad libitum from farrowing to weaning, be housed in a thermoneutral environment and have their skin wetted to remove excess heat when exposed to high temperatures.     

Increased survival of neonatal pigs by supplementing medium-chain triglycerides in late-gestating sow diets

Two experiments were conducted to study the efficacy and causes of medium-chain triglycerides (MCT) in sow diet in improving the survival of neonatal pigs. In Experiment 1, beginning on d84 of gestation and continuing through d28 of lactation, 51 sows were fed corn–soybean meal diet mixed with either soybean oil (SO; n=17), coconut oil (CO; n=18), or MCT (n=16) in a proportion of 9 : 1 by weight. The highest improvement in survival of pigs by sows fed MCT (p<0.01) or CO (p<0.05) was observed during the first three days after birth in pigs weighing <1100 g at birth, compared with sows fed SO. Their three-day survival was 98.6, 80.0 and 47.6%, respectively, for MCT, CO and SO groups. In Experiment 2, beginning on d84 of gestation and continuing through farrowing, 24 sows, 8 sows per treatment, were fed diets as in Experiment 1. Liver glycogen content of pigs 4 h after born from sows fed MCT (p<0.10) and CO (p<0.01), and muscle glycogen of pigs from sows fed MCT (p<0.01) and CO (p<0.10) were increased, compared to those of pigs from sows fed SO. Plasma albumin was increased by MCT and CO (p<0.01), relative to SO. The results suggest that MCT or CO in sow diets may enhance the body glycogen stores and maturity of pigs at birth and, hence, their survival, particularly in pigs with low birth weight during the first three days of life.     

Peripartum Ca and P homeostasis in multiparous sows fed adequate or excess dietary Ca

The recent increased prevalence of uterine prolapses in sows around parturition has led to inferences that the prolapses may be associated with hypocalcemia. However, limited data are available to support that hypocalcemia occurs in sows. Hypocalcemia in dairy cows is associated with feeding excess dietary Ca during late gestation. The excess Ca is assumed to suppress homeostatic mechanisms critical to maintain serum Ca concentrations as the Ca demand increases during the early stages of lactation. In this experiment, sows were fed diets with excess Ca during late gestation and early lactation to assess the potential development of hypocalcemia in the peripartum period. Twelve crossbred (Large White × Landrace) multiparous gestating sows were fed a control diet (CON), 0.65% Ca to 0.38% standardized total tract digestible P (STTD P) and 0.67% Ca to 0.38% STTD P in gestation and lactation diets, respectively) or a high Ca diet (HCa, 1.75% Ca to 0.46% STTD P and 1.75% Ca to 0.45% STTD P in gestation and lactation diets, respectively). The diets were fed from gestation day 86 þ ± 1 until the end of lactation (27 þ ± 2 days period). On day 112 of gestation, indwelling venous catheters were placed in each sow. Blood samples were collected at 15-min intervals within four designated times (0700, 1000, 1300 and 1700 h) on gestation day 113 and lactation days 1, 3 and 5. Venous blood pH, gases (pO₂, pCO₂ and HCO₃⁻), electrolytes (K⁺, Na⁺ and Cl⁻), ionized Ca (iCa), metabolites (glucose and lactate), plasma total Ca (tCa), and P were analyzed. Overall, sows fed HCa diet had greater (P < 0.001) concentrations of blood iCa and plasma tCa than sows fed CON diets. No clinical signs of Ca metabolism disorders were observed. Unexpectedly, concentrations of plasma P in sows fed HCa diets were lower (P < 0.001) than in sows fed CON diets. Plasma P tended to decrease (P = 0.057) as day of lactation increased. Differences between dietary treatments for blood pH, gases, electrolytes and metabolites were not detected (P > 0.05). No evidence for hypocalcemia was detected in peripartum sows fed CON or HCa diets. These data imply that excess Ca in late gestation diets did not result in hypocalcemia during the peripartum period. Future experiments should focus on factors other than hypocalcemia to identify causes of uterine prolapses in sows.