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In this study we aimed to identify possible causes of within-litter variation in piglet birth weight (birth weight variation) by studying follicular development of sows at weaning in relation to their estimated breeding value (EBV) for birth weight variation. In total, 29 multiparous sows (parity 3 to 5) were selected on their EBV for birth weight variation (SD in grams; High-EBV: 15.8±1.6, N =14 and Low-EBV: −24.7±1.5, N =15). The two groups of sows had similar litter sizes (15.7 v. 16.9). Within 24 h after parturition, piglets were cross-fostered to ensure 13 suckling piglets per sow. Sows weaned 12.8±1.0 and 12.7±1.0 piglets, respectively, at days 26.1±0.2 of lactation. Blood and ovaries were collected within 2 h after weaning. The right ovary was immediately frozen to assess average follicle size and percentage healthy follicles of the 15 largest follicles. The left ovary was used to assess the percentage morphologically healthy cumulus-oocyte complexes (COCs) of the 15 largest follicles. To assess the metabolic state of the sows, body condition and the circulating metabolic markers insulin, IGF1, non-esterified fatty acid, creatinine, leptin, urea and fibroblast growth factor 21 were analysed at weaning. No significant differences were found in any of the measured follicular or metabolic parameters between High-EBV and Low-EBV. A higher weight loss during lactation was related to a lower percentage healthy COCs (β = −0.65, P =0.02). Serum creatinine, a marker for protein breakdown, was negatively related to average follicle size (β = −0.60, P =0.05). Backfat loss during lactation was related to a higher backfat thickness at parturition and to a higher average follicle size (β =0.36, P <0.001) at weaning. In conclusion, we hypothesise that modern hybrid sows with more backfat at the start of lactation are able to mobilise more energy from backfat during lactation and could thereby spare protein reserves to support follicular development. [ABSTRACT FROM AUTHOR]

This study investigated the relationship between ovulation rate (OR) and embryonic characteristics in gilts. Landrace (n = 86) and Yorkshire x Landrace (n = 212) gilts were inseminated with semen stored for 3 to 5 d (SS1, n = 59), 6 to7 d (SS2, n = 133), or 8 to 10 d (SS3, n = 106), and slaughtered at 35 d of pregnancy. Ovulation rate was assessed by dissection of the corpora lutea on both ovaries. Embryos were classified as vital (VE) by visual appearance and individually weighed (VEg) and the SD of the weight calculated (SDVEg). Early embryonic mortality (EM) was estimated as the difference between OR and the number of vital plus nonvital embryos. Embryonic characteristics were analyzed with a model that included linear and quadratic terms of OR and fixed class effects of semen storage duration (SS) and genetic line (GL). Landrace gilts had a higher OR than Yorkshire x Landrace gilts (22.1 ± 0.4 vs. 20.3 ± 0.2, P ≤ 0.05) and also a higher EM (6.1 ± 0.4 vs. 3.5 ± 0.3, P ≤ 0.05). EM was also higher in gilts inseminated with semen stored for more than 8 d. Also, Yorkshire x Landrace gilts had a higher number of VE (16.9 ± 0.7) than the Landrace gilts (13.3 ± 0.8) when inseminations were done with semen stored for up to 5 d. Yorkshire x Landrace gilts had the highest VEg when inseminated with semen stored for 3 to 5 d (SS1: 4.9 ± 0.2 g, SS2: 4.1 ± 0.1 g, and SS3: 4.0 ± 0.2 g; P ≤ 0.05). VE and VEg did not differ within Landrace gilts between different SS classes. A quadratic relationship of OR (P ≤ 0.05) was found with VE: a maximum of 16.8 VE was observed at 26 ovulations [(2.5 (± 0.6)*OR- 0.05 (± 0.01)*OR²]. A quadratic relationship of OR (P ≤ 0.05) was also found for EM: a minimum of 3.33 EM was observed at 15 ovulations [(-1.1 (± 0.6)*OR -0.03 (± 0.01)*OR²]. VEg was not related with OR, but SDVEg had a positive linear relationship with OR [0.01 (± 0.003)*OR, P ≤ 0.05]. Results show that Yorkshire x Landrace gilts perform better than Landrace when inseminated with fresh semen, but not with semen stored for longer time. Also, the VE increases with an increase in OR up to 26, but at a lower level at higher OR, which is likely related with the increase in EM. The higher EM at higher OR might arise from a higher variation in follicular/oocyte quality leading to a higher variation in embryonic quality and development, increasing mortality before uterine implantation and the variation in embryonic weight already at 35 d of pregnancy. [ABSTRACT FROM AUTHOR]

Osteochondrosis (OC) is a degenerative joint condition developing in a short time frame in young growing gilts that may cause lameness at an older age, affecting welfare and leading to premature culling of breeding sows. Causes of OC are multifactorial including both genetic and environmental factors. Floor type has been suggested to affect OC prevalence and effects might be age dependent during the rearing period. The aim of this study was to investigate possible age-dependent effects of floor type, conventional concrete partially slatted versus wood shavings as deep bedding, on OC prevalence in gilts (Dutch Large White x Dutch Landrace) at slaughter (24 wk of age; 106.5 [14.7 SD] kg of BW). At weaning (4 wk of age; 6.9 [1.3 SD] kg of BW), 212 gilts were subjected to 1 of 4 flooring regimens. Gilts were either subjected to a conventional floor from weaning until slaughter (CC), wood shavings as bedding from weaning until slaughter (WW), a conventional floor from weaning until 10 wk of age after which gilts were switched to wood shavings as bedding (CW), or wood shavings as bedding from weaning until 10 wk of age after which gilts were switched to a conventional floor (WC). After slaughter the elbow, hock, and knee joints were macroscopically examined for OC and scored on a 5 point scale where 0 indicates no OC and 4 indicates the severest form of OC. There was no significant difference (P > 0.4) between treatments on the overall OC prevalence for any joint assessed or at the animal level (all joints combined). At the animal level, however, gilts had greater odds to have OC scores 3 and 4 in the CW treatment (odds ratios [OR] = 2.3; P = 0.05), WC treatment (OR = 2.6; P = 0.02), and WW treatment (OR = 3.7; P < 0.001) compared with gilts in the CC treatment. The results indicate that there are no age-dependent effects of floor types on overall OC prevalence. However, wood shavings as bedding seems to increase the odds for severe OC and might affect animal welfare in the long term. [ABSTRACT FROM AUTHOR]

This paper presents follicle development and hormone profiles for sows with normal ovulation or cystic follicles during an intermittent-suckling (IS) regime that started at Day 14 of lactation. Sows were subjected to separation from their piglets during blocks of 6 h or 12 h. In total, 8 out of 52 sows developed cystic follicles; either full cystic ovaries (n = 6) or partial ovulation (n = 2). Increase in follicle size of these sows was similar to that of normal ovulating sows until pre-ovulatory size at Day 5 after the start of separation, but from then on became larger (P < 0.05). LH surge was smaller or absent in sows that developed (partially) cystic ovaries (0.4 ± 0.1 vs 3.6 ± 0.3 ng mL-1; P < 0.01). Peak levels of oestradiol (E2) were similar but high E2 levels persisted in sows that developed (partly) cystic ovaries and duration of oestrus tended to be longer. The risk of developing (partly) cystic ovaries was higher when IS occurred in blocks of 6 h versus 12 h (33 vs 10%). In conclusion, the appearance of cystic ovaries at approximately Day 20 of ongoing lactation was related to an insufficient LH surge, as is also the case in non-lactating sows. Cystic ovaries can be a problem in sows and there are many questions related to cyst formation. In the present study, development of cysts in non-hormonally-treated, lactating sows was studied and the results show that cyst formation is related to insufficient LH pools and disturbed oestradiol feedback, resulting in continued follicle growth. Risk of cyst development can be reduced by not weaning sows too early. [ABSTRACT FROM AUTHOR]

Osteochondrosis (OC) is one of the main causes of leg weakness causing premature culling in breeding sows and develops in a short time frame in young growing gilts. Dietary restriction may have different effects on OC prevalence depending on the age of the gilts. The aim of this study is to investigate age-dependent effects of dietary restriction, ad libitum vs. restricted (80% of ad libitum), on the occurrence of OC in gilts at slaughter (26 wk of age). At weaning (4 wk of age), 211 gilts were subjected to one of 4 treatments of a feeding regime. Gilts were administered either ad libitum feeding from weaning until slaughter (AA); restricted feeding from weaning until slaughter (RR); ad libitum feeding from weaning until 10 wk of age, after which gilts were switched to restricted feeding (AR); or restricted feeding from weaning until 10 wk of age, after which gilts were switched to ad libitum feeding (RA). At slaughter, the elbow, hock, and knee joints were harvested. Joints were scored macroscopically for articular surface deformations indicative of OC. Gilts in the RA treaUnent had significantly higher odds of being affected by OC than gilts in the RR and AR treatments in the hock joint (OR = 3.3, P = 0.04 and OR = 8.5, P = 0.002, respectively) and at animal level (OR = 2.5, P = 0.001 and OR = 1.9, P = 0.01, respectively). Gilts in the AA treatment had higher odds of being affected by OC than gilts in the AR treatment in the hock joint (OR = 5.3, P = 0.01). The results indicate a possible pathway to reduce the prevalence of OC in breeding gilts that will have to last several parities. Switching from restricted feeding to ad libitum feeding after 10 wk of age increases OC prevalence as opposed to restricted feeding after 10 wk of age. [ABSTRACT FROM AUTHOR]

Contents Our objective was to study reproductive consequences of lactation bodyweight loss occurring in primiparous sows with mild feed restriction and to relate these lactation weight losses and its consequences to metabolic profiles during lactation and subsequent early gestation. After weaning, 47 first-litter sows were retrospectively assigned to a high- (HWL, >13.8%, n = 24) or low (LWL, ≤13.8%, n = 23)-weight loss group. Thirty-six animals received an indwelling jugular vein catheter to determine lactational and gestational profiles of insulin-like growth factor-1 (IGF-1), non-esterified fatty acids (NEFA) and urea and gestational profiles of progesterone. At day 35 after insemination, sows were euthanized and their reproductive tract collected. Pregnancy rate was 75% (18/24) for HWL and 96% (22/23) for LWL sows. High-weight loss sows had a lower number of implantation sites (17.2 ± 0.8 vs 19.5 ± 0.7, respectively, p = 0.03) and a lower embryonic survival (65.6 ± 3.4 vs 77.4 ± 2.9%, p = 0.02), resulting in fewer vital embryos (14.9 ± 0.9 vs 16.8 ± 0.7, p = 0.07) than LWL sows. Progesterone peak values were reached later in HWL than in LWL sows (day 13.4 ± 0.5 vs 12.0 ± 0.5, respectively, p = 0.05). Gestational concentrations of IGF-1, NEFA and urea were almost identical for HWL and LWL sows, whilst numerical differences were seen during lactation. The current study shows negative consequences of lactational weight loss in mildly feed-restricted primiparous sows for embryonic survival and shows that these consequences seem only mildly related with metabolic alterations during lactation and not with metabolic alterations during subsequent gestation. [ABSTRACT FROM AUTHOR]

Contents Normally, sows are in anoestrus during lactation and start their new cycle at the day of weaning. Modern hybrid primiparous sows that suckle large numbers of piglets may lose substantial amounts of body reserves during lactation. This compromises follicle development during lactation. As modern sows have short weaning-to-oestrus intervals, these compromised follicles are recruited for ovulation directly after weaning, resulting in lower ovulation rates and lower embryo survival. Postponing or skipping first oestrus after weaning in primiparous sows may help to limit the negative consequences of lactation on subsequent reproduction. Multiparous sows may have very high litter sizes, especially after long lactations as applied in organic sows. These high litter sizes compromise piglet birthweight and survival and subsequent performance. Inducing lactation oestrus in multiparous sows may help to limit litter size and improve piglet survival and performance. This study discusses physiological and reproductive effects of extending the start of a new pregnancy after lactation in primiparous sows and induction of lactation oestrus in multiparous sows. We thereby challenge the view that weaning is an ideal start for the reproductive cycle in modern sows. [ABSTRACT FROM AUTHOR]

Contents This study used split-weaning (SW) to induce differences in follicle size at weaning and study its consequences for follicle development during and after post-weaning altrenogest feeding and for reproductive performance. Multiparous sows (n = 47) were assigned to SW (n = 23; litter size reduced to the six smallest piglets 3 days before weaning) or control (C; n = 24; normal weaning). Altrenogest (20 mg/day) was fed to all 47 sows from Day −1 till Day 5 (complete weaning = Day 0). Follicle size on Day 1, 2 and 8 was smaller in C than in SW (p ≤ 0.05). Ovulation rate was similar, but C sows had higher embryo survival rate (ESR) than SW sows (83 ± 19 and 58 ± 31%, respectively; p = 0.001). SW sows with low ESR (<63%; n = 10) had a greater follicle size on days 3-6 than SW sows with high ESR (>63%; n = 10; p ≤ 0.04). A decrease in follicle size between Day 5 and 6 of altrenogest feeding was associated with increased ESR in both treatments (p = 0.002). Follicle pool analyses (assessment of all follicles >2 mm) revealed that on Day 3, sows with low ESR had a higher % of follicles >5 mm compared with sows with high ESR (30% vs 10%; p = 0.04). Thus, sows in which follicle growth was less suppressed during altrenogest feeding had a lower ESR. These effects on follicle development and ESR were more pronounced in split-weaned sows. [ABSTRACT FROM AUTHOR]

Effects of different carbohydrate sources on plasma glucose, insulin and insulin-like growth factor-I (IGF-I) levels were compared to subsequently be able to study effects of insulin-stimulating diets on follicle development in sows. The following feed components were tested in 12 sows during six consecutive test periods of 9.5 days: dextrose (DEX), sucrose (SUC), lactose (LAC), dextrose plus lactose (DL), sucrose plus lactose (SL), dextrose plus sugarbeet pulp (DSBP) and control (CON). On day 2, 5 and 9 of each test period, plasma glucose (only at day 9), insulin and IGF-I profiles were determined. Despite similar glucose profiles for all diets, the postprandial insulin response was higher for DL and SL compared with CON and LAC; the other diets were intermediate. Plasma IGF-I levels were higher in CON, LAC and SL compared with DSBP, but differences were only marginal. It was concluded that dextrose and sucrose have the potential to stimulate fast and high insulin peaks, especially when combined with additional lactose. Despite the high dextrose in the DSBP diet, the insulin response was flattened, probably due to the viscosity of sugarbeet pulp. The results show that modulation of plasma insulin levels by dietary carbohydrates seems possible in anabolic sows, but IGF-I levels are less easily modified. [ABSTRACT FROM AUTHOR]

Contents Insulin-stimulating sow diets before mating improve piglet uniformity. We studied effects of nutritionally induced differences in insulin levels during the weaning-to-ovulation interval (WOI) on luteal development, progesterone secretion and pre-implantation conceptus development and uniformity (d10). To create insulin contrasts, 32 multiparous sows were fed either a dextrose plus lactose containing diet (each 150 g/day) at 4 h intervals (DL treatment) or an isocalorically control diet (containing soybean oil) at 12 h intervals (CTRL treatment) during the WOI. After ovulation, all sows received a standard gestation diet at 12 h intervals. Ovulation rate, plasma progesterone levels, pregnancy rate and embryo survival did not differ between treatments. CTRL sows had a higher total luteal weight (11.2 vs 9.7 g; p = 0.03) than DL sows. Conceptus diameter at d10 of pregnancy tended to be larger in CTRL sows (diameter: 7.1 vs 6.4 mm; p = 0.07). Conceptus uniformity was not influenced by treatment. Insulin area under the curve (AUC) and mean insulin during the WOI were positively related with mean progesterone (β values were 0.78 (ng/ml)/1000 μU and 0.14 (ng/ml)/(μU/ml) for AUC and mean, respectively; p < 0.05) and maximal progesterone (β values were 1.46 (ng/ml)/1000 μU and 0.27 (ng/ml)/(μU/ml) for AUC and mean, respectively; p < 0.05) levels during the first 10 days of pregnancy, but not with conceptus development and uniformity. In conclusion, high insulin levels during the WOI seem to be beneficial for progesterone secretion in sows, probably mediated through beneficial effects of insulin on follicle development. [ABSTRACT FROM AUTHOR]

This study evaluated the effect of feeding level and protein content in feed in first- and second-parity sows during the first month of gestation on sow BW recovery, farrowing rate, and litter size during the first month of gestation. From d 3 to d 32 after first insemination, sows were fed either 2.5 kg/d of a standard gestation diet (Control, n = 49), or 3.25 kg/d (+ 30%) of a standard gestation diet (Plus Feed, n = 47), or 2.5 kg/d of a gestation diet with 30% greater level of ileal digestible AA (Plus Protein, n = 49). Feed intake during the experimental period was 29% greater for Plus Feed sows compared with Control and Plus Protein sows (93 vs. 72 kg, P < 0.05). Plus feed sows gained 10 kg more BW during the experimental period compared with Control and Plus Protein sows (24.2 ± 1.2 vs. 15.5 ± 1.2 and 16.9 ± 1.2 kg, respectively, P < 0.001). Backfat gain and loin muscle depth gain were not affected by treatment (P = 0.56 and P = 0.37, respectively). Farrowing rate was lesser, though not significantly, for Plus Feed sows compared with Control and Plus Protein sows (76.6% vs. 89.8% and 89.8%, respectively, P = 0.16). Litter size, however, was larger for the Plus Feed sows (15.2 ± 0.5 total born) compared with the Control and Plus Protein sows (13.2 ± 0.4 and 13.6 ± 0.4 total born, respectively, P = 0.006). Piglet birth weight was not different among treatments (P = 0.65). For both first- and second-parity sows, the Plus Feed treatment showed similar effects on BW gain, farrowing rate, and litter size. In conclusion, an increased feed intake (+ 30%) during the first month of gestation improved sow BW recovery and increased litter size but did not significantly affect farrowing rate in the subsequent parity. Feeding a 30% greater level of ileal digestible AA during the same period did not improve sow recovery or reproductive performance in subsequent parity. [ABSTRACT FROM AUTHOR]

In a previous study, we showed that follicle size at weaning affects the response of a sow to a short-term altrenogest treatment after weaning. In this study, an attempt was made to prevent the growth of follicles into larger size categories before weaning by using different altrenogest treatments before weaning to improve reproductive performance after postweaning altrenogest treatments. Sows (87 primiparous and 130 multiparous) were assigned to the following treatments: control (no altrenogest treatment; n = 59), RU0-20 (20 mg of altrenogest from d -1 to 6; weaning = d 0; n = 53), RU40-20 (40 mg of altrenogest from d -3 to 0 and 20 mg of altrenogest from d 1 to 6; n = 53), and RU20-20 (20 mg of altrenogest from d -3 to 6; n = 52). Follicle size was assessed daily with transabdominal ultrasound. Follicle sizes on d -3 (3.6 ± 0.7 mm) and at weaning (4.0 ± 0.7 mm) were similar for all treatments. Altrenogest-treated sows had larger follicles at the beginning of the follicular phase than did control sows [5.4 ± 0.1 and 3.8 ± 0.2 mm (least squares means), respectively; P < 0.0001] and on d 4 of the follicular phase [8.0 ± 0.1 and 6.7 ± 0.2 mm (least squares means), respectively; P < 0.0001]. Multiparous sows had larger follicles than did primiparous sows at the beginning of the follicular phase [5.3 ± 0.1 and 4.7 ± 0.1 mm (least squares means), respectively; P < 0.01] and on d 4 of the follicular phase [8.0 ± 0.1 and 7.0 ± 0.1 mm (least squares means), respectively; P < 0.0001]. Farrowing rate and litter size (born alive + dead) were not affected by treatment or parity. However, in primiparous sows, when mummies were included in litter size, altrenogest-treated sows had larger litters than did control sows (13.4 ± 0.5 and 11.9 ± 0.7 piglets, respectively; P = 0.02). In primiparous control sows, backfat depth at weaning and litter size were positively related (slope of the regression line = 0.82; P < 0.05), which was not the case in primiparous sows receiving altrenogest. In conclusion, the different altrenogest treatments before weaning did not prevent the growth of follicles before weaning and similarly affected subsequent follicle development and fertility. In primiparous sows, altrenogest treatment after weaning increased the number of fetuses during pregnancy, but positive effects seemed limited by uterine capacity. Altrenogest treatment after weaning improved litter size in primiparous sows with reduced backfat depth at weaning, which suggests a specific positive effect of a recovery period after weaning in sows with reduced BCS at weaning. [ABSTRACT FROM AUTHOR]

This study investigated follicular development during and after postweaning altrenogest treatment of primiparous sows in relation to subsequent reproductive performance. Primiparous sows (n = 259) were randomly assigned at weaning (d 0) to 1 of 4 groups: control (no altrenogest, n = 71), RU4 (20 mg of altrenogest from d -ito 2, n = 62), RU8 (20 mg of altrenogest from d -ito 6, n =~65), or RU15 (20 mg of altrenogest from d -ito 13, n = 61). Average follicular size (measured by ultrasound) increased during altrenogest treatment and resulted in larger follicles at the start of the follicular phase for RU4, RU8, and RU15 compared with controls (5.3 ± 0.9, 5.5 ± 1.3, 5.1 ± 1.2, and 3.4 ± 0.6 mm, respectively; P < 0.0001). Farrowing rate was greater in RU15 (95%) than in RU8 (76%; P = 0.04). The RU15 group also had more piglets (2 to 3 more piglets total born and born alive; P < 0.05) than the other treatment groups. Follicular development at weaning clearly affected reproductive performance. At weaning, average follicular size: small (<3.5 mm), medium (3.5 to 4.5 mm), or large (≥4.5 mm), was associated with farrowing rates of 86, 78, and 48%, respectively (P < 0.001). Sows with large follicles at weaning had low farrowing rates (71%) in RU4, very low farrowing rates (22%) in RU8, but normal farrowing rates in RU15 (83%). In conclusion, this study showed that 15 d of postweaning altrenogest treatment of primiparous sows may allow follicle turnover in sows that had large follicles at weaning and that this was associated with an improved reproductive performance. It also showed that shorter treatment with altrenogest (4 or 8 d) is beneficial for sows with small follicles at weaning, but is not recommendable for sows with large follicles at weaning. [ABSTRACT FROM AUTHOR]

We investigated effects of loose housing of the sow during lactation and enrichment of the pen pre-and postweaning on performance of newly weaned piglets. Before weaning, piglets (n = 320) were housed in an enriched (straw, wood shavings, peat, and branches) or barren pen with a confined or loose-housed sow (n = 32). Loose-housed sows and their piglets could eat together from a family feeder, whereas confined sows and piglets had separate feeding troughs. Piglets (n = 256) were mixed postweaning, and 4 piglets from each litter were relocated to a barren pen (n = 32 pens) and 4 other piglets were housed in an enriched pen (n = 32 pens). Growth from d 15 until weaning was greater for piglets from enriched pens (4.38 + 0.29 vs. 4.71 ± 0.21 kg/pig, P < 0.05) and tended to be greater for piglets with a loose-housed sow compared with piglets with a confined sow (4.41 ± 0.26 vs. 4.67 ± 0.24 kg/pig, P = 0.10). Preweaning feed intake was not affected by preweaning conditions (P > 0.25). Piglets from enriched preweaning pens ate more in the first 2 d postweaning than piglets from barren pens (first 48 h, barren 0.45 ± 0.05 kg/pig, enriched 0.53 ± 0.04 kg/ pig, P < 0.05). Piglets relocated to an enriched pen after weaning showed a greater growth in the 2 wk after weaning (barren 5.5 ± 0.2 kg/pig, enriched 6.2 ± 0.2 kg/pig, P < 0.0001), had a profoundly reduced diarrhea prevalence than piglets housed in barren pens after weaning (barren 2.4 ± 0.4 d, enriched 1.0 ± 0.3 d, P < 0.0001), and had a greater feed efficiency (barren 0.81 + 0.03, enriched 0.85 + 0.02, P < 0.05). Enrichment of the preweaning environment likely stimulates development of feeding behaviors and consequently increases feed intake immediately after weaning. Providing piglets with an enriched environment after weaning positively affected postweaning growth, feed efficiency, and incidence of diarrhea, which may be caused by decreased stress or increased gut health. Enrichment of the pre- and postweaning environment seems important in improving performance and health of newly weaned pigs. [ABSTRACT FROM AUTHOR]

Contents Effects of dextrose plus lactose in sow’s feed were tested on subsequent reproductive performance and within litter birth weight variation. During the last week of gestation and lactation, sows were either fed a commercial lactation diet (Control: C), or an isocaloric diet containing 25 g/kg dextrose plus 25 g/kg lactose (Treatment: T). In the subsequent weaning-to-oestrus interval (WEI), all sows received the same amount of a commercial feed, but T sows were supplemented with 150 g dextrose plus 150 g lactose per day. Weight and backfat changes were recorded as well as litter characteristics during the treatment period and the subsequent parity. No significant effect of treatment was found on the subsequent reproductive performance, including the number of piglets born, although the number of live born piglets was 0.51 larger (p = 0.31) and weight of the live born piglets was 84 g higher in the T sows (p = 0.07) than in the C sows. When sows were categorized in sows with 12 or less and more than 12 total born piglets in the previous litter, treatment of sows with dextrose plus lactose resulted for the group with 12 or less piglets in a strong increase in subsequent total born piglets (13.97), whereas in the untreated sows the subsequent litter size was 11.89. In the group with more than 12 total born piglets, no effect of treatment was found (interaction between previous litter size and treatment p = 0.03). The within litter variation in birth weight in the subsequent litter was numerically lower in the T sows. We concluded that the use of dextrose and lactose during lactation and WEI seems to enhance litter size in sows with low previous litter size and seems to have the potential to reduce the within litter variation in birth weight. [ABSTRACT FROM AUTHOR]

Daily separation of sows and piglets during lactation, intermittent suckling (IS), improves feed intake and postweaning adaptation in piglets. The aim of the current study was to determine how, in pig- lets that have been subjected to IS, age at weaning and the duration of the preceding IS period contribute to postweaning adaptation through effects on feed in- take, growth, and gut characteristics. All piglets had ad libitum access to creep feed from d 7. Litters were subjected to conventional weaning (CW) or to 1 of 3 IS regimens. In CW, litters (n = 29) had continuous access to the sow until weaning (d 26, d 0 = farrowing). During IS, litters had access to the sow between 1600 and 0600 h. Litters in the IS treatments were subjected to IS 1) from d 19 onward and weaned at d 26 (IS19- 7D, n = 33), 2) from d 19 onward and weaned at d 33 (IS19-14D, n = 28), or 3) from d 26 onward and weaned at d 33 (IS26-7D, n = 33). The IS19-7D regimen resulted in a relative growth check within the first 2 d after weaning similar to CW litters (72 ± 13 and 90 ± 7%, respectively), but in a greater piglet growth (P = 0.0 14) and feed intake (P = 0.001) between d 2 and 7 postweaning. Moreover, IS19-7D was not associated with a (further) reduction in villus height as observed at d 2 postweaning in CW litters. In IS piglets weaned after an extended lactation (d 33), a markedly smaller weaning-associated relative growth check was observed shortly postweaning (11 ± 18 and 32 ± 19% for IS19-14D and IS26-7D litters, respectively). In these litters, feed intake and growth within the first 2 d after weaning were slightly greater when piglets were subjected to IS for 2 wk (IS19-14D) rather than for 1 wk (IS26-7D; P = 0.032 and P = 0.037 for feed intake and growth, respectively). Irrespective of duration of IS, weaning at d 33 with IS was not associated with a reduction in villus height. Irrespective of treatment, plasma citrulline concentrations were reduced at d 2 and 8 postweaning compared with the values at weaning (P ≤ 0.01). No correlation was observed between postweaning plasma citrulline concentrations and postweaning small intestinal villus height. This study indicates that 1 wk of IS before weaning at d 26 of lactation improves feed intake and growth between d 2 and 7 postweaning and does not result in a reduction of villus height as observed in CW piglets, although it did not prevent a profound growth check shortly after weaning. However, combining 1 wk of IS with an extended lactation improved postweaning adaptation markedly in terms of growth, feed intake, and gut characteristics. Increasing the du- ration of IS from 1 to 2 wk slightly improved growth and feed intake shortly after weaning, but the contribution to postweaning adaptation seemed to be relatively small compared with extending lactation. [ABSTRACT FROM AUTHOR]

Contents Intermittent suckling (IS), a system in which the sow and the piglets are separated for a number of hours per day during lactation, is put forward as a system that can increase piglet welfare around weaning and also induce lactational oestrus. To be of practical use, IS regimes need to result in a predictable oestrus and good reproductive performance. This review describes the effects of IS on sow reproductive performance. During IS, the LH pulsatility pattern switches to a high frequency, low amplitude release during separation, as is normally observed at weaning. In sows that ovulate during IS, LH pulsatility remains higher than in anovulatory sows. Around 90% of the IS sows show follicle growth up to pre-ovulatory size in a similar time period as sows post-weaning. Depending on the stage of lactation that IS commenced, 13% (day 21) to 21% (day 14) of the sows with pre-ovulatory follicles did not ovulate, but follicles either regressed or developed into cystic follicles. In the ovulatory IS sows oestradiol production is comparable but the LH surge is lower with an early start of IS (day 14) when compared with the weaned sows. Continuation of IS post-ovulation has negative effects on pregnancy rate, embryo development and progesterone levels. Factors related to lactation (e.g. a high metabolic clearance rate), may play a role in this. In conclusion, IS can result in a fertile oestrus when the timing of start of IS and duration of IS are taken into account, but for practical use IS regimes result in a too variable reproductive performance. [ABSTRACT FROM AUTHOR]

Contents In pig husbandry, stress is being considered an important cause of impaired reproductive performance. Therefore, an experiment was performed to quantify effects of repeated stressors during the follicular phase and/or during early pregnancy on reproductive performance of gilts. Eighty-one cyclic gilts were assigned to one of four treatments, namely, stress treatment during the follicular phase (n = 20), stress treatment during early pregnancy (n = 20), stress treatment during both phases (n = 21) and no stress treatment (n = 20). All gilts were housed individually, but gilts in the stress treatments had no opportunity for visual or physical contact with other gilts. Further, animals in a stress-treatment were grouped for half an hour at the start of the treatment and during the treatment period nose-sling and an unpredictable feeding scheme were applied regularly. The extent of stress was monitored using heart rate measurements, behavioural observations and saliva cortisol levels during nose-sling fixation. Of the 81 gilts, 93% showed oestrus and were inseminated. Of these, 93% were pregnant at day 35, having 17.9 ± 0.3 ovulations and 15.6 ± 0.3 foetuses. These parameters were not affected by treatment. The stress treatment during the follicular phase tended to shorten cycle length (stress: 20.8 ± 0.20; control: 21.2 ± 0.17 days, p = 0.07) and weight of foetuses at day 35 (stress: 4.47 ± 0.08 g; no stress: 4.69 ± 0.08 g, p = 0.06); stress during early pregnancy did not affect any of the reproduction parameters. Percentage stereotypic behaviour, heart rate and saliva cortisol levels varied greatly between animals and between days, but did not differ between the treatments. No relationships were found between any of the reproductive parameters and any of the stress parameters (heart rate, cortisol, stereotypic behaviour). These results indicate that the repeatedly applied acute stressors did not generate a chronic stress-response and that these stressors during the follicular phase and/or during early pregnancy did not affect reproductive processes. It is not clear how these findings relate to suggested effects of stress(ors) on reproductive performance in pig husbandry. [ABSTRACT FROM AUTHOR]

The effects of feeding additional starch or fat from d 85 of gestation until parturition on litter performance and on glucose tolerance in sows that were fed a diet with a high level of fermentable nonstarch polysaccharides (NSP) were studied. The day after breeding, 141 multiparous sows were assigned to the experiment. At d 85 of gestation, sows were assigned to the treatments. Sows were fed 3.4 kg/d (as-fed basis) of a high-NSP diet or the same quantity of the high-NSP diet and an additional 360 g of starch (from wheat starch) daily, or the same quantity of the high-NSP diet and an additional 164 g of fat (from soybean oil) daily. During lactation, all sows were given free access to the same lactation diet. Approximately i wk before the expected time of parturition, an oral glucose tolerance test was performed in 38 randomly chosen sows by feeding pelleted glucose (3 g/kg BW0.75). Blood samples for glucose analyses were taken at −10, 10, 20, 30, 40, 50, 60, 70, 80, 90, 105, and 120 min after glucose was fed. The supply of additional dietary starch or fat did not increase piglet birth weight or total litter weight at birth. Sows that were fed the high-NSP diet had more (P = 0.097) live-born piglets and fewer (P = 0.084) still-born piglets than did sows that were fed additional fat, whereas sows that were fed additional starch were intermediate for these variables. Piglet mortality after birth was not affected by dietary treatment. Body weight and backfat gains in the last month of gestation were higher for sows fed additional starch or fat than for sows fed the high-NSP diet (P < 0.001 and P = 0.017, respectively). Feed intake in lactation was greatest by sows fed the high-NSP diet, least by sows fed additional starch at the end of gestation, and intermediate by sows fed additional fat (P = 0.099). The differences in lactation feed intake did not result in differences in BW and backfat losses during lactation. Sows that were fed additional fat had the greatest glucose area under the curve (P = 0.044), indicating that these sows were less tolerant to glucose. In conclusion, feeding additional energy (starch or fat) in late-gestating sows that are fed a high-NSP diet did not increase litter weight at birth or piglet survival, but did increase maternal gain. Feeding sows additional energy from fat might induce glucose intolerance, whereas feeding sows additional energy from starch did not induce glucose intolerance. [ABSTRACT FROM AUTHOR]

The objective of this experiment was to study the effects of feeding group-housed gestating sows a diet with a high level of fermentable nonstarch polysaccharides (NSP; approximately 45% sugar beet pulp as fed) ad libitum on the development in individual feed intake characteristics and reproductive performance during three successive reproduction cycles. Performance of the ad libitum-fed sows was compared to the performance of sows that were fed a conventional diet restrictedly. Feed intake characteristics during gestation were only measured in the ad libitum-fed sows. One hundred and nineteen sows were assigned to one of two gestation feeding regimens. Gestating sows were fed a conventional Dutch diet restrictedly or a diet with a high level of fermentable NSP ad libitum. During lactation, sows were given free access to a commercial lactation diet from d 6 after parturition onward. The ad libitum-fed sows ate 1.3 kg/d more during gestation than the restrictedly fed sows (P < 0.001), resulting in higher body weight and backfat gains during gestation (P < 0.05). Sows that were fed ad libitum during gestation lost more body weight and backfat during lactation (P < 0.001) than sows that were fed restrictedly during gestation. Feed intake during lactation, however, did not differ between sows that were fed restrictedly or ad libitum during gestation. The numbers of total piglets born, live-born and stillborn piglets, piglet birth weight, weaning-to-estrus interval, and percentage of sows that returned to estrus after first insemination were not affected by gestation feeding regimen. Mean daily voluntary feed intake (as-fed basis) over the three reproduction cycles in the ad libitum-fed gestating sows was 4.2 kg/d. Depending on the number of preceding reproduction cycles during which a sow was fed ad libitum, the maximum voluntary feed intake was reached in Parity 3, 4, or 5 and then remained stable in subsequent parities. Mean daily feed intake of the ad libitum-fed sows increased from wk 2 to 6 of gestation and then decreased to wk 15 of gestation. The mean number of daily visits with feed intake over the three reproduction cycles was 13.8. On average, ad libitum-fed sows spent 90 min/d on eating. This study shows that it is possible to feed gestating sows a diet with a high level of fermentable NSP ad libitum during three successive reproduction cycles without negative effects on reproductive performance. [ABSTRACT FROM AUTHOR]

Summary A trial was conducted with twenty group-housed pregnant sows to study the adaptation in nutrient digestibility to a starch-rich diet or a diet with a high level of fermentable non-starch polysaccharides (NSP) during a time period of 6 weeks. The starch-rich diet was primarily composed of wheat, peas and tapioca, whereas soya bean hulls and sugar beet pulp, which both are highly fermentable NSP sources, were used to formulate the NSP-rich diet. The starch-rich diet and the NSP-rich diet were formulated to contain different levels of starch (298 vs. 78 g/kg) and fermentable NSP (100 vs. 300 g/kg), but a similar level of net energy (NE) (8.36 MJ/kg). The trial consisted of a 1-week adaptation period followed by a 5-week collection period. Weekly apparent faecal digestibilities of dry matter (DM), crude protein (CP), crude fat, ash and NSP were measured by using the acid-insoluble ash marker method. Apparent faecal digestibilities of DM and organic matter (OM) of both diets were similar. Faecal digestibility of CP and crude fat was lower (p < 0.001) whereas that of NSP was higher (p < 0.001) for sows that received the NSP-rich diet. Calculated NE values of both diets were similar. Sows fed the NSP-rich diet produced faeces that contained a lower (p < 0.001) DM content compared with sows that were fed with the starch-rich diet. The quantity of dry faeces was the same on both diets, therefore total faeces production (as-is basis) was higher (p < 0.01) for the sows fed the NSP-rich diet. During the 5-week collection period, no changes were observed in the digestibility of DM, OM and NSP in the NE value of the diets. Digestibilities of CP and fat, however, were lower in week 1 (p < 0.05) compared with weeks 2–5 for both diets. The DM content of the faeces and the quantity of dry faeces did not change from weeks 1–5. Diet by time interaction was not observed for any of the response variables indicating that sows adapt as quickly to a diet with a... [ABSTRACT FROM AUTHOR]

Studies the optimization of insemination strategies in the management of sows. Effects of insemination-to-ovulation interval on partial fertilization and embryonic development; Basis of the timing of insemination.

Contents Nine multiparous cyclic sows with permanent jugular catheters were introduced to a boar at day 10 (n = 9) or 11 (n = 5) after ovulation to study the effect on oxytocin (OT) release. If it occurs, the release of OT might play a role in embryo migration which occurs around this time, by stimulating uterine contractions. Blood samples were taken before introduction of the boar and at 2-min intervals up to 10 min after boar introduction. On average, OT levels after boar introduction were not higher than before. In only three out of the 14 occasions of boar introduction, a rise in OT level was observed that was higher than two times the standard deviation above base level. However, even on these occasions OT levels were far below the range normally observed during other events where exogenous stimuli cause OT release, such as boar introduction during estrus and suckling during lactation. We conclude that boar contact around day 10 of the estrous cycle does not induce a biologically significant OT release in sows. [ABSTRACT FROM AUTHOR]

In two experiments the effect of Progenos in pregnant sows was examined on litter traits and farrowing rate. Progenos contains 25% L-Arginine. Two hundred ten multiparous Hypor sows were used in Exp. 1. One hundred thirty six primiparous and two hundred ten multiparous PIC sows were used in Exp. 2. In both experiments, one hundred g Progenos was fed to pregnant sows from day 14 throughout day 28 of gestation. Control groups received a placebo without L-Arginine. In Exp. 1, Progenos increased (P<0.05) litter size (+0.8 piglet/litter) and farrowing rate (+11.6%). Progenos did not affect the fraction of still born piglets and birth weight, but increased (P<0.05) the within-litter standard deviation for birth weight (+31g). In Exp 2, Progenos increased in primiparous and multiparous (P<0.05) total born piglets (+1.25/litter and +1.18/litter) and piglets born alive (+1.08/litter and +0.93/litter), respectively. Farrowing rate was not affected (P>0.1) by treatment. A potential explanation for the effect of Progenos might be that L-Arginine stimulates angiogenesis and might thereby influence placental efficiency. This leads to extra survival of those fetuses that normally do not survive. It is concluded that Progenos has a positive effect on litter size in primiparous and multiparous sows. [ABSTRACT FROM AUTHOR]

Abstract: Our objective was to investigate follicle development in sows during and after different Altrenogest treatments post-weaning and relate this to subsequent ovulation rate and embryonic development. Primiparous UPB sows (n =47) were randomly assigned to (weaning=Day 0): control (no Altrenogest, n =12), RU8-15 (15mg of Altrenogest, Day-1 till Day 7, n =12), RU8-20 (20mg of Altrenogest, Day-1 till Day 7, n =12) or RU15-15 (15mg of Altrenogest, Day-1 till Day 14, n =11). From weaning onwards, trans-abdominal ultrasound was performed daily. Sows were slaughtered on Day 4 or 5 after ovulation. Follicle size increased during Altrenogest treatment and reached a plateau around Day 6, regardless of dose (4.6±1.5, 4.6±1.6 and 4.6±1.6mm for RU8-15, RU8-20 and RU15-15, respectively). This increase resulted in larger follicles (P =0.0002) at the onset of the follicular phase (i.e. time of weaning for control sows and 24h after last administration of Altrenogest for treated sows); 4.8±1.8, 4.8±1.4, 4.9±0.9mm and 2.9±0.8, for RU8-15, RU8-20, RU15-15 and controls, respectively. Pre-ovulatory follicle size tended (P =0.07) to be larger for treated animals (7.9±2.4, 7.9±0.7, 8.6±1.3 and 6.9±0.9mm for RU8-15, RU8-20, RU15-15 and controls, respectively). The interval follicular phase-oestrus was shorter (P =0.005) for treated animals. Treatment did not affect ovulation rate or early embryonic development. However, for treated animals, the increase in follicle size during treatment was positively related with ovulation rate (P =0.05). In conclusion, post-weaning treatment with Altrenogest of first litter sows influenced follicle size and shortened the follicular phase, but did not affect ovulation rate or early embryonic development. [Copyright &y& Elsevier]

Abstract: Effects of supplementation of dextrose to the diet of sows during the weaning-to-estrus interval (WEI) on subsequent litter size and within-litter variation were investigated. After weaning, 223 sows (first to fifth parity) were fed 3.5kg/d. Half of the sows additionally received 150g of dextrose per day as topdressing on the feed. WEI and estrus duration were determined as well as subsequent pregnancy rate and litter size. Piglets were weighed individually at birth and at weaning (day 26.4; S.D.: 2.5). Supplementation of dextrose to the diet during the WEI did not affect WEI (106h), pregnancy rate (88.2%), farrowing rate (84.2%), subsequent litter size (total born: 13.70), or birth weight (1599g). The within-litter variation in birth weight was lower in sows on the dextrose treatment (CV: 17.5% versus 21.2% for the dextrose and control group, respectively, P =0.03). From this experiment, we concluded that addition of dextrose during the weaning to estrus interval did not increase litter size, but seems to affect the uniformity in birth weight of the litter. [Copyright &y& Elsevier]

Abstract: In female pigs feeding level has important effects on reproductive performance. This review is focused on the follicular development after low and high feeding levels during the luteal phase in gilts. Although aspects of diet composition seem to have a role in regulating reproductive performance, the most important aspect appears to be the plane of nutrition. Similar effects are described during lactation in primiparous sows, when their metabolism is challenged to its maximum. Also in this situation feeding level clearly affects weaning to oestrus interval, follicular development, oocyte maturation, ovulation rate and subsequent embryonic survival. [Copyright &y& Elsevier]

The effect of feeding sows a starch diet or a diet with a high level of fermentable non-starch polysaccharides (NSP) during gestation, lactation or both gestation and lactation over the first two parities on the development of stereotypic behaviour was studied in sows housed in groups during gestation and individually during lactation. A total of 119 postpubertal gilts were allotted to a 2×2 factorial experiment. Treatments were diet composition during gestation (G-Starch: 274 g/kg starch and 123 g/kg fermentable NSP or G-NSP: 86 g/kg starch and 300 g/kg fermentable NSP) and diet composition during lactation (L-Starch: 293 g/kg starch and 113 g/kg fermentable NSP or L-NSP: 189 g/kg starch and 216 g/kg fermentable NSP). Sows on both gestation diets were fed iso-energetic. During lactation, sows were given free access to the lactation diets. Behavioural measurements were carried out in weeks 3, 12 and 15 after start of the experiment or after weaning in parity 1 and 2 sows, respectively, 3 days before the expected date of parturition and 1 week before weaning in the first 3 h after the morning meal using a scan-sampling technique. Feeding group-housed sows a diet high in fermentable NSP during gestation reduced the frequency of total non-feeding oral activities (=sham chewing + other non-feeding oral activities) in gestation compared with a starch diet (P<0.001 and <0.05, in parities 1 and 2, respectively). In both parity 1 and 2 sows, the greatest reduction was realised in week 15 and the smallest reduction in week 3. During lactation, the composition of the gestation diet did not affect the frequency of total non-feeding oral activities. Feeding sows a diet high in fermentable NSP during lactation reduced the frequency of total non-feeding oral activities in lactation in parity 2 sows (P<0.05) but not in parity 1 sows compared with a starch diet. Moreover, it tended to reduce, although not statistically significant (P=0.15), the frequency of total non-feeding oral activities during subsequent gestation. This study shows that diets high in fermentable NSP during gestation reduce the level of stereotypic behaviour in gestation. It seems that diets high in fermentable NSP during lactation may have an additional reducing effect on the development of stereotypic behaviour in subsequent gestation. [Copyright &y& Elsevier]

Abstract We investigated whether maternal dietary nitrate supplementation, leading to nitric oxide (NO) formation, would affect duration of farrowing, levels of asphyxiation, vitality of piglets at birth and/or loss of potential viable piglets in the form of stillbirth and pre-weaning mortality. Data were collected from 190 crossbred (Yorkshire x Dutch Landrace) sows, which were allocated, balanced for parity, to six dietary nitrate levels (0, 0.03, 0.06, 0.09, 0.12 or 0.15% of nitrate). Sow received the lactational diet containing nitrate from approximately 7 days before farrowing until 5 days after farrowing. Blood acid-base parameters (pH, p O 2 , p CO 2 , BE ecf , HCO 3 , sO 2 and lactate) and nitrate concentration were determined in umbilical cord blood. The farrowing process was video recorded and later analysed for total duration of farrowing, piglet birth interval, piglet vitality was scored and piglet latency to stand right after birth. Placentas were collected after expulsion during and after farrowing. Placenta length and width were measured and placental color scores were assessed based on redness of the placenta. The probability of a higher vitality score of piglets (being more vital) linearly increased with increasing levels of maternal dietary nitrate. This higher vitality score however, was not reflected by changes in the blood acid-base parameters in umbilical cord blood, except for a tendency for a higher p O 2 with increasing levels of nitrate, which could have been caused by a quicker onset of respiration or an increased blood flow to the piglets during birth. Placenta width increased with increasing levels of maternal dietary nitrate, but no effect on placenta length and redness was found. Neither duration of farrowing nor birth interval were affected by maternal dietary nitrate level. In conclusion, maternal nitrate supplementation may affect piglet vitality via vasodilatation (placental characteristics) rather than an increase in exercise efficiency (duration of farrowing). Highlights • Duration of farrowing was not affected by nitrate supplementation. • p O 2 in umbilical cord blood tended to increase with increasing dosage of nitrate. • Placenta width increased with increasing levels of sow nitrate supplementation. • Piglet vitality increased linearly with increasing levels of supplemented nitrate. [ABSTRACT FROM AUTHOR]

Osteochondrosis (OC) is a consequence of necrotic growth cartilage formation early in life and suggested to be associated with lameness and premature culling of sows. Higher insulin, glucose, and insulin-like growth factor-1 (IGF-1) are associated with increased OC in horses and are affected by carbohydrates. If dietary composition can affect OC through metabolic parameters in sows, it could be a tool in practice to reduce OC prevalence. This study examined if OC prevalence in rearing gilts can be influenced by dietary carbohydrates and/or arginine by affecting IGF-1, insulin, glucose, and nitric oxide (NO) levels. Gilts (n=212; Dutch Large White x Dutch Landrace) were acquired after weaning (4 weeks of age). At 6 weeks of age, gilts were subjected to a 2×2 factorial treatment design of dietary carbohydrate and arginine level scale fed at pen level. Carbohydrate level consisted of 12.5% cornstarch and 12.5% dextrose added to a basal diet (C+) versus an isocaloric diet in which cornstarch and dextrose were replaced with 8.9% soya bean oil (C−). Arginine supplementation consisted of 0.8% arginine supplemented to a basal diet (A+) versus 1.64% alanine as the isonitrogenous control (A−). At 24 weeks of age, blood samples of in total 34 gilts around feeding were taken and assessed for insulin, glucose, IGF-1, and NO levels. After slaughter at 25 weeks of age, OC was scored on the elbow, knee, and hock joints. Gilts in the C− treatment had higher glucose and insulin levels 90 min after feeding onwards and higher IGF-1 levels than gilts in the C+ treatment ( P< 0.05). Arginine supplementation did not significantly affect metabolic parameters. Arginine supplementation tended to decrease OC prevalence ( P= 0.07) at the animal level (all joints combined) and in the knee joint. Carbohydrate treatment affected prevalence of OC only in the knee joint in which gilts in the C− treatment had a higher odds ratio (OR) to have OC (OR=2.05, CI: 1.18–3.58) than gilts in the C+ treatment. Additionally, body weight at slaughter was significant when added to the statistical model ( P <0.01) in the knee joint and the animal level (per 10 kg increase OR=1.33, CI=1.11–1.6 and OR=1.17, CI=1.05–1.31, respectively). This study found effects of carbohydrates on OC prevalence in gilts at slaughter. The dietary treatment effects found in the current study likely have been mediated through effects on body weight. [ABSTRACT FROM AUTHOR]

Osteochondrosis (OC) develops at a young age and has been associated with lameness and reduced longevity of sows. Early detection of OC is therefore beneficial for selection against OC. Possibly, immunological components within the blood may serve as an indicator for OC development and could therefore be used as a biomarker. Levels of naturally occurring (auto-) antibodies (N[A]Ab) have been associated with homeostatic imbalance and various forms of inflammation, and may have an association with OC. The aim of this study was to investigate possible associations between the presence and levels of N(A)Ab of the IgM and IgG isotypes at an early age with OC in growing gilts at slaughter (24 weeks of age). Plasma samples were obtained from 212 Topigs 20 (Dutch Large White x Dutch Landrace) gilts at 6, 10, and 24 weeks of age and analyzed for N(A)Ab titers against 11 (auto-) antigens using ELISA. After slaughter, the elbow, hock, and knee joints were macroscopically examined for OC status. Due to low prevalence of OC in the elbow joint (5.4%), the elbow joint was not taken into account in analyses. Significant ( P ≤0.05) associations with OC in both the hock joint and at the animal level (all joints combined) were found for IgM titers against chondroitin sulfate A at 6 weeks of age (OR 1.4 and 1.5), actin at 6 weeks of age (OR 1.4 and 1.3), thyroglobulin at 24 weeks of age (OR 1.5 and 1.3), and IgG titers against insulin at 6 weeks of age (OR 1.7 and 1.4). Additionally, significant ( P ≤0.05) associations with OC were found at the knee joint for IgM titers against albumin at 6 weeks of age (OR 2.3), at the hock joint for IgM titers against keyhole limpet hemocyanin at 6 weeks of age (OR 1.4), and at the animal level for IgM titers against actin at 24 weeks of age (OR 1.3). This study indicated for the first time associations between the presence and levels of N(A)Ab at a young age and OC at 24 weeks of age in breeding gilts. [ABSTRACT FROM AUTHOR]

The aim of this study was to demonstrate successful breeding of sows with a single fixed-time insemination following ovulation induction by buserelin, a GnRH analogue. In a first step, the optimal dose of buserelin (6, 10, or 16 μg) injected at 77 hours after weaning was determined in weaned sows (N = 15, 11, and 12, respectively) using its ability to induce an LH surge of similar magnitude as in control sows (N = 15) and induce ovulation. In 29/38 treated sows (76%), ovulation was induced and synchronized between 32 and 44 hours after injection, and the proportion of females ovulating during this time window was similar between groups at 73%, 73%, and 83% (6, 10, or 16 μg, respectively). Interestingly, whereas ovulation of 100% multiparous sows was induced and synchronized in the 32 to 44 hours posttreatment time window, successful induction was achieved in a lower proportion of primiparous sows (50%, 50%, and 67% following 6, 10, or 16 μg, respectively), the dose effect being nonsignificant. The magnitude of the LH surge was similar between control and treated sows, irrespective of the buserelin dose injected. Neither ovulation rate nor the number of good embryos on Day 5 postovulation differed between groups. Interestingly, the frequency of follicular cysts at slaughter was significantly affected by treatment (P < 0.05), being minimal and maximal in sows treated with 10 or 6 μg buserelin, respectively. In a second step, 419 sows from commercial herds in Spain, Germany, and France were randomly allocated to a control or treated group. The control sows were inseminated twice 12 ± 4 hours apart once estrus was detected. Treated sows received 10 μg buserelin at 86 ± 3 hours after weaning and were inseminated once 30 to 33 hours later. Farrowing rate of treated sows (87%, 166/192) was similar to that of control sows (84.5%, 169/200). Litter size was also similar between treated and control sows (13.6 ± 3.8 vs. 13.7 ± 3.2). In multiparous sows, neither duration of lactation nor magnitude of the fat loss during lactation significantly affected treatment effects. It is concluded that ovulation of weaned multiparous sows can be tightly synchronized by buserelin (10 μg) administration at 86 hours postweaning. This allows breeding once at a fixed time following buserelin injection while maintaining reproductive performance at a level similar to that of sows bred twice during estrus. [ABSTRACT FROM AUTHOR]

Abstract: Three intermittent suckling (IS) regimes were evaluated for their effects on lactational oestrus and subsequent fertility. Control sows were weaned (CW; n =38) at d 26±2 of lactation. In IS19-7D (n =40) and IS19-14D (n =42) sows, IS started at d 19±1 of lactation and sows were weaned 7 or 14d later. In IS26-7D (n =41), IS started at d 26±1 of lactation and sows were weaned 7d later. During IS, sows were separated from their piglets for 10h/day. Oestrus detection was performed twice daily without a boar and ovulation was confirmed by ultrasound once a week. In IS19-7D, IS19-14D and IS26-7D, respectively, 50%, 64% and 61% of the sows showed oestrus and ovulation during IS (P >0.05), and, of the remaining sows, 100%, 93%, and 69% showed oestrus in the first week after weaning. In CW sows, 95% showed oestrus in the first week after weaning. Parity 1 sows were considerably less likely than older parities (23% vs. 68%) to show oestrus in lactation. Pregnancy rate of the first post partum oestrus (during lactation or after weaning) was 89% (CW), 92% (IS19-7D), 80% (IS19-14D) and 77% (IS26-7D) (P >0.05) and subsequent litter size was 14.5±0.5, 14.5±0.6, 15.3±0.5 and 15.2±0.8, respectively (P >0.05). Sows mated during lactation had similar pregnancy rate and litter size to those mated after weaning. Hence, ongoing lactation for the first 2–9d of pregnancy did not negatively affect fertility. A total of 50–64% of IS sows showed lactational oestrus, regardless of the stage of lactation. Pregnancy rates and litter size were similar to control sows, and were not affected by stage of lactation at mating. [Copyright &y& Elsevier]

Abstract: This study assessed pulsatile release of LH during altrenogest treatment after weaning in primiparous sows and related this to follicle development, estrus and ovulation rate. Weaned sows (n =10) received altrenogest 20mg/day from D-1 to D13 (weaning=D0) at 0800h. On D13, blood samples were collected every 12min from 1000 until 1900h (1st sampling period) and from 2300h until 0800h (2nd sampling period). During the 1st sampling period, LH concentrations remained low and no LH pulses were detected in 8/10 sows. During the 2nd sampling period, average and basal LH concentrations (P <0.04) and frequency of pulses (P <0.0001) were higher than during the 1st sampling period. Sows with short vs. long intervals to estrus (<5 days vs. ≥5 days) had higher basal and average LH concentrations during the 2nd sampling period (P ≤0.004) and showed more follicular growth during treatment (P =0.007), generating larger follicles at D14 (P =0.005). Sows with high ovulation rate (≥25) displayed more LH pulses in total than sows with low (<25) ovulation rates (P =0.03). In conclusion, this study showed that altrenogest efficiently prevented LH pulsatility during the first bleeding period and that low frequency/high amplitude LH pulses were generally present during the second bleeding period. This variability in LH release in between two altrenogest administrations (24h) may explain why follicular growth progresses to 5mm during altrenogest treatments. LH pulsatility was related to length of the follicular phase and ovulation rate, which signifies its relevance. [Copyright &y& Elsevier]