Reproductive performance of first parity sows.

An investigation of the reproductive performance of first parity sows is described. In a retrospective study it was found that the size of the second litter was significantly greater in those sows with a prolonged weaning to oestrus interval of more than 15 days. Deliberately delaying mating until at least 12 days after weaning produced a similar increase in second litter size. This improvement was not associated with an increase in ovulation rate.     

Reproductive performance of sows fed elevated calcium and phosphorus levels during growth and development

A cooperative regional study (S-145) involving 586 farrowings was conducted at five state experiment stations (Georgia, Mississippi, South Carolina, Tennessee and Virginia) to determine the influence of feeding elevated Ca and P levels during growth and development on general reproductive efficiency and longevity of confined, housed females kept for three consecutive parities. Two dietary Ca and P levels (100 vs 150% of 1979 NRC-recommended amounts) were fed ad libitum from weaning to 100 kg. A diet containing .8% Ca and .6% P was limit-fed to all gilts and to all sows during gestation and lactation. Growth rate and feed efficiency from weaning to 100 kg were similar (P greater than .10) for gilts fed 100 vs 150% Ca and P levels. A similar total number of litters (292 vs 294) was farrowed by each previous treatment group. From the previously-fed-100% Ca and P group, 78 and 65% of the sows that completed the first parity completed the second and third farrowing, respectively. Similarly, from the previously-fed-150% Ca and P group, 81 and 57% completed the second and third farrowing, respectively. Across all locations, total pigs born, live pigs born, stillborns, birth weight, number and weight of pigs at 21 d of age, sow weight at 110 d of gestation and at weaning did not differ (P greater than .10) between the two previously fed sow groups. There were significant location and farrowing effects, but most two-way interactions with Ca and P levels were not significant.(ABSTRACT TRUNCATED AT 250 WORDS)     

苜蓿素和胎次对母猪繁殖性能的影响

试验旨在研究苜蓿素和胎次对母猪繁殖性能的影响,选择90头母猪,头胎、二胎和三胎各30头,每个胎次分为2个处理,分别饲喂试验日粮(添加500 g/t苜蓿素)和基础日粮,共6个处理,每个处理15个重复,每个重复1头母猪,饲养试验时间为配种至产仔。结果表明,日粮添加苜蓿素能显著降低弱仔数(P<0.05),在延长母猪妊娠期的同时提高产仔均重(P<0.01),但有增加死胎的趋势;胎次能显著提高健仔数(P<0.05)和死胎数(P<0.01),影响产仔均重(P<0.05),有增加产仔数和降低弱仔数的趋势;苜蓿素和胎次在弱仔数上有交互作用(P<0.05)。结果提示,随母猪胎次的增加会同时提高健仔数和死胎数,日粮添加苜蓿素可以延长妊娠期,提高健仔重,降低弱仔数,提高繁殖性能。     

Association between limb conformation and retention of sows through the second parity

OBJECTIVE: To determine the association between limb conformation scores in gilts and retention through the second parity. ANIMALS: 961 gilts. PROCEDURE: Gilts were monitored for 1 year. Baseline data recorded were conformation scores for the forelimbs and hind limbs and backfat thickness. Primary outcome was time to removal from a herd, and the secondary outcome was time to removal as a result of lameness. RESULTS: 662 of 961 (68.89%) females remained in herds through the second parity, whereas 299 (31.11%) were removed before the second parity. Survival time for females on the basis of conformation scores for the forelimbs and hind limbs differed significantly for total sow removals and removals as a result of lameness. Females with poor conformation scores for the hind limbs had an increased risk of being removed, compared with risk for females with better conformation scores. Risk of removal specifically as a result of lameness increased as conformation score for the hind limbs became poorer. Proportion of the total population that was removed and could be attributed to undesirable limb conformation was 16.13% for forelimbs and 12.90% for hind limbs. CONCLUSIONS AND CLINICAL RELEVANCE: Females with undesirable conformation were removed earlier than females with desirable conformation. This was particularly true for females with low conformation scores for the hind limbs. Selection of gilts on the basis of limb conformation may result in reduced attrition of females and improved performance of herds over time.     

Reproductive performance and profitability of heifers fed to weigh 272 or 318 kg at the start of the first breeding season

Reproductive performance and weaning weight of the first calf was determined in 221 Brahman crossbred heifers fed to weigh either 272 (TW1) or 318 kg (TW2) at the start of their first breeding season (target weight). Heifers were divided into light- (below average) and heavyweight (above average) groups on the basis of initial weight. Within each target weight, heifers were fed in three lots. One lot contained lightweight heifers, the second contained heavy heifers and the third was composed of one-half heavy- and one-half lightweight heifers. Heifers were fed for 200 d before the start of the first breeding season. More heifers in TW2 showed estrus and became pregnant in the first 20 d of the breeding season and more were pregnant at the end of the first breeding season. These same differences in reproductive performance were also noted the second year. Each heifer exposed in TW2 weaned 43.4 kg more calf than those in TW1. An average heifer in TW2 was fed 220 kg more corn and 100 kg less hay than a corresponding heifer in TW1. Estrus and pregnancy rate for lightweight heifers in TW1 and TW2 were not improved by sorting and feeding them separately.     

Feeding motivation and plasma metabolites in pregnant sows fed diets rich in dietary fiber either once or twice daily

The present study investigated the effects of source and level of dietary fiber (DF) and feeding frequency (once vs. twice daily) on feeding motivation and plasma metabolites at 4 different time points post feeding. Sixty pregnant sows (Sus scrofa, 4 blocks of 15 sows) were allocated to 1 of 5 diets within blocks. Four diets were restricted (approximately 35 MJ ME/d): a barley and wheat control diet (171 g DF/kg DM; 12 g DF/MJ ME), and 3 fiber diets formulated to contain 35% DF by including pectin residue (323 g DF/kg DM; 25 g DF/MJ ME), potato pulp (404 g DF/kg DM; 29 g DF/MJ ME), or sugar beet pulp (367 g DF/kg DM; 25 g DF/MJ ME). The fifth diet was a mixture including an equal amount of the 3 fiber diets offered semi ad libitum (ad libitum access to feed during 6 periods of 1 h starting at 0300, 0600, 1100, 1500, 1800, and 2300; 354 g DF/kg DM; 25 g DF/MJ ME). The experimental period included 2 periods of 4 wk each. Restricted-fed sows were fed once daily (0800 h) during the first period and twice daily (0800 and 1500 h) during the second period, or vice versa. Semi ad libitum fed sows had access to feed 6 times a day in both periods. In each period, the feeding motivation was assessed in an operant conditioning test, and samples of peripheral blood were taken in a balanced design, at 0900, 1200, 1900, and 0700 h, corresponding to 1, 4, 11, and 23 h after feeding for restricted sows fed once daily. No differences in the feeding motivation were found between the 4 restricted diets at any of the time points post feeding, but semi ad libitum fed sows had a decreased feeding motivation (P < 0.001). Among the restricted-fed sows, feeding twice daily resulted in decreased feeding motivation at 1900 h (P < 0.001) and at 0700h (P < 0.05) compared with feeding once daily, but not at 0900 and 1200 h, indicating that feeding twice daily reduced feeding motivation during the night compared with feeding once daily. Among restricted-fed sows, plasma concentrations of short-chain fatty acids (SCFA) were greater in sows fed high-fiber diets compared with the control (P = 0.02). Nonesterified fatty acid was least in sows on the control diet and greatest in sows on the potato diet, whereas sows on the pectin and sugar beet diets were intermediate (P < 0.001). Less diurnal variation in glucose (P < 0.001) was seen in sows on high-fiber diets. In spite of the found effects on plasma metabolites, the applied level of fiber in the diet of restrictedly fed sows did not reduce their feeding motivation irrespective of fiber source.     

Dietary L-carnitine increases plasma leptin concentrations of gestating sows fed one meal per day

Thirty-four sows (parity=1.8; BW=206 kg) were used to determine the influence of L-carnitine and/or chromium tripicolinate on plasma leptin concentrations of gestating sows fed one meal daily. Treatments were arranged in a 2 x 2 factorial with main effects of carnitine (0 or 50 ppm) and chromium (0 or 200 ppb). Diets were fed for approximately 167 days (through one gestation, the following lactation, the interval from weaning to estrus, and 28 days into the following gestation) prior to blood collection. Leptin concentration was determined in plasma that was collected at feeding, every 15 min for the first 3h after feeding, and at 6, 9, 15, 20, and 24h after feeding. Sows fed diets containing carnitine had greater (P<0.02) overall mean plasma leptin concentrations and greater (P<0.05) leptin concentrations at 2.25, 3, 6, 15, 20, and 24h after feeding compared to sows fed either the control diet or the diet containing chromium. Leptin concentrations of sows fed diets containing carnitine also were greater (P<0.05) than control sows at 2.5 and 2.75 h postprandial and greater than (P<0.05) sows fed diets with both carnitine and chromium at 6h after feeding. Chromium had no effect (P>0.10) on plasma leptin concentration. These results suggest that dietary carnitine, but not chromium, increases circulating leptin in gestating sows fed one meal per day. These results may help to explain the improvements in reproductive function previously observed from feeding sows diets containing carnitine.     

日粮中添加多肽菌素对妊娠母猪繁殖性能和新生仔猪生长性能的影响

试验旨在研究母猪日粮中添加多肽菌素对妊娠母猪繁殖性能和新生仔猪生长性能的影响。试验选取胎次、体况相近,预产期前45 d的母猪23头,随机分为2组,试验组12头,对照组11头。每头母猪单栏饲喂,作为一个重复。对照组饲喂基础日粮,试验组在基础日粮中添加2 g/kg多肽菌素。试验期69 d(妊娠期45 d,哺乳期24 d)。结果表明:(1)试验组母猪窝产仔总数比对照组高2.98%,窝产活仔数比对照组高4.98%,窝产健仔数比对照组高6.95%,健仔率比对照组高3.90%,但差异均不显著(P0.05)。(2)试验组仔猪初生窝重、初生个体重、断奶窝重、断奶个体重、平均窝增重及平均个体增重均比对照组显著提高(P0.05);(3)试验组仔猪初生窝重均匀度及断奶窝重均匀度分别比对照组提高32.23%和38.78%,差异极显著(P0.01)。说明妊娠母猪日粮添加2 g/kg多肽菌素可提高妊娠母猪繁殖性能和初生仔猪生长性能,提高生猪养殖的实际效益。     

Reproductive characteristics of endophyte-infected or novel tall fescue fed ewes

Reduced pregnancy rates often occur in ruminants grazing endophyte-infected (EI) tall fescue. The objectives were to characterize basal and oxytocin-induced PGF_2α concentrations in serum and reproductive function in ewes fed tall fescue seed and to determine whether addition of fish meal (FM) to a diet of EI fescue would alter PGF_2α production. Ewes were fed a diet with novel or non-toxic endophyte-infected (NE) or EI tall fescue seed containing either corn gluten meal (CG) or FM. Serum concentrations of prolactin, a measure of severity of fescue toxins, were reduced in ewes fed EI compared with NE forage seed (forage × day, P < 0.02) and were greater in NEFM than NECG-fed ewes (P < 0.03). Size and number of corpora lutea (CL), determined by trans-rectal ultrasonography, were similar between diets (P > 0.10). Serum concentrations of progesterone were reduced in ewes with two CL fed EI compared with NE seed (forage × CL number × day, P < 0.001). Oxytocin-induced PGFM concentrations during the luteal phase were determined as a measure of uterine function. On the day of oxytocin administration, peak plasma concentrations of PGFM were reduced in EI compared with NE-fed ewes (forage × time, P < 0.003), but FM did not influence PGFM concentrations. Estrous cycle length was more variable in EI than NE-fed ewes. There appears to be some asynchrony between NE and EI-fed ewes leading to changes in uterine responsiveness to oxytocin. Inclusion of FM did not alter uterine responsiveness to oxytocin.     

Reproductive performance of sows supplemented with dietary L-carnitine over three reproductive cycles.

The effect of L-carnitine supplementation during pregnancy and lactation on the reproductive performance of sows was studied in two separate trials over three reproductive cycles. Both trials were identical in design and conduct but were performed with different animals. The trials comprised of a total of 127 sows (trial 1) and 100 sows (trial 2) which were divided into control and treatment groups. All animals were fed individually and received basic feed mixtures with low native carnitine concentrations. The rations of the sows in the treated group were supplemented with 125 mg L-carnitine per head and day during pregnancy and 250 mg L-carnitine per head and day during lactation. The animals of the control group received identical feed mixtures in identical amounts, but without the L-carnitine supplement. In the first trial, 212 litters were produced and evaluated for number and body weight of the animals, in the second trial, 173 litters were produced. L-carnitine supplementation significantly increased body weight gains of the sows between day 1 and day 85 of weaning. The number of born piglets, stillborn piglets and piglets fit for rearing was not influenced by dietary L-carnitine supplementation. However, L-carnitine supplementation significantly increased the weights of piglets and litters at birth, weight gains of litters during suckling and weights of litters at weaning. These effects of L-carnitine were seen in both trials; they were independent of the age of the sows and remained over three reproductive cycles in which the sows where continuously treated with L-carnitine. Overall, the study shows that dietary supplementation with L-carnitine during pregnancy and lactation improves the reproductive performance of sows over several reproductive cycles, independent of the age of the sows.     

Survival and postweaning performance of pigs from sows fed fat during late gestation and lactation

Sows were fed a control corn-soybean meal gestation diet to d 80 of gestation. One group of sows (n = 25) continued receiving the control diet until the end of lactation, whereas two groups were placed on other treatments. One group (n = 27) was fed a diet containing 5% added solid fat pellets from gestation d 80 through lactation, whereas another group (n = 25) was fed a diet with 10% added solid fat pellet from gestation d 100 through d 14 of lactation. Feed supply was 2.27 kg/d during gestation and to appetite during lactation. Pigs from sows fed the control diet or 5% solid fat pellet diet were weaned with an age range of 22 to 28 d and immediately allotted in a 2 x 3 factorially designed 4-wk feeding trial. Pigs from these two sow groups were fed diets 1) without fat, 2) with 4.5% choice white grease or 3) with 5% solid fat pellet. Sow weight loss, backfat change and pig weights were not different at weaning among treatments. Survival rates of all pigs to 21 d averaged 90% with no significant differences between treatments. Pigs from fat-fed sows had more (P less than .05) glycogen per gram of liver, 41% more total liver glycogen and 16% more serum glucose at birth. Weanling pigs from fat-fed sows grew slower (P less than .05) than pigs from control sows. Supplemental fat during gestation increased liver glycogen of pigs, which should help survival, but the feeding of fat throughout lactation had a negative effect on ADG during a 4-wk postweaning period.     

Digestibility of fiber components and reproductive performance of sows fed high levels of alfalfa meal

Two experiments were conducted with second-parity sows fed either 5 or 50% alfalfa meal diets (Exp. 1) or 5, 50 or 95% alfalfa meal diets (Exp. 2) beginning 30 d after breeding and continuing through lactation, 21 d postpartum. Diets in both experiments were calculated to be equal in crude protein, but different in metabolizable energy content. Feed intake was restricted to 2 kg/d during gestation and ad libitum during lactation. Sows were tethered in metabolism crates 45 d after breeding. Total feces were collected during two 5-d collection periods, 60 and 100 d after breeding. Digestibilities of dry matter, fiber components (neutral detergent fiber, acid detergent fiber, hemicellulose and cellulose), protein and energy were determined in both experiments for all diets and periods of gestation. In both experiments, there was a reduction (P less than .05) in digestibility of dry matter, fiber components, protein and energy with increasing fiber levels for both periods of gestation. In Exp. 1, the decrease in digestibility of dry matter, neutral detergent fiber, acid detergent fiber, cellulose and energy was greater at 100 d gestation than at 60 d in sows fed 50% alfalfa. In Exp. 2, 50 and 95% dietary alfalfa reduced 60-d digestibilities of dry matter, all fiber constituents, energy and protein; these digestibilities were further reduced (P less than .05) at 100 d of gestation. In Exp. 1, weight gains of sows fed 5 and 50% alfalfa diets from breeding to 109 d gestation, were 42 and 18 kg/sow (5 greater than 50% level, P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Timing and temperature thresholds of heat stress effects on fertility performance of different parity sows in Spanish herds

High temperature is an environmental factor that impairs sow fertility. In this study, we identified the critical weeks for heat stress effects on aspects of fertility performance, namely weaning-to-first-service interval (WSI) and farrowing rate (FR). We also examined the threshold temperatures above which the fertility performance deteriorated and whether there were any differences between parities regarding heat stress effects or thresholds. Performance data of sows in 142 herds from 2011 to 2016 were matched to appropriate weekly averaged daily maximum temperatures (T_max) from weather stations close to the herds. Two types of ratios (i.e., ratio for WSI and odds ratio for FR) were used to identify the critical weeks for heat stress by comparing the respective measures for two sow groups based on T_max in different weeks around weaning or service events. The ratios for WSI were calculated between groups of sows exposed to T_max ≥ 27 °C or <27 °C in each week before weaning, with the T_max cutoff value based on a recent review study. Similarly, the odds ratios for FR for the two groups were calculated in weeks around service. The weeks with the largest differences in the fertility measures between the two T_max groups (i.e., the highest ratio for WSI and the lowest odds ratio for FR) were considered to be the critical weeks for heat stress. Also, piecewise models with different breakpoints were constructed to identify the threshold T_max in the critical week. The breakpoint in the best-fit model was considered to be the threshold T_max. The highest ratios for WSI were obtained at 1 to 3 wk before weaning in parity 1 and 2 or higher sow groups. The threshold T_max leading to prolonged WSI was 17 °C for parity 1 sows and 25 °C for parity 2 or higher sows. Increasing T_max by 10 °C above these thresholds increased WSI by 0.65, and 0.33 to 0.35 d, respectively (P < 0.01). For FR, the lowest odds ratios were obtained at 2 to 3 wk before service in parity 0, 1, and 2 or higher sow groups. The threshold T_max leading to reductions in FR was 20, 21, and 24 to 25 °C for parity 0, 1, and 2 or higher sow groups, respectively. Increasing T_max by 10 °C above these thresholds decreased FR by 3.0%, 4.3%, and 1.9% to 2.8%, respectively (P < 0.01). These results indicate that the critical weeks for heat stress were 2 to 3 wk before service for FR and 1 to 3 wk before weaning for WSI. The decreases in fertility performance in parity 0 to 1 sows started at temperatures 3 to 8 °C lower than in parity 2 or higher sows.     

Reproductive performance of sows with and without PRRS modified live virus vaccination in PRRS-virus-seropositive herds

Porcine reproductive and respiratory syndrome (PRRS) virus infection causes reproductive failures including return to oestrus, abortion, mummified foetuses, stillborn, and weak-born piglets. The objective of the present study was to investigate reproductive performance of sows in PRRS-virus-seropositive herds with and without PRRS modified live virus (PRRS-MLV) vaccination. The study was conducted in 20 PRRS-virus-seropositive commercial swine herds in Thailand. The data included 211,009 mating and 180,935 farrowing records. The analysed variables included farrowing rate (FR), return rate (RR), abortion rate (AR), total number of piglets born per litter (TB), number of piglets born alive per litter (BA), percentage of stillborn (SB), percentage of mummified foetuses (MM), and number of piglets weaned per litter (WP). The results revealed that FR in non-vaccinated sows was lower than that in vaccinated sows (85.0 vs 89.7 %, respectively, P?<?0.001), and RR in non-vaccinated sows was higher than that in vaccinated sows (6.9 vs 3.7 %, respectively, P?<?0.001). AR did not differ significantly between non-vaccinated and vaccinated sows (1.6 and 2.0 %, respectively, P?=?0.964). TB (11.2 and 11.5, respectively, P?<?0.001), BA (10.0 and 10.6, respectively, P?<?0.001), and WP (9.2 and 9.6, respectively, P?<?0.001) in non-vaccinated sows were lower than those in vaccinated sows. SB (6.9 and 5.1 %, respectively, P?<?0.001) and MM (3.2 and 2.2 %, respectively, P?<?0.001) in PRRS-MLV-vaccinated sows were higher than those in non-vaccinated sows. The improvement in sow reproductive performance in PRRS-MLV-vaccinated herds was most pronounced in gilts and primiparous sows.     

Influence of dietary L-carnitine and chromium picolinate on blood hormones and metabolites of gestating sows fed one meal per day

Gestating sows (n = 44; parity = 2.0; BW = 208 kg) were used to determine the effects of dietary L-carnitine and Cr picolinate (CrP) on daily blood hormone and metabolite profiles. Diets were formulated as a 2 x 2 factorial with L-carnitine (0 or 50 ppm) and CrP (0 or 200 ppb) and were fed from breeding through gestation, lactation, and 28 d into the subsequent gestation, at which time blood collection occurred. Sows were fed 1 meal per day during gestation (2.04 kg from breeding until d 100 and 2.95 kg from d 100 until farrowing) and ad libitum during lactation. Sows were fitted with indwelling venous catheters, and blood (plasma) was collected at feeding, then once every 15 min for the first 3 h after feeding, and at 6, 9, 15, 20, and 24 h after feeding. Postfeeding and overall insulin and connecting peptide of insulin (c-peptide) was decreased for sows fed diets with CrP or L-carnitine and was greatest for sows fed the control diet; however, sows fed both L-carnitine and CrP had an intermediate response (L-carnitine x CrP, P < 0.01). Postfeeding glucose peak was decreased (P < 0.05) in sows fed diets with L-carnitine, CrP, or both, vs. the control, and mean glucose concentration was decreased (P < 0.01) for sows fed diets with CrP. L-Carnitine decreased (P < 0.04) the NEFA concentration. Sows fed diets with CrP exhibited increased (P < 0.03) postfeeding and overall NEFA and greater (P < 0.02) fasting and overall glycerol. Overall plasma urea N was lowest for sows fed the diet with L-carnitine; however, diets containing CrP had intermediate responses compared with the control (L-carnitine x CrP, P < 0.005). Sows fed diets with L-carnitine had greater (P < 0.008) IGF-I from 3 to 24 h after feeding and tended to exhibit greater (P < 0.06) overall IGFBP-3. Sows fed the diets with CrP had greater (P < 0.05) IGFBP-3 from 2 to 20 h after feeding. No differences were observed for glucagon or triacylglycerol (P > 0.10). The changes in metabolites and metabolic hormones indicate that both L-carnitine and CrP influence energy metabolism of gestating sows; however, their effects on blood hormones and metabolites differ. Thus, the improvement in energy status from adding both L-carnitine and CrP may have an additive effect on reproductive performance of sows.