Effect of dietary gestation and lactation protein levels on reproductive performance and body composition of first-litter female swine

A 2 X 3 factorial split-plot experiment was conducted to determine the effect of dietary protein on the performance and calculated body compositions of 45 first-litter sows using the D2O dilution technique at various reproductive stages. Animals were initially fed 1.82 kg daily of a 14% protein diet to 14 d post-coitum. Subsequently, two gestation protein levels (5 or 14%) were daily fed at 1.82 kg from 15 d postcoitum to parturition with three dietary lactation protein levels (5, 14 or 23%) fed from parturition to 28 d postpartum. Maternal body compositions were determined at 17, 35, 70, 85 and 105 d postcoitum and 7, 14 and 28 d postpartum using prediction equations reported previously. Gravid sows demonstrated higher maternal tissue accretion of all body chemical components from 14 to 70 d than from 70 to 105 d postcoitum. Sows fed the 5% protein gestation diet had more maternal fat but less protein accretion than those fed the 14% protein at each measurement interval. During the last trimester, those sows fed the 5% protein diet catabolized body protein reserves. Gravid sows fed the 14% protein gestation diet catabolized more maternal protein and water between 105 d postcoitum and 7 d postpartum than those fed the 5% protein diet. Litter and pig birth weights were lower and postpartum mortality higher for sows fed the 5% rather than the 14% protein gestation diet. Sows fed the 5% protein lactation diet mobilized more maternal tissue, particularly fat, between 7 and 28 d postpartum than those fed 14 or 23% protein lactation diets. These results suggest that labile maternal body protein reserves are used by gravid and nursing dams to fulfill reproductive needs and that dietary protein sequence affects the dam's performance and body composition.     

Lactation and reproductive performance of mares fed added dietary fat during late gestation and early lactation

Eighteen pregnant mares were randomly allotted to one of two treatment groups. The control group was fed a conventional concentrate and the fat group was fed a concentrate containing 5% feed-grade rendered fat. Both concentrates had the same nutrient:calorie ratio and were fed in amounts required to maintain zero change in percent body fat of the mares. During the study, which began 60 d prior to expected foaling date and ended 60 d postpartum, mares were monitored for feed intake, body weight, rump fat thickness, ration digestibility, plasma glucose and lipid concentrations, milk composition and reproductive efficiency. Birth weight, growth rate, and plasma glucose and lipid concentrations were also measured in foals. Mares fed fat consumed less concentrate (P<.09 during the last 60 d of gestation but consumed similar amounts of concentrate over 60 d of lactation. Protein and ether extract digestion was higher (P<.05 and P<.09, respectively) in the mares fed fat during the postpartum period. Dietary treatment had no influence on plasma glucose or lipid concentrations of the mares or plasma glucose concentrations of their foals, but foals whose dams were fed fat had higher plasma lipid concentrations at birth (P<.01), d 10 and d 30 (P<.05). Percent fat was higher in milk samples from mares fed fat at d 10 (P<.09, 1.23 vs .99%) and d 60 (P<.01, .72 vs .43%) of lactation. Reproductive performance was not significantly different between treatment groups, however there was a trend for a shorter postpartum interval and fewer cycles per pregnancy in the mares fed added fat. Foals from both groups were of similar size and weight at birth and had similar weight gains over 60 d, however, foals nursing mares fed fat tended to gain more weight in the first week of life (1.85 vs 1.56 kg/d) and have more rump fat at d 60 (.53 vs .44 cm) than foals nursing control mares.     

Effects of dietary salt level during gestation and lactation on reproductive performance of sows: a cooperative study

Two experiments involving 1,020 litters were conducted at eight research stations to determine the effects of dietary NaCl (salt) concentration during gestation and lactation on reproductive performance of sows. Primiparous and multiparous sows were fed fortified corn- or grain sorghum-soybean meal diets at 1.82 kg/d during gestation. During the winter months (December, January, February) the feeding level was increased to 2.27 kg/d. Sows had ad libitum access to diets during lactation. Dietary concentrations of added salt were .50 and .25% in Exp. 1 and .25 and .125% in Exp. 2. When more feed was fed during gestation, the salt concentrations were reduced to .40, .20, .20 and .10%, respectively, in order to maintain a constant daily intake of Na and Cl during gestation. Gestation weight gain and lactation (21-d) weight loss of the sows were not affected by dietary salt level in either experiment. In Exp. 1, lowering the salt concentration did not influence the number of pigs farrowed, but it resulted in a .05 kg/pig reduction (P less than .01) in average birth weight. Average 21-d pig weights also tended (P less than .19) to be lower in the low-salt group. There was a decrease in litter size from the first to the second farrowing for sows fed low salt, but not for sows fed the higher salt concentration. In Exp. 2, reducing the salt content from .25 to .125% did not alter reproductive performance. The overall ratio of males to females at birth in the population of greater than 10(4) pigs was 52.3:47.7. Lower salt intakes tended to reduce the percentage of males born in both experiments, although the differences were not significant (P greater than .3). The results indicate that reducing the salt concentration in sows diets from .50 to .25 or .125% reduces birth weight in newborn pigs. When continued for more than one reproductive cycle, feeding less than .5% salt appears to reduce litter size at birth and weaning.     

Effect of pad-fan cooling and dietary organic acid supplementation during late gestation and lactation on reproductive performance and antioxidant status of multiparous sows in hot weather

A 2?×?2 factorial arrangement (rearing room with or without pad-fan cooling?×?diet with or without 2.5 kg/t organic acid) was used to evaluate the effect of pad-fan cooling and dietary organic acid supplementation during perinatal period on reproductive performance and antioxidant status of sows in hot weather. This study was conducted in a subtropical city in Guangdong Province in South China between August and October, 2015. At day 85 of gestation, a total of 112 sows were randomly assigned to the four treatments with 28 sows per treatment, and maintained until day 21 of lactation, and the feeding trial lasted for 51 days. During the experimental period, room temperature and humidity were recorded hourly. The lactation feed intake of sows (P?=?0.109) and stillbirths (P <?0.05) increased when the sows were reared in the room with the pad-fan cooling against the room without pad-fan cooling. The number of weak newborns per litter and the malondialdehyde content in days 14 and 21 milk decreased (P <?0.05), while the lactation feed intake of sows, weaned litter weights, and individual pig weights increased when the sows were fed the organic acid (P <?0.05). In conclusion, pad-fan cooling in rearing room improved the lactation feed intake of sows, and dietary organic acid supplementation improved reproductive performance and milk antioxidant status of sows. Pad-fan cooling is recommended in farrowing room, but not in gestating room.     

日粮多不饱和脂肪酸对猪繁殖性能的影响

本文主要从多不饱和脂肪酸(PUFA)的来源、合成途径、作用机理及使用效果等方面阐述了多不饱和脂肪酸影响猪繁殖性能的研究进展。     

Effect of protein intake during gestation and lactation on the lactational performance of primiparous sows.

The effect of protein intake during gestation and lactation on the lactational performance of primiparous sows was evaluated using 35 Yorkshire x Landrace gilts, allocated to six dietary treatments in a 3 x 2 factorial arrangement. Treatments consisted of three protein levels during gestation, providing approximately 4, 8, and 16 g of lysine/d, and two protein levels (low [L] and high [HI), providing approximately 15 and 45 g of lysine/d, during lactation, respectively. Diets provided similar amounts of ME and all other nutrients. As dietary protein increased during gestation, sows gained more weight and tended to decrease their backfat thickness. There was no gestation x lactation treatment interaction for lactational performance of sows. Feed intake by sows during lactation was usually low but increased (P < .05) with increasing gestation and lactation protein intake and increased linearly (P < .001) as lactation progressed. This linear increase over time was greater (P < .05) in sows fed the H than in sows fed the L protein level. Increased protein intake during lactation reduced (P < .001) 21-d sow weight loss. Milk yield and pig weight gain increased as protein intake increased during gestation (P < .05) and lactation (P < .01). Milk yield did not increase as lactation progressed (P > .05). Pig weight gain increased (P < .05) from wk 1 to 2 of lactation and decreased thereafter. Simple linear regression analysis detected few important relationships between yield of milk components and metabolites or metabolic hormone concentrations. The R2 values for these relationships were < or = .30, except for some relationships between milk component yields and blood urea nitrogen (the range was between .17 and .55). Covariate adjustment for metabolite and metabolic hormone concentrations did not eliminate treatment effects in most cases. This suggests that effects of increased protein intake on milk yield are not fully mediated through metabolite and metabolic hormone concentrations.     

The influence of gestation feeding strategy on body composition of gilts at farrowing and response to dietary protein in a modified lactation

Previous experiments have indicated that reproductive function in lean, modern genotypes may be more dependent on body protein mass than, as previously believed, on body lipid reserves. This was investigated in a 3 x 2 factorial arrangement of treatments, involving 60 first-parity sows, comparing three pregnancy feeding strategies and two lactation diets. During pregnancy, sows were fed either a basal diet (5 g lysine/kg, 13 MJ of DE/kg [C]) or the same quantity of basal diet + energy source [E], or additional basal diet supplying both protein and energy [A]. The level of supplement for E and A was adjusted weekly to achieve a backfat thickness measurement (P2 position) of 28 mm at farrowing. Isoenergetic lactation diets were fed to appetite and provided either high (180 g CP/kg, 9 g lysine/kg [H]) or low lysine (120 g CP/kg, 6 g lysine/kg [L]). From d 21 of lactation, sows were separated from their litters and housed next to a boar for 8 h each day; final weaning occurred on d 31. Pregnancy treatment differences in backfat and weight were achieved, with C sows having less backfat on d 1 of lactation than E and A sows (E = 28.1, A = 28.0, C = 22.7 kg, P < 0.001). Sows fed additional basal diet were heavier than E sows, which were heavier than C sows (E = 190, A = 201, C = 178 kg, P < 0.001). Average feed intake over lactation showed a pregnancy feeding effect, with E sows eating less than A or C sows (E = 4.9, A = 5.2, C = 5.4 kg/d, P < 0.005). Total lactation weight loss was affected by pregnancy feeding (E = 18.0, A = 19.0, C = 8.4 kg, P < 0.05) and by lactation diet (L = 19.0, H = 11.3 kg, P < 0.05), whereas total lactation backfat loss was affected only by pregnancy treatment (E = 6.9, A = 6.5, C = 4.6 mm, P < 0.05). No pregnancy treatment or lactation diet effects were observed for litter performance. Lactation diet affected weaning-to-estrus interval, with more sows on the H diet coming into estrus within 6 d of partial weaning (P < 0.05), but there was no pregnancy treatment effect. Therefore, voluntary feed intake during lactation was suppressed by increased fat reserves at a limited body protein mass but not when body protein mass was also increased. Partial weaning-to-estrus interval was increased by reduced dietary protein.     

Comparison of three methods of feeding sows in gestation and the subsequent effects on lactation performance

A total of 684 sows from breeding groups over 6 wk was used to compare three methods of feeding during gestation on gestation and lactation performance. Control gilts and sows were fed according to body condition based on a scale of 1 to 5 (1 = thin, 5 = fat). Sows were visually assessed for body condition at breeding and were assigned a daily feed allowance to achieve a BCS of 3 at farrowing. Treatment 2 used feeding levels based on backfat thickness (measured between d 0 and 5 after breeding) and weight at weaning for sows or service for gilts. Feed allowance was calculated to achieve a target backfat of 19 mm at farrowing, and remained constant from d 0 to 101 of gestation. Feed allowances were based on modeled calculations of energy and nutrient requirements to achieve target sow maternal weight and backfat gains. Treatment 3 was identical to Treatment 2, except that feeding pattern was altered for thin sows and gilts (<15 mm at service) in an attempt to reach 19 mm by d 36 of gestation. Sows were weighed at the previous weaning, and gilts were weighed at service, with both weighed again between d 112 and 114 of gestation. Backfat was measured between d 0 and 5, and again between d 108 and 113 of gestation. At farrowing, sows on Treatments 2 and 3 had 19 and 19.1 mm of backfat, respectively, whereas control sows tended to have greater (P < 0.07) backfat (20 mm). On average, sows targeted to gain 6 to 9 mm of backfat failed to reach target gains regardless of feeding method. Feeding sows in gestation based on backfat (Treatments 2 and 3) resulted in a numerically higher proportion of sows in the target backfat range of 17 to 21 mm (40.2, 53.3, and 52.6% for control and Treatments 2 and 3, respectively) at farrowing and a numerically lower percentage of fat sows (>21 mm), but no difference in the percentage of thin sows (<17 mm) compared with feeding based on body condition. In conjunction with this observation, sows fed based on BCS were fed higher (P < 0.05) feeding levels in gestation than were sows fed based on backfat depth. Gestation feeding method had no effect on performance during lactation. Feed intake in lactation was lower (P < 0.05) for high backfat sows (>21 mm) at farrowing compared with sows with <21 mm. The high proportion of sows in the optimal backfat category demonstrates that feeding based on backfat and BW has potential for facilitating more precise feeding during gestation.     

Effect of lasalocid on reproductive performance and subsequent lactation in the sow

The effect of lasalocid (140 mg . head-1 . d-1) on sow reproductive performance and subsequent piglet performance during lactation were examined in a trial that involved 114 sows. Treatments consisted of 1) control diet with no lasalocid during gestation and lactation; 2) lasalocid diet during gestation, control diet during lactation; 3) control diet during gestation and lasalocid diet during lactation; and 4) lasalocid diet during gestation and lactation. The addition of lasalocid either to gestation or lactation diets had no effect (P greater than .10) on sow weight gains or days to return to estrus postweaning. Milk protein percentages were similar (P greater than .10) for sows in all treatment groups for samples taken at 3, 7 and 14 d postfarrowing. Milk fat percentages were higher (P less than .05) in fall-bred sows at d 3 for Treatments 1, 3 and 4 than for Treatment 2 No significant differences (P less than .10) were observed for litter size at birth, 21 d postfarrowing or at weaning. Piglet weights at birth, 21 d and weaning were similar (P less than .10) among treatment groups. However, litter size and litter weight gains tended to be heavier at 21 d postfarrowing and at weaning for fall-bred sows fed lasalocid in either gestation and (or) lactation compared with those fed the control diet.     

泌乳期母猪的饲喂频率对其体况、生产和繁殖性能的影响

文章评估了哺乳期间母猪的饲喂频率(2或3次/d)对母猪体况、繁殖性能及仔猪生长性能的影响。试验选择68头母猪,随机分为8组(每组8~10头母猪),哺乳期间其中4组母猪每天饲喂2次,另外4组每天饲喂3次,母猪分为青年母猪(<2胎次)和老龄母猪(≥3胎次),试验结束后记录母猪体况评分、肩部组织病变、发情率、母猪生产及仔猪生长性能。结果显示:每天饲喂3次的母猪比饲喂2次的母猪采食量高(P<0.05),肩部组织病变低(P<0.05)。在每天饲喂3次的母猪中,青年母猪返情率为0%,老龄母猪返情率为29%,而在每天饲喂2次的母猪中,青年母猪发情率为20%,老龄母猪为5%。综上所述,在哺乳期,母猪每天饲喂3次较每天饲喂2次提高了采食量,对母猪体况评分和肩部组织病变有改善作用,同时也降低了年轻母猪的返情率。     

Effects of dietary protein level on nutrients digestibility and reproductive performance of female mink(Neovison vison)during gestation

The objective of this study was to determine whether nutrient digestibility and reproductive performance of pregnant mink(Neovison vison) were affected by different dietary protein levels. One hundred and twenty female mink were randomly assigned to four groups, receiving diets of fresh material with different protein levels. The dietary protein levels,expressed as percentage of dry matter(DM),were 32,36, 40 and 44% respectively. These values corresponded to average 320, 360, 400 and 440 g protein/kg DM, respectively. Results were as follows. All of crude protein digestibility, nitrogen(N) intake, N retention increased along with dietary protein level increasing. Low protein level(32%) significantly reduced the above indicators(P 0.05). DM digestibility and ether extract digestibility were not affected by dietary protein level. Results of mated females, barren females, kids per litter, live born kids per mated female, birth survival rate, and birth weight showed that mink achieved optimal reproductive performance when dietary protein level was 36%. In conclusion, dietary protein was anticipated to significantly influence some nutrients' utilization. Adopting the appropriate dietary protein level allow better reproduction performance. The most preferable reproductive performance was achieved when diet contained 275.5 g digestible protein per kg DM for female mink in gestation.     

Effects of supplemental biotin during gestation and lactation on reproductive performance of sows: a cooperative study

A cooperative experiment to evaluate biotin addition to sow diets was conducted at three research stations using 303 litters. Primiparous and multiparous sows (overall average parity 2.8) were fed a 14% CP corn-soybean meal diet (140 micrograms/kg biotin), with or without supplemental biotin (330 micrograms added biotin per kg feed), throughout gestation and lactation. As many sows as possible were fed their respective diets through three successive parities. During gestation, sows were given from 1.82 to 2.27 kg of feed per day, depending on environmental conditions; during lactation sows had ad libitum access to feed. Supplemental biotin had no effect (P greater than .35) on sow weights at breeding, at d 109 of gestation, at farrowing or at weaning. No differences were found in litter size at birth (P greater than .18), but at d 21 of lactation, sows fed the diet containing supplemental biotin had larger litters than sows fed the unsupplemented diet (9.4 vs 8.7 pigs, respectively; P = .01). Pig weights at birth and d 21 of lactation were not affected (P greater than .20) by dietary treatment. Biotin supplementation did not affect (P greater than .28) the length of the interval from weaning to estrus. No evidence was found that feet cracks or bruises were reduced by biotin supplementation. The results indicate that biotin supplementation of a corn-soybean meal diet during gestation and lactation increased the number of pigs at d 21 of lactation, but it did not decrease the incidence of foot lesions.     

Effect of feeding on reproductive performance in Finnish dairy cows

The effect of 2 types of feeding on the involution of the genital tract and on the fertility was studied in 79 Finnish dairy cows on a research farm. The cows were fed twice a day with home-produced feed in accordance with the Finnish feeding standard. The cows were divided according to the type of feed into a hay-urea group and a silage group. The cows were examined clinically by rectal palpation 3 times a week during 8 weeks postpartum. The time required for the complete involution of uterus and cervix was recorded. The cows in the silage group had a significantly longer time in uterine involution, a lower fertility rate at first insemination and a longer interval from calving to conception than those in the hay-urea group. The pregnancy rate in the first insemination was in the hay-urea group 91% and in the silage group 57%. The interval between calving and the first insemination was shorter in the hay-urea group than in the silage group: 71.4 +/- 10.6 and 74.0 +/- 10.3 days, respectively. The interval between calving and conception was in the hay-urea group significantly (p less than 0.01) shorter than in the silage group; 74.8 +/- 15.1 and 89.5 +/- 24.4 days, respectively.     

日粮蛋白、能量水平对母猪繁殖性能的影响

选用36头配种日龄相近，其父母代繁殖性能无显著差异的长大初产母猪，研究妊娠和哺乳28d3个不同蛋白和能量水平的日粮对母猪繁殖性能的影响。在保持日粮的蛋能比基本不变的条件下，为妊娠和哺乳母猪分别设置3个不同蛋白和能量水平的日粮，即高能高蛋白，低能低蛋白和原用日粮。结果表明：妊娠日粮蛋白能量水平对母猪产仔数，活仔数影响显著（P＜0．05），妊娠日粮蛋白能量水平对仔猪初生重无显著影响（P＞0．05），但高能高蛋白的试验组2略高于试验组1和对照组。仔猪断奶前的平均日增重受妊娠和哺乳日粮蛋白能量水平的影响不大。     

Effect of streptozotocin-induced diabetes in primiparous swine on subsequent reproductive performance

A follow-up study was conducted to determine the effects of streptozotocin-diabetes during the first parity on subsequent reproductive performance of sows. Only in the first parity, two doses of streptozotocin (50 and 100 mg/kg body weight) were administered to two groups of pregnant gilts at 80 d of gestation; a third group of gilts served as a control. Second-parity reproductive performance showed that gestation length, placental weight, mean birth weight of the litter, litter size and number of pigs born alive were not affected (P greater than .05) by maternal diabetes. Maternal serum glucose and fructose were greater (P less than .01) in high-dose sows than in the low-dose and the control dams. Serum free fatty acids (FFA) were higher (P less than .05) in high-dose dams than in control dams at d-1 and d 112 of gestation; no differences were observed between the high-dose and the low-dose during the same period. Liver and kidney weight, as well as DNA and RNA content, were greater (P less than .01) in pigs from high-dose dams than in those of the other treatments. Liver protein was elevated (P less than .01) in the progeny of high-dose dams. Dry matter and percent lipid were higher (P less than .05 and P less than .01, respectively), in pigs from high-dose sows than those from other treatment. Serum glucose, fructose and FFA of piglets were not affected by previous treatment of the dam.(ABSTRACT TRUNCATED AT 250 WORDS)