Experimental studies on the stimulation of prenatal development in swine by PMSG treatment in early pregnancy. 1. Clinical results of embryonic development in young slaughtered sows and litter results in young and old sows after PMSG treatment on the 11th day of pregnancy

Thirty-eight gilts were slaughtered on the 25th and 39th days of pregnancy, after they had received 400 I.U. PMSG treatment on the eleventh day of pregnancy. Treated and untreated animals in a group of 140 gilts and 195 adult sows were compared with each other for post-farrowing fertility performance. Weight development of embryos obtained from the slaughtered sows depended on the number of embryos alive. The survival rate of embryos from treated sows was about 5% higher than that recorded from untreated animals. Clearly increased litter sizes which, however, were associated with lower piglet birth weights were recorded from farrowing gilts and adult sows, following PMSG treatment. The conclusion is drawn that PMSG treatment, via luteotrophic action of luteinising hormone, is capable of stabilising pregnancy-related corpora lutei, resulting in higher litter sizes. Further studies will be necessary, and emphasis will have to be laid on the problem of weight development of newborn piglets, following litter-size boosting treatment.     

Experimental studies on the stimulation of prenatal development in swine by PMSG treatment in early pregnancy. 2. Analytic studies of hormones in young sows after PMSG treatment on the 11th day of pregnancy

Tens gilts received 400 I.U. of Pregmagon on the 11th day of pregnancy (day of KB2 = 1 day of pregnancy), while 8 sows were used as controls. Blood was sampled 4 times a day between the 11th and 25th day of pregnancy, with an indwelling catheter being used. Progesterone, oestradiol-17 beta, and luteinising hormone were radio-immunologically determined. The hormone profiles of pregnant sows were found to differ unambiguously from those of non-pregnant animals for both concentrations and frequencies. They were indicative of close correlations and time links of gonadotrophic and steroid hormones in early pregnancy and in oestrus. PMSG treatment in pregnancy resulted in increase in the oestradiol-17 beta concentration and attenuation in pulsatile luteinising hormone release at the time of implantation. Progesterone concentrations in peripheral blood were not affected by PMSG injection.     

配种前营养策略对母猪妊娠早期胚胎成活率的影响

提高母猪妊娠早期胚胎成活率可以增加产仔数，提高经济效益。配种前营养对妊娠早期胚胎成活率具有重要的影响．这种影响的途径与卵泡发育和卵母细胞质量密切相关。本文综述了配种前营养．包括营养水平、能量来源、蛋白质、纤维等对后备母猪和哺乳母猪妊娠早期胚胎成活率的影响。     

Effect of L-carnitine supplementation on performance parameters in gilts and sows

The effect of L-carnitine supplementation during pregnancy and lactation on performance parameters of sows was studied. The trial comprised a total of 127 sows (40 gilts, 87 mature sows) which were divided into a control and a treatment group. All animals were fed individually and received basic feed mixtures for pregnancy and lactation with low carnitine concentrations (gestation diet: 4.7 mg/kg feed, lactation diet: 12.5 mg/kg feed). 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. L -carnitine supplementation resulted in higher sow liveweight gains between day 1 and day 85 of pregnancy. The number of piglets per litter and the number born alive did not differ between the control sows and those treated with L -carnitine. However, the L -carnitine-supplemented sows produced only half as many non-viable piglets as the control animals. Moreover, litter weight and mean birth weight of piglets from L -carnitine-treated sows were higher than in the control sows. This effect was more marked in gilts (+8% higher litter weight, +9% higher piglet weight) than in sows (+7% and +6%, respectively). Piglets from sows whose ration was supplemented with L -carnitine showed higher liveweight gains during the suckling period (+12% for gilts, +4% for sows), which is why litter weights post weaning were also higher among the sows treated with L -carnitine than in the control sows (+14% for gilts, +10% for sows). Overall, the study shows that dietary supplementation with L -carnitine during pregnancy and lactation improves the reproductive performance of sows.     

Effect of prepubertal feeding regimen on reproductive development and performance of gilts through the first pregnancy

Development of gilts that conceive early and continue to produce offspring is an objective of swine production. We investigated different patterns of growth on reproductive development and performance of gilts through the first farrowing. At 13 wk of age and 43 kg BW, 286 white crossbred gilts were penned individually and assigned to treatments: Ad lib, ad libitum intake from 13 to 25 wk of age; Control, ad libitum intake from 13 wk of age until 100 kg BW and then 90% of ad libitum intake until 25 wk of age; and Restricted, 74% of ad libitum intake from 13 wk to 25 wk of age. Feed was formulated to restrict energy intake. The study was replicated in three seasons. At 25 wk of age, gilts were moved by treatment to group pens, fed for ad libitum consumption, and estrus detection was initiated. Gilts were inseminated at first estrus, and those recycling were remated. Postmating gilts were fed 1.5x maintenance until 105 to 110 d of pregnancy. Gilts were moved either to the farrowing facility or the abattoir at 105 to 110 d of pregnancy. Those taken to the abattoir were slaughtered and number, weight, and condition of the fetuses were recorded. Gilts moved to the farrowing facility were allowed to farrow, and number, weight, and condition of the piglets were recorded. Daily feed intake during breeding was 3.4 kg/d by Restricted gilts, 2.9 by Control gilts, and 2.7 kg/d by Ad lib gilts. Increased feed intake by Restricted gilts during breeding resulted in compensatory gains that overcame the reduced reproductive performance that resulted from the reduced BW and backfat these gilts carried at the start of breeding. Days to first estrus and pregnancy were not influenced by development period treatment (P < 0.13). Percentage of Ad lib, Control, and Restricted gilts that successfully completed their pregnancies were 61, 74, and 66, respectively (P > 0.19). Total feed fed from 13 wk of age to end of the first pregnancy per gilt assigned did not differ among Ad lib (506 kg) and Control (498 kg) gilts but was less (P < 0.01) in Restricted gilts (451 kg). Number of piglets born per gilt assigned (P > 0.09) and piglets produced per kilogram of feed fed from 13 wk of age to term (P > 0.29) were 6.47 and 0.0134 in Ad lib gilts, 7.26 and 0.0150 in Control gilts, and 6.38 and 0.0149 in Restricted gilts, respectively. Moderate feed restriction, 74% of ad libitum intake, reduced feed consumed from 13 wk of age to end of the first pregnancy with no significant impact on efficiency of piglet production.     

母猪繁殖力与仔猪生产效益研究

选不同比例梅山猪血缘（1／4，3／4，1／2，1）杂种母猪和大白母猪共131头，在同一饲养条件下，对母猪的繁殖力和饲料消耗连续测定5个繁殖周期，研究母猪繁殖力高低对仔猪生产效益的影响，结果表明，梅山猪及其杂种母猪产仔数，断奶仔猪数显著高于大白母猪（P＜0．01），经产1／4梅山，3／4梅山，1／2梅山，梅山的产全数分别比大白母猪多1．5，1．9，4．5，4．1头，断奶仔猪数分别多1．9，1．8，3．5，2．7头；梅山猪及其杂种母猪繁殖周期总耗料比大白猪少（P＜0．01），梅山和1／2梅山母猪的仔猪生产成本最低，产仔数和断奶仔猪与母猪繁殖周期耗料呈线性变化，与仔猪每头分摊耗料呈倒数曲线变化。     

Energetics of sows and gilts in gestation crates in the cold

Seventy pregnant sows and gilts in gestation crates with unbedded concrete-slat floors and partitions in common (which permitted contact by neighbors) in a closed house with air temperature 10 to 12 degrees C during cold weather were studied for 3 wk. The animals' lower critical temperature and thermoregulatory heat and feed requirements were estimated from measured variables, including ME intake, body weight and its change and body surface temperature, and other calculated values and assumptions. Estimates for a 165-kg sow or gilt in such an environment were: lower critical temperature = 15 degrees C; thermoregulatory heat requirement = 126 to 161 kcal/d per 1 C degree of coldness (higher as pregnancy progresses); and thermoregulatory feed requirement = 42 to 54 g/d per 1 C degree of coldness (assuming 3 kcal ME/g of diet). The sow's lower critical temperature was affected by state of pregnancy; in late pregnancy it was 1.6 to 2.6 C degrees lower than in early pregnancy. These estimates of the pregnant sow's thermoregulatory heat and feed requirements at effective environmental temperatures below the lower critical temperature accord well with those published before. But this estimate of the pregnant sow's lower critical temperature is approximately 5 C degrees lower than several made in laboratory settings on animals held individually, with no opportunity to huddle. The fact that every sow and gilt in this experiment could make mechanical contact with at least one neighbor at all times, and sometimes two, might account for much of the difference in lower critical temperature estimates.     

The effect of steroid hormone doses after ovariectomy on the peripheral hormone processes and uterine development in gilts. 2. Effects on gilts during early pregnancy

Experimental studies were conducted into ovariectomized pregnant gilts to establish effects of exogenic hormone administration, with endogenic ovarian steroids excluded, upon uterus and fetus development as well as on hormone levels in blood plasma, endometrium, and allantoic fluid. Hormone concentrations in blood plasma were found to depend clearly on hormone doses applied after ovariectomy to preserve pregnancy. 2 to 3 weeks of smooth gravidity, following ovariectomy, were ensured on the 6th or 14th day after KB1 by daily application of very low doses of progesterone only (80 mg) or in combination with estrogens, the ratio being 480:1.     

Influence of supplementary iron in late pregnancy on the performance of sows and litters

On eight farms alternate sows and gilts within three weeks of their expected farrowing date were injected intramuscularly in the neck with 8 ml of an iron (gleptoferron) preparation containing 200 mg iron/ml, or kept as uninjected controls. Data from 513 iron-injected and 488 control animals were used in the analysis of results. Small, but not statistically significant, improvements were observed in the numbers of piglets born alive and dead/litter, the birth weights and weaning weights at three weeks, the numbers of piglets fostered on and off/litter, piglet mortality, the number weaned/litter and the weaning to service interval. The condition scores of the iron-injected sows were marginally below those of the controls at weaning, but their condition scores at farrowing had also been slightly below those of the controls. A summation of these trends would suggest an overall benefit of approximately 0.45 pigs/sow/year in favour of the iron-injected sows.     

Effect of dietary beta-carotene on the early embryonic development and uterine fluid composition of gilts

The role of beta-carotene in reproduction was investigated in gilts assigned to three dietary supplementations: VA (4000 IU vitamin A); VA + VA (4000 IU + 8300 IU); VA + BC (4000 IU + 100 mg beta-carotene) per kg diet for 14 weeks. Gilts were slaughtered at day 12 of gestation. In the VA + BC group, number of corpora lutea was lowest, but the number of embryos was greatest, resulting in a non-significant decreased prenatal mortality (p<0.07). The proportion of less developed spherical and tubular embryos compared with filamentous was greatest in the VA + BC group (p<0.01). No differences were observed for vitamin A and retinal binding protein (RBP) in the uterine fluid. When animals were grouped according to the development of blastocysts, vitamin A and RBP levels were higher in the VA + BC group with only filamentous embryos (p<0.01). This indicates that the supplementation of beta-carotene to gilts might affect embryonic losses possibly because of slower alterations in the uterine environment, resulting in a higher and less variable number of embryos, despite an apparently more heterogeneous development.     

Control of fertility outcome in artificially inseminated gilts and old sows. 1: Electric stimulation of estrous sows. Its effect on insemination results

Fifty gilts and 33 old sows which exhibited oestrous after bio-engineering treatment were electrically stimulated during insemination, using an A.C. mains-connected unit. The average voltages applied were 3.7 volt for gilts and between 2.5 and 2.8 volt for the old sows. The current was applied rectally, and the responsiveness differed individually. The treated animals then were compared to unstimulated controls, and the achievement in terms of born piglets was 1.18 more for gilts and 1.20 more for the old sows. Those better results were attributed to electric acceleration of sperm transport.     

The course of ovulation in gilts after the partial replacement of HCG by GnRH for ovulation stimulation

The ovulation status and the amount of ovulated follicles were determined in 3 experiments from 197 gilts which had been given differentiated treatment and which were subsequently slaughtered. Ovulation stimulation produced high synchronisation effects, as compared to untreated animals. Partial substitution proved possible of Gn-RH vet. "Berlin-Chemie" for 500 I.U. of HCG which were generally used to stimulate ovulation, since the amount of ovulated follicles 169 hours from the last application of Suisynchron premix was in all 3 cases above the specified value of 85.0 per cent even after injection of 300 I.U. HCG/300 micrograms Gn-RH.     

Effect of exogenous administration of steroids during the 1st month of pregnancy in sows and gilts on certain characteristics of the litter

Four trials were performed to evaluate the influence of i. m. application of progesterone and estrogens to 444 experimental and control sows and gilts, kept mostly under large-scale production conditions, during the first month of pregnancy, as exerted on the number of born piglets, live born piglets and on the average birth weight of the live born piglet in litter. In the first trial the experimental sows and gilts on the 16th and 17th days of gravidity were applied 25 mg of progesterone (P4) and 12.5 micrograms of estrone (E1), in the second trial in the same phase of gravidity 25 mg of P4 with 1.25 micrograms of estradiol-17 beta (E2) and in the third trial in the identical gestation phase only 12.5 micrograms of E2 per head/day. In the fourth trial, experimental animals were given 0.55 mg of P4 with 0.275 micrograms of E1 per one kg of live weight, for six subsequent days between the 25th and 30th day of gravidity. In all trials the control animals were administered, under the same conditions, only the vehicle. None of the performed trials proved a significant difference in the studied parameters of litters of experimental and control animals (P greater than 0.05). The application of 25 mg of P4 with 1.25 micrograms of E2 on the 16th and 17th days of gravidity per sow/day under the conditions of small-scale production with the extension of the evaluated criteria of litter quality had no significant influence (P greater than 0.5) on the above-mentioned indicators, nor on the average birth weight of the whole litter and on the average number and weight of piglets of experimental sows at weaning. These results document that the verified application of hormonal substances in the above-mentioned phases of the first month of sow and gilt gravidity do not represent, in view of the intensive reproduction of pigs, a suitable procedure.     

Effect of gilt development diet on the reproductive performance of primiparous sows

The objective of this study was to evaluate the effect of development diet on first-parity reproductive performance across different genetic types of females. Gilts (n = 708) 8 to 15 d of age from five genetic lines were assembled using a segregated early weaning protocol. Genetic types represented industry variation for reproductive capacity and lean growth potential. Sampling procedures were not designed to evaluate performance differences among the genetic lines. When the gilts weighed approximately 20 kg, they were moved from the nursery facilities to a slotted-floor, environmentally controlled facility, and seven to eight animals within a genetic type were penned together. When the gilts weighed approximately 40 kg, they were moved to a modified open-front facility. Nineteen gilts were allotted to each pen (.92 m2 per pig). Gilts were assigned to one of three development diets at 120 d of age. Diet 1 (high energy, 18% CP) and Diet 2 (high energy, 13% CP) were provided for ad libitum consumption to the assigned gilts until they weighed approximately 113 kg. Gilts receiving Diet 3 (23% CP) were fed 1.8 kg/d from 82 kg until they reached 180 d of age (approximately 100 kg). Gilts were fed 2 kg daily of a gestation diet from 180 d to 200 d of age and 2.7 kg daily from 200 d until mating. To stimulate the estrus cycle, gilts were commingled and exposed to vasectomized boars beginning at 180 d of age. Gilts that were in estrus and 210 d of age or older were artificially inseminated with commercial semen. Gilts not detected in estrus within the first 50 d of observation were injected with PG600 and estrus detection continued for 30 additional days. Of the 657 gilts entering breeding pens, 422 farrowed. Bred gilts were distributed to 10 cooperator facilities before farrowing. Mixed model procedures were used to analyze the data. Significant (P < .05) genetic type x gilt development diet interactions were found for number of pigs born, number of pigs born alive, total litter birth weight, and litter birth weight of pigs born alive. Significant interactions consistently involved one genetic line and gilt development Diets 1 and 2. Gilts from this genetic line-diet subclass had poorer farrowing performance (P < .05) than gilts from the same line fed development Diet 3. Only two other significant genetic line x gilt development diet interactions were found. Gilt development diet had little influence on first-parity reproductive performance.     

Effect of day of transfer and treatment administration on the recipient on pregnancy rates after equine embryo transfer

Veterinary Research Communications -     

半胱胺对泌乳母猪生产性能影响的研究

此文研究泌乳母猪饲粮中添加半胱胺对其采食量及生产性能的影响。采用单因子试验设计,按照半胱胺添加水平设0mg/kg组(对照组)、125mg/kg组和150mg/kg组3个处理,选择胎次(3～5胎)和体重相近、距离预产期7d之内的经产大白母猪12头,随机分到3个处理中,每个处理4个重复,每个重复1头。试验期21d。结果显示,半胱胺能有效提高母猪泌乳期的总采食量,减少泌乳期体重损失,促进哺乳仔猪生长。此试验条件下,半胱胺最佳添加水平是125mg/kg,超过此剂量,半胱胺的效果反而随添加剂量增加呈降低趋势。     

A field study on the effect of in-feed inclusion of a natural zeolite (clinoptilolite) on health status and performance of sows/gilts and their litters

The study was conducted to evaluate the effect of the long-term dietary use of a natural zeolite (clinoptilolite, NZ) on health status and reproductive performance of sows/gilts and performance of their litters, along with its compatibility with antibacterials (chlortetracycline, CTC) periodically used in medication programmes. Two hundred and forty sows/gilts and their litters were assigned to two main experimental groups and four subgroups, depending on the inclusion of NZ and CTC in their feed. During the trial, frequent sampling of pregnancy feed for mycotoxicological analysis revealed a high contamination level with zearalenone. No adverse or side effects attributed to NZ were noticed. Furthermore, the combined use of NZ and CTC revealed no clinically apparent interactive effect on the availability of the latter. Reproductive performance was significantly improved by the dietary inclusion of both NZ and CTC. The results also suggested that the beneficial effect of NZ could be additionally considered as an indicator of the amelioration of zearalenone exposure consequences.     

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。     

母猪妊娠期背膘厚度对仔猪均匀度及繁殖性能的影响

为研究母猪不同阶段的背膘厚度与仔猪均匀度及部分繁殖性能之间的关系,试验采用二次项回归拟合的方法,对9458头纯种长白母猪和13317头纯种大白母猪的分娩、背膘厚度进行分析。结果表明:母猪背膘厚度处于合理的范围有利于提高其产仔性能和窝产仔均匀度,母猪过肥和过瘦均不利母猪繁殖效率的提高。该场的长白母猪配种当天、妊娠30日龄、妊娠80日龄和妊娠105日龄背膘厚度分别为14.0~18.0mm、15.0~20.0mm、16.0~20.0mm、17.0~20.0mm更有利于仔猪均匀度及母猪繁殖性能的提高;该场的大白母猪配种当天、妊娠30日龄、妊娠80日龄和妊娠105日龄背膘厚度分别为13.0~16.0mm、14.0~17.0mm、15.0~18.0mm、15.0~19.0mm更有利于仔猪均匀度及母猪繁殖性能的提高。妊娠期间的背膘厚度对仔猪均匀度及繁殖性能有一定影响,但母猪产仔性能最好的背膘状态并不是产仔均匀度最佳值。