从江香猪、苏太猪不同杂交组合繁殖性能比较

为了提高从江香猪的繁殖性能,试验选择苏太猪对其进行正交和反交,比较不同杂交组合和纯繁组母猪的产仔及哺育成绩,探索不同杂交组合母猪的繁殖性能,包括母猪产仔数、仔猪初生窝重和个体重、仔猪21日龄窝重和个体重、仔猪断奶窝重和个体重、断奶头数等指标。结果表明:从江♂×苏太♀正交组合(香苏猪)仔猪哺乳期生长性能最佳,初生个体重、初生窝重显著高于纯繁组和苏香猪(P0.05);21日龄个体重、21日龄窝重、断奶窝重显著高于纯繁组和苏香猪(P0.05);其余指标差异不显著(P0.05),但香苏猪、苏香猪指标均优于纯繁组。说明选择从江香猪和苏太猪进行正反交可提高母猪窝产仔数和仔猪哺育成绩,从而提高从江香猪杂交猪的繁殖性能。     

胎次对丹系大白猪繁殖性能的影响分析

对江苏省某国家生猪核心育种场丹系大白母猪各胎次的产仔数、产活仔数、断奶仔猪数及初生窝重、断奶窝重等繁殖性状进行了比较和相关性分析,旨在进一步了解丹系大白猪的繁殖性能,为后备母猪的选种选育提供参考。结果表明,丹系大白母猪第1、2胎产仔数较少,至第3胎达到最高为10.39头,后趋于稳定。不同胎次对产活仔数与断奶仔猪数的影响与产仔数的变化趋势基本一致。不同胎次的仔猪初生窝重基本持平,并以第3胎最高为14.81 kg。各胎次断奶窝重基本稳定。相关性分析表明,丹系大白母猪第3胎与第4胎产仔数、产活仔数、初生窝重呈显著正相关,第2胎与第5胎的产仔数、产活仔数、初生窝重间均呈显著负相关。第4胎与第5胎断奶仔猪数有显著负相关。第4胎和第5胎的断奶窝重有显著正相关。第3胎繁殖性能相对稳定,可以反映母猪繁殖性能,因此丹系大白母猪第3胎次的繁殖性能可作为选育后备母猪的重要依据。     

苏太猪SLA-DQA基因SNP检测及其对部分经济性状的遗传效应分析

实验对苏太猪SLA-DQA基因的第4外显子进行多态性分析,并初步探讨DQA基因作为影响苏太猪经济性状候选基因的可能性。PCR-SSCP分析共检测到CC、CD和DD 3种基因型;在第4外显子检测到G5233A突变,导致了氨基酸Thr到Ala的改变。结果表明:苏太猪3种基因型个体的初生重、35日龄断奶体重、4月龄体重、6月龄体重以及60 kg体尺和背膘厚等生长发育指标差异不显著(P0.05);DD基因型第3胎次总产仔数、产活仔数、初生窝重均高于CC和CD基因型的个体,尤其是断奶仔猪数和断奶窝重显著高于CC和CD基因型的个体(P0.05),但CC和CD基因型个体间繁殖性能差异不显著(P0.05)。     

不同胎次梅山猪繁殖性能的比较分析

为了进一步了解梅山猪的繁殖性能,试验对不同胎次的梅山猪核心群100头母猪繁殖性能进行比较,测定了总产仔数、产活仔数、断奶仔猪数、初生重、断奶重、断奶成活率。结果表明:梅山猪第1胎产仔数最少,之后逐步上升,第5胎开始下降;第3胎断奶成活率最高,第4胎后呈稳定趋势;不同胎次仔猪初生重基本持平,第2胎和第3胎断奶重呈上升趋势,并且在第4胎开始下降。相关性分析表明,第1~5胎的总产仔数、产活仔数、断奶仔猪数、初生重和断奶重均没有显著的相关关系。     

皖南花猪不同头型母猪繁殖性能比较研究

皖南花猪按头型可分为狮子头型、马脸型和桩头型,为研究皖南花猪母猪不同头型母猪间的繁殖性能差异,研究通过整理安徽省皖南花猪保种场以往数据,现场记录等方法,统计皖南花猪不同头型经产母猪(370窝)的窝产仔数、窝产活仔数、初生窝重、35日龄窝断奶仔猪数和35日龄断奶窝重等繁殖性能指标,并进行比较分析。结果如下:皖南花猪马脸型母猪窝产仔数、窝产活仔数、仔猪初生窝重、35日龄断奶仔猪数、35日龄断奶窝重均显著高于狮子头型及桩头型母猪(P0.05);皖南花猪桩头型母猪在窝产仔数、窝产活仔数、仔猪初生窝重等繁殖性能上优于狮子头型母猪,但在35日龄断奶窝重这一指标中低于狮子头型母猪。研究表明皖南花猪马脸型母猪繁殖性能与狮子头型、桩头型母猪相比更为优异,为皖南花猪种质资源保护与开发利用提供了一定的参考依据。     

不同胎次与配种季节对金华猪繁殖性能的影响

根据浙江加华种猪有限公司2004—2008年的388头金华猪母猪(与长白猪公猪杂交)生产记录,分析了金华猪母猪不同胎次、不同配种季节的繁殖性能。结果表明:金华猪母猪的第1胎产活仔数最低,第2～9胎次的产活仔数较高,说明金华猪母猪的有效利用年限较长;第2～8胎次金华猪的初生重、初生窝重、21日龄窝重、断奶重、断奶窝重均表现良好,而第9胎后其生产水平下降;冬季配种的母猪繁殖性能优于其他季节。     

后备母猪初情日龄对母猪繁殖性能及哺乳仔猪生长性能的影响

为了探讨后备母猪不同初情日龄对母猪繁殖性能和哺乳仔猪生长性能的影响,试验采用单因子设计方法,将738头后备母猪按照初情日龄的早晚分为4个处理组(初情日龄200 d为Ⅰ组;200 d≤初情日龄220 d为Ⅱ组;220 d≤初情日龄≤240 d为Ⅲ组;初情日龄240 d为Ⅳ组),检测母猪第1胎、第2胎、第3胎及综合6胎的母猪产仔数、母猪产活仔数、仔猪初生均重、哺乳仔猪断奶均重、哺乳仔猪日均增重等指标。结果表明:(1)母猪头胎,Ⅱ组与Ⅰ组相比,母猪产活仔数、哺乳仔猪断奶均重、哺乳仔猪日均增重均显著提高(P0.05);(2)母猪第2胎,Ⅱ组、Ⅲ组与Ⅰ组、Ⅳ组相比,母猪产仔数、母猪产活仔数均显著提高(P0.05);(3)母猪第3胎,Ⅱ组与Ⅰ组、Ⅲ组、Ⅳ组相比,母猪产仔数、母猪产活仔数均显著提高(P0.05);(4)母猪综合6胎,Ⅱ组与Ⅰ组、Ⅲ组、Ⅳ组相比,母猪产仔数、母猪产活仔数、哺乳仔猪日均增重均显著提高(P0.05)。说明后备母猪初情日龄对母猪繁殖性能和哺乳仔猪生长性能存在显著影响,最佳初情日龄为200 d～220 d。     

胎次对杜洛克、长白和大白母猪繁殖性能的影响

为了研究胎次对杜洛克、长白和大白母猪繁殖性能的影响,根据江苏省某国家级生猪核心育种场2009-2011年出生的繁殖母猪资料,分别选取128头杜洛克、681头长白和610头大白母猪共7280窝生产数据,统计分析不同胎次母猪的总产仔数、产活仔数、断奶仔猪数、初生窝重及校正21日龄窝重。此外,依据胎次将母猪分为3个繁殖阶段（1～2胎、3～6胎及7～8胎）来探究品种差异对母猪繁殖性能的影响。结果表明：胎次对母猪繁殖性能有显著影响（P<0.05）,母猪1～4胎的总产仔数、产活仔数、断奶仔猪数及初生窝重随胎次呈增加趋势,第4胎达到高峰,且显著高于其他胎次（P<0.05）;3～6胎繁殖性能较好,7胎之后出现迅速下降趋势;除在第4胎略有下降外,其他胎次的校正21日龄窝重随胎次递增。品种对母猪繁殖性能的影响显著（P<0.05）,长白和大白母猪的繁殖性能均极显著高于杜洛克母猪（P<0.01）;长白母猪的产活仔数和校正21日龄窝重显著高于大白母猪（P<0.05）,2个品种其他繁殖性能无显著差异（P＞0.05）。综上所述,杜洛克、长白和大白母猪的最佳繁殖胎次为3～6胎,长白猪的繁殖性能总体上优于大白猪,就本试验所在的育种场而言,长白猪可能更适合作为二元母猪生产中的母本。     

从江香猪与苏太猪不同组合杂交性能比较研究

为了提高从江香猪生长、繁殖性能,筛选优质香猪杂交组合配套系,以从江香猪(香)和苏太猪(苏)为亲本,开展香♂×苏♀(香苏猪)、苏♂×香♀(苏香猪)杂交试验,在相同饲养管理环境和营养水平下,对杂交猪的繁殖性能和生长性能进行测定,比较不同杂交组合后代的杂交性能。结果显示:繁殖性能方面,香苏猪优于苏香猪,香苏猪平均产仔数9.67头,苏香猪平均产仔数9.33头,差异不显著(P0.05);初生指标中初生窝重差异显著(P0.05);21日龄指标中个体重和窝重差异显著(P0.05);香苏猪平均断奶活仔数为9.56头,苏香猪平均断奶活仔数为8.0头,差异不显著(P0.05);断奶窝重差异显著(P0.05);生长性能方面,杂交猪母猪的1月龄体长、体高,2月龄胸围、3月龄体高差异显著(P0.05),香苏猪母猪除6月龄平均体重低于苏香猪母猪,其余指标均优于苏香猪母猪,随着生长月龄增加,体重、体高、胸围、臀腿围差距在缩小;杂交猪公猪的1月龄的体重、体长、胸围、臀腿围差异显著(P0.05);2月龄的体重、体高、体长、胸围差异显著(P0.05);6月龄体长差异显著(P0.05);香苏猪公猪各项指标均优于苏香猪公猪;其余指标差异不显著(P0.05)。结果表明:引入苏太猪与本地从江香猪进行杂交改良试验,可显著提高其繁殖性能和生长性能,其中以香苏猪杂交组合效果最好。     

苏太猪引种效果试验

近年来,绍兴市有关部门从苏州苏太公司引进苏太猪50头,为进一步研究测定苏太猪在本地区的适应性及生产性能,随机选择苏太母猪30窝进行繁殖性能跟踪测定,30头育肥猪进行育肥性能测定。结果表明,苏太猪繁殖性能较高,基本保持了地方品种繁殖性能较高的优良特性,初产母猪胎均产仔9.17头,经产母猪胎均产仔11.05头,育成率达92.50%;肥育期日增重616.96 g,料重比为3.2∶1,屠宰率为72.85%,瘦肉率达55.48%。     

母猪断配间隔的影响因素分析及其对下一胎繁殖性能的影响

分析影响母猪断配间隔（Weaning-Estrous Interval,WEI）的因素,并分析不同WEI对母猪下一胎繁殖性能的影响。根据新疆某场繁殖母猪2019-2020年12个月的生产分娩记录情况进行统计整理,采用单因素方差分析月份、胎次、品种和哺乳天数对母猪WEI的影响和WEI对母猪下一胎繁殖机能的影响。结果表明：月份间WEI差异显著（P < 0.05）;胎次间WEI差异显著（P < 0.05）;大白初产母猪WEI=4 d发情数最多,而杜洛克与长白猪初产母猪WEI=5 d时最多;3个品种经产母猪均在WEI=4 d时最多;不同哺乳天数下的母猪WEI差异显著（P < 0.05）;大白、长白和杜洛克初产母猪最早可在哺乳20 d、17 d和20 d断奶,经产母猪最早可在哺乳17 d、17 d和16 d断奶而不影响WEI;断奶后第4天和第5天配种,母猪繁殖性能表现最稳定,配种分娩率最高,死胎数最少。     

长大、PIC、混血母猪繁殖性状研究

对红河州某猪场长大母猪311窝、PIC母猪138窝及当地农村饲养混血母猪753窝的繁殖性状进行测定,探讨品种、胎次和分娩季节对母猪繁殖性状的影响。结果表明,品种因素对母猪产仔性能有显著影响,长大母猪和混血母猪的总产仔数、产活仔数、初生窝重、28 d校正断奶窝重均极显著高于PIC母猪（P〈0.01）,长大母猪和混血母猪间除初生窝重、初生个体重和28 d校正断奶成活率有极显著差异（P〈0.01）外,其它指标差异均不显著（P〉0.05）。胎次因素对母猪产仔性能产生显著影响,经产母猪显著高于初产母猪（P〈0.05）,长大、PIC母猪2~8胎、混血母猪3胎以上产仔性能较好,其中长大、PIC母猪以第4胎最佳。分娩季节对PIC、混血母猪的繁殖性状无显著影响（P〉0.05）,而对长大母猪的产活仔数有显著影响（P〈0.05）。     

Effects of breeding at the second oestrus or after post-weaning hormonal treatment with altrenogest on subsequent reproductive performance of primiparous sows

This study investigated the effects of breeding at the second oestrus after weaning or after feeding an orally active progestagen (altrenogest) on the subsequent reproductive performance of primiparous sows. After 3 weeks of lactation, 663 weaned sows of two genotypes were allocated into three groups: G1--breeding at the first oestrus after weaning; G2--breeding at the second oestrus after weaning and G3--treatment with altrenogest for 5 days after weaning and breeding at the first oestrus after the end of the treatment. Body weight at breeding was lower in G1 and G3 than in G2 sows (p < 0.05). The interval to show oestrus was similar for G1 and G2 groups (p > 0.05) but higher (p < 0.05) than that observed in G3 group. Within genotype A, percentages of females in oestrus within 10 days were not different (p > 0.05) among groups, whereas in genotype B, more G1 and G2 sows (p < 0.05) showed oestrus than G3 sows. In both genotypes, lower farrowing rates were observed in G3 than in G1 and G2 sows (p < 0.05) and a greater litter size (p < 0.05) was observed in G2 sows. In genotype A, the number of total born piglets was similar for G1 and G3 groups (p > 0.05), whereas in genotype B, G1 sows had a greater litter size than G3 sows (p < 0.05). Body weight at weaning and at breeding was similar (p > 0.05) between farrowed and non-farrowed sows in all groups. Reproductive performance is not improved in primiparous sows treated with altrenogest during 5 days after weaning. The reproductive performance of genotype B sows is compromised in Control and Altrenogest-treated sows but not in those bred at the second oestrus after mating. Breeding at the second oestrus after weaning allows primiparous sows to gain weight between weaning and service, and increases their farrowing rate and subsequent litter size.     

Duration of lactation,endocrine and metabolic state,and fertility of primiparous sows

The objectives of this study were to determine factors affecting the reproductive performance of primiparous sows early weaned (EW; n = 35) at d 14 or conventionally weaned (CW; n = 35) at d 24 of lactation. Sow BW and backfat were recorded at farrowing, weekly until weaning, and at standing heat. Feed intake was controlled throughout lactation to standardize nutritional effects on subsequent reproductive performance. Litter size was standardized across treatments within 48 h after farrowing, and litter weight was recorded until weaning. In subsets of sows, blood samples were collected from 10 h before to 10 h after weaning, and then every 6 h until ovulation. Sows were heat checked twice daily and bred at 24-h intervals during standing heat using pooled semen. Ultrasonography every 6 h determined time of ovulation. Sows were either slaughtered within 24 h after ovulation to assess ovulation rate, fertilization rate, and embryonic development in vitro, or at d 28 of gestation to determine ovulation rate and embryonic survival. Compared with CW sows, EW sows had more backfat at weaning (15.9 +/- 0.5 vs. 14.7 +/- 0.5 mm; P < 0.001). Also, CW sows tended to lose more BW and to have lower IGF-I concentrations, indicating poorer body condition. Duration of lactation did not affect ovulation rate (EW = 17.6 +/- 0.7; CW = 18.7 +/- 0.6), fertilization rate (EW = 96.0 +/- 2.2; CW = 88.2 +/- 4.7%), or embryo survival to d 28 (EW = 62.5 +/- 4.5; CW = 63.1 +/- 5.0%). There was a marginal effect of duration of lactation on weaning-to-estrus interval (EW = 120 +/- 3; CW = 112 +/- 3 h; P < 0.06) and duration of estrus (EW = 52.4 +/- 2.3; CW = 46.3 +/- 2.2 h; P < 0.08). Overall, embryonic survival, not ovulation rate, seems to be the limiting factor for potential litter size in the second parity. Although fertility in both EW and CW sows studied was compromised, endocrine and metabolic data indicate that the mechanisms affecting reproductive performance may differ between the two weaning systems. The LH, FSH, and estradiol data from the EW sows are characteristic of animals with limited follicular development and incomplete recovery of the hypothalamic-pituitary-ovarian axis; consequently, the integrity of the uterine environment may be adversely affected and limit embryonic survival. In CW sows, variability in metabolic state seemed to be the key factor limiting the fertility, again adversely affecting embryonic survival.     

Polymorphism of Mx1 Gene Exon 14 and its Relationship with Reproductive Performance in Meishan Pigs

To analyze the effect of different genotypes in Mx1 gene exon 14 on the reproductive performance in Meishan pigs,PCR-RFLP method was used to amplify DNA and detect the polymorphisms of Mx1 gene exon 14, and the relationship between different genotypes and the reproductive performance was further analyzed by generalized linear model (GLM) in this study.The results of PCR-RFLP showed that there was a G36T mutation on Hin6 Ⅰ restriction site in Mx1 gene exon 14 and three genotypes were detected named as AA,AB and BB,in which BB was a dominant genotype.The results of correlation analysis showed that the reproductive performance of three genotypes in Mx1 gene presented the increasing tendency of BB >AB >AA in total number born (TNB),number born alive (NBA),little size at weaning (LBW),birth weight (BW) and weaning weight (WW) in gilts sows on the whole.Moreover,there was significant difference in TNB,NBA,LBW and WW in gilts sows (P< 0.05).However,there was no significant difference among all reproductive performance in multiparous sows (P >0.05).The results of this study indicated that the polymorphisms of Mx1 gene exon 14 had significantly genetic effects on production performance in Meishan gilts sows instead of multiparous sows.     

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.     

Should weaning be the start of the reproductive cycle in hyper-prolific sows? A physiological view

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.     

梅山猪Mx1基因第14外显子多态性及其与繁殖性能的关联分析

为了探讨梅山猪Mx1基因第14外显子的多态性及其对梅山猪繁殖性能的影响,本研究采用PCR-RFLP方法对所采个体Mx1基因第14外显子进行DNA扩增并检测其多态性,同时利用广义线性模型(GLM)分析不同基因型与繁殖性能间的关系。PCR-RFLP结果表明,梅山猪Mx1基因第14外显子Hin6Ⅰ酶切位点存在G36T突变,共检测到2种等位基因,分别定义为:A、B,其中B基因为优势等位基因;共检测到3种基因型,分别定义为:AA、AB、BB,其中BB基因型为优势基因型;关联分析结果表明,在初产母猪中,总产仔数(TNB)、产活仔数(NBA)、断奶仔猪数(LBW)、初生重(BW)及断奶重(WW)这5个繁殖性状在Mx1基因的3种基因型中的差异均存在BB >AB >AA的趋势,BB基因型为有利基因型;且在总产仔数、产活仔数、断奶仔猪数和断奶重中表现出显著差异性(P<0.05);但在经产母猪中均没有显著差异(P>0.05)。本研究结果提示,Mx1基因第14外显子多态性对梅山猪初产母猪的繁殖性能有显著的遗传效应,而对经产母猪的繁殖性能没有显著的影响。     

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.