杜洛克种猪抗腹泻新品系选育研究

猪肠毒素性大肠杆菌(ETEC)是引起断乳前后仔猪腹泻的主要致病菌,试验利用分子检测技术鉴别MUC13基因型,选育具有腹泻抗性基因型群体,在种猪世代选育中培育抗腹泻专门化新品系,从种源上提高新生仔猪及断奶前后仔猪抗腹泻能力,降低新生仔猪及断奶前后仔猪腹泻率,最大限度挖掘并提高猪场断奶仔猪成活率的潜能,提高猪场的经济效益和国外引进种猪的使用价值。试验地点为贵州省种畜禽种质测定中心猪场,试验猪群为贵州省种畜禽种质测定中心2007年从美国引进的杜洛克种猪。2016年,对美系杜洛克种猪父母本按照2种组合进行选配:1)GG♂×GG♀,从9窝不同父母本选配所生的F1代中,每窝选留符合种用要求仔猪1~2头,共11头,采耳组织样作MUC13基因型检测,检测结果显示,11头均为腹泻抗性有利基因GG型个体,腹泻有利基因GG型检出率100%(11/11),进一步将F1代按照GG♂×GG♀选配,从1窝F2代仔猪中选出符合种用要求的5头仔猪作为选留后备猪,抗腹泻基因检测结果 5头均为GG型基因个体,说明父母本按照GG♂×GG♀选配方案,其后代可以稳定遗传抗腹泻基因GG型。2)GA♂×GA♀,采用常规选留方法,从1窝杜洛克仔猪中选出符合种用要求的8头作为选留后备猪,抗腹泻基因检测结果 8头均为GA型,未检测出GG、AA型个体。     

大约克种猪大肠杆菌F4ac MUC13基因的不同基因型组合选配选育

猪肠毒素大肠杆菌(ETEC)是引起断乳前后仔猪腹泻的主要致病菌,而F4ac型是ETEC中的流行性最为广泛的类型,利用分子检测鉴别MUC13基因型,筛选具有腹泻抗性个体是选育抗腹泻种猪的基本方法。试验在贵州省种畜禽种质测定中心种猪场内进行,试验猪群为美系大约克,且已经检测明确其腹泻相关基因型,根据血统、系谱将不同基因型的种公猪与种母猪进行组合选配,从其不同组合选配的F1代中选留后备种猪,并进行抗腹泻基因检测,选留抗腹泻后代,从而得出抗腹泻后代的最佳选配组合及优秀选配组合。研究结果表明:2窝按照GG♂×GG♀组合选配,其后代符合后备猪预留选条件的16头仔猪中,检出抗腹泻GG型个体16头,GG型个体检出率100%(16/16);3窝按照GA♂×GG♀组合选配,其后代符合后备猪预留选条件的21头仔猪中,检出抗腹泻GG型个体8头,GG型个体检出率38.1%(8/21);3窝按照GA♂×GA♀组合选配,其后代符合后备猪预留选条件的23头仔猪中,检出抗腹泻GG型个体为0头,GG型个体检出率0,说明该组合选配方式其后代抗腹泻基因型GG的检出率极低;因此,选育的最佳组合选配为GG♂×GG♀组合选配,其次为GA♂×GG♀或GG♂×GA♀组合选配。     

手工克隆公猪繁殖性能跟踪

对3头克隆公猪的精液指标和配种效果进行了跟踪,并与同期普通公猪进行了对比,结果表明,克隆公猪的采精量、精子活力和精子畸形率与普通公猪差异不显著(P0.05),但精子密度极显著低于普通公猪(P0.01);克隆公猪能达到85%的配种受胎率和81.67%的配种分娩率,已能达到正常集约化养猪需要的标准;克隆公猪所配母猪的窝均总仔、窝均活仔均显著低于普通公猪所配母猪(0.01P0.05),分别为11.14头和9.94头,其窝均畸形数则显著高于普通公猪(0.01P0.05),窝均死胎、窝均木乃伊和窝均弱仔数则差异不显著(P0.05)。克隆公猪完全可以用于扩大优秀种公猪群体并应用于集约化养猪生产。     

哺乳仔猪伪狂犬病和传染性胸膜肺炎混合感染的诊断与防治

<正>1发病情况2013年11月,广东省某猪场出现以哺乳仔猪高热、咳嗽、喘气、高发病率及高死亡率为主症的病例。该场存栏经产母猪346头,后备母猪198头,从2013年10月24日第1窝开始发病,到2014年1月18日最后1窝发病期间,共产仔208窝,产活仔1 904头,从出生到断奶死亡仔猪462头,死亡率24.3%;208窝中有96窝哺乳仔猪发病,发病窝占总产仔窝数46.2%,此     

提高母猪繁殖力试验初报

母猪繁殖力高低是直接影响母猪生产效益的关键。为探索在陆良农村饲养条件下，提高母猪繁殖力的有效途径，从而达到高产、低耗、优质、高效的目的。选择陆良县三贫河镇杨家坝办事处作为试验基点，在试验区用4个不同杂交组合，共63窝进行参试，通过对种猪采取选种选配，科学饲养管理，改进、完善母猪繁殖技术，加强仔猪培育等一系列挖掘母猪 繁殖潜力技术措施。结果表明，母猪群体受胎率由原来的85.04%提高到92.11%；年产仔窝数由1.89窝提高到2.20窝；产仔数由16.34头提高到21.82头，育成仔猪数由13.94提高到19.73头；育成仔猪窝重由197.66kg提高到343.07kg，窝均年多获利1096.60元。     

手术法克隆猪胚胎移植研究

为优化克隆猪胚胎移植技术,利用手术法,开展了26头克隆猪胚胎移植试验。第1批16头受体母猪的胚胎移植试验,分娩率仅为12.5%(2/16)。经对手术法深入分析和优化,第2批移植的10头受体母猪,分娩率达到60%(6/10),窝均分娩活仔6.33头。研究表明,利用优化的手术法能得到较好的克隆效果。     

种猪群猪圆环病毒病的净化技术研究

为探究种猪群猪圆环病毒病(PCVD)的净化控制措施,通过对种猪群实施猪圆环病毒2型(PCV-2)灭活疫苗免疫(基础免疫2次,以后每隔4个月加强免疫1次),检测(基础免疫前、二免后20d和二免后3个月、加强免疫后3个月分别采集前腔静脉血,分离血清,采用ELISA检测PCV-2抗体、猪瘟抗体,PCR方法检测PCV-2核酸),淘汰加强免疫后PCV-2核酸仍为阳性的种猪,结合分析母猪PCV-2疫苗免疫前后繁殖性能的差异。为期1年净化措施实施的结果显示,种猪群的PCV-2核酸阳性率从33.33%显著下降到3.42%,其中后备猪的PCV-2核酸阳性率从39.02%下降到8.57%,种公猪从33.33%下降到0、经产母猪从15.38%下降到1.56%;母猪窝产仔数增加0.52头(P0.05),窝产活仔数增加0.78头(P0.01),窝产木乃伊胎数减少0.3头(P0.01);种猪群猪瘟免疫抗体合格率从53.73%提高到83.49%,平均阻断率从43.31%升高到63.46%,与种猪群PCV-2核酸检测阳性率呈现负相关。结果表明,实施免疫、检测、淘汰措施对于种猪群PCVD的净化成效明显,该技术可为规模化猪场开展PCVD的净化提供科学依据,具有推广应用价值。     

采用促性腺激素释放激素类似物和人绒毛膜促性腺激素提高母猪繁殖性能的研究

试验在实行发情后配种二次或三次且母猪窝产仔数不同的两个猪场进行,在第一次配种前6～14小时给母猪分别颈部肌注促性腺激素释放激素GnRH类似物(Receptal或促排三号LRH-A3)20μg或hCG1000IU,探讨在配种前使用这两类激素对母猪受胎率和产仔数的影响。在A猪场,GnRH类似物(LRH-A3和Receptal结合计算)处理使受胎率从对照组的78%(35/45)提高到93%(39/42),平均窝产总仔数和平均窝产活仔数分别从对照组的9.50头±0.50头和9.23头±0.47头提高到9.95头±0.46头和9.76头±0.45头。在B猪场,GnRH类似物LRH-A3和hCG处理使一部分猪(10%～15%)在发情后期丧失性欲不能进行第三次配种,而对照组则无此现象发生。LRH-A3和hCG处理使受胎率从对照组的96.08%(48/50)分别降低到92.31%(36/39)和86.48%(32/37);平均窝产总仔数和平均窝产活仔数从对照组的12.26头±0.32头和11.38头±0.30头分别降低到LRH-A3处理组的11.91头±0.42头和11.08头±0.44头,和hCG处理组的11.37头±0.52头和10.71头±0.49头。这些结果说明在母猪配种前注射GnRH类似物或hCG,可以提高发情后只配种二次的母猪的受胎率和产仔性能,但会降低发情后配种三次的母猪的受胎率和产仔数。     

不同利用方式、分娩季节和胎次对中型梅山猪繁殖性能的影响

为了揭示中梅山猪保种场中梅山猪的繁殖性能,试验以保种有限公司中梅山猪场3年所测的7个繁殖性状为依据,分析不同年份、利用方式、分娩季节和胎次对中梅山猪繁殖性能的影响,统计分析结果显示:中梅山猪1~8胎平均窝产仔数13.61头,产活仔数12.92头,变异系数分别达25.44%和24.08%;中梅山猪4~8胎平均窝产仔数14.76头,产活仔数13.74头,变异系数分别达到25.80%和23.93%,变异程度均较大。纯繁时的窝产仔数和窝产活仔数分别极显著(P0.01)和显著(P0.05)高于杂交,而杂交后20日龄和45日龄窝重极显著地高于纯繁(P0.01)。不同季节窝产仔数、窝产活仔数差异不显著(P0.05),但20日龄和45日龄窝重春夏季显著高于秋冬季(P0.05)。中梅山猪4胎时窝产仔数显著高于1~3胎(P0.05),而与4胎后的其他胎次比较差异不显著(P0.05)。结果表明:中梅山猪繁殖性能好,杂交会降低窝产仔数,4胎时窝产仔数最高,4胎后窝产仔数稳定。     

酵母培养物对母猪生产性能的影响

本研究将80头妊娠后期母猪按胎次配对的原则(胎次分布2～6胎)分为两组,每组40头,每头为1个重复。对照组饲喂基础日粮,试验组在基础日粮中添加0.5%酵母培养物,试验从妊娠85d开始至断奶后再发情结束,为期65d。结果表明,试验组与对照组比较,哺乳期采食量(4.13kg/d·头VS.4.22kg/d·头)无显著差异(P0.05),母猪产程缩短了8.2%(P0.05),断奶后10d内发情的比例提高了24%。试验组和对照组窝产仔数分别为11.70头、10.92头(P0.05),仔猪初生重为1.82kg、1.69kg(P0.01),仔猪断奶重为6.98kg、6.68kg(P0.05),窝断奶仔猪数为8.53头、8.35头(P0.05)。说明酵母培养物对母猪的生产性能具有一定的改善作用,以仔猪初生重较为明显。     

Effects of Inulin Supplementation in Low‐ or High‐Fat Diets on Reproductive Performance of Sows and Antioxidant Defence Capacity in Sows and Offspring

This experiment was conducted to investigate the effects of inulin supplementation in low‐ or high‐fat diets on both the reproductive performance of sow and the antioxidant defence capacity in sows and offspring. Sixty Landrace × Yorkshire sows were randomly allocated to four treatments with low‐fat diet (L), low‐fat diet containing 1.5% inulin (LI), high‐fat diet (H) and high‐fat diet containing 1.5% inulin (HI). Inulin‐rich diets lowered the within‐litter birth weight coefficient of variation (CV, p = 0.05) of piglets, increased the proportion of piglets weighing 1.0–1.5 kg at farrowing (p < 0.01), reduced the loss of body weight (BW) and backfat thickness (BF) during lactation (p < 0.05) and decreased the duration of farrowing as well as improved sow constipation (p < 0.05). Sows fed fat‐rich diets gained more BW during gestation (p < 0.01), farrowed a greater number of total (+1.65 pigs, p < 0.05) and alive (+1.52 pigs p < 0.05) piglets and had a heavier (+2.06 kg, p < 0.05) litter weight at birth as well as a decreased weaning‐to‐oestrous interval (WEI, p < 0.01) compared with sows fed low‐fat diets. However, it is worth noting that the H diet significantly decreased the serum activities of superoxide dismutase (T‐SOD) and glutathione peroxidase (GSH‐Px) and increased the serum malondialdehyde (MDA) levels in sows and piglets (p < 0.05). In contrast, HI diet enhanced the activities of T‐SOD and GSH‐Px and decreased the serum MDA concentrations (p < 0.05) in sows and piglets. In summary, the fat‐rich diets fed to sows during gestation had beneficial effects on reproductive performance, but aggravated the oxidative stress in sow and piglets. Inulin‐rich diets fed to sow during gestation had beneficial effects on within‐litter uniformity of piglet birthweight and enhanced the antioxidant defence capacity of sows and piglets.     

中草药制剂对母猪分娩和哺乳效果的试验研究

为观察复方中草药制剂对母猪分娩和泌乳效果的影响,试验选择妊娠80-90 d的68头妊娠母猪,按配种日龄、胎次、体况、品种随机均分为中草药制剂组和对照组,每组34头,每头母猪为1个重复。两组基础饲粮相同,中草药制剂组在基础饲粮中按每吨300 g添加中草药制剂,试验期为妊娠80 d至断奶。结果表明,与对照组相比,中草药制剂组窝均产活仔数和断奶窝均仔猪数分别提高0.93头（P＜0.05）和1.09头（P＜0.01）;产活仔率和健仔率分别提高5.91和4.52个百分点;仔猪初生个体均重、断奶个体均重、仔猪平均日增重分别提高0.05 kg、0.5 kg、22.6 g,差异均显著（P＜0.05）。中草药制剂可有效提高母猪分娩质量和泌乳水平。     

The importance of a high feed intake during lactation of primiparous sows nursing large litters

The objective of this study was to investigate whether nursing a large number of piglets has negative effects on lactation and postweaning performance of primiparous sows and whether a greater lactation feed intake can prevent possible negative effects. Data were recorded on 268 ad libitum-fed sows of three genotypes (G1, G2, and G3) in an experiment where litter size was standardized to 8, 11, or 14 piglets during a 4-wk lactation. Compared to G1 and G2, G3 sows were heavier (P < 0.05) and leaner (P < 0.05) at weaning of their litters, lost similar amounts of BW and backfat, and their piglets grew faster (P < 0.05). Compared to G1, feed intake during lactation was higher for G3 sows (P < 0.05), and their risk of a prolonged weaning-to-estrus interval was lower (P < 0.01). Daily feed intake by sows was not affected by litter size in G1 and G3, but it was quadratically affected in G2 (P < 0.05), with a maximum at 10.8 piglets. Backfat loss of the sows increased linearly with litter size (P < 0.05) in G1 and G3. In G2, backfat loss increased only at litter sizes > 9.8 piglets (P < 0.01). Body weight loss of the sow and litter weight gain increased linearly with litter size (P < 0.001). Per extra piglet nursed, sows had a 23% (P < 0.01) higher probability of a prolonged weaning-to-estrus interval. A higher daily feed intake during lactation reduced tissue loss of the sow, increased litter weight gain (P < 0.01), and reduced the probability of a prolonged weaning-to-estrus interval (by 42% per extra kilogram; P < 0.01). Sows with a lower daily body weight loss during first lactation had a larger second litter (1.28 piglets/kg; P < 0.01), and their probability of a prolonged weaning-to-estrus interval was reduced by 61% per kilogram (P < 0.001). With increasing litter size, it is therefore recommended to reduce body weight loss during lactation by stimulating daily feed intake and by genetic selection.     

养殖规模对不同胎次母猪生产力的影响

为了比较不同规模猪场不同胎次母猪繁殖力的高低,本研究采集了106家不同规模猪场母猪的详细生产数据。按母猪实际存栏头数将猪场划分为<1 000、1 000~5 000、5 000~10 000和≥10 000头4个规模,分析不同规模猪场母猪1~9胎次活仔率、健仔率、畸形仔率、死胎率、木乃伊率、断奶活仔率及窝均产总仔数、窝均产活仔数、窝均产健仔数、窝均产死胎数、窝均断奶活仔数、窝均出生个体重、窝均出生窝重等相关繁殖指标的差异。结果表明,在胎次相同的情况下,猪场活仔率、健仔率和断奶活仔率随着饲养规模的扩大呈逐渐升高的趋势,而畸形仔率、死胎率和木乃伊率则呈相反趋势。母猪实际存栏头数≥10 000头的猪场1~7胎次（第4胎除外）的活仔率、健仔率和断奶活仔率均显著高于<1 000头猪场（P<0.05）,而与其他两个规模猪场差异不显著（P>0.05）。母猪存栏数<1 000头的猪场1、2、3、5、7胎次的死胎率显著高于其他3个规模猪场（P<0.05）。各个胎次的窝均产总仔数、产活仔数、产健仔数、畸形仔数、死胎数、木乃伊数、出生窝重都随着猪场饲养规模的扩大呈逐渐降低的趋势。<1 000头的猪场第2、3胎的母猪窝均产总仔数、产活仔数、产死胎数、窝均断奶活仔数、窝均出生窝重均显著高于其他3个规模猪场（P<0.05）。综上,养殖规模对不同胎次母猪生产力均产生较大影响,中大规模猪场（≥1 000头）的母猪繁殖力整体上低于小规模猪场（<1 000头）,但仔猪的体况和成活率要优于小规模猪场。     

中兽药解暑抗热散抗妊娠母猪热应激效果的研究

为了解中兽药解暑抗热散对妊娠母猪热应激的缓解效果,选取14头怀孕1月龄的2~3胎次的母猪,按窝体质量及胎次相近的原则随机分成2组,即解暑抗热散组(每800 kg基础日粮中添加解暑抗热散1 kg)和对照组(基础日粮),每组7头,分别测定其热应激相关指标,试验期8 d。结果显示:解暑抗热散组母猪的呼吸频率比对照组降低3.57次/min,体温比对照组降低0.99℃,2组间呼吸频率差异不显著(P0.05),但平均体温显著低于对照组(P0.05);母猪产健仔猪数比对照组提高10.52%,发病数比对照组降低5.49%。试验结果表明,解暑抗热散在高温条件下能够显著降低妊娠母猪体温,提高产健仔猪数,降低猪只的发病数,具有良好的抗应激作用。     

Effect of feeding sorghum ergot (Claviceps africana) to sows during mid‐lactation on plasma prolactin and litter performance

Diets containing 3% sorghum ergot (16 mg alkaloids/kg, including 14 mg dihydroergosine/kg) were fed to 12 sows from 14 days post‐farrowing until weaning 14 days later, and their performance was compared with that of 10 control sows. Ergot‐fed sows displayed a smaller weight loss during lactation of 24 kg/head vs. 29 kg/head in control sows (p > 0.05) despite feed consumption being less (61 kg/head total feed intake vs. 73 kg/head by control sows; p < 0.05). Ergot‐fed sows had poorer weight gain of litters over the 14‐day period (16.6 kg/litter vs. 28.3 kg/litter for controls; p < 0.05) despite an increase in consumption of creep feed by the piglets from the ergot‐fed sows (1.9 kg/litter compared with 1.1 kg/litter by the control; p > 0.05). Sow plasma prolactin was reduced with ergot feeding after 7 days to 4.8 μg/l compared with 15.1 μg/l in the control sows (p < 0.01) and then at weaning was 4.9 μg/l compared with 8.0 μg/l (p < 0.01) in the control sows. Two sows fed ergot ceased lactation early, and the above sow feed intakes, body weight losses with litter weight gains and creep consumption indirectly indicate an ergot effect on milk production.     

Body composition and muscle glycogen contents of piglets of sows fed diets differing in fatty acids profile and contents

To study the influence of sow dietary fat on piglet body characteristics, multiparous sows were allocated to one of four different dietary treatments: a conventional low fat (3%) diet (LF) and three high fat (6%) diets; high fat saturated (HFS), high fat oats (HFO), and high fat linseed (HFL). All sows were fed the allocated diet from weaning of the preceding litter until the day after farrowing. At farrowing, one liveborn piglet per litter (NB), was sacrificed and dissected immediately after birth. The heaviest (H) and the lightest (L) piglets in the litter were killed and dissected in the same manner at one day of age. Measurement of body length and circumference, organ weight, body chemical composition and muscle glycogen content were determined. Body measurements were adjusted to the mean body weight (1.67 kg). Dietary treatment did not have any significant influence on body components or carcass traits except for lung weight, being lower in HFO and HFL than in LF piglets. Piglet category affected almost all parameters considered, showing the lowest values for NB piglets, except for lung and circumference that were higher in NB than in L and H piglets; and length which was lower in NB than in L piglets. NB piglets had the highest amount of muscle glycogen content, no difference was found between H and L piglets. Dietary treatments influenced piglet chemical composition, showing the highest overall values of dry matter (DM), protein, and fat for the HFL piglets' carcasses. The present data provide additional information on the depletion of energy reserves; it would appear that sow dietary fat has relatively little effect on progeny since only body chemical composition was significantly influenced by HFL diet.     

饲粮中添加不同水平L-精氨酸对妊娠母猪繁殖性能及血液生化指标的影响

本研究探讨饲粮中添加不同水平L-精氨酸(L-Arg)对母猪繁殖性能及血浆一氧化氮相关指标的影响。试验选择36头2胎次母猪(长白×大约克),随机分为4组,每组9头母猪。各组饲粮分别在基础饲粮中添加0 L-Arg+1.70%L-丙氨酸(L-Ala)(0 L-Arg组)、0.4%L-Arg+1.02%L-Ala(0.4%L-Arg组)、0.7%L-Arg+0.51%L-Ala(0.7%L-Arg组)和1.0%L-Arg+0 L-Ala(1.0%L-Arg组),各组添加L-Ala以满足等氮平衡需要。试验期从母猪配种当天到分娩。结果表明:1.0%L-Arg组比0 L-Arg组显著提高了窝产活仔数和初生窝重(P<0.05),随着饲粮中L-Arg水平的提高,窝产仔总数和初生个体重有上升趋势(P>0.05);母猪妊娠第30、60和90天,1.0%L-Arg组血浆中Arg、鸟氨酸含量均显著或极显著高于0.7%、0.4%、0 L-Arg组(P<0.05或P<0.01);母猪妊娠第90天,各组间的血浆脯氨酸含量均有极显著差异(P<0.01),但第30、60天差异均不显著(P>0.05);母猪妊娠第30、60、90天,1.0%L-Arg组血浆一氧化氮含量和第90天血浆总一氧化氮合酶(TNOS)、诱导型一氧化氮合酶(iNOS)活性均显著或极显著高于0.7%、0.4%、0 L-Arg组(P<0.05或P<0.01)。经回归分析,母猪的窝产仔总数、窝产活仔数、初生窝重、血浆中各氨基酸、一氧化氮含量及TNOS和iNOS的活性与饲粮L-Arg水平均有显著或极显著的线性关系(P<0.05或P<0.01)。结果提示,饲粮中L-Arg水平变化对母猪妊娠后期血液生化指标影响明显,饲粮中添加1.0%L-Arg对提高母猪繁殖性能效果最佳。     

Effects of tryptophan supplementation on aggression among group-housed gestating sows

The objective of this study was to determine the effects of dietary Trp supplementation on mixing-induced aggression and the associated stress, and on reproductive performance in gestating sows. After weaning, sows were mixed in pens with electronic sow feeders on concrete-slatted floors. Each pen housed 21 ± 2.8 sows, with approximately 2.7 ± 0.43 m(2)/sow of floor space allowance. Multiparous sows (n = 168) from 8 breeding groups were used, with 4 groups assigned to a control diet and 4 groups assigned to a high-Trp diet. Control sows received corn- and soybean meal-based diets throughout gestation (0.15% Trp) and lactation (0.21% Trp). Three days before and after mixing, sows assigned to the high-Trp treatment received approximately 2.3 times the dietary Trp (0.35% in the gestation diet and 0.48% in the lactation diet) fed to control sows. Six focal sows (2 sows from each of parity 1, 2, and 3 or greater) in each pen were designated and videotaped for 72 h after mixing to determine the type and number of aggressive interactions among sows. Before and 48 h after mixing, saliva samples were collected from focal sows, and scratches were assessed on all sows. Data were analyzed using the FREQ and GLIMMIX procedures (SAS Inst. Inc., Cary, NC). Aggression among sows was intense during the initial 6 h and decreased between 6 and 72 h after mixing. The initial aggression caused scratches and increased cortisol concentrations (P < 0.05). Mature sows tended to fight for longer periods (112 vs. 52 s/h per sow, SE = 23.8; P < 0.10) but had fewer scratches caused by aggression (injury score = 4.3 vs. 6.5, SE = 1.13; P < 0.01) than parity-1 sows. Supplementation of dietary Trp reduced the total duration of head-to-head knocking (P < 0.05) but did not affect other aggressive behaviors. There was no difference between dietary treatments in injury scores or saliva cortisol concentrations. Sows in the high-Trp treatment had more total piglets born (12.5 vs. 10.5 pigs/litter, SE = 0.55; P < 0.05) and more stillborn piglets (1.5 vs. 0.8 pigs/litter, SE = 0.20; P < 0.05), but had no significant change (P = 0.12) in piglets born alive (10.8 vs. 9.7 pigs/litter, SE = 0.42) compared with control sows. The results indicate that the initial aggression after mixing caused more injuries in young sows than in mature sows. Supplementation of dietary Trp at 2.3 times the control amount for a short period did not effectively reduce aggression and the associated stress in sows at mixing.     

母猪饲粮添加β-羟基-β-甲基丁酸对母猪繁殖性能及仔猪生长性能和免疫功能的影响

本试验旨在研究母猪饲粮添加β-羟基-β-甲基丁酸(HMB)对母猪繁殖性能及仔猪生长性能和免疫功能的影响。选取20头3～6胎次、妊娠74 d的"长×大"母猪,随机分成2组,每组10个重复,每个重复1头母猪,对照组饲喂基础饲粮,试验组在对照组基础饲粮中添加2 000 mg/kg HMB。试验从母猪妊娠第74天开始,至仔猪21日龄断奶结束。结果表明:与对照组相比,试验组仔猪初生个体重显著提高14.1%(P<0.05),仔猪7、21日龄窝重分别显著提高16.6%、11.7%(P<0.05),仔猪初生至7日龄、初生至21日龄窝增重分别显著提高28.3%和12.5%(P<0.05);与对照组相比,试验组母猪在妊娠第98天和分娩当天血清免疫球蛋白G(IgG)含量分别提高35.3%(P<0.01)、13.0%(P>0.05),免疫球蛋白M(IgM)含量分别提高34.7%(P<0.05)、12.6%(P>0.05);与对照组相比,试验组母猪初乳中IgG含量显著提高19.0%(P<0.05),分娩后第14天常乳中IgM含量显著提高21.4%(P<0.05);与对照组相比,试验组仔猪7日龄血浆IgG、IgM含量分别显著提高11.4%和40.1%(P<0.05)。上述结果提示,母猪妊娠后期及哺乳期饲粮中连续添加2 000 mg/kg HMB,可显著提高仔猪初生重和哺乳期增重,改善母猪及仔猪免疫功能。