明智的淘汰方案所带来的益处

通过做出更加明智的母猪淘汰决定,养猪生产者能从中增加收益。     

Genetic association between leg conformation in young pigs and sow longevity

Longevity is important in pig production with respect to both economic and ethical aspects. Direct selection for longevity might be ineffective because ‘true’ longevity can only be recorded when a sow has been culled or died. Thus, indirect selection for longevity using information from other traits that can be recorded early in life and are genetically correlated with longevity might be an alternative. Leg conformation has been included in many breeding schemes for a number of years. However, proving that leg conformation traits are good early indicators for longevity still remains. Our aim was to study genetic associations between leg conformation traits of young (5 months; 100 kg) Swedish Yorkshire pigs in nucleus herds and longevity traits of sows in nucleus and multiplier herds. Data included 97 533 animals with information on conformation (Movement and Overall score) recorded at performance testing and 26 962 sows with information on longevity. The longevity traits were as follows: stayability from 1st to 2nd parity, lifetime number of litters and lifetime number of born alive piglets. Genetic analyses were performed with both linear models using REML and linear‐threshold models using Bayesian methods. Heritabilities estimated using the Bayesian method were higher than those estimated using REML, ranging from 0.10 to 0.24 and 0.07 to 0.20, respectively. All estimated genetic correlations between conformation and longevity traits were significant and favourable. Heritabilities and genetic correlations between conformation and longevity indicate that selection on leg conformation should improve sow longevity.     

高瘦肉率猪需要更多的B族维生素

充足的B族维生素水平是猪强化日粮的一个重要部分。在最新版的NRC(1988)中,日粮维生素需要量的估计值主要是基于20～50年前的研究结果推算获得的。     

Effect of sow history features on growth and feed intake in grow-finish pigs

The sow provides a specific environment to her offspring during gestation and lactation. Certain features in the early life of the sow (sow history features) may affect her ability to deliver and feed a healthy litter. In genetic analyses of grow-finish traits, these effects are estimated as common litter or permanent sow effects. The objective of this research was to identify sow history features that affect the growth rate (GR) and feed intake (FI) of her offspring during the grow-finish stage. Data from 17,743 grow-finish pigs, coming from 604 sires and 681 crossbred sows, were recorded between May 2001 and February 2010 at the experimental farm of the Institute for Pig Genetics (Beilen, the Netherlands). The grow-finish stage was divided into 2 phases (phase 1: 26 to 75 kg; phase 2: 75 to 115 kg). The sow history features were birth litter size, birth year and season, birth farm, weaning age, age of transfer to the experimental farm, and age at first insemination. The sow features were added to the basic model one at a time to study their effect on the grow-finish traits of the pigs. Subsequently, significant sow features (P < 0.1) were fitted simultaneously in an animal model. With every extra piglet in the birth litter of the sow, the GR of her offspring decreased by 1 g/d and the FI decreased by 4 g/d. Every extra day to the first insemination increased the GR of grow-finish pigs by 0.1 g/d. The heritability estimates for GR and FI (only in phase 2 of the grow-finish stage) decreased after adding the sow features to the model. No differences were found in estimates of the common litter effects between the basic model and the model with all significant sow features. The estimates of the permanent sow effect changed for FI from 0.03 (basic model) to 0.00 (model with sow features), and for FI in phase 1, the permanent sow effect decreased from 0.03 (basic model) to 0.01 (model with sow features). In conclusion, selected sow features do affect the grow-finish traits of the pigs, but their estimates are small and explain only a small proportion of the differences in the GR and FI of grow-finish pigs. The sow features partially explained the permanent sow effect of FI-related traits and did not explain the common litter effect. Although the sow early life features can affect piglet traits, they do not predict which sows produce better performing offspring in the grow-finish stage.     

Relationship between litters per sow per year sire breeding values and sire progeny means for farrowing rate,removal parity and lifetime born alive

The objective of this study was to determine the relationship between individual sire estimated breeding values (EBV) for litters/sow/year (LSY) and sire progeny means for farrowing rate (FR), removal parity and lifetime born alive (LTBA). Genetic parameters and breeding values were estimated using ASREML. The heritability estimate for LSY was 0.11. When all sires with 10 or more daughters with records were included in the analysis, Spearman rank correlations between the sire's LSY EBV and the sires' daughter means for FR, removal parity and LTBA were 0.49, 0.23 and 0.25 (p < 0.01). The sire EBV for LSY was favourably correlated with sires' daughter means for all three traits. This provides evidence that selecting sires with high EBV for LSY could improve herd FR, removal parity and LTBA. By including LSY as part of the selection criterion, the LTBA may be indirectly improved. The positive genetic correlation between LTBA and LSY may be a result of the improved longevity of sows with greater LSY compared with sows with lower LSY. The relationships between LSY and FR, removal parity and LTBA are strongly supported by the correlations between the sire progeny means for each trait and the sire LSY EBV.     

魏氏梭菌毒素疫苗研制及其免疫家兔抗体消长规律

从山东省莱芜、泰安、潍坊等3个养兔场发生疑似梭菌性下痢的病兔体内分离到3株魏氏梭菌，鉴定为A型。利用该分离菌株和A型魏氏梭菌标准株(CVCC37)所产外毒素经甲醛灭活并加入氢氧化铝胶佐荆吸附浓缩后制备了A型魏氏梭菌类毒素疫苗。对该疫苗分别进行了安全性检验、有效免疫剂量试验和接种家兔1～23周血清中抗毒素(Ab)消长规律研究。结果表明，魏氏梭菌外毒素用0．3％甲醛32h能够彻底灭活，并最大可能地保持其抗原性；制备的魏氏梭菌类毒素疫苗无毒副作用，安全可靠；用野毒株和标准株制备的类毒素疫苗对家兔的有效免疫剂量为2mL／只，免疫保护效果可靠；采用野毒株和标准株制备的类毒素疫苗免疫接种家兔后第2周血清抗毒素效价迅速升高，到第4周达最高峰，分别为6．6 log2和7．125 log2，较高抗体滴度维持约17周后缓慢下降，至23周时血清平均抗毒素滴度仍维持在4．0 log2和3．4 log2以上，所以，该类毒素疫苗的免疫保护期可以设定为6个月。     

On the transferrin concentration in serum of sows and growing pigs and in sow colostrum

Immunologically pure transferrin was isolated from swine serum by means of ammoniumsulphate precipitation and ion-exchange chromatography. Rabbit anti-swine transferrin serum was prepared and used for immunological determinations of transferrin in serum and colostrum. The transferrin concentration in serum from piglets was 180 ± 56 mg/100 ml at birth and rather constant by the first days of life. The levels increase to 610 ± 78 mg/100 ml at 6 weeks after birth. The transferrin level of colostrum was 100 mg/100 ml and decreased rapidly. A negative correlation was established between the concentration of haemoglobin and transferrin. The importance of transferrin is discussed.     

Genetic analysis for sow stayability at different parities in purebred Landrace and Large White pigs

Genetic parameters for sow stayability were estimated from farrowing records of 10,295 Landrace sows and 8192 Large White sows. The record for sow stayability from parity k to parity k + 1 (k = 1, …, 6) was 0 when a sow had a farrowing record at parity k but not at parity k + 1, and 1 when a sow had both records. Heritability was estimated by using single-trait linear and threshold animal models. Genetic correlations among parities were estimated by using two-trait linear–linear and single-trait random regression linear animal models. Genetic correlations with litter traits at birth were estimated by using a two-trait linear–linear animal model. Heritability estimates by linear model analysis were low (0.065–0.119 in Landrace & 0.061–0.157 in Large White); those by threshold model analysis were higher (0.136–0.200 & 0.110–0.283). Genetic correlations among parities differed between breeds and models. Genetic correlation between sow stayability and number born alive was positive in many cases, implying that selection for number born alive does not reduce sow stayability. The results seem to be affected by decisions on culling made by farmers.     

Producing Salmonella-free pigs: a review focusing on interventions at weaning

Salmonella infection in pig production is typically endemic and largely asymptomatic. It is a cause of substantial concern among food safety bodies, prompting voluntary and legislative responses aimed at monitoring and reducing the number of Salmonella-infected animals entering the human food chain. Elimination of the problem at an early stage of production is highly desirable, and to this end the present review examines published evidence on the carriage of Salmonella by piglets before and after weaning, as well as evidence on the dynamics of Salmonella infection in the weaner and grower stages of pig production, the effects of maternal immunity, and risk factors for Salmonella excretion after weaning. Various interventions to reduce or eliminate Salmonella infection in young pigs have been tried, such as vaccination, competitive exclusion, treatments in feed and water, antibiotic administration, disinfection of animals, and segregated weaning to clean accommodation. The evidence on the effectiveness of these is considered, and the last is examined in some detail, as it appears currently to offer the best chance of eliminating Salmonella from growing stock.     

Genetic correlation between leg conformation in young pigs,sow reproduction and longevity in Danish pig populations

Abstract

Selection for sow longevity using information from traits, which are expressed in early life and genetically highly related to longevity, is expected to be more effective than direct selection as it can overcome the disadvantage of late recording of true longevity. Our aim was to investigate the correlation between leg conformation recorded on young pigs, litter size at first parity and longevity of Danish Landrace and Yorkshire sows. Information on conformation from 116,733 Landrace and 89,963 Yorkshire pigs and information on reproduction and longevity from 27,070 Landrace and 11,895 Yorkshire sows were analyzed. All considered traits were low to moderately heritable, ranging from 0.02 to 0.41. In general, both conformation and reproduction traits were favorably genetically correlated with longevity (0.07–0.39 and 0.00–0.58, respectively). These estimates suggest a potential of improving sow longevity by selection on conformation recorded at young age and litter size at first parity.     

Antibody response to Mycoplasma hyopneumoniae infection in vaccinated pigs with or without maternal antibodies induced by sow vaccination

Vaccination with bacterins is an important tool for the control of Mycoplasma hyopneumoniae infection of pigs. Because such vaccination often involves piglets that have suckled M. hyopneumoniae antibody-positive dams it is important to understand the effect of pre-existing (passively acquired) antibody on vaccine-induced immunity. To investigate this issue experimentally, 20 sows that were seronegative for M. hyopneumoniae were selected from a M. hyopneumoniae-infected herd and then randomly allocated to one of four treatment groups (five sows/group): Group A, vaccinated sows/vaccinated piglets; Group B, vaccinated sows/non-vaccinated piglets; Group C, non-vaccinated sows/vaccinated piglets; Group D, non-vaccinated sows/non-vaccinated piglets. Sows (Groups A and B) were vaccinated 14 days before farrowing and seroconverted within the next 14 days. Conversely, none of the non-vaccinated sows was seropositive at farrowing. Piglets (Groups A and C) were vaccinated when they were 7 days of age. Regardless of treatments none of the piglets had any evidence of an active immune response until many of those of Groups A and C and a few of those of Groups B and D seroconverted after it had been shown that at least some pigs of all groups had been naturally infected with a field strain of M. hyopneumoniae. This pattern of immune responsiveness (i.e. the collective results of Groups A, B, C and D) suggested that vaccination of pigs had primed their immune system for subsequent exposure to M. hyopneumoniae, and that passively acquired antibody had little or no effect on either a vaccine-induced priming or a subsequent anamnestic response. According to the statistical analysis sow serological status did not interfere with the antibody response in early vaccinated piglets. In conclusion, the results pointed out that early vaccination of piglets may assist M. hyopneumoniae control independently from the serological status of sows.     

母猪饲养新概念

母猪饲喂体系应用的表面方式和循环周期已经给养猪生产者留下诸多疑惑。如今真正需要思考的是现代母猪的基因型及如何将其与母猪营养研究最新的成果结合起来。如今瘦肉型母猪及小母猪食欲往往较低,从营养学的角度来看这种情况容易出现很多的问题。科学技术的发展同样已对母猪的饲养产生了一定的影响,例如母猪电子给料器,这意味着我们可以按照事先拟定的"饲喂方案"对每头母猪分别进行饲喂。     

限制母猪的体重损失

克罗地亚的研究表明了如何通过减少母猪泌乳期的体重损失来改善其繁殖性能     

Genetic analysis of sow longevity and sow lifetime reproductive traits using censored data

Sow longevity is a key component for efficient and profitable pig farming; however, approximately 50% of sows are removed annually from a breeding herd. There is no consensus in the scientific literature regarding a definition for sow longevity; however, it has been suggested that it can be measured using several methods such as stayability and economic indicators such as lifetime piglets produced. Sow longevity can be improved by genetic selection; however, it is rarely included in genetic evaluations. One reason is elongated time intervals required to collect complete lifetime data. The effect of genetic parameter estimation software in handling incomplete data (censoring) and possible early indicator traits were evaluated analysing a 30% censored data set (12 725 pedigreed Landrace × Large White sows that included approximately 30% censored data) with DMU6, THRGIBBS1F90 and GIBBS2CEN. Heritability estimates were low for all the traits evaluated. The results show that the binary stayability traits benefited from being analysed with a threshold model compared to analysing with a linear model. Sires were ranked very similarly regardless if the program handled censoring when all available data were included. Accumulated born alive and stayability were good indicators for lifetime born alive traits. Number of piglets born alive within each parity could be used as an early indicator trait for sow longevity.     

Genetic, phenotypic and environmental relationships between sow body weight and sow productivity traits

Yorkshire and Duroc litter records were used to estimate genetic, phenotypic and environmental relationships between sow body weight and sow productivity traits. Two data sets with two subsets each were used to complete this study; 663 and 460 records included litter traits only, while 522 and 359 records also contained sow body weight for Yorkshires and Durocs, respectively. Heritability estimates for number born (NB), number born alive (NBA), total birth weight of live pigs (BWLIT), litter weight at 3 wk (WT3WK), sow weight at parturition (WTDAMPAR) and sow weight at weaning (WTDAMWN) were .24 +/- .14, .21 +/- .14, .42 +/- .16, .19 +/- .14, .72 +/- .21 and .42 +/- .18, respectively, for Yorkshires and .05 +/- .10, .04 +/- .10, .21 +/- .14, .25 +/- .15, .85 +/- .25 and .87 +/- .26, respectively, for the Durocs. Repeatability estimates for NB, NBA, BWLIT, WT3WK, WTDAMPAR and WTDAMWN were .13 +/- .06, .17 +/- .06, .27 +/- .06, .13 +/- .06, .64 +/- .05 and .54 +/- .05, respectively, for Yorkshires and .17 +/- .06, .21 +/- .06, .14 +/- .06, .17 +/- .06, .28 +/- .07 and .39 +/- .07, respectively, for Durocs. Genetic correlations among litter traits were high and positive in the Yorkshire data. Genetic correlations between NBA and WTDAMPAR, NBA and WTDAMWN, WT3WK and WTDAMPAR, and WT3WK and WTDAMWN were .37 +/- .25, .18 +/- .34, .60 +/- .29 and .29 +/- .45, respectively, in the Yorkshire data. Genetic correlations among litter traits in the Duroc analysis had large standard errors but were generally similar to the estimates obtained from the Yorkshire data. The genetic correlation between WTDAMPAR and WTDAMWN was .93 +/- .09 for Yorkshire sows. The primary conclusion from this study is that as selection increases sow productivity traits, there will be a positive correlated response in sow body weight.     

三元母猪留做繁殖母猪的问题探讨及建议

三元母猪做繁殖母猪是现下一种很无奈又很普遍的现象,但由于母猪没有经过专业的选育及科学的饲喂,往往产仔后问题很多,最常见的问题表现在新生仔猪腹泻,这种腹泻多是因为三元母猪在生长的过程中没有添加脱霉剂,导致霉菌毒素中毒,霉菌毒素破坏了仔猪的肝脏及免疫系统,导致新生仔猪对乳脂利用率差以及自身免疫力低下的双重原因引起腹泻。文章针对仔猪的腹泻情况做详细阐述及针对三元母猪留做繁殖母猪给出一些相应的建议。     

Abortifacient agents in the sow

Abortion in sows may be complete, or much more often partial, since the average litter size is about 10. This review describes the clinical and serological findings, mode of transmission and recommended treatment for the most common parasitic, fungal, mycotoxin, deficient, and toxic causes of abortion in sows. The most likely possibilities in France are brucellosis, leptospirosis, Aujeszky virus, mycotoxin, or dietary deficiencies. The bacterialtion in French sows are Brucella species, Leptospira species, E. coli, streptococci, staphylococci, Pseudomonas, Hemophilus, Corynebacterium pyogenes, salmonellae, Listeria monocytogenes, Mycobacteriumr fetus, Chlamydia and Mycoplasma bovi genitalium. Toxoplasma gondii are parasites known to cause abortion in sows. Mycotoxins from Fusarium species may contaminate feed. Noninfectious causes include poisoning from nitrates, nitrites, estrogens, or insecticides and deficiencies of Vitamins-A, -B, in abortion.