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1.
Litter characteristics at birth were recorded in 4 genetic types of sows with differing maternal abilities. Eighty-two litters from F(1) Duroc x Large White sows, 651 litters from Large White sows, 63 litters from Meishan sows, and 173 litters from Laconie sows were considered. Statistical models included random effects of sow, litter, or both; fixed effects of sow genetic type, parity, birth assistance, and piglet sex, as well as gestation length, farrowing duration, piglet birth weight, and litter size as linear covariates. The quadratic components of the last 2 factors were also considered. For statistical analyses, GLM were first considered, assuming a binomial distribution of stillbirth. Hierarchical models were also fitted to the data to take into account correlations among piglets from the same litter. Model selection was performed based on deviance and deviance information criterion. Finally, standard and robust generalized estimating equations (GEE) procedures were applied to quantify the importance of each effect on a piglet's probability of stillbirth. The 5 most important factors involved were, in decreasing order (contribution of each effect to variance reduction): difference between piglet birth weight and the litter mean (2.36%), individual birth weight (2.25%), piglet sex (1.01%), farrowing duration (0.99%), and sow genetic type (0.94%). Probability of stillbirth was greater for lighter piglets, for male piglets, and for piglets from small or very large litters. Probability of stillbirth increased with sow parity number and with farrowing duration. Piglets born from Meishan sows had a lower risk of stillbirth (P < 0.0001) and were little affected by the sources of variation mentioned above compared with the 3 other sow genetic types. Standard and robust GEE approaches gave similar results despite some disequilibrium in the data set structure highlighted with the robust GEE approach.  相似文献   

2.
本文系对103头360窝太湖猪的繁殖性能进行系统研究。结果是60头母猪在6个繁殖周期中共繁殖360窝,平均繁殖周期158.33天,年产仔2.31胎。窝产仔16.35头,活仔15.10头,35日龄断奶育成14.44头,窝重83.48公斤。每头母猪年产仔37.69头,年产活仔34.81头,年提供断奶仔猪33.29头。其中窝产仔达到18头以上,出现1胎或连续4胎高产的母猪69头,占试验母猪群66.99%。  相似文献   

3.
This study comprised 48,931 litters in 89 sow herds. During the study (1976-82) weaning age decreased from approx. 42 days to approx. 30 days. The mean incidence of post-weaning diarrhoea was 6.0% of litters weaned, with little variation by year but with considerable variation among herds. Within the individual herd increased incidence occurred over limited periods, probably associated with specific infections. Litters with diarrhoea during the suckling period had increased risk of post-weaning diarrhoea. The incidence of post-weaning diarrhoea increased with litter size at weaning. Thus, a litter of 11-12 piglets at weaning had 1.2 times higher risk than litters with 8-10 piglets. In contrast to pre-weaning diarrhoea, there was no association between parity of the sow and diarrhoea in the litter after weaning. Litters weaned below 2 weeks of age had a 2-fold risk of developing diarrhoea after weaning and a 2.4-fold higher mortality rate than did litters weaned at 6-7 weeks. Similarly, litters weaned at an individual piglet weight below 3 kg bodyweight had a 3-fold higher risk of developing diarrhoea after weaning and a 5-fold higher mortality rate than did pigs from litters weaned at a bodyweight of 7-8 kg. The incidence of post-weaning diarrhoea decreased with increasing herd size. Piglets from litters with post-weaning diarrhoea had reduced weight gains after weaning and were 2.3 days older at 25 kg bodyweight than piglets from non-diarrhoeic litters. Likewise, diarrhoea after weaning was associated with an increased incidence of diseases of the skin and respiratory tract. Thus the risk of contracting respiratory disease was 4 times greater in diarrhoeic litters.  相似文献   

4.
我国是养猪大国,但生产效率相较于发达国家仍然相差很大,缩短母猪的繁殖周期是提高猪场综合生产效率和经济效益的有效手段.本文通过分析四川某种猪场包括大约克和长白猪的15665条繁殖数据,从母猪品种、公猪品种、配种季节和胎次等不同因素分析其对母猪妊娠期长短的影响,以及妊娠期长短对母猪产仔数的影响.结果表明,品种对母猪妊娠期有...  相似文献   

5.
The influence of suckling interval on milk production of sows   总被引:3,自引:0,他引:3  
The objective of this study was to determine whether sow milk yield per gland could be increased by reducing the interval between suckles (suckling interval). Eighteen sows were allocated at their first farrowing to three treatments comprising litter sizes of 6 or 12 piglets or a cross-suckling treatment that was imposed to increase suckling frequency. The cross-suckled treatment comprised two groups of six piglets each. Each suckling group was allowed to suckle the sow during 30-min intervals each day between d 6 and d 28 of lactation. The suckling interval was shorter (P < .05) for cross-suckled sows than for sows suckling single litters of 6 or 12 piglets during early lactation (d 10 to 14) and late lactation (d 24 to 28). Average piglet growth rate between birth and 28 d of age was greatest (P < .05) for piglets in the single litters of six and lowest for piglets in the cross-suckled treatments. Single litters of 12 piglets had the highest (P < .05) litter growth rates, followed by the cross-suckled litters and then the single litters of six piglets. The concentration of lactose and fat in milk from sows remained relatively stable, although milk from the cross-suckled sows contained more protein in early lactation (P < .05). Milk yield of sows was not significantly increased (P > .05) by the cross-suckle treatment, although during early lactation, milk yield tended to be greater from sows in the cross-suckle treatment than from sows suckling single litters of six (8,920 g/d vs 7,819 g/d, P < .1). The concentration of DNA and total RNA and the RNA:DNA ratio in mammary glands was unaffected by treatment (P > .05). Sows with single litters of 12 piglets had the greatest total DNA in their udders (P < .05). However, individual gland weights were heavier (P < .05) in cross-suckled sows than in sows with single litters of 6 or 12 piglets. Increased suckling frequency seemed to play a role in increased mammary gland weight and milk production during lactation.  相似文献   

6.
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。  相似文献   

7.
To determine the effect of within-litter neonatal-weight variation on pre-weaning mortality and weight gain, we analyzed piglet survival and weight gain within 400 litters from 10 commercial farms. Neonatal-weight variation (independent of mean neonatal weight, litter size and sow parity) was associated with pre-weaning survival and weaning-weight variation-but not with mean weaning weight. Neonatal piglets with weights well below the range of most of the litter (low-birth-weight piglets) had an increased risk of dying and were unable to obtain normal weight gains by weaning if they survived. These piglets experienced lower survival and poorer weight gain in larger litters. These piglets also tended to have lower survival but normal (albeit low) weaning weights if they survived in litters from middle-aged and old sows. High neonatal-weight variation resulted in lower survival and more variable weaning weights. Small piglets had a greater risk for poor survival and weight gain compared to their heavier litter-mates (a disadvantage that was exacerbated in large litters).  相似文献   

8.
Performance measures were evaluated for 125 outdoor sows and litters of two crossbred genotypes (Camborough-15 and 25% Meishan) and in two farrowing hut designs (American-style and English-style hut). Contemporary breeding groups of second-parity sows were evaluated in an intensive, outdoor research unit. Sow genotype and hut designs were arranged factorially. Seven complete blocks were evaluated over a 21-wk period. No interactions between environment and genotype were identified for sow and litter productivity. Litters farrowing in the English-style huts weaned 1.5 more (P < .05) piglets per sow (because of a lower preweaning mortality, P = .05) than did litters in the American-style huts. The 25% Meishan weaned 1.7 more (P < .01) pigs per sow than Camborough-15, because of a greater number of piglets born alive. The effects of hut style and genotype were additive and 25% Meishan sows in English-style huts weaned an average (+/- SEM) of 11.1 +/- .83 piglets per sow. The English-style arc hut design may improve outdoor pig production and increase competitiveness of the intensive, outdoor system. The 25% Meishan genotype has potential for increased pigs weaned per litter that must be considered in light of other features of this genotype such as body composition.  相似文献   

9.
Reduction in the variability of piglet birth weight within litter and increased piglet survival are key objective in schemes aiming to improve sow prolificacy. In previous studies, variation in birth weight was described by the sample standard deviation of birth weights within one litter, and the genetic impact has been proved. In this study, we additionally considered the sex effect on piglet's birth weight and on its variability. The sample variance of birth weights per litter separated by sex was assigned as a trait of the sow. Different transformations of the trait were fitted by linear and generalized linear mixed models. Based on 1111 litters from Landrace sows, the estimates of heritability for the different measures ranged from 11 to 12%. We analysed the influence of including birth weight of stillborn piglets on the variability of birth weight within litter. With omitted stillborns, the heritability was estimated approximately 2% higher than that in investigations of all born piglets, and the impact of sex on birth weight variability was increased. Because the proportion of intrapartum deaths is rather high, it is recommended to consider the total number of piglets born per litter when analysing birth weight variation.  相似文献   

10.
Causes of preweaning mortality were examined on a large intensive piggery. Diagnosis was made using comprehensive clinical histories combined with post-mortem data. Two thousand four hundred and twenty-six piglets were born in 238 litters. Pre-parturient and parturient losses were 2.9% and 5.4% of the total numbers of piglets born. Birth to weaning mortality was 11.3%. Among piglets born alive, overlaying was the most frequent cause of death (2.1%), followed by deaths due to diarrhoea (1.7%), anaemia (1.2%), savaging (1.1%) and losses of small weak piglets (0.9%). Most deaths, including stillbirths, were associated with below average birth weight, and two-thirds of all deaths of liveborn pigs occurred within 4 days of birth. Increased litter size resulted in decreased birth weights, an increased percentage of stillborn piglets and mummified foetuses, but duration of parturition was not affected. Stillborn piglets were born late in the litter and after a longer interval between pigs born (interpig interval). Over 70% of deaths due to overlay were in previously healthy piglets, but some were associated with illness of the sow (18%) or both sow and piglet (3%). Savaging was confined mainly to first parity sows and was responsible for 20% of all deaths in these litters. Sixty-two per cent of all piglets with a birth weight of less than 800g were stillborn or died before weaning compared with 18.7% mortality for all piglets. Anaemia in piglets was considered to be due to umbilical haemorrhage. Anaemic piglets had a 36% mortality to weaning compared with 10% for non-anaemic piglets.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

11.
Altogether 129 F1 sows from a commercial sow farm with at least four litters were genotyped for the oestrogen receptor 2 gene (ESR2) and cytochrome P450 hydroxylase 21 gene (CYP21) and investigated for associations on the litter‐size parameters: total number born and number born alive. Five novel polymorphisms were found in the 3′‐untranslated region for the CYP21 gene. Genotype and allele frequencies for the CYP21 (position 3462G > A) single‐nucleotide polymorphism (SNP) were 0.434 (GG), 0.504 (AG), 0.062 (AA) and 0.69 (G):0.31 (A), respectively. No association was found between this polymorphism and litter‐size parameters. For the ESR2 gene, the SNP in exon 5 associated with an amino acid substitution MET (allele A) > VAL (allele G) was investigated. Only two genotypes were found leading to allele frequencies of 0.34 (A):0.66 (G). Only number born alive piglets were significantly increased for the AG genotype (p = 0.034) with 11.64 piglets per sow and litter in comparison with the GG genotype, leading to only 10.96 piglets per sow and litter. From these data, it can be concluded that the investigated SNP of the ESR2 gene is associated with the number of liveborn piglets in the commercial population considered, and hence could be useful in selection for litter size. Therefore, this gene should be investigated in additional populations.  相似文献   

12.
Two studies assessed sow and litter performance when design features of farrowing huts varied. A fender is a structure that extends out the front of the hut to create a veranda that prevents young piglets from leaving. In Exp. 1, 206 lactating sows and their litters were used to assess litter performance and the time required to process litters for two fender designs (short wooden [WS] vs. tall metal with a board front [MT-b]) and insulation status (insulated [IN] vs. uninsulated [UN]) farrowing huts. A significant fender x insulation interaction was observed for total litter weaning weight. Lighter litters weaned (P = 0.013) from WS fenders with UN huts compared with the other treatments. Fender design did not (P > 0.05) influence the time required to process a litter with one stockperson. Less total time (P = 0.001) was required to process a litter when two people were present (10.60 +/- 0.74 min) compared with one stockperson (14.52 +/- 0.74 min). There were no (P > 0.05) differences between IN and UN huts for temperature and relative humidity measurements. In Exp. 2, 331 lactating sows and their litters were used to determine sow and litter performance when using one of two fender front designs (boards [MT-b] vs. roller [MT-r]). The front design of the fender did not influence (P > 0.05) most litter performance measures. We conclude that fender design, fender fronts, and insulation effects did not have large influences on sow and litter performance in a West Texas environment.  相似文献   

13.
The aim of this study was to investigate piglet preweaning survival and its relationship with a total merit index (TMI) used for selection of Large White terminal boars for dry-cured ham production. Data on 13,924 crossbred piglets (1,347 litters), originated by 189 Large White boars and 328 Large White-derived crossbred sows, were analyzed under a frailty proportional hazards model, assuming different baseline hazard functions and including sire and nursed litter as random effects. Estimated hazard ratios (HR) indicated that sex, cross-fostering, year-month of birth, parity of the nurse sow, size of the nursed litter, and class of TMI were significant effects for piglet preweaning survival. Female piglets had less risk of dying than males (HR = 0.81), as well as cross-fostered piglets (HR = 0.60). Survival increased when piglets were nursed by sows of third (HR = 0.85), fourth (HR = 0.76), and fifth (HR = 0.79) parity in comparison with first and second parity sows. Piglets of small (HR = 3.90) or very large litters (HR >1.60) had less chance of surviving in comparison with litters of intermediate size. Class of TMI exhibited an unfavorable relationship with survival (HR = 1.20 for the TMI top class). The modal estimates of sire variance under different baseline hazard functions were 0.06, whereas the variance for the nursed litter was close to 0.7. The estimate of the nursed litter effect variance was greater than that of the sire, which shows the importance of the common environment generated by the nurse sow. Relationships between sire rankings obtained from different survival models were high. The heritability estimate in equivalent scale was low and reached a value of 0.03. Nevertheless, the exploitable genetic variation for this trait justifies the inclusion of piglet preweaning survival in the current breeding program for selection of Large White terminal boars for dry-cured ham production.  相似文献   

14.
Maternal effects might affect the response to selection for litter size. An experiment was carried out to determine the effect of the size of litter in which a gilt was raised on its production and reproduction characteristics. Gilts raised in large litters (12 piglets) produced smaller litters (?0.48 piglets) compared to those raised in small litters (six piglets). Results obtained suggest that a low standardization level positively affects weaning weight and development of the uterus. Lower weight at weaning, in combination with a larger pool of primordial follicles, might explain the positive effect on litter size.  相似文献   

15.
以华南某1 500头规模种猪场2009年到2010年1 502窝长白猪分娩信息进行优化、选配减少近交畸形的研究,结果显示血缘选配优化时将近交系数控制在1%比3%效果明显,平均产活仔数从10.39头/窝提高到10.46头/窝(P>0.05),畸形率从10.30%下降到4.79%(P<0.01);对其中402窝出现畸形仔猪...  相似文献   

16.
Analyses of the records of 244 litters of purebred Yorkshire, Landrace, the crosses, backcrosses and crisscrosses of these two breeds were carried out to evaluate some of the factors influencing the losses of piglets prior to weaning.

There were differences in percentage survival between mating systems, with crossbred Landrace x Yorkshire piglets showing the highest rate of survival.

A direct relationship existed between the duration of farrowing and the incidence of stillbirths. The incidence of stillbirths was higher for male piglets than for female piglets.

Litter size at birth and weight loss of sow from parturition to weaning were important factors in determining litter size at weaning. Litter size at birth however, exerted a more important influence on litter performance than weight loss.

Age of sow had no significant effect on the number of piglets alive at weaning and implied that gilts were apparently as good mothers as sows.

From computed least squares estimates, it was implied that in general, piglets of low birthweights had much less chance of survival than those born with heavier weights.

  相似文献   

17.
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.  相似文献   

18.

Background

Piglets are born with eight sharp teeth that during nursing can cause facial lesions on littermates and teat lesions on the sow. Teeth grinding in piglets is therefore often practiced to reduce these lesions. The aim of this study was to assess the consequences of grinding piglet teeth in regard to the occurrence of lesions.In this study the piglets'' teeth were grinded in 28 litters, and in 36 litters the piglets'' teeth were kept intact. Twice, one time during the first week and one time during the second week after birth facial lesions of the piglets were scored and the teats of the sows were examined for lesions. The facial lesion score accounted for the amount and severity of lesions. The individual observations on piglets in the litter were synthesized in a litter facial lesion score.

Findings

69.8% and 43.5% of the piglets had facial lesions in week 1 and week 2 respectively. The effect of treatment was not significant on litter facial lesion score. The litter facial lesion score was higher in week 1 than in week 2 (p < 0.001) and higher in large litters (p = 0.003) than in small litters. Mortality between week 1 and week 2 was higher in litters with intact teeth (p = 0.02). Sow teat lesions only occurred if litters had intact teeth.

Conclusions

According to our results teeth grinding is only justifiable in large litters.  相似文献   

19.
Summary Piétrain boars of different ryanodine receptor (RYR1) genotypes (NN, Nn and nn, three boars each) were mated with approximately 10 Czech Large White × Czech Landrace sows (genotype NN) each to produce one litter per sow. The progeny of nn boars had a significantly higher individual weaning weight (7.31 kg versus 6.86 kg) and average daily gain from birth to weaning (252 g/day versus 240 g/day) than the progeny of NN boars. Furthermore, piglets from nn boars differed statistically significant also from piglets of boars with the Nn genotype for these two traits. The litters of the NN boars were greater by 0.5 piglets than the litters of the nn boars for the total number of piglets born, piglets born alive and piglets weaned, but the differences were not significant. The Nn genotype showed for all litter size traits and the number of stillborn piglets the best values. The difference between the genotypes Nn and nn was statistically significant at the 0.05 level for the number of piglets born alive and the number of piglets weaned.  相似文献   

20.
为了解约互母猪与长约互母猪在繁殖性能上的特点和差异,在大通县种猪场选用30窝杂种猪(其中约互7窝,长约互23窝),比较分析其产仔数,初生体质量,初生窝体质量等5个性状,结果表明:长约互母猪的仔猪的初生窝体质量和35 d龄断奶窝体质量明显高于约互母猪的仔猪(P<0.05),其它性能无明显差异。  相似文献   

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