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1.
Since cloned pig was successfully produced, a new opportunity for porcine breeding industry to conserve genetic resources has been opened. However, there has been no report to investigate whether both somatic cell nuclear transfer (SCNT) pigs and their offspring have the characteristics of the donor breed. In this study, we compared the reproductive and growth performance of American Large White boars cloned by SCNT with the donor boar, and analyzed the test parameters, including semen quality, re‐service rate, rate of parturition, and average daily gain. The results showed that these cloned boars and the donor boar had no significant differences in the tests (P > 0.05) and the growth performance of their offspring was similar to the naturally bred American Large White pigs. In summary, the reproductive and growth performance of cloned pigs are similar to the donor pig and within the normal range. This suggests that pigs cloned by SCNT have the potential to be used in reproduction and breeding.  相似文献   

2.
A pedigree including 1538 individuals of the endangered pig breed ‘Bunte Bentheimer’ and 3008 records of the fertility traits ‘number of piglets born alive’ (NBA) and ‘number of piglets weaned’ (NW) were used to i) characterize the population structure, ii) to estimate genetic (co)variance components and estimated breeding values (EBVs) and iii) to use EBVs for the application of the concept of optimal genetic contributions. The average coefficient of inbreeding increased from F = 0.103 to F = 0.121 within the two recent cohorts. Average rate of inbreeding amounted to 1.66%, which resulted in an effective population size of Ne = 30 animals in the recent cohort. Average generation interval was 3.07 years considering the whole pedigree, and in total, only 612 sows and boars generated offspring. Estimated heritabilities for both traits NBA and NW were 0.12, and the estimated genetic correlation between both traits was 0.96. The variance component due to the service sire was higher than in commercial pig breeds, presumably due to the widespread use of natural service boars. The EBVs for NBA from 333 selection candidates (63 boars and 270 sows) were used to determine optimal genetic contributions. Based on selected animals and their optimal genetic contributions, specific mating designs were evaluated to minimize inbreeding in the next generation. Best results were achieved when using a simulated annealing algorithm and allowing artificial insemination.  相似文献   

3.
We simulated a genomic selection pig breeding schemes containing nucleus and production herds to improve feed efficiency of production pigs that were cross‐breed. Elite nucleus herds had access to high‐quality feed, and production herds were fed low‐quality feed. Feed efficiency in the nucleus herds had a heritability of 0.3 and 0.25 in the production herds. It was assumed the genetic relationships between feed efficiency in the nucleus and production were low (rg = 0.2), medium (rg = 0.5) and high (rg = 0.8). In our alternative breeding schemes, different proportion of production animals were recorded for feed efficiency and genotyped with high‐density panel of genetic markers. Genomic breeding value of the selection candidates for feed efficiency was estimated based on three different approaches. In one approach, genomic breeding value was estimated including nucleus animals in the reference population. In the second approach, the reference population was containing a mixture of nucleus and production animals. In the third approach, the reference population was only consisting of production herds. Using a mixture reference population, we generated 40–115% more genetic gain in the production environment as compared to only using nucleus reference population that were fed high‐quality feed sources when the production animals were offspring of the nucleus animals. When the production animals were grand offspring of the nucleus animals, 43–104% more genetic gain was generated. Similarly, a higher genetic gain generated in the production environment when mixed reference population was used as compared to only using production animals. This was up to 19 and 14% when the production animals were offspring and grand offspring of nucleus animals, respectively. Therefore, in genomic selection pig breeding programmes, feed efficiency traits could be improved by properly designing the reference population.  相似文献   

4.
Village breeding programmes are being developed by an integrated long-term project for smallholders in Northwest Vietnam to improve pig production in different production systems. In total, 120 smallholders with 169 sows in 5 of the 9 project villages were approached in single person interviews, using a structured questionnaire. Frequency analysis of data on breeding management and ranking of smallholders' trait preferences and selection criteria used for pigs were performed with SAS 9.1, using the FREQ procedure. Survey results indicate that both improved local breeds and exotic genotypes should be incorporated in future village breeding programmes for market-oriented smallholder pig production, improving the reproductive and growth performance as well as the carcass quality. In a next step, a model reflecting the status quo at farms with market-oriented pig production was developed integrating data from farmers' survey and information from the project's current recording scheme. A deterministic approach was used to assess the profitability and genetic merit of the current recording scheme. Modelling results show that the current recording scheme is unprofitable (− 33.90 € sow− 1). As continued success of village breeding programmes depends on the profitability of breeding measures, the long-term sustainability of the current recording scheme seems unlikely. Genetic gains are achieved in production and carcass quality traits, while a small reduction in reproduction traits can be observed. In a last step, possible effects of increased pig performances on the profitability and genetic merit of the current recording scheme were evaluated. Effects of increased pig performances on the genetic and economic success of the recording scheme are generally limited. Further model calculations are necessary for finding possibilities to improve smallholder pig breeding in a profitable way.  相似文献   

5.
Selection for increased leanness and improved food efficiency in pigs has resulted in a decreased voluntary food intake. It has been argued that voluntary food intake during lactation should be considered in sow breeding programmes. The aim of the present study was to investigate the phenotypic correlation of food intake during growth and food intake at maturity with maximum lactation food intake in a mouse model. A total of 179 records were available on female mice selected for litter size at birth (S-line) and non-selected control females (C-line) from 3 weeks of age to 21 days in lactation. Half of the litters were standardized to eight pups per litter (s) and half were not standardized (ns). Growth intake was measured as the average intake between 21 and 42 days of age, mature intake was measured from a linear regression of food intake against age between 42 and 69 days of age, and lactation intake was measured as a linear regression of food intake against days in lactation between 5 and 14 days in lactation. In both lines, females with a higher growth intake also had a higher mature intake (r = 0.63 to 0.75, P < 0.0001). Lactation intake was related with growth intake and mature intake in Sns females (r = 0.50 and 0.46, P < 0.01) and with growth intake in Ss females (r = 0.32, P < 0.05). In both lines, lactation intake was highly correlated with litter weight (r = 0.48 to 0.94, P < 0.001). Sns and Ss females with higher growth intake supported larger litter weights during lactation (r = 0.32 and 0.30, respectively, P < 0.05) and Sns females with higher mature intakes tended to support larger litter weights (r = 0.28, P = 0.060). It is suggested that lactating C-line females eat to support a given litter size, while S-line females support the maximum litter weight that is allowed for by their intake capacity, and still produce at high levels when litters are standardized. Since lactating sows mobilise body reserves, the relationship of food intake during growth with that during lactation may be reflected in the relationship between growth intake and body condition.  相似文献   

6.
To assess the performance of boars derived by somatic cell cloning, we analyzed various aspects of their reproductive characteristics and the expression of two imprinted genes. Cloned boars (cloned Duroc × Jinhua) were analyzed for birth weight, growth rate, age at first ejaculation, semen characteristics and fertility, in comparison with naturally bred control boars of the same strain. The expression of imprinted genes was analyzed using the microsatellite marker SWC9 for the paternally expressed gene insulin‐like growth factor ‐2 (IGF2) and with single nucleotide polymorphisms (SNPs) for the gene maternally expressed 3 (MEG3). The cloned boars had high production of semen and were nearly equal in level of fertility to conventional pigs; they showed similar characteristics as naturally bred boars of the same strains. The expression of IGF2 was partially disturbed, but this disturbed expression was not linked to a change in developmental fate or reproductive performance. These results indicate that use of cloned boars could be highly effective for proliferation of pigs with desirable characteristics, preservation of genetic resources and risk reduction against epidemic diseases, such as foot‐and‐mouth disease, through storage of somatic cells as a precautionary measure for use in regenerating pig populations after a future pandemic.  相似文献   

7.
The aims were to evaluate sperm DNA fragmentation (SDF) in boars through the dispersion of their chromatin in raw semen samples, quantifying the extent of SDF, and to assess dynamic aspects of sperm DNA damage after incubation to obtain the rate of sperm DNA fragmentation (rSDF) under thermal conditions similar to the uterus (37°C) over a period of up to 24 hr and to correlate the reproductive outcome of the sows with the SDF of the boars at ejaculation. The study was performed on a pig‐breeding farm in southern Uruguay. Sixty‐one ejaculates from five of the most frequently used hybrid boars were evaluated. Semen was collected weekly from each of the boars, using the gloved‐hand technique and discarding the jelly‐like fraction of the ejaculate. Fresh semen was kept in a water bath at 37°C and protected from light, and was thereafter processed with Sperm‐Sus‐Halomax® to evaluate SDF. The smears for time 0 (T0) were made on farm, and thereafter smears were made at the laboratory at 4 hr of obtaining the semen (T4), then every 2 hr (T6, T8, T10, T12) and a final fixation at 24 hr (T24). Differences in SDF were observed among exposure times for all boars (p < .05), but not between T10 and T12 (p = .7751) nor T4 and T24 (p = .9113). In none of the T24 samples, sperm heads could be seen with chromatin dispersion halos. Furthermore, there were differences among boars when comparing sperm rSDF (p < .05). Farrowing rate was not affected by SDF at T0 (r = .38, p = .75), nor was litter size (r = .16, p = .70). With the present experimental conditions, we have not been able to show a relationship between sperm DNA fragmentation at ejaculation and reproductive performance. However, this could be a result of the low number of ejaculates and boars used.  相似文献   

8.
Bovine growth hormone (bGH) gene polymorphism of leucine (Leu)-threonine (Thr) (allele A), valine (Val)-Thr (allele B), and Val-methionine (Met) (allele C) at codons 127 and 172 was shown to relate with carcass trait variations in Japanese Black cattle. In this study, 10-mo-old Japanese Black heifers with growth hormone (GH) genotypes AA, AB, BB, AC, BC, and CC (N = 141) were compared for basal GH, insulin-like growth factor-1 (IGF-1), insulin, ghrelin, glucose, and nonesterified fatty acid (NEFA) concentrations. Growth hormone release was also measured as response to growth hormone–releasing hormone (GHRH) (0.4 μg/kg body weight [BW]) using 18 heifers with GH genotypes AA, BB, and CC (n = 6 for each group). The genotype AA heifers showed the greatest BW among genotypes (P < 0.05). Genotype AC, BC, and CC heifers showed greater GH concentrations than genotype AA, AB, or BB heifers, in which genotype CC heifers had the highest concentrations (P < 0.05). However, IGF-1 concentrations did not significantly differ. The genotype AA and BB heifers had a greater GH release at 60 min following GHRH injection than did the genotype CC heifers. The area under the curve (AUC; P < 0.07) and incremental area (IA; P < 0.08) of GH responses to the GHRH challenge tended to be the highest in the genotype AA heifers and the lowest in the genotype CC heifers. In conclusion, GH gene polymorphism altered GH, which may have contributed to differences in BW and carcass traits among genotypes.  相似文献   

9.
养殖环境对生猪的健康生长有至关重要的影响,会严重威胁不同年龄和不同猪的健康生长和繁殖。生猪养殖中如果不能严格控制养殖环境,易造成种公猪的精液质量下降,精子活性降低,母猪不能正常发情,隐性发情。不规律发情,影响母猪正常排卵,使繁殖率显著下降。对于养殖场的育肥猪养殖环境还会影响整体的育肥效果,使饲料的成本显著增加,不利于提高养殖效益。因此在发展生猪养殖中,注重做好养殖环境的控制,减少各种污染物的产生,确保生猪健康生长。该文主要论述养殖环境对不同年龄阶段猪的影响,并提出养殖环境的改善措施。  相似文献   

10.
  相似文献   

11.

Background

To achieve a competitive reproductive performance in organic pig farming is a major challenge for this farming practise. Practices and research data regarding conventional pig production are not always applicable to organic production, why field studies are needed to identify differences in performance between organic and conventional pig farms in order to identify areas for improvement.

Results

Performance data for one year was collected from 5 organic herds that had more than 30 sows in production and used a computerized recording system, and data from five nearby conventional farms with more than 30 sows and the same recording system were used as a comparison. In total data from 4697 farrowings were analyzed. In the organic pig herds, there were a higher total number of piglets born per litter (p=0.001), a higher number of piglets stillborn per litter (p<0.001), but a tendency (p<0.06) to lower number of weaned pigs per litter and longer nursing period (p<0.001) and farrowing interval (p<0.001).

Conclusions

The reproductive performance was lower in the organic herds and the variation in reproductive performance among the organic herds was larger than among the conventional ones, suggesting options for improvement in the organic herds.  相似文献   

12.
In pig breeding programmes breeding values for growth and carcass traits are generally estimated in test environments, e.g. central test or on-farm test. The breeding goal, however, should be defined at the level of commercial growing. Genotype × environment (G × E) interaction (test and commercial environment) will lower the efficiency of a breeding scheme based on testing in test environments. The effect of G × E interaction on the response to selection can be examined by interpreting the interaction as a genetic correlation between a trait measured in one environment and a similar trait in another environment. Here, two types of genetic correlation need to be considered: rG for the correlation between test and commercial environment, and rg, for the correlation among various commercial environments. In this paper procedures to estimate these genetic correlations are reviewed. Furthermore, some testing strategies are compared in model calculations. The objective was to determine at which (low) levels of rG testing of individuals, sibs or progeny in commercial environments is more efficient than testing in a test environment. It is concluded that generally central testing is to be preferred and that additional testing of sibs in commercial environments may be of value.  相似文献   

13.
We estimated heritabilities of semen production traits and their genetic correlations with litter traits and pork production traits in purebred Duroc pigs. Semen production traits were semen volume, sperm concentration, proportion of morphologically normal sperms, total number of sperm, and total number of morphologically normal sperm. Litter traits at farrowing were total number born, number born alive, number stillborn, total litter weight at birth, mean litter weight at birth, and piglet survival rate at birth. Litter traits at weaning were litter size at weaning, total litter weight at weaning, mean litter weight at weaning, and piglet survival rate from birth to weaning. Pork production traits were average daily gain, backfat thickness, and loin muscle area. We analyzed 45,913 semen collection records of 896 boars, 6,950 farrowing performance records of 1,400 sows, 2,237 weaning performance records of 586 sows, and individual growth performance records of 9,550 animals measured at approximately 5 mo of age. Heritabilities were estimated using a single-trait animal model. Genetic correlations were estimated using a 2-trait animal model. Estimated heritabilities of semen production traits ranged from 0.20 for sperm concentration to 0.29 for semen volume and were equal to or higher than those of litter traits, ranging from 0.06 for number stillborn and piglet survival rate at birth to 0.25 for mean litter weight at birth, but lower than those of pork production traits, ranging from 0.50 for average daily gain to 0.63 for backfat thickness. In many cases, the absolute values of estimated genetic correlations between semen production traits and other traits were smaller than 0.3. These estimated genetic parameters provide useful information for establishing a comprehensive pig breeding scheme.  相似文献   

14.
The ARR allele of the prion protein gene is associated with resistance to classical scrapie, while the ARQ allele is associated with susceptibility. The objective of this study was to estimate the effect, on lamb growth and carcass traits, of replacing an ARQ allele with an ARR allele. Pedigree rams (22 Suffolks, 18 Texels and 18 Charollais) were sourced in pairs, from the same flock (by the same sire where possible), with one member being ARR/ARR and the other being ARQ/ARQ and these rams were progeny tested through single-sire mating in six flocks. Effects of ram genotype on reproductive performance of ewes and on growth and carcass traits of progeny were estimated using mixed model procedures with sire as a random effect. Ram genotype had no effect on litter size at birth or on lamb survival as measured by the number of lambs reared. The differences between the performance of progeny by ARR/ARR and ARQ/ARQ sires provided an estimate of the effect of substituting an ARR allele for an ARQ allele. This allele substitution had no effect on birth weight, growth rate, weight at 5 or 14 weeks, weight or ultrasonic fat depth at 120 days of age or on carcass classification traits (conformation, fatness) for the Suffolk, Texel or Charollais breeds. Substituting an ARR allele for an ARQ allele had a negative effect on ultrasonic muscle depth at 120 days for the progeny of Suffolk rams (P = 0.01) but had a positive effect on ultrasonic muscle depth at 120 days for the progeny of Charollais rams (P = 0.02). The ARR substitution effect was negative for slaughter age in the Suffolk (P < 0.05) and positive for carcass weight in Texel progeny (P < 0.05). The magnitude of these effects was quite small, however, and the overall results support the hypothesis that substituting an ARR allele for an ARQ allele has no important negative effect on lamb growth or carcass traits in any of the breeds examined.  相似文献   

15.
The crossbred sire: experimental results for swine   总被引：2，自引：0，他引：2  
Experiments aimed at comparing crossbred and purebred boars were reviewed. These experiments showed that crossbred boars matured sexually more quickly than corresponding purebred boars: they exhibited greater testis weight, large ejaculate volume and had better semen quality. Young crossbred boars were more aggressive sexually and achieved a higher conception rate, particularly on first service. Differences between the two types of boars for litter size and weight were generally small and variable in direction. Growth rate, feed efficiency and carcass characteristics of progeny of purebred and crossbred boars were generally similar. In addition, there was little evidence that use of crossbred sires had any effect on variability of pig performance.  相似文献   

16.
适当降低每次输精时猪精的有效精子数可提高公猪利用效率、减少公猪饲养规模,同时能更充分地利用优秀的公猪.试验以15亿/80 mL规格猪精为对照组,比较12亿/80 mL、12亿/60 mL和10亿/60 mL规格猪精的深部输精对经产母猪繁殖性能的影响.结果显示:受胎率15亿/80 mL>12亿/60 mL>10亿/60 ...  相似文献   

17.
A total of 413 pig faecal samples were collected from pre-weaners (119), starters (131), pre-growers (123) and sows (40) from a farm with a closed breeding system segmented into two breeding complexes and a growing complex in the region of Vysočina, Czech Republic and screened for the presence of Cryptosporidium using staining methods and genotyping (SSU rRNA). Cryptosporidium oocysts were detected by microscopy in the faeces of 21.1% of the samples (87/413). Sequence analyses and RFLP identified C. suis in 44, Cryptosporidium pig genotype II in 23 and C. muris in 2 samples. No mixed infections were found.Pigs under 7 weeks of age were infected with C. suis only. Cryptosporidium pig genotype II was found in animals from 7 weeks of age. No relationship was found between diarrhoea and any Cryptosporidium infection in any of the different age groups (P < 0.05). The pre-weaned pigs shed significantly more Cryptosporidium oocysts than older pigs and it was associated with C. suis infection.  相似文献   

18.
The semen movement and sperm head size patterns of boar ejaculates were analysed using computer-assisted semen analysis (CASA)-Mot and -Morph systems. The aim of the present study was to compare morphometric and kinematics variables from boars and to determine the relationship with sow fertility variables related to litter size. The females were from maternal crossing schemes such as the continuous 3-generation cross between York (Y), Landrace (L), and Pietrain (P) hybrid sows and Pietrain boars. Semen samples were collected from 11 sexually mature boars from two sire lines. Samples were analysed using the ISAS®v1 system to evaluate eight kinematic variables of sperm velocity, progressiveness and undulations. Four morphometric parameters of sperm head size (length, width, area and perimeter) were analysed. Bayesian analysis revealed relevant differences in four kinematic variables (VSL, LIN, STR and WOB) between sire lines, with a probability of relevance (PR) of 0.79–0.91, and Pietrain boars were associated with higher progressive motility compared with Duroc x Pietrain boars. Moreover, there were relevant differences in all morphometric variables (PR = 0.82–0.85) between sire lines. The dam line Y-L-50 (½ Y × ½ L) had higher total born per litter and piglets born alive, and YLP-75 (1/8 Y × 1/8 L × 3/4 P) was associated with higher values of litter weight at birth (highest posterior density region at 95% = 9.92, 16.41 kg). There are relevant differences in kinematic variables between the assessed sire lines and the differences in morphometric and litter size variables were also relevant. The York-Landrace hybrid sows had higher total born per litter and piglets born alive, and there were relevant differences when compared with YLP-50 (¼ York × ¼ Landrace × ½ Pietrain). Differences in kinematic and morphometric variables between sire and dam lines related to fertility need to be further studied.  相似文献   

19.
Litter size determined ultrasonographically at 45–90 days after mating in eight groups of commercial sheep (n = 2609) treated with slow release melatonin implants immediately prior to the natural breeding season showed a 19% treatment effect averaged over the eight groups, from 148% to 167% (P < 0.01) compared with controls (n = 2499). Control groups had a litter size ranging from 124% to 194% thereby representing most commercial production systems in the UK sheep industry. This is the first large scale study of slow release melatonin implants in commercial UK flocks to demonstrate a significant positive effect on litter size when used before the natural breeding season. The data indicate that increased productivity and profitability could be achieved while maintaining desirable purebred characteristics.  相似文献   

20.
In this study, we investigated whether a selection programme based on boar genetic evaluation obtained with a classical BLUP animal model can change allele frequencies in a pig population. All Italian Large White boars born from 1992 to 2012 with estimated breeding value reliability >0.85 (n = 200) were selected among all boars of this breed. Boars were genotyped with markers in major genes (IGF2 intron3‐g.3072G>A, MC4R p.D298N, VRTN PRE1 insertion, PRKAG3 p.I199V and FTO g.276T>G). Genotyping data were analysed grouping boars in eight classes according to their year of birth. To evaluate the influence of time on allele frequencies of the genotyped markers, multinomial logistic regression models were computed. Four of five polymorphic sites (IGF2, MC4R, VRTN and FTO) showed significant (p < 0.01) changes in allele frequencies over time due to a progressive and continuous increase of one allele (associated with higher lean meat content, higher average daily gain and favourable feed: gain ratio) and, consequently, decrease of the other one, following the directional selection of the selection programme of this pig breed. The retrospective analysis that was carried out in Italian Large White boars suggests that selection based on methodologies assuming the infinitesimal model is able to modify in a quite short period of time allele frequencies in major genes, increasing the frequency of alleles explaining a relevant (non‐infinitesimal) fraction of the overall genetic variability for production traits.  相似文献   

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