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1.
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   

2.
The goal of this study was to determine whether the presence of the bovine alpha-lactalbumin transgene in first-lactation gilts enhances lactational performance and litter growth. Transgenic and sibling nontransgenic gilts were bred to nontransgenic boars. Litters were standardized to 10 piglets within 24 h of farrowing. Milk production was measured by the weigh-suckle-weigh method on d 3, 6, 9, and 12 of lactation. Bovine alpha-lactalbumin was present in the colostrum and milk of transgenic gilts throughout lactation. The expression of the transgene was associated with alterations in composition of mammary secretions, especially in early lactation. Lactose concentrations were greater (P < 0.05) in mammary secretions of transgenic gilts during the first 12 h postpartum compared with controls. In contrast, total solids concentration in mammary secretions from transgenic gilts were lower (P < 0.05) relative to controls during the first 6 h postpartum. Transgenic gilts produced more milk than controls on d 3, 6, and 9 of lactation (P < 0.01). By d 12, differences in milk production between transgenic and control sows were no longer different. Lactose intake by transgenic-reared litters was greater than lactose intake by control-reared litters on d 6 of lactation (P < 0.05). Total solids intake was significantly greater (P < 0.05) by transgenic-reared litters on d 3 and 6 compared to control-reared litters. The day x genotype interaction on litter weight gain after birth was highly significant (P = 0.011), with transgenic-reared litters gaining weight at a greater rate than control-reared piglets. Expression of the transgene was associated with increased milk production in lactating gilts and increased growth of transgenic-reared piglets. Increased lactose synthesis in response to the presence of the transgene may result in increased milk production in early lactation, leading to increased milk component intake by transgenic litters, and ultimately to increased growth of litters reared by first-parity transgenic gilts.  相似文献   

3.
Lameness in piglets up to nine weeks old was studied in a research station herd for four years; 9411 piglets were born alive, of which 9.8 per cent were treated for lameness. In litters born to gilts, 9.9 per cent of the piglets were treated for lameness, in litters born to sows of parity 3, 11.4 per cent of the piglets were treated, but in litters born to sows of parity 4 to 7 the proportion of piglets treated for lameness decreased to about 8 per cent. Around 75 per cent of all cases were observed in piglets less than three weeks old; the incidence risk of lameness decreased from 2.7 per cent during the first week of life to 0.3 per cent after weaning. The average weight of affected piglets was reduced by approximately 8 per cent at nine weeks of age. There was no overall association between lameness and sex or birth weight within sex. The mortality among lame gilts was higher at all ages than among healthy gilts, but among barrows a higher mortality was observed only during the late suckling period. Litters with 12 or more piglets had a higher incidence of lameness. Clinical signs of disease in the sow and whether the piglets were given an intramuscular injection of 200 mg of iron on their second, third or fourth day of life had no effect on the incidence of lameness.  相似文献   

4.
Two outbreaks of porcine parvovirus occurred in a unit of 380 sows, with a subsequent decrease in the size of gilts' litters. Of the 203 gilts and 64 primiparous sows which were seronegative at the time of insemination, 134 gilts and 55 primiparous sows seroconverted during pregnancy. Of the second parity sows nine of 271 were still seronegative at the time of insemination but all nine seroconverted during their third gestation. The gilts that seroconverted during their first pregnancy produced on average 0.9 fewer live piglets than the gilts that did not seroconvert. Second litter sows which seroconverted produced 0.3 fewer piglets than those which did not seroconvert. There were no significant differences between sows which seroconverted or did not seroconvert in the numbers of returns to service, or in the percentages of piglets which were born dead or died before weaning.  相似文献   

5.
Experiments were conducted to determine if a nocturnal rise in serum melatonin occurs in prepubertal gilts and whether acute exposure of gilts to light during the dark period abruptly reduces serum concentrations of melatonin. In experiment 1, 12 prepubertal crossbred gilts (Duroc x Hampshire x Chester White x Yorkshire) weighing 96.4 + 1.3 kg at 5.1 + .1 mo of age were housed in an LD cycle of 10:14. Following a 3-wk acclimation period, blood samples were drawn at 1-hr intervals from indwelling jugular catheters. Serum concentrations of melatonin were similar (P greater than .05) among blood samples collected during light and dark periods. In experiment 2, serum concentrations of melatonin did not change (P greater than .05) when gilts were abruptly exposed to light during the normal dark period. In experiment 3, serum concentrations of melatonin were similar (P greater than .05) in blood samples collected at 2-hr intervals under 700 lux of light or in total darkness from gilts maintained in either LD 9:15 or LD 24:0. Data from experiment 4 demonstrated that serum melatonin could be detected in nighttime samples if exogenous melatonin was ingested by gilts at night. Together, these experiments clearly indicate that prepubertal gilts do not exhibit a nocturnal rise in serum melatonin when maintained under short daylengths (10L:14D or 9L:15D), and serum melatonin concentrations are unaffected by abrupt changes in light/dark conditions.  相似文献   

6.
A system was designed to allow a small swine farm in a northern latitude to use its own boars for artificial insemination (AI) conveniently. Semen was collected twice weekly for 3 day use (days 0, 1 and 2), extended in an egg yolk extender and stored at 5°C. Farm personnel were trained to manage the entire AI programme. For simplicity all semen collected was used for insemination. In the first test 47 gilts and 15 sows were inseminated with semen from four boars. One boar was subfertile with a farrowing rate of 36%. The averages for the other boars ranged from 71 to 100%. Then semen was collected from seven boars and all was used to inseminate 70 gilts and 55 sows with 3 × 109 or more sperm. Overall 63% farrowed an average of 10.1 piglets per litter. Litter size for sows was 1.5 piglets larger than for gilts. There was no difference in farrowing rate when more than 3 × 109 sperm were inseminated. The feasibility of initiating a complete AI programme within a small herd using herd boars was established. However, selection of the boars, use of only high quality semen, and experience with detecting oestrus was required to increase the farrowing rate. The use of various agents to protect sperm against cold shock below 15°C is worthy of further investigation. A new type of electronic probe, which measures the conductivity of cervical mucus, could be helpful if a boar is not available for conventional detection of oestrus.  相似文献   

7.
The accuracy of urinary estrone sulphate (E1S) concentrations as an indication of pregnancy was compared to that of plasma E1S concentration. Urine and plasma were collected from 145 sows 18 to 30 days after mating. Concentrations of E1S in urine were indexed to creatinine concentration (CR) and specific gravity (SG) to correct for urine dilution. There was no significant difference in E1S concentration between urine corrected for CR or SG and uncorrected urine (UN) from pregnant sows. Urinary E1S concentrations were 20 to 100 times higher than plasma E1S concentrations. The E1S test was accurate in the detection of pregnancy in sows using both plasma and urine (test sensitivity, 98.8% vs. 96.4%, respectively) during the optimal sampling period of 20 to 30 days post mating. The test was slightly more accurate (NS) using plasma than urine in detecting non-pregnant sows (test specificity, 100.0% vs. 91.9%, respectively) 20-30 days after mating. Urinary E1S concentrations could be used to predict litter size, but the precision was poor ( +/- 3 piglets), and thus could only be used to predict small (less than 5 piglets), medium (6-10 piglets) and large (greater than 11 piglets) litters.  相似文献   

8.
Previous studies have shown that supplementation of sow diets with L-carnitine increases the body weight of piglets at birth. This study was conducted to elucidate the reasons for this phenomenon. Three experiments with 24 (experiment 1), 40 (experiment 2) and 12 (experiment 3) sows were conducted. In all three experiments, sows were allotted to two groups which had free access to a nutritionally adequate diet. Sows of one group were supplemented with 125 mg L-carnitine/day during pregnancy; sows of the other group (control group) did not receive L-carnitine. In experiment 1, plasma samples were collected at day 95 of pregnancy, in experiment 2 plasma samples were collected at days 80 and 100 of pregnancy. In experiment 3, chorions of the sows were collected at parturition. L-carnitine-treated sows had higher plasma concentrations of total L-carnitine than control sows (p < 0.05). The number of piglets born and weights of litter and individual piglets at birth were not different between both groups in all three experiments. L-carnitine-treated sows had higher plasma concentrations of insulin-like growth factor-I (IGF-I) on day 80 of pregnancy (experiment 2, p < 0.05) and on day 95 (experiment 1, p < 0.10), and a higher plasma concentration of IGF-II on day 80 (experiment 2, p < 0.05) than control sows. Moreover, sows supplemented with L-carnitine had heavier chorions (+22%, p =0.10) with greater amounts of protein (+45%, p < 0.05) and DNA (+38%, p < 0.10) and a higher protein concentration of glucose transporter-1 (+62%, p < 0.05). Plasma concentrations of 17beta-oestradiol, progesterone and thyroid hormones as well as concentrations of urea and total free amino acids were not different between both groups of sows. Plasma concentrations of non-esterified fatty acids, ketone bodies, triacylglycerols and cholesterol were also largely indifferent between both groups of sows. In conclusion, this study shows that L-carnitine has less influence on lipid metabolism and utilization of nitrogen in pregnant sows but increases their plasma concentrations of IGFs. This in turn may enhance development of the placentae and the intrauterine nutrition of the fetuses. This may be the reason for increased birth weights observed in recent studies in sows supplemented with L-carnitine.  相似文献   

9.
Pregnant gilts were vaccinated with two doses of alhydrogel adsorbed fimbrial antigens of Escherichia coli (K88ab, K88ac, K99 and 987P) supplemented with beta toxoid of Clostridium perfringens type C. Their piglets, and piglets of nonvaccinated gilts, were subsequently orogastrically challenged with one or other of the four fimbrial types of enteropathogenic E coli. Some of the vaccinated animals were reinjected with a single dose of the vaccine during second gestation and their piglets, and piglets of non-vaccinated sows, were challenged the same way as were litters of gilts. Blood serum and colostra were examined for antibodies to the four fimbrial antigens of E coli and for antitoxin to beta toxin of C perfringens type C. It was found that: (1) a highly significant reduction in mortality and morbidity was achieved in vaccinated litters against all four challenge strains of E coli; (2) excretion of K88ab and K88ac but not of K99 and 987P challenge strains was significantly reduced; (3) revaccination of sows by a single dose of the vaccine during second gestation conferred complete protection against mortality and highly significant protection against morbidity; (4) no correlation was noted between colostral or seroagglutinins to fimbrial antigens of E coli and mortality rates in litters challenged with homologous fimbrial types of E coli, but good correlation was found between colostral precipitins to K88 antigens and mortality rates in litters; (5) antitoxin value in 97 per cent of colostrum of vaccinated sows was 10 iu equivalent of C perfringens type C toxin or more per ml of colostrum.  相似文献   

10.
主要通过比较丹系和加系纯种、二元和三元母猪的窝产健仔数,分析不同遗传背景及胎次的母猪产仔性能差异,为评估三元母猪产仔性能及其替代更新提供参考依据。研究整理了国内某规模化企业2019年5月至2020年8月间猪场的209 963条产仔记录,其中丹系56 016窝,加系153 947窝,通过单因素方差分析及邓肯检验对2个品系的母猪产健仔数进行统计分析。结果表明,丹系种猪平均窝产健仔数〔（12.54±2.61）头,n=56 016〕极显著高于加系种猪〔（11.21±2.89）头,n=153 947〕（P<0.01）。进一步分析品系内二元母猪与三元母猪的产仔性能差异,发现丹系二元母猪平均窝产健仔数〔（12.59±2.69）头,n=43 007〕显著高于丹系三元母猪〔（11.12±2.95）头,n=1 236〕（P<0.05）;加系二元母猪平均窝产健仔数〔（11.55±2.81）头,n=84 374〕显著高于加系三元母猪〔（10.73±2.87）头,n=47 185〕（P<0.05）。研究还对比了胎次对产仔性能的影响,丹系二元母猪第2胎产健仔数〔（13.28±2.32）头,n=9 396〕显著高于其他胎次,加系二元母猪第3胎产健仔数〔（12.11±2.61）头,n=12 208〕显著高于其他胎次。结果说明,三元母猪的产仔性能与二元母猪相比存在明显劣势,大规模使用三元母猪可能对企业的PSY和MSY有较大影响。当有足够二元后备母猪补充群体时,应该将使用过4~5胎的三元母猪主动淘汰,将其对企业的种猪成本及收益不利影响控制在最小范围,降低对企业经济效益的影响。  相似文献   

11.
Following weaning at 24 +/- 1 d of age, crossbred boars were subjected to removal of the cranial cervical ganglia (GX, n = 8) or sham surgery (SHAM, n = 8). At 213 +/- 1 d of age, a catheter was inserted into a jugular vein or vena cava, and all boars were housed in environmentally controlled rooms at 22 degrees C with an equatorial photoperiod. After 2 wk of exposure to this photic environment, samples of plasma and serum were collected at hourly intervals for 24 h. The plasma was assayed for adrenocorticotropic hormone (ACTH) and the serum was assayed for cortisol and melatonin by RIA. The time-trends for all three hormones were described by regression models, which were tested for heterogeneity of regression between SHAM and GX treatments. The circadian rhythm of cortisol in serum was similar for SHAM and GX treatments. The profiles of ACTH were also similar between the two treatments, but circadian changes in concentrations of ACTH paralleling those of cortisol were not evident in either treatment. Overall, concentrations of ACTH were reduced (P = .06) for GX boars compared to SHAM boars. The time-trends of melatonin in serum differed (P less than .001) for GX and SHAM treatments, with a nocturnal rise in melatonin evident in some SHAM boars but not in GX animals. Four SHAM boars had profiles of melatonin that obviously entrained to the light-dark cycle. None of the boars in GX treatment had elevated concentrations of melatonin in serum during the dark period, relative to concentrations during the light.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

12.
Previous studies showed that supplementation of sows' diets with L-carnitine increases body weights of their piglets at birth. This study was performed to investigate whether piglets of sows treated with L-carnitine differ in their growth potential from that of piglets of untreated control sows after weaning. It was also investigated whether supplementation of piglets' diets with L-carnitine improves their growth after weaning. In two trials, piglets of the first litters of primiparous sows (trial 1) and the second litters of the same sows (trial 2) were divided into four groups: group 1, piglets of control sows, fed a control diet; group 2, piglets of control sows fed a diet supplemented with 30 mg L-carnitine/kg; group 3, piglets of L-carnitine-treated sows, fed a control diet; group 4, piglets of L-carnitine-treated sows fed a diet supplemented with 30 mg L-carnitine/kg. Mean initial body weights of the piglets of the four groups were identical. They were 8.5 kg in trial 1 and 12.5 kg in trial 2. Diets were fed ad libitum over a period of 35 days. Piglets from sows treated with L-carnitine did not differ in body weight gains, feed intake and gain : feed ratio from those of control sows. In trial 1, piglets supplemented with L-carnitine had higher body weight gains (p < 0.005) and showed a tendency towards a higher gain : feed ratio (p = 0.09) than piglets fed the control diets. In trial 2, no significant difference in these parameters emerged between piglets fed the diet supplemented with L-carnitine and those fed the control diet. In conclusion, this study shows that dietary L-carnitine treatment of sows does not improve the growth potential of their piglets after weaning under the conditions of equal initial body weights. The study also shows that L-carnitine supplementation of their diets improves the growth performance in light piglets of primiparous sows.  相似文献   

13.
Previous studies have reported conflicting data on gender differences in plasma IGF-I in postnatal pigs. There is also debate over the role of IGF-II in regulation of postnatal growth. We have, therefore, determined the concentrations of plasma IGF-I, IGF-II, and IGF-binding protein-3 (IGFBP-3) in boars, barrows, and gilts and related these to postnatal growth characteristics. Plasma concentrations of IGF-I were higher in boars than in gilts or barrows from 13 wk. of age, and plasma IGF-II levels were generally higher in barrows than in boars or gilts. Plasma IGFBP-3 levels were higher in boars than in gilts or barrows at most ages. Between 15 and 23 wk. of age, IGF-I and IGFBP-3, but not IGF-II, were positively associated with growth rate, voluntary feed intake, and gain:feed ratio. Plasma IGF-II, but not IGF-I or IGFBP-3, was positively associated with backfat depth during this period. These results support the hypothesis that circulating IGF-I and IGF-II are regulators of lean and adipose tissue growth, respectively.  相似文献   

14.
The investigation included 1413 Belgian Landrace litters (305 first, 278 second and 832 later farrowings) issued from matings between 190 halothane-positive (HP) and 304 halothane-negative (HN) sows and 139 HP and 49 HN boars on seven commercial farms of West Flanders. Four groups of matings were investigated: HP × HP; HP × HN; HN × HP and HN × HN. All HN sows and boars were heterozygotes for halothane sensitivity.The results were statistically analysed by a linear model according to Harvey (1977), including the following factors: mean, farm, year, sensitivity group, interaction year × sensitivity group. This model explained between 10 and 24% of the total variance; within this an important portion is caused by the sensitivity × farm interaction factor. Abstracting this interaction there are indications that HN sows are more prolific, but only from the second farrowings, the number of piglets born alive in the second litter being on average 9.2 in HP vs 9.6 in HN sows and in the following litters on average 9.3 vs 10.3. In all litters of HN sows an additional gain of 0.2 piglets at weaning was found. No significant conclusions could be drawn for the effect of halothane sensitivity on the age at first farrowing and on the farrowing interval.  相似文献   

15.
Samples of serum from 76 gilts, 1440 sows, 1473 piglets and 3093 finishing pigs from 96 farrow-to-finish herds were tested for antibodies to encephalomyocarditis virus (EMCV) in microtitre serum neutralisation tests employing two strains of virus, one associated with myocarditis and the other with reproductive failure. The total seroprevalence of EMCV infection was 2.48 per cent. There was no significant difference between the seroprevalence of the reproductive failure strain (1.6 per cent) and the myocardial strain (1.85 per cent). The seroprevalence was higher in the gilts (6.57 per cent) and sows (5.13 per cent) than in the piglets (1 per cent) and finishing pigs (1.84 per cent), and the highest titres were observed in the sows (1:540) and finishing pigs (1:640). In the gilts, the difference in seroprevalence between the reproductive failure strain (3.95 per cent) and the myocardial strain (5.33 per cent) was wider than in the other groups.  相似文献   

16.
Serological surveys were conducted on the gilts and adult sows in 4 herds endemically infected with porcine parvovirus. The study assessed the influence of the type of management of breeders on the spread of virus infection and the influence of endemic parvovirus infection on reproductive parameters of the herd. The practice of holding gilts and sows in groups did not reliably promote infection or maintain a 100% level of active immunity amongst adult sows in 2 of 3 group husbandry herds. In the 4 herds, the prevalence of adult sows (greater than 12 months) with active immune haemagglutination inhibition titres (greater than or equal to 256) ranged between 44% and 100%, while between 0% and 100% of gilts (6 to 12 months of age) had active immune titres. Fully susceptible gilts older than 9 months of age held in groups, failed to become infected by 12 months of age on farms endemically infected with PPV. In 2 herds a continued low infection rate of gilts resulted in increasing the potential of breeding animals becoming susceptible to parvovirus infection as infected sows were replaced by noninfected gilts. In both herds, epidemics of parvovirus infection followed, which were characterised by an increase in reproductive failure. Parvovirus infection during the first 70 days of pregnancy reduced the average number of piglets born alive per litter by 1.6 piglets (p less than 0.05). This was due to the combined effect of more piglets being born dead per litter and an overall reduction in litter size.  相似文献   

17.
The object of this investigation was to study the plasma levels of cortisol during the day of parturition and the first two weeks post partum in primiparous zero-weaned (weaned within 12 hr after birth) and lactating sows. Fourteen primiparous sows were used. They were grouped as follows: group A, (3 sows) zero-weaned, ovulating; group B, (4 sows) zero-weaned, anovulatory; group C, (4 sows) lactating with normal litter size; group D, (3 sows) lactating with small litter size. The peripheral plasma levels of cortisol were determined by radioimmunoassay throughout the experimental period,The peripheral plasma levels of cortisol were significantly higher in the anovulatory than in the normally ovulating sows. The lactating sows had almost the same levels of cortisol as the zero-weaned sows with anovulatory estrus. There was no difference in cortisol levels between sows nursing small or normal litters.It may be concluded that elevated plasma levels of cortisol might be one of several factors inhibiting the LH surge during the first estrus after zero-weaning. No relationship was found between cortisol levels and number of suckling piglets.  相似文献   

18.
In commercial pigs, the greatest susceptibility for pre-weaning mortality occurs in low birth-weight piglets. Despite their overall decreased birth weight, Meishan (MS) piglets have decreased pre-weaning mortality rates compared with contemporary Western breeds. The objective of the current study was to determine the contributions of the maternal uterine environment, piglet genotype, and their interaction on the development of neonatal piglets pertaining to pre-weaning survivability using reciprocal embryo transfer between MS and White crossbred (WC) pigs. Twenty-five successful pregnancies were produced from 2 farrowing seasons, generating litters of maternal uterine environment (MUE) by piglet genotype (PigG) combinations; MS × MS (n = 4 litters), MS × WC (n = 7 litters), WC × MS (n = 7 litters), and WC × WC (n = 7 litters). At approximately 24 h of age (Day 1), piglets (n = 173) were weighed and a blood sample was taken. Hematocrit, hemoglobin, glucose, plasma urea nitrogen, albumin, NEFA, lactate, and cortisol were measured in all blood samples. Representative piglets (n = 46) from each litter were harvested and body measurements (i.e., organ weights, tissue glycogen content, and body composition) were determined. Piglet data were analyzed by ANOVA using MIXED model procedures. Both MUE (P < 0.001) and PigG (P < 0.01) affected piglet BW, illustrating that piglets gestated in WC gilts were heavier than piglets gestated in MS gilts, and WC piglets were heavier than MS piglets. Serum albumin concentrations were increased (P < 0.05) in MS piglets compared with WC piglets, indicating greater liver maturity. Significant MUE × PigG interactions were observed for hematocrit and hemoglobin, in which the greatest concentrations were observed in MS piglets gestated in MS and WC gilts, and the lowest concentrations were observed in WC piglets gestated in WC gilts, demonstrating increased oxygen-carrying capability. The percentage of fat and nitrogen, as well as the GE of the body, were greater (P < 0.05) in MS piglets, indicating greater energy stores. Liver, bicep femoris, and LM glycogen concentrations were greater (P < 0.01) in WC piglets compared with MS piglets, demonstrating increased glycogen catabolism in MS piglets. This study demonstrated limited interactions between the maternal uterine environment and piglet genotype on weaning survivability potential, suggesting that the MS piglet is a viable model for pre-weaning survivability.  相似文献   

19.
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   

20.
In the period 1996–2006 two specific sperm defects, the knobbed acrosome (KA) defect and the immotile short‐tail sperm (ISTS) defect, showed a strong negative association with fertility in Finnish breeding boars. In this study, we examined the incidence of these two sperm defects in two pig breeds, their effects on fertility and their associations with sperm morphology and testicular histology. Semen samples from 2048 (1097 Yorkshire, 951 Landrace) boars were collected. None of the Landrace boars revealed either the KA defect or the ISTS defect. Of the Yorkshire boars, 0.8% were afflicted with the KA defect and 7.6% with the ISTS defect. Boars diagnosed with the ISTS defect produced no litters. Fertility data were available from two artificially inseminated (AI) boars and six farm breeding boars affected with the KA defect. Breeding boars with 45–81% knobbed spermatozoa (n = 6) did not produce any litters out of 71 sows bred. AI boars with 25–30% knobbed spermatozoa had a poor non‐return rate (on average 47% compared with 85% for normal control boars) and produced small litters, on average 2.5 piglets less than other boars of the same breed. Morphometry of testicular tissue and distribution of different cells in the seminiferous tubules were examined in nine boars. Boars with the KA defect had a smaller diameter of the seminiferous tubules (p < 0.05) and a lower number of Sertoli cells (p < 0.05) than controls. ISTS boars, in turn, had a significantly lower number of elongated spermatids (p < 0.05), and they also produced on average only 12% of the spermatozoa of normal boars. The ISTS defect is a manifestation of an autosomal recessive disease caused by an insertion in the KPL2 gene in porcine chromosome 16. Although we tried to map the KA defect, its aetiology remains unclear.  相似文献   

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