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1.
OBJECTIVE: To characterize patterns of removal and evaluate the associations among culling because of lameness and sow productivity traits among culled gilts and sows. DESIGN: Cross-sectional study. SAMPLE POPULATION: Data from a convenience sample of 11 farms pertaining to the removal of 51,795 gilts and sows from January 1991 to December 2002. Mean culling and mortality (death and euthanasia) rates for all inventoried gilts and sows ranged from 23% to 50% and 4.7% to 9.5%, respectively. PROCEDURE: An analysis of categories of removal (cull, death, or euthanasia) and reasons for removal of gilts and sows was performed. Multivariate logistic regression was used to determine associations among culling because of lameness and sow productivity traits among culled gilts and sows. RESULTS: Among sows that were removed, the proportion of parity > or = 1 sows that died (both death and euthanasia) was > 3 times the proportion of parity > or = 1 sows that were culled within 20 days after farrowing. Among lame sows that were removed, the proportion of parity > or = 1 sows that died (death and euthanasia) was higher than the proportion of parity > or = 1 sows that were culled within 20 days after farrowing. Among sows that were removed, the proportion of sows that died (deaths and euthanasia) was higher during lactation than nonlactation. This was also observed among lame sows that were removed. CONCLUSIONS AND CLINICAL RELEVANCE: The proportion of death among removed sows, especially lame sows, was higher during lactation than nonlactation. Results indicated that risk of death is not the same for sows throughout their lifetime.  相似文献   

2.
Preweaning mortality risks, recorded death reasons and related factors for preweaning mortality were studied in 105 breeding herds. Preweaning mortality risk at the herd level was calculated as the difference between the number of pigs born alive in farrowed litters and the number of weaned pigs divided by the number of pigs born alive in litters that farrowed and weaned. The mean of annual preweaning mortality risk was 10.7%. In regression analysis, higher mortality risks were associated with higher parity at farrowing, greater numbers of pigs born alive, and longer lactation length. The period from July to September had a higher mortality risk than that from April to June. The means of cause-specific proportional mortality ratios (PMR) in trauma with low viability and scours were 80.4 and 6.2%, respectively. Sows with pig age 0-1 day during lactation had the highest daily PMR. Sows with pig age 0 to 7 days had higher PMR due to trauma and low variability than those with pig age 8 days older. Sows with pig age over 7 days had higher PMR due to scours than those with pig age 0-7 days. Careful management at farrowing and in early lactation on high parity sows with large litters should be considered to prevent piglets from death due to trauma and low viability, and appropriate herd health programs should be implemented for reducing preweaning mortality due to scours during late lactation.  相似文献   

3.
A prospective study of sow mortality in breeding herds.   总被引：1，自引：0，他引：1       下载免费PDF全文
This investigation was conducted to study the incidence and the causes of sow mortality in breeding herds. Data were obtained from 24 swine breeding herds with an average inventory of 3755 sows and served gilts for the total sample. Producers were involved for 12 consecutive months and agreed to submit to the diagnostic laboratory every dead or moribund sow and served gilt. The average herd death rate was 3.3% +/- 0.5 (SEM), but varied considerably among herds, ranging from 0% to 9.2%. A total of 137 sows and mated gilts died during the year, and these females had produced an average of 4.2 litters +/- 0.2 (SEM). The number of deaths was significantly higher during the months of July, August and October. The peripartum period appeared to be when sows were most at risk, with 42% of all deaths occurring during this short period of the reproductive cycle. The three major causes of death were heart failure (31.4%), torsions and accidents of abdominal organs (15.3%) and cystitis-pyelonephritis (8.0%). Other causes included endometritis (6.6%), uterine prolapses (6.6%), pneumonia (3.6%), gastric ulcers (3.6%), downer sow syndrome (2.2%), miscellaneous (8.0%) and unknown (14.6%).  相似文献   

4.
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5.
Re-serviced females on commercial swine breeding farms   总被引：1，自引：0，他引：1  
The objectives of this study were to observe subsequent reproductive performance of re-serviced females by the number of services within a parity, to measure mean days to re-service and culling intervals, to determine lifetime performance in re-serviced gilts, and to investigate re-serviced females across parities on commercial farms. Reproduction records on 539 U.S.A. farms were used to observe re-serviced females by the number of service groups at the herd level. Farrowing rate decreases by approximately 10%, and re-service occurrence increases by approximately 5% for each increase in the number of services increase within a parity group (P<0.05). Only in parity 0 to 2 groups, average pigs born alive at subsequent farrowing in the second or later service groups were greater than in the first service group (P<0.05), but in parity >or=3, the third or later service groups produced fewer pigs born alive than the other service groups (P<0.05). Lifetime performance and re-service events were observed in 39945 individual females on the 149 selected farms that had complete 5-year records. Means of days to re-service, first-mating-to-culling intervals in gilts and weaning-to-culling intervals in sows were 46.3 days, 95.2 days, and 48.2 days, respectively. Re-serviced gilts had longer NPD (>50 days), a lower parity at culling (>0.5) and fewer lifetime pigs born alive (>2 pigs) than non-return gilts (P<0.05), but no difference in average pigs born alive per parity was found between re-serviced gilt groups and non-return gilts. Of 19677 re-serviced females, 35.6% had two or more re-services across parities in pig life, 10.6% had 3 or more re-services, and 1.95% had four or more re-services. Accurate estrus detection with a boar and improved mating techniques on re-serviced females are suggested to improve herd productivity.  相似文献   

6.
Culling patterns in selected Minnesota swine breeding herds.   总被引：2，自引：0，他引：2       下载免费PDF全文
This investigation was conducted to study culling patterns in swine breeding herds. Data were obtained from 89 Minnesota swine breeding herds and included 5918 sows and 1324 gilts for a total of 7242 culled femaled. Each producer was involved for 12 consecutive months. They were asked to record every female that was removed from the herd, the reason for its culling and its parity. The annual culling rate for the sample averaged 50%, but varied considerably between herds ranging from 15% to 85%. Culled females had produced an average of 3.77 litters. Half of the females culled did not produce more than three litters. Reproductive failure accounted for 32% of all removals. The average parity of the females culled in that category was only 2.37: almost 33% were gilts. Failure to conceive represented 75% of all females culled for reproductive failure. Proportionally, culling as a result of anestrus was higher in gilts. It accounted for 33% of all gilts culled for reproductive failure which was twice as much as for sows. Inadequate performance accounted for 17% of all removals. These sows had produced an average of 5.11 litters. These results indicated that few animals were culled on the basis of first litter performance. Old age comprised 14% of all removals and the average parity at culling for this category was 7.11. Death accounted for 12% and the average parity for these females was 3.40. Locomotor problems and peripartum problems were the cause of 28% and 23% of all deaths, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

7.
Sixty-two gilts were paired at breeding and assigned randomly to one of the following dietary treatments: (1) low P or (2) high P during gestation and lactation. Two sets of diets (A and B) were formulated; each set to provide a low (10 g) and high (15 g) daily P intake (equal Ca daily intake, 15 g) when fed at 1.82 and 2.27 kg daily, respectively for sets A and B. Females were fed 1.82 kg daily of set A diets during the first 11 wk of gestation, 2.27 kg daily of set B diets for the next 3 wk and 3.34 kg of the appropriate set B diets containing 20% wheat bran until farrowing, at which time the bran was gradually removed from set B diets and the feed level increased to 4 kg daily until weaning. The proportions of defluorinated phosphate and limestone were varied to provide the appropriate level of Ca and P (low and high). At approximately 5 wk before farrowing at each parity, up to 12 females from each group were used in Ca, P and N balance trials that lasted about 2 wk. Dietary P intake did not affect the apparent absorption and retention of N and Ca; 88% of the consumed N was absorbed and one-half of the absorbed was retained, and 37% of the Ca was absorbed and 94% of the absorbed was retained. Females fed the higher P intake, although excreting higher levels of P in the feces and urine, absorbed and retained a larger amount of P; but the low P-fed sows were more efficient in the retention of P when expressed as a percentage of intake or as a percentage of the absorbed P. With the exception of average total litter weight at birth that favored high P-fed sows, live, dead and total pigs at birth, average birth weight and breeding performance were not statistically different between P levels. Except for the first parity, most characteristics favored sows fed the higher P intake. Serum Ca and P levels and hair P concentration were similar between P levels. Hair Ca concentration, however, was higher for the high P-fed sows. Sows fed the higher daily P intake retained more P and there was a trend for better farrowing performance. However, breeding performance, serum Ca and P levels, hair P concentrations and Ca and N balance were similar between dietary P intakes. These results would support current National Research Council-suggested Ca and P levels for sows.  相似文献   

8.
An observational cohort study was conducted using a producer group of 33 farms selected based on their completeness of reproduction data, including dates of birth, entry to a herd, and removal. Average lifetime pig production and parity at removal in a cohort of 2,265 females born in 1990 were 67.2 pigs born alive and 5.6 parities, respectively. Approximately 90% of farrowings occurred from the second through the fourth year from birth. Farrowing rates between parities of 2 and 4 were higher than other parities, and pigs born alive from parities 3 to 5 were the greatest among parities. The 10th and 90th percentiles of age at first conception were 227 and 322 days. Increasing the age at first mating was associated with low farrowing rate (P<0.01) in parity 0. Older age at first conception was associated with lower parity at removal, shorter reproductive herd life, and fewer lifetime pigs born alive (P< 0.01). Of the 2,265 breeding females, 253 (11.2%) were re-mated at parity 0 and farrowed. These sows with a record re-mating at parity 0 had lower parity at removal, less lifetime pig production and lower lifetime productivity than those with no re-mating at parity 0 (P<0.01). It is recommended that unbred gilts 230 days of age or older should be mated soon.  相似文献   

9.
Factors affecting length of productive life in Swedish commercial sows   总被引：2，自引：0，他引：2  
The objective of this study was to investigate factors that might influence the length of productive life in Swedish crossbred (Landrace x Yorkshire) sows. The data set consisted of 20,310 sows farrowing between 2001 and 2004 in 21 commercial piglet-producing herds. Productive life (PL) was defined as the number of days between first farrowing and removal or termination of data collection. In addition to the overall risk analysis of PL, another 4 longevity traits were analyzed (competing risk analyses): reproductive disorder-determined length of PL (RPL), udder problem-determined length of PL (UPL), lameness-determined length of PL (LPL), and mortality-determined length of PL (MPL). Analyses were performed by using survival analysis, applying a Weibull model with 6 time-dependent and 1 time-independent variable (age at first farrowing). The factor with the largest contribution to the likelihood function for PL was days after farrowing, followed by parity, the herd x year combination, the total number of piglets born, days between weaning and next farrowing, farrowing month, and age at first farrowing. For all 4 competing risk traits, the factors contributing most to the likelihood function were days after farrowing, the herd x year combination, and parity, with a varied order between traits. The hazard for removal was greatest 30 to 40 d after farrowing (after weaning) for PL, UPL, and LPL (P < 0.001). However, for MPL the hazard was greatest just after farrowing (0 to 10 d), and for RPL the hazard peaked at 70 to 100 d after farrowing. The hazard for removal was, compared with parity 1, less in parities 2 to 7 and greater from parity 8 for PL (P < 0.001). The hazard was greatest in parity 1 (P < 0.01) for RPL, UPL, and LPL, whereas for MPL the hazard increased with greater parity number and was markedly greater from parity 9 (P < 0.001). Sows with litters of 9 piglets or less had a greater hazard for removal than sows with litters of 12 to 13 piglets (P < 0.001). Intervals between 120 and 122 d from weaning to the next farrowing showed the lowest hazard for removal (P < 0.001). The influence of farrowing month displayed no clear pattern for PL. Sows of 14 mo or older at their first farrowing had a 20% greater hazard for removal than younger sows (P < 0.001). The hazard for removal was greater for smaller litters in all parities but was more accentuated in greater parities. Overall, days after farrowing was the main risk factor for sow removal. Removal hazard was greatest shortly after weaning, and this peak increased with greater parity number.  相似文献   

10.
The response per generation to 10 generations of mass selection for ovulation were 0.49 ova, ?1.6% in embryo survival and 0.06 piglets per litter at birth. Line differences (select-control) in generation 9 and 10 gilts and sows ranged from 3.4 to 5 ova. Control line gilts and sows had 5.4 to 10.6% higher embryo survival to days 30 and 70 of gestation than did select line females. One generation of random selection followed by four generations of litter size selection, selection for decreased age at puberty or relaxed ovulation rate selection in the high ovulation rate line has resulted in lines that differed from the control line in litter size at birth by 0.78 ± 0.22, 0.37 ± 0.39 and 0.84 ± 0.52 pigs per litter at first, second and third parity, respectively. These results were used to derive a selection index to increase litter size by selection for its components (ovulation rate, OR, and embryo survival, ES). A technique of selection based on laparotomy to increase the number of females tested with a given set of farrowing places is presented. Rate of response in LS from use of the selection index, I = 10.6 OR + 72.6 ES, in a population of 40 farrowing females and 15 males per generation, is expected to increase litter size 2.5 times faster than selection on LS due to higher selection intensity and optimum emphasis on the component traits.  相似文献   

11.
The aim of the present study was to investigate the effects of farrowing duration, parity number, and type of anti-inflammatory drug used postpartum on the incidence of postparturient disorders in sows. The duration of farrowing and postparturient disorders were examined in 64 sows at Days 0, 1, 2, and 3 after farrowing. The sows were classified according to parity number (1, 2–4, and 5–7), duration of farrowing (<2, 2–2.9, 3–3.9, and 4–8 h), and the type of anti-inflammatory drugs (flunixin méglumine and dipyrone). The farrowing duration was 178.0?±?73.5 min (2.96 h). The percentage of sows with fever increased from 40 to 100 % when the farrowing duration increased from <2 to 4–8 h. On Day 1 of the postpartum, 93.7 % of primiparous sows had fever, while 52.6 and 47.6 % of sows parity 2–4 and 5–7 had a fever (P?<?0.05). The presence of vaginal discharge on Day 1 of the postpartum was higher in sows of parity 5–7 than sows of parity 2–4 (85.7 and 52.6 %, P?=?0.029). The use of flunixin méglumine after parturition in sows reduced the percentage of sows with a fever from 61.3 to 22.6 % within 2 days (P?=?0.002), while, the percentage of sows with a fever was not decreased in sows treated with dipyrone. It can be concluded that the incidence of postparturient disorders in sows was affected by sow parity, farrowing duration and the type of anti-inflammatory drug used. Sows with a farrowing duration of ≥4 h were at a high risk of having fever at Day 1 after parturition.  相似文献   

12.
Lawsonia intracellularis is an obligate intracellular organism that causes porcine proliferative enteropathy, a widespread infectious disease. Very little is known about the immune response and the epidemiologic features of the disease in the field. The aims of this study were to evaluate the duration and titers of antibody specific for L. intracellularis in gilts after an outbreak of proliferative hemorrhagic enteropathy (PHE), to evaluate maternal antibodies in piglets, and to evaluate seroconversion and fecal shedding in growing–finishing pigs. Thirty-six gilts in a herd that had recently experienced an outbreak of PHE, including 13 that had recovered, were bled 3 wk after the beginning of the outbreak and then every 3 wk until they became seronegative in 2 consecutive tests. Fourteen piglets from 5 gilts seropositive at farrowing and 5 piglets from 2 sows that remained seronegative were bled once or twice at the farrowing house and then every 3 wk until they reached market age. Fecal samples from these pigs were tested by polymerase chain reaction at 7 wk of age and then on the days of blood collection. After the PHE outbreak, the gilts had high serum antibody levels; the levels decreased over time, but antibody was still detectable for up to 3 mo in some animals. Four piglets from sows that were seropositive at farrowing had detectable passive antibodies up to 5 wk of age. Some nursery pigs started shedding L. intracellularis around 7 wk of age; peak shedding was observed between 13 and 16 wk. Antibody was not detected until 16 wk of age and was more often detected between 19 and 22 wk.  相似文献   

13.
A study was conducted to examine effects of mating systems composed of natural service (NS) and AI in swine on farrowing rate, litter size, and labor requirements. Sows and gilts were bred once per day via one of the following treatments (d 1/d 2): NS/NS, NS/AI, AI/AI, and NS/none. Gilts bred with NS/AI, AI/AI, and NS/NS had higher (P less than .05) farrowing rates than gilts bred with NS/none matings. Similarly, farrowing rates were higher (P less than .05) in NS/AI than in NS/NS gilts. Numbers of pigs born alive were greater (P less than .05) in NS/NS, NS/AI, and AI/AI than in NS/none gilts. In sows, a treatment x time interaction (P less than .01) was present for farrowing rate. In the AI/AI treatment, farrowing rate increased (P less than .01) from 70.0% (wk 1 through 3) to 88.5% (wk 4 through 10). Farrowing rates were 87.3, 93.2, and 76.0% in the NS/NS, NS/AI, and NS/none groups, respectively, and did not change (P = .72) over time. Sows bred via NS/NS and NS/AI had larger litters (P less than .05) than NS/none sows. In the present study, if four or more sows and gilts were bred, then AI required less (P less than .05) time per animal than NS. Furthermore, gilts required more (P less than .05) time for breeding than sows. Results from this study demonstrate that gilts and sows responded differently to combinations of NS and AI in terms of reproductive performance. In addition, differences in labor requirements per sow or gilt between NS and AI matings were dependent on parity and daily breeding demands.  相似文献   

14.
The objective of the present study was to investigate culling guidelines for gilts and sows in Japanese commercial herds and to compare differences between culling guidelines and actual culling practices in different herd productivity groups. A questionnaire survey was undertaken to obtain information on culling guidelines in 115 commercial swine herds that participated in the PigCHAMP data-share program. The questionnaire included questions on guideline values for culling intervals and the number of conception failure occurrences that would trigger a culling decision to be made. Ninety-two of the 115 herds (80.0%) returned appropriate data for the study and were included in the present study. In addition to questionnaire data, culling data regarding the actual culling intervals and number of reservices for gilts and sows culled during 2007 to 2008 were also obtained for the same herds from a PigCHAMP database. Culled gilts and sows were divided into 4 female groups on the basis of the stages of their reproductive life when they were culled: unmated gilts, mated gilts, unmated sows, and mated sows. Culling intervals in unmated gilts and sows were defined as the number of days from birth or weaning to culling, respectively, whereas in mated gilts and sows culling intervals were the number of days from last service to culling. Three herd productivity groups were formed on the basis of the upper and lower 25th percentiles of pigs weaned mated female(-1)·yr(-1):high-,intermediate- or low-performing herds. For unmated gilts and sows actual culling intervals were 15 d shorter than the guideline culling intervals in the surveyed data submitted by producers (P < 0.05). This shorter actual culling period for unmated gilts and sows did not vary significantly between herd productivity groups in any parity. However, for mated gilts and sows the actual culling intervals were at least 30 d longer than the guideline culling intervals (P < 0.05). Guideline and actual culling intervals for mated gilts and sows were at least 10 d shorter in high-performing herds than in low-performing herds (P < 0.05). High-performing herds had lower proportions of sows culled after the second reservice than intermediate- or low-performing herds in parity groups 0 to 5 (P < 0.05). In conclusion, culling guidelines for mated sows differed between herd productivity groups, and culling guidelines for mated gilts and sows were not strictly followed in any herd group in the commercial herds.  相似文献   

15.
Pregnant gilts (n = 126) were assigned randomly to 12 0.4-ha old world-spar bluestem (Bothriochloa ischaemum) pastures in an outdoor swine (Sus scrofa) production system to examine effects of stocking rates (17.5 or 35 gilts/ha; 7 or 14 gilts per pasture) and dietary N on percentage of ground cover, soil nitrate (NO3-) concentration, and reproductive performance. Treatments were arranged factorially with two stocking rates and two diets equivalent in dietary lysine but different in CP (control = 14.7% CP vs experimental = 12.6% CP) with three pastures per treatment. The experiment was repeated during a second parity with the same animals on the same treatments. Each triangular gestation pasture was subdivided into three regions: 1) near the point or radial center; 2) the middle region that contained a hut and a wallow area; and 3) the outer section where gilts were fed each day. Soil samples (15 cm deep) were taken at the beginning and end of the 306-d study, and soil nitrate-N concentrations were determined. Percentage of ground cover was visually estimated initially and every 30 d thereafter through d 306. Before farrowing, gilts were moved to identical pastures for farrowing and were fed a common 16% CP sorghum (Sorghum bicolor)-based lactation diet beginning at the time of movement to the farrowing pasture. Pregnant gilts were weighed at the time of assignment to treatments in the gestation pastures, when they were moved to farrowing pastures, and at weaning. Production data included total number of pigs born per sow, number of pigs born alive or dead, average birth weight, number of pigs weaned, average weaning weight, and mortality. No differences (P > 0.05) were observed between treatments in soil NO3- concentrations. Percentage of ground cover was decreased (P < 0.01) by the higher stocking rate when grazing was initiated in March/April but recovered rapidly after removal of pigs. More (P < 0.01) pigs were weaned per sow (8.4 vs 7.1+/-0.34) from higher gestation-stocking rate groups. Pig mortality in farrowing was greater (P < 0.05) for lower gestation-stocking rates (25.7% vs. 18.1+/-1.9%). A stocking rate of 35 sows/ha might have increased production potential but was associated with a rapid loss of ground cover during spring.  相似文献   

16.
A total of 796 sows and gilts from 30 Danish sow herds were examined three times at intervals of 6 weeks for serum antibodies to Leptospira bratislava by the microscopic agglutination technique (MAT) test. The prevalence of seroreactors with positive titer values, 1:100, at the three successive tests were 2.7%, 2.5% and 2.9%; 4.5% of the animals were positive in at least one of the three tests, and 2.2% showed a greater than two-fold rise in titer between two consecutive samplings. Of the 30 herds, 21 (70%) had ever-positive within-herd prevalences in sows and gilts of 4–13%. The risk of a herd having one or more positive sow was positively associated with a herd size of > 141 sows, and distinct regional differences in the prevalence of positive herds were observed. The reproductive performance of the 21 herds with seroreactions was poorer than the performance of the nine herds without positive reactions concerning the variables: ‘days from weaning to last service’ (2.7 days more, P = 0.07), ‘percentage of sows returning to heat’ (4.0 percentage units more, P = 0.03), ‘services per farrowing’ (0.04 more, P = 0.04), ‘farrowing percentage’ (4.3 percentage units lower, P = 0.06), and ‘stillborn pigs per farrowing’ (0.16 more, P = 0.02). No association between the MAT serological status of the herd and the incidence of medical treatments of sows and gilts could be found. A high prevalence and low cumulative incidence of seroreactors was demonstrated in first-parity gilts, followed by a low prevalence and cumulative incidence from parity 2 to 3, and a high prevalence and cumulative incidence at the fifth parity.  相似文献   

17.
Sow removal in Swedish commercial herds   总被引：3，自引：0，他引：3  
The objective of this study was to describe the sow removal pattern in Swedish commercial piglet producing herds, with group-housing of non-lactating sows. The data collection, based on a PC herd monitoring program used in 21 piglet producing herds in the south-central part of Sweden, was prospective, started in 2002 and continued for 3 years. During this period, information on 14 234 removed sows was recorded. For all parameters studied a large variation between herds was found. The average annual removal rate was 49.5% (range 33.6–66.3%). Among the removed sows, 85.2% were sent to slaughter, 10.5% were euthanised and 4.3% were found dead. The most common removal reasons were ‘reproductive disorders’ (26.9%), ‘old age’ (18.7%) and ‘udder problems’ (18.1%), followed by ‘low productivity’ (9.5%), ‘lameness and/or foot lesions’ (8.6%) and ‘traumatic injuries’ (7.1%). The proportion of sows sent to slaughter was higher than the proportion euthanised for all categories of removal except ‘traumatic injuries’ (in which 81.6% of the sows were euthanised). The average parity number at removal for all sows was 4.4. Lowest average parity numbers were found for sows removed due to ‘traumatic injuries’ (2.6). Among removed sows, the proportion removed per parity decreased up to parity 6. Sows removed due to ‘old age’ had the highest piglet production, while sows removed due to reproductive disorders had the highest number of non-productive days (NPD) per parity and the longest interval from last farrowing to removal. With increasing removal parity number, the number of piglets produced increased and NPD decreased. In lower parities (1–3) most sows were removed due to ‘reproductive disorders’, but this proportion fell as parity number rose. Removals due to ‘udder problems’ were most frequent in medium parity numbers (4–6). Most sows removed after parity 7 were removed due to old age. The proportion of the sows found dead was highest just after farrowing; otherwise only a low percentage of sows were removed during the lactation period. The proportion of euthanised sows was high in the week after farrowing and during the 4-week period following weaning. The proportion of sows sent to slaughter increased considerably 4 weeks after farrowing (i.e. after weaning) and stayed high during the subsequent 3 weeks. The study revealed a considerable amount of unplanned removal of young sows. Not only the sows sent to slaughter, but also those euthanised and found dead, must be included in studies on sow removal.  相似文献   

18.
The objective of this study was to identify the risk factors of stillbirth and foetal mummification in 565 farrowings of four commercial pig farms in Brazil. Stillborn piglets were observed in 31.3% of the litters and the stillborn risk was 5.6%. Mummified foetuses occurred in 42.1% of the litters and the mummification risk was 3.4%. The potential risk factors were included in multivariable logistic regression models as categories: herd (1–4); parity (1, 2–5 and >5); litter size (<10, 10–12 and >12 piglets); farrowing length (≤3 or >3 h); presence of mummified foetuses (yes or no); farrowing induction (yes or no); use of oxytocin (yes or no); use of vaginal palpation (yes or no); body condition score (<3, 3 and ≥4), and placental production index (PPI) (≤5 or >5) which was measured as the ratio of total foetal weight to total placental weight. Duration of farrowing and use of farrowing induction, oxytocin or vaginal palpation were not included in the model that investigated the risk factors of foetal mummification. Two models were used to investigate the risk factors of stillbirth, one with and the other without the inclusion of farrowing length. When compared to sows of parity 2–5, sows of parity >5 had 1.7- and 1.6-times higher odds (P < 0.05) for stillbirth in the models with and without the inclusion of farrowing length, respectively. In both models, sows with more than 12 piglets/litter had 3.6-times higher odds of stillbirth occurrence compared to sows with less than 10 piglets (P < 0.05). Sows with prolonged farrowing (>3 h) had 2.0-times higher odds of stillbirth occurrence than sows with short farrowing (P < 0.05). Sows with more than 12 piglets/litter had 14.5-times higher odds of mummification compared to sows with less than 10 piglets (P < 0.05). Sows of parities 1 and >5 had 3.5- and 2.0-times, respectively, higher odds of mummification in comparison to sows of parity 2–5 (P < 0.05). Sows with low PPI had 1.7-times higher odds of mummification compared to those with high PPI (P < 0.05). A large litter, a high-parity and a prolonged farrowing increased the risk of stillbirth. The probability of having a mummified foetus was increased in very young and older sows, when having a large litter and a litter with a less efficient placenta.  相似文献   

19.
The first 100 single-boar services of 140 boars were analyzed to determine whether the farrowing rate resulting from initial services predicted the farrowing rate of subsequent services. The data were analyzed for the influence of parity, number of matings per estrus, season of service, and interaction of these variables on farrowing rate. Sow parity influenced farrowing rate. Sows with parity greater than 8 and gilts had the lowest farrowing rates (P less than 0.01). Sows with parity 2 through 5 had the highest farrowing rates (P less than 0.01). One and 2 matings/estrus resulted in reduced farrowing rates (P less than 0.01), compared with farrowing rates of greater than 2 matings/estrus. Farrowing rate for services during the summer was lower than that for other seasons of the year (P less than 0.01). Evidence of interaction among these variables was not found. Therefore, the results of each service recorded was adjusted to the mean farrowing rate of sows with parity 2 through 5, sows mated greater than or equal to 3 times/service, and sows serviced in the spring. After these adjustments, the farrowing rates for the first 10, 20, 30, 40, and 50 services were analyzed to determine associations with farrowing rates for subsequent services through 100 farrowings. These data also were analyzed to determine whether the associations were strengthened by removal of the first 10 services from the data. The best farrowing rate association indicated that for each 1% increase in farrowing rate subsequent to the first 50 services, the farrowing rate for the second 50 services increased 0.33% (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

20.
Of the 825 pig farms in USA that mailed in their electronic file containing production records, 604 farms were used to observe breeding-female mortality risk and related factors (herd size, lactation length, parity and season). Multiple regression was used to determine factors associated with annual mortality risk. Analyses of variance were used for comparisons of mortality risks among parity and season groups. Average annual mortality risks during the 1997 period was 5.68%. Average breeding-female inventories and average lactation length on USA farms were 733 and 18.3 days, respectively. Higher annual breeding-female mortality risk was associated with larger herd size, greater parity at farrowing and shorter lactation length (P<0.02). For example, as herd size increases by 500 females, mortality risk increases by 0.44%. Older parity was associated with higher mortality risks. Summer season was also associated with higher mortality risk. Using five-years’ records on 270 farms, annual mortality risk in 1997 was higher than those of 1993 and 1994, while average breeding-female inventory increased and lactation length decreased. It is recommended that producers, especially in large herds, pay more attention to breeding females.  相似文献   

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