Epidemiological approach to the association between economic efficiency and productivity on swine farms in Prince Edward Island.

Regression analysis was used to determine the ability of a number of biological parameters to predict economic efficiency. Detailed feed, financial, and production records were maintained by a random sample of eighteen Prince Edward Island (PEI) swine producers (each producing over 1000 market hogs per year). Relative economic efficiency of the operations was measured using return to management and labor (RML). Of the routinely monitored biological parameters, RML on PEI farrow-finish operations was best predicted (R2 = 64.8%) by: marketed per square meter per year (p = 0.008) and marketed per sow per year (p = 0.096). Regression of fixed costs revealed that biological parameters had limited ability to predict fixed costs per hog on farrow-finish operations (R2 = 30.7%). The only parameter contributing to the prediction of the fixed cost component of RML was feeder hog density (p = 0.077). The variable cost component of RML on farrow-finish operations was predicted (R2 = 94.3%) by feed cost per kg gain (p = 0.000), and marketed per sow per year (p = 0.044). The routinely recorded biological parameters on feeder farms had only limited ability to predict RML in this study (R2 = 43.7%). The only parameter of any importance was marketed per square meter per year (p = 0.106). Prediction of the fixed cost component of RML on feeder farms (R2 = 67.4%) was best realized by measuring feeder hog density (p = 0.045). The variable cost component of RML on feeder farms was reasonably well predicted (R2 = 74.7%) by feed cost per kg gain (p = 0.012). Although this parameter is difficult to monitor from records currently maintained on most farms, it points out the need to monitor feed consumption on swine farms.     

Reproductive productivity measurements in Japanese swine breeding herds

To set productivity standards and targets, and investigate inter-relationships between key measurements in swine breeding herds, farm productivity measurements were analyzed on 87 Japanese commercial farms in 14 prefectures. The 87 herds were ranked on the basis of number of pigs weaned per mated female per year (PWMFY), and 23 herds in the upper 25th percentile of this ranking were designated as high-performing farms. Productivity measurements on the high-performing farms were compared with values for the remaining farms. The high-performing farms had shorter farrowing intervals, greater litters per mated female per year (LMFY), greater pigs weaned per sow (PWS), and greater mean parity of culled sows than the remaining farms (P<0.01). No difference in lactation duration was found between the two groups (P>0.10). For both farm groups, correlations of key reproductive measurements were determined. Lactation duration was not correlated with LMFY, PWS and PWMFY on the high-performing farms, while short lactation duration was correlated with greater LMFY and PWMFY on the remaining farms (P<0.01). In contrast to lactation duration, farrowing interval was correlated with PWS on the high-performing farms, but not on the remaining farms. Mean parity of culled sows were correlated to PWS and pigs born alive per sow on the high performing farms, but not with any measurements on the remaining farms. These results suggest that high-performing farms have used different herd management from the remaining farms.     

Productivity characteristics of high-performing commercial swine breeding farms

OBJECTIVE: To determine productivity characteristics of high-performing swine breeding herds in the United States and to determine associations among number of litters per mated female per year (LMFY), number of pigs weaned per sow (PWS), and lactation duration. DESIGN: Cohort study. SAMPLE POPULATION: 1997 productivity records for 685 herds. PROCEDURE: Herds were ranked on the basis of number of pigs weaned per mated female per year, and herds in the upper 10th percentile of this ranking were designated as high-performing herds. Productivity measurements for these herds were compared with values for the remaining herds. RESULTS: High-performing herds had shorter lactation durations and higher mean breeding female inventories than did the remaining herds. High-performing herds also had better reproductive efficiency and used farrowing facilities more efficiently than did the remaining herds. For the high-performing herds, lactation duration was significantly associated with PWS but was not significantly associated with LMFY. In contrast, for the remaining herds, lactation duration was not significantly associated with PWS but was significantly associated with LMFY. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that high-performing commercial swine farms could increase PWS by improving preweaning mortality rate and number of pigs born alive, but that LMFY was already maximal. For other herds, however, shortening lactation duration would likely decrease farrowing interval and improve efficiency of the reproductive cycle without reducing litter size.     

Effects of a novel carbohydrate and protein source on sow performance during lactation

Ninety-one primiparous and multiparous sows and their pigs were used to evaluate the effects of a novel carbohydrate- and protein-based feed ingredient (Nutri-Pal, NP) on sow and litter performance during lactation. Nutri-Pal is a feed supplement for sows that consists of a blend of milk chocolate, brewer's yeast, whey products, and glucooligosaccharides. The dietary treatments consisted of a corn-soybean meal control and a corn-soybean meal plus 5% NP fed from d 110 of gestation to weaning. The diets were formulated to be equal in total Lys and ME. Sows were allotted to treatment based on parity, body weight, and the date of d 110 of gestation. There were 46 and 45 sows per treatment over four farrowing groups. Litters were standardized to 10 pigs and weighed within 1 d of farrowing, and all sows weaned at least 8 pigs at an average age of 21 d. Sows were weighed on d 110 of gestation, d 1 postfarrowing, and at weaning. Sows were fed three times daily during lactation. Sows were checked twice daily after weaning for signs of estrus. The weaning weight of sows fed NP was increased (P < 0.10) compared with those fed the control diet. Sows fed the control diet tended (P = 0.11) to lose more weight per day from d 110 of gestation to weaning than the sows fed NP. Otherwise, sow response variables (sow weight on d 110 of gestation and d 1 postfarrowing, d 110 of gestation to d 1 postfarrowing and lactation weight change per day, d 110 of gestation to d 1 postfarrowing, lactation, and total feed intake, days to estrus, pigs born alive or dead, and litter and average pig birth weight) were not affected (P > 0.10) by diet. There were no effects (P > 0.10) of diet on litter performance response variables (pigs weaned, litter and average pig weaning weight and gain, and survival percent). The NP feed ingredient had minor effects on sow productivity, but it did not affect litter productivity indices.     

不同规模工厂化养猪的成本及效率分析

我国生猪养殖规模和水平参差不齐,本文以26家规模化猪场为研究对象,其中包括规模Ⅰ(2000头以下基础母猪)3家、规模Ⅱ(2000~3000头基础母猪)3家、规模Ⅲ(3000~4000头基础母猪)4家、规模Ⅳ(4000头以上基础母猪)16家,比较不同养殖规模工厂化养猪场的生产成本和生产效率。结果表明:不同规模的工业化猪场在生产成本与生产效率方面有显著差异。随着规模增加,生长育肥期饲料成本、兽药疫苗、固定资产折旧及人工费用降低,生长育肥阶段成本明显下降,出栏猪成本与规模呈现负相关。仔猪哺乳及仔猪保育阶段对管理水平要求较高,随着养殖规模增大,管理难度相应加大,需要强调实施精细管理,以维持平均每头基础母猪年提供断奶仔猪头数(PSY)以及平均每头基础母猪年提供出栏猪头数(MSY),达到最大限度的规模效益。     

Farrowing hut design and sow genotype (Camborough-15 vs 25% Meishan) effects on outdoor sow and litter productivity

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.     

Technical note: High-performing swine herds improved their reproductive performance differently from ordinary herds for five years

The objectives of this study were to determine changes in herd productivity and the performance of female pigs over time in commercial swine herds. Annual measurement data from 1999 to 2003 were obtained from the record files of 113 herds in Japan. Two groups were formed according to the 25th percentile of pigs weaned/mated females per year (PWMFY) in 2003; the 2 groups were high-performing herds (those constituting the top 25%) and the remaining ordinary herds. The effects of group based on PWMFY in 2003, year, and the group x year interaction on repeated measures between 1999 and 2003 were analyzed by using mixed-effects models. A regression analysis was also used to compare key measurements in productivity between the 2 groups, with years as a continuous variable. Variance components were obtained to determine herd repeatability of PWMFY for the 2 herd groups. The average female inventory increased from 290 +/- 31 to 355 +/- 42 females for these 5 yr. The PWMFY also changed from 20.9 +/- 0.21 to 21.2 +/- 0.30 pigs. An interaction between year and group was detected (P < 0.05) for PWMFY. In the regression comparison, high-performing herds increased their PWMFY by 0.31 +/- 0.09 pigs each year, whereas the ordinary herds did not increase. The number of pigs weaned per sow increased by 0.07 +/- 0.02 pigs each year in high-performing herds and increased by 0.03 +/- 0.01 pigs each year in ordinary herds. In high-performing herds, for each year, the percentage of sows mated by 7 d after weaning increased by 0.92 +/- 0.25%, the percentage of reserviced females decreased by 0.63 +/- 0.26%, and culling rate increased by 1.53 +/- 0.50%. Repeatability of PWMFY for high-performing herds and ordinary herds was 28.8 and 54.0%, respectively. This study shows that productivity in high-performing herds was improved compared with that of ordinary herds.     

Randomised, placebo-controlled trial of a live vaccine against porcine reproductive and respiratory syndrome virus in sows on infected farms

A randomised, double-blinded, placebo-controlled study into the effectiveness and safety of a vaccine against porcine reproductive and respiratory syndrome virus (PRRSV) was carried out on three farms with a history compatible with chronic PRRSV infection; representative groups of sows and gilts were injected with a live vaccine against PRRSV, and during the next six weeks no side effects were observed. The remaining sows and gilts on the three farms were then vaccinated with the same vaccine. Again, no side effects were observed. There were significant reductions in abortion, reproductive disease, returns to oestrus and the numbers of stillborn pigs per sow, and significant increases in the numbers of liveborn pigs per sow and weaned pigs per sow among the vaccinated animals.     

养殖规模对不同胎次母猪生产力的影响

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。     

Estimation of lifetime productivity of female swine

OBJECTIVE: To develop estimates of lifetime productivity for breeding female swine calculated longitudinally during time in the breeding herd, and to compare estimates of lifetime productivity for female swine removed from the herd at different parities. DESIGN: Retrospective cohort study. ANIMALS: 9,416 breeding female swine from 29 herds. PROCEDURE: A frequency distribution for parity at the time of removal was generated. Estimates of lifetime productivity (lifetime nonproductive days [NPD], lifetime NPD as a proportion of herd life, total number of pigs born per litter weaned, number of pigs born alive per litter weaned, number of pigs weaned per litter weaned, number of NPD per year in the herd, number of litters weaned per year in the herd, and number of pigs weaned per year in the herd) were calculated for females with parity > or = 1 at the time of removal. RESULTS: For 58% of all females, parity at the time of removal was < or = 3. On average, 20.7% of herd life was spent in nonproductive activities, but the proportion of herd life that was nonproductive decreased significantly as parity at the time of removal increased. Number of NPD per year in the herd decreased and number of litters weaned per year in the herd and number of pigs weaned per year in the herd increased significantly as parity at the time of removal increased. CLINICAL IMPLICATIONS: Higher parity at the time of removal from the herd is associated with improved lifetime productivity for female swine. Parity at time of removal is commonly used as an approximation for lifetime productivity, but it does not take into account the impact of NPD, especially NPD during early reproductive cycles.     

Within-farm variability in number of females mated per week during a one-year period and breeding herd productivity on swine farms

OBJECTIVE: To determine the effect of within-farm variability in the number of females mated per week during a 1-year period on annual breeding herd productivity in swine breeding herds and to apply statistical process control charts to measures of within-farm variability. DESIGN: Longitudinal study. SAMPLE POPULATION: 84 swine farms with a female inventory of 390 to 1,491 sows and gilts (mean, 761 females). PROCEDURE: As a measure of within-farm variability in a breeding herd, SD for the number of females mated per week during a 1-year period was evaluated. Two types of production records for 84 farms were evaluated. One file contained within-farm variability (SD) in mated females for each farm, and the second included annual productivity 19 weeks after week of mating. We also defined forewarning limits as mean +/- 2 SD, using a statistical process control chart. RESULTS: Larger within-farm variability in number of mated females was associated with lower annual measurements, such as fewer pigs weaned per mated female per year and lower farrowing rate. In addition, farms that did not have any weeks outside the forewarning limits for number of mated females produced more pigs weaned per mated female per year than those with 1 or more weeks of over- or underproduction. Furthermore, the number of weeks outside of forewarning limits was positively associated with within-farm variability in number of mated females. CLINICAL IMPLICATIONS: We recommend that farm managers determine a target range for the number of females mated per week to prevent large week-to-week variations in breeding herd operations.     

Health and production measures for smallholder pig production in Kikuyu Division, central Kenya

A longitudinal study was carried out in Kikuyu Division (a peri-urban area in central Kenyan highlands) between January 1999 and December 1999 to estimate the baseline parameters on reproductive performance of the sow, as well as health and productivity of grower and preweaning pigs of smallholder herds. Data were collected on 155 breeding pigs, 795 grower pigs and 801 preweaning piglets in 74, 50 and 40 smallholder herds, respectively, using record cards that were updated during monthly visits.

The sow-level medians were: weaning-to-service interval 3 months; interfarrowing interval 6.4 months; number of live-born piglets 9.0; and number of piglets weaned per litter 7.5. The piglet crude morbidity incidence risk was 29%. The cause-specific incidence risks for the important health problems encountered in preweaned piglets were diarrhea (4.3%), pruritus (17.1%), and skin necrosis (4.2%). The estimated crude mortality incidence risk to 8 weeks of age was 18.7%. The cause-specific mortality incidence risks to 8 weeks of age for the important causes of mortality were overlying (9.9%), savaging (2.4%), unviable piglets (2.0%) and unknown (1.9%). Overall, 78.8% of the total live-born piglet mortality occurred during the first week postpartum with 69% of these deaths being caused by overlying. The grower-pig crude morbidity incidence risk was 20% and the cause-specific incidence risks of the important health problems encountered were gut edema (1.3%), pruritus (21.1%), and unknown (2.3%). The crude mortality incidence risk was 3.8% and the important causes were gut edema and unknown causes (cause-specific mortality incidence risks of 1.3 and 1.6%, respectively). The median weight:age ratio and average daily weight gain for the grower pigs were 5.1 kg/month of age and 0.13 kg/day, respectively. For preweaning pigs, the median average daily weight gain was 0.13 g/day.     

A serological survey of leptospirosis in Prince Edward Island swine herds and its association with infertility.

A serological survey was undertaken to determine the prevalence of leptospirosis, and to investigate associations between leptospiral antibody titers, and herd measures of reproduction. Production records and leptospirosis serology were analyzed for 25 slaughter hogs from each of eleven randomly sampled farrow-finish operations on Prince Edward Island. The effect of selected leptospiral serovars on nonproductive sow days per parity (NPSD/P) and the proportion of pigs born dead was evaluated. The four most common serovars to which antibodies were detected were Leptospira icterohaemorrhagiae, L. bratislava, L. autumnalis and L. pomona, with respective prevalences of 57.1%, 35.1%, 3.4% and 1.5% of PEI slaughter hogs. None of these serovars was associated with increased frequency of stillbirths (p greater than 0.05). However, farms with a higher prevalence of L. bratislava antibody titers tended to have more infertility, as measured by NPSD/P (r = 0.738, p = 0.036 with Bonferroni adjustment). Also, farms with L. pomona antibody titers had higher NPSD/P than farms without L. pomona antibody titers (p = 0.0008 with Bonferroni adjustment). There was no association between NPSD/P and antibodies to either L. autumnalis or L. icterohaemorrhagiae (p greater than 0.05).     

Six component intervals of nonproductive days by breeding-female pigs on commercial farms

Of 105 swine herds using a production record system for breeding female pigs, 95 farms were used to analyze nonproductive female days (NPD), the six component intervals of NPD, and related measurements. The NPD was defined as the days when mated gilts and sows were neither gestating nor lactating, and it was calculated by summing the six component intervals in the average mated female inventory. The mean NPD was 57.9 d (SD = 20.5), and the proportions of six component intervals of gilt first-mating-to-pregnancy interval, gilt first-mating-to-culling interval, unmated weaning-to-culling interval, weaning-to-first-mating interval, sow first-mating-to-pregnancy interval, and sow first-mating-to-culling interval were 9.24, 7.82, 6.85, 27.9, 18.9, and 29.3%, respectively. Farms in the upper 25th percentile of the ranking for number of pigs weaned.mated female(-1).yr(-1) were designated as 25 high-performing farms. The remaining farms were designated as an ordinary farm group for comparisons. High-performing farms had 21.1 d fewer NPD, and five of the six component intervals were lower compared with the ordinary farms (P < 0.05). Regression analyses indicated that the number of litters.mated female(-1).yr(-1) increased by 0.07 in both farm groups as NPD decreased every 10 d. Fewer NPD were correlated with a higher percentage of multiple matings during estrus (P < 0.05) but were not correlated with removal risk and replacement risk in both farm groups. The average parity of culled females was negatively correlated with NPD in the ordinary farm group, and the average farrowed parity was positively correlated with NPD in the high-performing farm group (P < 0.01). Decreasing each component interval of the NPD six components is critical to increasing herd productivity. A high percentage of multiple matings during estrus and appropriate culling management may be key factors to decrease NPD.     

Photoperiod and heat stress influence on lactating sow performance and photoperiod effects on nursery pig performance

Three experiments were conducted to evaluate sow and piglet productivity under extended photoperiod. In Exp. 1, 98 crossbred, lactating sows were housed in one of four treatments: thermoneutral air temperature (23.6 degrees C) in either (h of light:dark) 1:23 or 16:8 photoperiods, or heat stress (30.4 degrees C) in either 1:23 or 16:8 photoperiods. Heat stress reduced (P less than .05) sow feed intake, piglet mortality and piglet weaning weight and increased (P less than .01) sow lactation weight loss. Number of pigs weaned per litter was increased (P less than .01) when sows were heat-stressed. Extended photoperiod reduced (P greater than .05) time for sows to rebreed postweaning by .4 d. The interaction between air temperature and photoperiod was significant only for sow lactation weight loss. Heat stress increased sow lactation weight loss, but this effect was more severe in the 1:23 than in the 16:8 photoperiod. Experiments 2 and 3 examined the effects of 1:23 or 16:8 photoperiods on nursery pig performance when pigs were weaned from sows experiencing 1:23 (Exp. 3) or 16:8 (Exp. 2) photoperiods. In both nursery studies, photoperiod did not influence (P greater than .10) postweaning pig mortality, feed intake, weight gain or gain:feed ratio. In conclusion, extended photoperiod reduced days to return to estrus and reduced sow lactation weight loss, especially during heat stress. No benefits in preweaning or postweaning piglet weight or survival were observed by use of extended photoperiod.     

Farm factors associated with the use of antibiotics in pig production

The aim of this study was to investigate farm-level economic and technical factors that are associated with the use of antibiotics on pig farms. Identification of such factors, like farm size and net farm result, may help to increase epidemiological knowledge and to specify farm advice and policy making to reduce inappropriate use of antibiotics. The study used over 300 farm-year records collected during 2004 to 2007 from pig farms in the Netherlands. Data included economic and technical factors as well as antibiotic administration. Data were statistically analyzed for factors associated with antibiotic use, both for fattening pig and sow farms (piglets only), separately. The response variable was the average number of daily dosages per average pig year. Statistical analysis was performed on 16 and 19 potential explanatory factors for the fattening pig and sow farms, respectively. The results showed that, both on the fattening pig and sow farms, the average use of antibiotics increased from 2004 to 2006, but decreased during 2007, but the effect of year was not significant (P > 0.05). Use of antibiotics varied between individual farms. Large farm repeatability for the use of antibiotics in the different years was found. Factors associated (P < 0.05) with the use of antibiotics included: farm system, number of pigs, and population density in the region of the farm (for sow farms only). As these factors are easy to collect and to register, they can be used to specify farm advice and investigation, as well as for policy making. The majority of the technical and economic factors were not significantly (P > 0.05) related to the on-farm use of antibiotics. Therefore, it is recommended to focus future research on the potential role of socioeconomic factors associated with antibiotic use on pig farms.     

The effects of health classification and housing and management of feeder pigs on performance and meat inspection findings of all-in-all-out swine-finishing herds

The effects of health classification and of housing and management on performance and meat inspection findings were studied in 166 all-in-all-out finishing herds in Finland in 1995 and 1998. Producers could buy either health-classified (certified free of certain diseases) or standard-class pigs for their farms. Herds that had attained a certain level of housing and management were eligible to join the LSO 2000 management system for finishing herds. In 1995, none of the study herds were LSO 2000 units. In 1998, 76 of them had become LSO 2000 units, while 90 had remained as non-LSO 2000 units. Continuous outcome variables (daily gain and time in the finishing unit) were analysed with a mixed-model procedure with repeated measurements from the same farms. Discrete variables were analysed either with Poisson regression (mortality, whole- and partial-carcass condemnations, organ condemnations, arthritis, abscesses) or logistic regression (liver condemnations, pneumonia, pleuritis). The models were adjusted for the year, size of the herd and the average slaughter weight of the batch.The benefits obtained by the health classification of the feeder pigs included a substantial increase in daily gain (37g, about 5%) and decrease in time in the finishing unit (4 days, about 4%), decrease in mortality (odds ratio, OR 0.68), a substantial decrease in pneumonia (OR 0.37) and pleuritis (OR 0.60), and a substantial decrease in liver (OR 0.45) and organ (OR 0.72) condemnations. Classification of the pigs did not have an effect on the prevalence of whole-carcass condemnations, arthritis or abscesses. The health-classified pigs had, unexpectedly, more partial-carcass condemnations (OR 1.15) than the standard-class pigs. The obtained benefits of the LSO 2000 units were an increase in daily gain (14g, about 2%), decrease in time in the finishing unit (2 days, about 2%), a decrease in mortality (OR 0.69) and a decrease in whole-carcass (OR 0.69) and partial-carcass (OR 0.81) condemnations. The LSO 2000 units did not have any advantage over the non-LSO 2000 units in their prevalence of liver or organ condemnations, arthritis, abscesses, pneumonia or pleuritis.     

Performance of gestating sows in bedded hoop barns and confinement stalls

The effects of gestation housing systems on sow and litter performance were evaluated for 2.5 yr in southwest Iowa. Gestation housing system treatments were as follows: 1) individual gestation stalls in a mechanically ventilated confinement building with a partially slatted floor and a manure flush system and 2) group pens with individual feed stalls in deep-bedded, naturally ventilated hoop barns. In all, 957 litters from 353 sows were evaluated. Number of pigs born alive per litter differed for the 2 housing treatments (P = 0.002). Sows gestated in hoop barns gave birth to more live pigs per litter (10.0 +/- 0.2 pigs) than sows gestated in stalls (9.3 +/- 0.2 pigs). Preweaning mortality was not different for the 2 housing treatments (P = 0.70). Cross-fostering was done to equalize litter size within 24 h of birth, which resulted in an equal number of weaned pigs per sow (P = 0.50) regardless of gestation housing treatment. The weaning-to-breeding interval was different (P = 0.01), with sows kept in stalls (4.3 +/- 0.6 d) returning to estrus sooner than sows gestated in hoop barns (6.0 +/- 0.6 d). These results indicate that gestating sows can be housed as groups in deep-bedded hoop barns equipped with individual feeding stalls and will perform comparably to gestating sows housed in confinement systems with individual gestation stalls.     

Effects of stocking rate and crude protein intake during gestation on ground cover,soil-nitrate concentration,and sow and litter performance in an outdoor swine production system

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.     

Effect of group size and feeder type on growth performance and feeding patterns in finishing pigs

The effects of four group sizes (2, 4, 8, and 12 pigs per pen) and two single-space feeder types (conventional and electronic feed intake recording equipment [FIRE]) on feed intake, growth performance, and feeding patterns were determined in 208 crossbred finishing pigs (equal numbers of barrows and gilts) between 84.4 (SD = 0.81) to 112.8 (SD = 1.08) kg BW over a 4-wk period. Pigs were given ad libitum access to a corn-soybean meal-based diet (15.9% CP; 0.79% lysine; 3,328 kcal ME/kg). The floor space allowance was 0.9 m2/pig for all treatments. Growth rates were not different for the two feeder types; however, feed intake was lower and gain:feed ratio higher for pigs on the FIRE feeders (P < 0.01). Feed intake, growth rate, and gain:feed ratio were not different (P > 0.05) among the group sizes. Number of feeder visits per day decreased and feed intake per visit, feeder occupation time per visit, feed consumption rate, and percentage of time the feeder was occupied increased with group size (P < 0.05). Feed intake per visit had the strongest correlation with daily feed intake (r = 0.54; P < 0.01) and was negatively correlated with gain:feed ratio (r = -0.38; P < 0.01). However, the correlations between growth performance and other feeding pattern traits were relatively weak (r < or = 0.30). As group size increased, diurnal variation in number of feeder visits and feed consumed per hour decreased. There was no difference in time spent sitting and standing between the two feeder types. The proportion of time spent eating was generally lower for the larger groups on both feeders. The proportion of time spent lying was similar across group sizes for pigs on the conventional feeders but was greater for pigs in the larger groups on the FIRE feeders. This study suggests that finishing pigs can maintain feed intake and growth rate by changing feeding behavior as group size increases from 2 to 12.