Non-productive Days Research Articles

Heritability of longevity in Large White and Landrace sows using continuous time and grouped data models

BackgroundUsing conventional measurements of lifetime, it is not possible to differentiate between productive and non-productive days during a sow's lifetime and this can lead to estimated breeding values favoring less productive animals. By rescaling the time axis from continuous to several discrete classes, grouped survival data (discrete survival time) models can be used instead.MethodsThe productive life length of 12319 Large White and 9833 Landrace sows was analyzed with continuous scale and grouped data models. Random effect of herd*year, fixed effects of interaction between parity and relative number of piglets, age at first farrowing and annual herd size change were included in the analysis. The genetic component was estimated from sire, sire-maternal grandsire, sire-dam, sire-maternal grandsire and animal models, and the heritabilities computed for each model type in both breeds.ResultsIf age at first farrowing was under 43 weeks or above 60 weeks, the risk of culling sows increased. An interaction between parity and relative litter size was observed, expressed by limited culling during first parity and severe risk increase of culling sows having small litters later in life. In the Landrace breed, heritabilities ranged between 0.05 and 0.08 (s.e. 0.014-0.020) for the continuous and between 0.07 and 0.11 (s.e. 0.016-0.023) for the grouped data models, and in the Large White breed, they ranged between 0.08 and 0.14 (s.e. 0.012-0.026) for the continuous and between 0.08 and 0.13 (s.e. 0.012-0.025) for the grouped data models.ConclusionsHeritabilities for length of productive life were similar with continuous time and grouped data models in both breeds. Based on these results and because grouped data models better reflect the economical needs in meat animals, we conclude that grouped data models are more appropriate in pig.

The occurrence of decreased numbers of pigs born alive in parity 2 sows does not negatively affect herd productivity in Japan

The objectives of this study were to assess the occurrence of decreased numbers of pigs born alive (PBA) in parity 2 (D-PBA) and to evaluate the importance of D-PBA sows and herds by analyzing against using the summed numbers of PBA in parity 1 and 2 (SPBA) and nonproductive sow days (NPD). The study assessed annual data from 2001 to 2005 from 106 herds, and sow data including 137,360 farrowing records of 68,680 sows farrowed in parity 1 and 2. D-PBA was defined as the same or fewer numbers of PBA in parity 2 than that in parity 1 at either the sow or herd level. Sows or herds were categorized into two groups: D-PBA or increased PBA in parity 2 (I-PBA). NPD was defined as the number of days that sows were neither gestating nor lactating in parity 1. Mixed-effects models were used to compare the reproductive performance between the two groups. Of the 68,680 sows, 49.5% had an occurrence of D-PBA. D-PBA sows had 0.3 pigs fewer SPBA than I-PBA sows, but those sows had 1.9 days shorter NPD in parity 1 than I-PBA sows ( P < 0.05). Over the five years studied the average annual proportion of D-PBA herds was 16%. No differences were found between the D-PBA and I-PBA herds in the number of pigs weaned per mated female per year (PWMFY), SPBA or NPD in any year. Additionally, the PWMFY was not correlated in any years with either the proportions of D-PBA sows or the difference in PBA between parity 1 and 2. In conclusion, the occurrence of D-PBA does not appear to be a serious problem in Japanese swine herds studied.

Optimizing Resource Leveling in Construction Projects

Construction schedules, generated by network scheduling techniques, often cause undesirable resource fluctuations that are impractical, inefficient, and costly to implement on construction sites. This paper presents the development of two innovative resource leveling metrics to directly measure and minimize the negative impact of resource fluctuations on construction productivity and cost. The first metric quantifies the total amount of resources that need to be temporarily released during low demand periods and rehired at a later stage during high demand periods. The second measures the total number of idle and nonproductive resource days that are caused by undesirable resource fluctuations. The two new metrics are incorporated in a robust and practical optimization model that is capable of generating optimal and practical schedules that maximize the efficiency of resource utilization. An application example is analyzed to illustrate the use of the model and demonstrate its capabilities. The results of this analysis show that the present model and metrics are capable of outperforming existing metrics and eliminating undesirable resource fluctuations and resource idle time.

By-Parity Nonproductive Days and Mating and Culling Measurements of Female Pigs in Commercial Breeding Herds

The objectives of this study were to determine by-parity nonproductive female days (NPD or NPDs) and mating and culling measurements, to determine correlations between by-parity NPDs, mating and culling measurements and herd productivity measurements, and to compare by-parity NPDs between three herd groups (105 herds) with differing reproductive productivities. NPD was defined as the number of days when mated females were neither gestating nor lactating. Correlation analysis and mixed-effects models were performed. On the basis of the 25th and 75th percentiles of pigs weaned per mated female per year, three herd groups were formed: high-, intermediate-, and low-performing herds. The mean NPD of 105 breeding herds (mean +/- SEM) was 52.7 +/- 1.6 days. The NPDs in parities 1, 6 and > or = 7 were higher than those in parities 0, 2, 3 and 4 (P<0.05). High-performing herds had a higher farrowing percentage and lower percentage of reserviced females than low-performing herds (P<0.05). Lower by-parity NPDs were correlated with lower percentages of reserviced females, higher farrowing percentages and lower culling rates from parities 1 to 5 (P<0.05). High-performing herds had NPDs that were > 25 days lower in parities 0 to 3 than low-performing herds (P<0.05). High-performing herds had lower culling rates in parities 2 to 5 and higher culling rates in parities 6 and > or = 7 than low-performing herds (P<0.05). The present study indicates that monitoring the by-parity NPD and mating and culling measurements is a good tool for improvement of herd productivity.

Effect of backfat loss during lactation on weaning-to-oestrus interval of sows at gonadotropin application

Abstract. A total of 984 primiparous and multiparous crossbred sows (Swedish Landrace × Large White) housed on a commercial pig farm were used to study the effect of the decrease in backfat thickness during lactation and the level of backfat at weaning on weaning-to-oestrus interval and conception rate of sows. Primiparous sows (n=213) received a single injection of 400 IU eCG + 200 IU hCG (PG600®, Intervet) at weaning and approximately 30 % of sows did not respond to the first treatment. First-farrowing sows produced significantly fewer live-born piglets, had markedly thinner backfat in late gestation, showed significant loss of backfat thickness during lactation and showed thinner backfat at weaning than sows with a greater number of parities. Primiparous sows with backfat thinner than 18 mm at weaning lost an average of 21 % of backfat during lactation and had a significantly longer weaning-to-oestrus interval (31.75 ± 2.22 days), even after a second treatment with PG600®, than both primiparous sows which responded to the first treatment (5.95 ± 0.16 days) and multiparous sows which were not treated (5.19 ± 0.12 days). The primiparous and multiparous sows with thicker backfat at farrowing also had thicker backfat at weaning (r=0.874 and r=0.938 for primiparous and multiparous sows, respectively). Sows with thicker backfat at weaning showed a shorter weaning-to-oestrus interval and this correlation was higher for primiparous than for multiparous sows (r=−0.192 and r=−0.100, respectively). Thicker backfat of the sows at weaning was moderately but significantly correlated with lower loss of backfat during lactation (r=−0.179 and r=−0.273 for primiparous and multiparous sows, respectively). The present study showed that monitoring of backfat thickness and loss of backfat during lactation represents a useful tool to decrease non-productive days and improve the efficiency of high-producing pig herds.

Deepwater Blowout: A Case Study

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 105914, "Deepwater Blowout - A Case History: Shallow Gas Hazards Hide in the Weeds," by William Flores Jr., John B. Garner, SPE, and Chris Scarborough, SPE, Boots &amp; Coots, prepared for the 2007 SPE/IADC Drilling Conference, Amsterdam, 20-22 February. The paper has not been peer reviewed. The full-length paper details the sequence of events of a blowout in 2,400-ft water depth of a deepwater development well adjacent to the discovery well. Loop current prevented running the blowout-preventer (BOP) stack and riser after cementing surface casing. After 3 weeks, the loop current abated, and a remotely operated vehicle (ROV) could be deployed. Upon deployment, it was discovered that the development well was blowing out, with the blowout plume carrying more than 300 ft. Introduction The prospect was drilled initially in 1997 and abandoned as a result of economics at that time. In the course of planning, a shallow gas hazard was identified from seismic, and records from the 1997 well reported several nonproductive days fighting lost circulation and gas. To avoid the nonproductive time encountered on the 1997 well, the operator designed a casing program for the first development well to include riserless drilling of the shallow gas hazard using the pump-and-dump process. Development Well 1 was drilled successfully in this manner and was completed as a producer in April 2006. The well currently is shut in, awaiting field development and production facilities. The rig was moved to a second location. Well 2 was spudded on 3 April 2006 less than 2,000 ft from Well 1 and drilled riserless through the shallow hazard. Structural pipe was jetted to 2,778 ft, which is 285 ft below the mudline. The 30-in. casing was allowed to soak for 4 hours. A 24-in. hole was drilled to 3,200 ft using seawater and gel sweeps. From 3,200- to 3,899-ft total depth (TD), a pump-and-dump system was used, maintaining a 10.5-lbm/gal equivalent mud density, by monitoring equivalent circulating density (ECD) with pressure-while-drilling (PWD) instrumentation and vortex mixing 16.0-lbm/gal water-based mud "on the fly" with seawater. A wiper trip was attempted. However, the well appeared to begin to flow with pipe at 3,597 ft. The pipe was tripped to bottom where circulation was begun and the equivalent mud weight (EMW) was increased to 10.7 lbm/gal. Circulation was stopped, and the well was observed to be static. A wiper trip then was made without problems. With no fill on bottom, the well was circulated again with a 10.7-lbm/gal EMW. While keeping the hole full, the pipe was pulled out of the hole to run 20-in. casing. The well, standing full of mud, was monitored by an ROV while preparing to run casing.

Sows having high lifetime efficiency and high longevity associated with herd productivity in commercial herds

The objectives of this study were to characterize sows having high lifetime efficiency and high longevity (HE–HL), to examine the relationship between lifetime measurements, and to determine the association between the sows and herd productivity. This study was conducted by obtaining sow data with 66,262 parity records of 13,786 sows born during 1999 and herd data with mean measurements of 4-year records from 2000 to 2003 in 92 herds. Sow lifetime efficiency was defined as the sum of pigs born alive in lifetime divided by the sow life days and multiplied by 365 days. Sows were categorized into three sow groups based on the upper 25 percentile of the lifetime efficiency and parity at culling ≥ 6. The three groups were sows having 1) the upper 25 percentile of the lifetime efficiency and parity at culling ≥ 6 (HE–HL sows), 2) less than the upper 25 percentile of the lifetime efficiency and parity at culling ≥ 6 (OE–HL sows), and 3) parity at culling ≤ 5 regardless of lifetime efficiency (LL sows). Mixed-effects models were used to compare reproductive performance between the three sow groups and to identify factors associated with a proportion of a HE–HL sow in the herd. Correlation analyses were done between lifetime performances in sows and between herd productivity measurements and the proportions of three sow groups in the herd. The proportions of HE–HL, OE–HL, and LL sows in 13,786 sows were 21.8%, 24.5%, and 53.7%, respectively. Lifetime efficiency was correlated with parity at culling ( r = 0.76; P < 0.01) and nonproductive days per parity ( r = − 0.46; P < 0.01). From first parity to the end, HE–HL sows had the greatest numbers of pigs born alive, the highest farrowing percentage, and the shortest nonproductive days per parity ( P < 0.01). Sows aged between 186 and 227 days at first mating were 1.09 to 1.11 times as more likely to become a HE–HL sow as those aged between 249 and 269 days at first mating ( P < 0.05). Of the 92 herds, mean proportion of HE–HL sows was 23.5%, and the proportions ranged from 0 to 57.6%. A higher proportion of HE–HL sows and a lower proportion of LL sows in the herd were correlated with more pigs weaned per mated female per year ( P < 0.01). In conclusion, HE–HL sows had high efficiency from the first parity to the end, which was attributed to herd productivity.

Sow removal in Swedish commercial herds

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.

Accuracy of Trans‐abdominal Ultrasound Pregnancy Diagnosis in Sows using a Linear or Sector Probe

The assessment of an early and reliable pregnancy diagnosis in sows is very important for limiting the number of non-productive days in sow herds. The aim of the present study was to investigate the accuracy of trans-abdominal ultrasound detection for early pregnancy diagnosis in sows under field conditions. Particular attention was paid to the time when a reliable diagnosis can be made, and to possible differences between two commonly used types of scanners. In total, 202 sows from two herds were tested daily with scanners A (linear transducer of 5 MHz) and B (sector transducer of 3.5 MHz) from day 16 until 25 after insemination. Ninety-three percentage of the sows were pregnant 36 days after insemination. Using ultrasound, the first pregnancy could be detected already 18 days after insemination. The sensitivity, specificity and overall accuracy were higher than 95% from day 24 (scanner A) or day 23 (scanner B) post-insemination onwards. The positive predictive values from day 19 onwards were consistently higher than 95% with both types of scanners, whereas the negative predictive values were consistently low for both scanners during the entire period. The sensitivity of testing tended to be slightly lower in sows with a litter size of <10 total born piglets, compared to sows with 10 or more piglets. In conclusion, pregnancy diagnosis in sows using trans-abdominal ultrasound testing can be assessed quickly and reliably under field conditions from day 23 of gestation onwards. Predictive values of positive test results were high in these herds, whereas those of negative test results were low. This implies that sows with a negative test result early in pregnancy should be retested later.

Six component intervals of nonproductive days by breeding-female pigs on commercial farms1

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.

Herd-Management Factors Associated with Nonproductive Days by Breeding-Female Pigs on Commercial Farms in Japan

A database containing production measurements was created by abstracting data files of 124 farms in Japan which participated in the PigCHAMP data-share program. Summary statistics for breeding-herd performance data in 2002 were presented. A model was built to assess the association between herd-management factors and nonproductive days by breeding-female pigs (NPD). The NPD was defined as days when mated gilts and sows were neither gestating nor lactating. The mean of NPD was 53.9 days (SD = 16.1). In regression analysis using backward elimination, higher percentage of multiple matings, higher percentage of sows mated by 7 days after weaning, higher parity of culled sows, lower percentage of reserviced females, lower female death rate and larger herd size were the herd-management factors identified as having important associations with shorter NPD (P<0.05). Lactation length, gilt pool size, parity of farrowed sows, replacement rate and culling rate were not significant (P>0.10) in the analysis. It is recommended that producers change their management systems to increase the percentage of multiple matings, the percentages of sows mated by 7 days after weaning, and the parity of culled sows, and to decrease the percentage of reserviced females and the female death rate in order to improve the NPD and breeding herd productivity.

Correlations of Prepartum Body Temperature and Postpartum Fever of Sows with Vulvovaginal Discharge: a Case Report

Franek S. P., G. Bilkei:Correlations of Prepartum Body Temperature and Postpartum Fever of Sows with Vulvovaginal Discharge: a case report. Acta Vet Brno 2005, 74: 2005: 395-399. In a large pig breeding unit, sows suffering from prepartum vulvovaginal discharge were selected (n = 159) for the trial. Rectal temperatures were recorded daily on days 110-113 of pregnancy and during the first 3 days post partum. Fifty-two sows (group one) had higher than 39.0 °C (39.3 ± 0.3 SE °C), 107 sows (group two) had lower than 39.0 °C (38.6 ± 0.2 SE °C) “three days average prepartal rectal temperatures”. While all sows in group one developed postparturient fever (40.5 ± 0.2 SE °C), only 19 of 107 (17.8%) sows with lower prepartum temperatures had postparturient fever (P < 0.001). Blood samples were collected on days 1, 3 and 5 post partum to determine the concentration of acute phase proteins. Mean serum alpha 1-acid glycoproteins (AGP) and haptoglobin (HPT) concentrations were higher on days 1, 3 and 5 (P < 0.001) post partum in sows suffering postparturient fever. Our results have shown that in farrowing units with high prevalence of preparturient vulvovaginal discharges, prefarrowing rectal temperatures might indicate impending postparturient disease of the sow. Swine, sow, parturition, prepartum body temperature, postpartum fever vulvovaginal discharge The reproductive performance of the breeding sow is a key measure in the pig production. While many factors influence the profitability of swine production, the number of piglets produced per sow per year (Pig/Sow/Year, PSY) and number of non-productive days (NPD) belong to the most important measures of productivity ( Stelzer et al. 1997). Both PSY and NPD are significantly influenced by postparturient diseases of the sows ( Akos and Bilkei 2004). Lactation failure and early postpartal diseases of sows belong to major causes of sow mortality and low reproductive performance in pig breeding units ( Karg and

Lactational estrus induction in the Mexican hairless sow

The purpose of this study was to determine the effects on the reproductive performance of the Mexican hairless pig (MHP) while inducing fertile lactational estrus. Lactational estrus was induced on day 8, postpartum, in 20 primiparous sows during two consecutive reproductive cycles. Boar presence and temporary litter withdrawal were used as stimuli. Group I did not receive stimuli (control, C); group II had a 15 min boar stimulus (B); group III had litter withdrawal for 4 h (LW), and group IV received both stimuli (B+LW). Fertile estrus was detected by sow behavior, exfoliative vaginal cytology, and 17β-estradiol and progesterone samples. Individual stimuli did not induce fertile lactational estrus; nevertheless, when used together, both stimuli induced 100% of females into estrus, and 80% of them got pregnant while lactating. The partial withdrawal of the litter had a significant and positive effect on the number of live born piglets. Sows pregnant during lactation had shorter reproductive cycles, by not having non-productive days and litter size was greater. Pregnancy induction during lactation allowed the Mexican hairless sow to reduce the period between parturition’s without diminishing the lactation length and litter performance.

Lifetime reproductive and financial performance of female swine.

To evaluate reproductive and financial performance for commercial swine herds grouped on the basis of pattern of removal of female swine. Cohort study. 25 swine herds. Lifetime reproductive productivity was summarized as number of pigs weaned per herd day per mated female and as number of herd days per pig weaned per mated female. Factors associated with these 2 measures were determined by use of linear regression. Financial data from a commercial database were used to estimate maximum number of parities at removal associated with profitability. Sensitivity analysis was used to simulate how variations in daily maintenance cost and value per weaned pig would influence profitability. Mean number of pigs weaned per herd day per mated female was 0.054; mean number of herd days per pig weaned per mated female was 20.2. Both these measures were associated with proportion of nonproductive days during herd life, preweaning mortality rate per litter weaned, mean lifetime number of pigs born alive per litter weaned, and mean lifetime lactation duration. Maximum parity at time of removal associated with profitability ranged from 5 to 8. Daily maintenance costs per female had a greater impact on lifetime profitability than did value per weaned pig. Results suggest that lifetime reproductive and financial performance is optimized among swine herds that have higher proportions of high-parity females.

Evaluation of the early conception factor dip stick test in dairy cows between days 11 and 15 post-breeding

A field study was conducted between February and November 1995 using 139 Holstein cows to determine the accuracy and the usefulness of the ECF Dip Stick Test performed between days 11 and 15 post-breeding. Results of the ECF tests were compared to pregnancy diagnosis after 25 days post-breeding using ultrasonography and transrectal palpation. The apparent conception rate of the study population based on transrectal palpation was 38%. The ECF test sensitivity, specificity, positive and negative predictive values were 81%, 26%, 40% and 69%, respectively. The Kappa value (0.06; 95%CI -0.19 to 0.30) demonstrated no agreement between the ECF test and the final pregnancy status of dairy cows. These results would indicate that the ECF test is not a good predictor of pregnancy because the proportion of false positive results was high at 46% (64/139). Furthermore, the accuracy of the test to detect open cows is not acceptable with the high proportion of false negative tests of 31% (10/32). This finding would indicate that 19% (10/53) of the cows diagnosed pregnant rectally were misdiagnosed as non-pregnant by the ECF test. Finally, many factors such as the incubation time, the personal assessment of the test reaction and the source of light can also affect the ECF test reading. Based on the current technology, the authors would not recommend the use of the ECF test to help dairy producers reduce non-productive days.

Lifetime reproductive performance in female pigs having distinct reasons for removal

This study describes the reasons for removal of female pigs distributed across parity categories, and evaluates how parameters of lifetime productivity differ for females having distinct removal reasons. The study analyzed lifetime records from 7973 females. Those records were obtained from 28 herds from the PigCHAMP ® research database having high-quality data during a five-year period. Female life expectancy corresponded to 3.3 parities at removal or 1.6 years spent in the breeding herd. The most common removal reason was culling attributed to reproductive disorders (33.6%), followed by culling for sub-optimal litter performance (20.6%). Sows culled for old age (8.7% of the removals) spent proportionally fewer days in non-productive periods, and produced more weaned pigs annually and over a lifetime than females removed for other reasons ( P<0.05). In contrast, females culled for reproductive failure accumulated the largest proportion of non-productive days (NPD) during the time spent in the breeding herd, and produced the fewest weaned pigs per lifetime and per year ( P<0.05). These findings indicate that culling for reproductive reasons is more common among low-parity females, which suggests that minimisation of NPD at early reproductive cycles is crucial to optimise female lifetime reproductive efficiency.

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 ≥ 1 at the time of removal. Results For 58% of all females, parity at the time of removal was ≤ 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. (J Am Vet Med Assoc 1999;214: 1056–1059)

Influence of equine chorionic gonadotropin on weaning-to-estrus interval and estrus duration in early-weaned, primiparous, female swine.

The weaning-to-estrus interval (WEI) influences the total nonproductive days (NPD) accumulated by the breeding herd and affects herd productivity. Short lactation lengths (LL) are commonly followed by prolonged WEI, which are also associated with short estrus duration (ED). Equine chorionic gonadotropin treatment is a tool that has been used to reduce WEI, especially for low-parity females. The objectives for this study were to evaluate the effect of LL on the association between WEI and ED and to estimate the effects of postweaning eCG administration on WEI and ED for early-weaned females. Two treatments (TREAT) consisting of 750 IU of eCG (n = 96) or control (n = 77) were applied 1 d after weaning to first-parity, weaned females. The study was conducted on a commercial farm having a target LL of 18 d. Estrus detection was conducted three times daily, and estrus duration was determined as the interval between the first and the last positive response to back pressure. Analyses of variance were conducted to estimate the effects of LL and TREAT on WEI and the effects of TREAT and WEI on estrus duration. Mean LL was 17.9+/-1.7 d, mean WEI was 106.6+/-29.2 h, and mean estrus duration was 55.9+/-15.5 h. Even though the frequency of short WEI tended to increase with longer LL, mean WEI was shortest for females weaned after 18 d and longest for those weaned after 20 d (P<.05). The WEI for females receiving eCG (98.7+/-2.7 h) was shorter (P = .0001) than that for control females (121.5+/-3.3 h). The WEI was also affected by a LL x TREAT interaction (P = .0014), indicating that the interval was longer (P<.05) for control females weaned after 17 and 20+ d than for other females. The LL and TREAT did not affect estrus duration (P = .20 and P = .157, respectively). However, estrus duration was reduced as the WEI increased (P = .0001), and it was also influenced by a WEI x TREAT interaction (P = .024). A linear regression model estimated that the association between WEI and estrus duration was stronger in the eCG group than in the control group (R2 = .51 and .15, respectively; both P<.001). In conclusion, the use of eCG postweaning was associated with more precise prediction of estrus duration as a function of the WEI and allows optimization of breeding management in early-weaned, primiparous females.

Validation of an infra-red sensor for oestrus detection of individually housed sows

Abstract Oestrus detection of sows is an important activity within pig husbandry. It takes about 30% of the overall labour input and financial losses related to non-productive days may vary considerably. Therefore, the principle of using an infra-red sensor has been evaluated to detect automatically oestrus of sows. A total of 58 multiparous individually housed sows were monitored from the day after the piglets were weaned. The infra-red sensor was mounted 50 cm above the front part of the sow’s body. Four parameters of body movement as quantified by the sensor’s output voltage were investigated: mean daily activity; standard deviation of mean daily activity; minimal; and peak value. The reference method was the standing behaviour before the boar and the inseminator. Four classes of behaviour were defined: (1) standing+increase of mean daily activity; (2) standing+no increase; (3) no standing+no increase; and (4) no standing+increase. Up to 80% of the sows could be classified correctly when using mean daily activity as the selection parameter. Up to 86% were classified correctly when daily peak activity was also included. Positive and false positive sows could be distinguished at the 95% level by using a canonical discriminant analysis. Increase of mean daily activity, increase of standard deviation and increase of daily peak activity were statistically significant explanatory variables of a logit function predicting the four classes of oestrous behaviour.

Management factors associated with swine breeding-herd productivity in the United States

A database containing 24 key production measurements was created by abstracting data files of 673 U.S. farms which participated in the PigCHAMP data-share program in 1995. Summary statistics for breeding-herd performance data were presented for the Cornbelt and the South or Eastern regions. Eight models were built to assess the association between production system, operation management factors and productivity outcomes. Lactation length, percentage of multiple matings, parity of culled sows, percent gilts in the breeding-female inventory, and female culling rate were the management factors identified as having important associations with productivity outcomes. For example, shorter lactation length, higher percentage of multiple matings, and lower culling rate were associated with more pigs weaned per mated female per year. In addition, a lower percentage of gilts in the breeding-female inventory and a higher percentage of multiple matings were associated with fewer average non-productive female days. We recommend that producers change their management systems to decrease lactation length, the percentage of gilts in the breeding-female inventory, and female culling rate, and increase percentage of multiple matings in order to improve breeding-herd productivity on swine farms.