Technical note: High-performing swine herds improved their reproductive performance differently from ordinary herds for five years1

Productivity analysis of 70 farrow-to-finish swine farms in Japan from 2013 to 2018

Improving productivity is an urgent issue in the swine industry if it is to compete internationally. However, lack of data about recent productivity transition obstructs stakeholder planning. This study investigated the yearly productivity trends among farrow-to-finish swine farms in Japan using annual productivity data from 2013–2018 obtained for 70 farms in Japan. The productivity parameters analyzed were pigs born alive per litter (PBA), preweaning mortality (PRWM), pigs weaned per litter (PWL), litters per mated female per year (LMFY), pigs weaned per mated female per year (PWMFY), post-weaning mortality (POWM) and marketed pigs per mated female per year (MP). Data were classified into three groups based on the size of the average female inventory and compared among groups. Results presented the mean PBA increased continuously over the 6-year period (P<0.001), and the PWL, PWMFY, and MP means began increasing after 2015 (P<0.001). These upward trends were particularly remarkable on large farms. The mean PRWM increased sharply in 2014, thus inhibiting the increases in PWL, PWMFY, and MP for the same year. The LMFY and POWM means did not change during the study period. Altogether, productivity in Japan improved markedly during the study period, indicating highly prolific sows were well utilized with suitable breeding techniques among farmers these days. Continued genetic improvement and sow management would aid further development in Japan.

Interactions between pre- or postservice climatic factors, parity, and weaning-to-first-mating interval for total number of pigs born of female pigs serviced during hot and humid or cold seasons

The objective of this study was to examine interactions between climatic factors, parity, and weaning-to-first-mating interval (WMI) for total number of pigs born at subsequent parity (TPB) of female pigs serviced during 2 seasons. The present study analyzed records of 27,739 gilts and 127,670 parity records of sows in 95 Japanese herds; the records included females that were serviced between June and September (hot and humid season) or between December and March (cold season) in 2007 through 2009. The climate data were obtained from 20 weather stations located close to the studied herds. Mean daily maximum temperatures (Tmax), mean daily minimum temperatures (Tmin), and daily average relative humidity (RH) for 21 d preservice and 15 d postservice for each female were coordinated with that female's reproductive data. Linear regression models with random intercept and slopes were applied to the data. Mean TPB (±SEM) was 11.9 ± 0.01 pigs. Mean values (ranges) of Tmax in the hot and humid season and Tmin in the cold season were 28.4 (13.6 to 39.8°C) and 2.0°C (-13.2 to 17.6°C), respectively. Also, mean RH in the hot and humid season and the cold season were 73.2 (35 to 98%) and 65.2% (25 to 99%), respectively. In the hot and humid season, TPB in gilts decreased by 0.05 pigs for each degree Celsius increase in preservice Tmax (P < 0.05). However, there was no association between gilt TPB and either postservice Tmax (P = 0.11) or pre- and postservice RH (P ≥ 0.66). In sows, as preservice Tmax increased from 25 to 30°C, TPB in parity groups 1 and 2 or higher decreased by 0.6 and 0.4 pigs, respectively (P < 0.05). Also, sow TPB decreased by 0.1 to 0.4 pigs as postservice Tmax increased from 25 to 30°C (P < 0.05). In sows with WMI of 0 to 12 d, TPB decreased by 0.2 to 0.5 pigs as pre- or postservice Tmax increased from 25 to 30°C (P < 0.05). However, in sows with WMI of 13 d or more, TPB was not associated with pre- or postservice Tmax (P ≥ 0.10). As preservice Tmax increased from 25 to 30°C, TPB in sows under 81.6% RH (90th percentile) decreased by 0.5 pigs (P < 0.05), whereas TPB in sows under 65.7% RH (10th percentile) decreased by only 0.3 pigs (P < 0.05). Postservice RH in the hot and humid season was not associated with sow TPB (P = 0.18). During the cold season there was no association between TPB and pre- or postservice Tmin (P ≥ 0.09) or RH (P ≥ 0.45). Therefore, we recommend that producers apply cooling management for females during periservice in summer to increase TPB.

Standard operating procedures for sows and piglets in farrowing and lactation in Japanese commercial herds

The objectives of the present study were to advance the development of standard operating procedures for sows and piglets during farrowing and lactation in Japanese herds by surveying management procedures and to examine the relationships between the procedures and herd reproductive performance. In 2009, 115 herds using the same recording system were asked to complete a questionnaire about their management procedures. Data from 96 (83.5%) returned questionnaires were coordinated with the respective herd reproductive performance. The participating herds were classified into two groups based on the upper 25th percentile of pigs weaned per mated female per year: high-performing (>23.8 pigs) or ordinary herds. ANOVA was used to compare the procedures between two herd groups. Modeling with backward elimination was performed to establish the most important procedures for herd performance. More high-performing herds practiced farrowing induction and high-performing herds also had a higher percentage of farrowing-induced sows than ordinary herds (P<0.05). Modeling showed that herds feeding lactating sows with dietary fiber had 1.4% lower preweaning mortality risk than those that did not (P<0.05). Herds practicing fostering techniques or using nurse sows had 0.2 kg heavier average pig weaning weight than those not using these procedures (P<0.05). There was no association between pigs born alive and any of the surveyed management procedures. Based on these results, we recommend improving performances in breeding herds by feeding lactating sows with dietary fiber, performing fostering techniques and using nurse sows.

Selection of impubertal gilts by ultrasonography optimizes their oestrus, ovulatory and fertility responses following puberty induction by PG600

In a group of gilts, occurrence of puberty is spread over several weeks. The optimal time to apply puberty induction is therefore difficult to define, as treatment of puberal gilts is meaningless. Changes in uterine aspect around puberty can be detected by ultrasonography. Two experiments were carried out to assess the effect of PG600(®) (400 UI of eCG and 200 UI hCG) administration to 6 months old gilts shown to be impubertal by ultrasonography on cyclicity and reproductive performance. Impubertal Large White gilts (n=94) were treated with either PG600 or solvent (controls). Administration of PG600 to impubertal gilts increased significantly the proportion of females displaying pubertal uterine ultrasound images 3 days after treatment (100% versus 65% in controls). The number of days to puberty was significantly reduced in gilts injected with PG600 (3.3 days) versus controls (4.7 days). In gilts of the PG600 group, ovulation rate was higher at the 1st oestrus compared to the 2nd, while this did not happen in controls. Progesterone concentrations were higher at mid-luteal phase in the PG600 treated gilts compared to controls (significant treatment by time interaction). Similar proportions of gilts returned to oestrus (89% versus 74% for controls). Following insemination at the 2nd oestrus, pregnancy rate and number of live embryos were unaffected by treatment. The combination of ultrasonography and PG600 optimizes the use of exogenous hormones by targeting treatment to gilts that need it, therefore facilitating the introduction of gilts into all in/all out system.

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.

An evaluation of the impact of increased lactation length on the reproductive efficiency of sows in commercial herds

The objective of this study was to evaluate the impact of increased lactation length (LL) on the reproductive efficiency of sows in herds that were performing differently. The present study used 69,314 parity records for 38,532 sows in 114 herds. Two herd groups, high-performing herds and other herds, were formed on the basis of the upper 25th percentile of pigs weaned per mated female per year. Reproductive efficiency was measured as the estimated number of pigs born alive per farrowed sow per year (PBASY) and was calculated as actual subsequent pigs born alive (PBA) multiplied by estimated litters per farrowed sow per year (LSY) for each farrowed sow. The estimated LSY was calculated as 365 days divided by the actual farrowing interval. Multilevel linear mixed-effects models were used. In our evaluation, an interaction between LL and the herd groups was found for the estimated PBASY (P<0.05). The estimated PBASY of high-performing herds did not decrease as LL increased (P>0.10), although the estimated PBASY of the other herds decreased by 0.04 pigs as LL increased by 1 day (P<0.05). As LL increased from 14 to 28 days, the estimated LSY decreased by 0.19 in the two herd groups (P<0.05). Furthermore, as LL increased by 1 day, subsequent PBA increased by 0.08 pigs in high-performing herds and increased by 0.04 pigs in the other herds (P<0.05). Increased LL may not decrease the performance of sows in high-performing herds, but it may decrease the performance in other herds.