Piglet Pre-weaning Mortality Research Articles

Risk factors associated with piglet pre-weaning mortality in a Midwestern U.S. swine production system from 2020 to 2022

Piglet pre-weaning mortality (PWM) is a significant issue in the U.S. swine industry, causing economic losses and raising sustainability and animal welfare concerns. This study conducted a multivariable analysis to identify factors associated with PWM in a Midwestern U.S. swine production system. Weekly data from 47 sow farms (7207 weaning weeks) were captured from January 2020 to December 2022. Initially, 29 variables regarding farm infrastructure, productivity parameters, health status, and interventions were selected for univariate analysis to assess their association with PWM. The initial multivariable analysis included the variables with P < 0.20 in the univariate analyses. A backward stepwise model selection was conducted by excluding variables with P > 0.05, and the final multivariable model consisted of 19 significant risk factors and 6 interaction terms. The overall average PWM for the study population was 14.02 %. Yearly variations in PWM were observed, with the highest recorded in 2020 (16.61 %) and the lowest in 2021 (15.78 %). Cohorts with a pond water source, lower farrowing rate (71.9 %), higher farrowing parity (5.1), shorter gestation length (116.2 days), and using oxytocin during farrowing had increased PWM. The higher productivity parameters such as mummies rate, stillborn rate, and average total born, the higher the PWM was. Additionally, health status and intervention-related factors were associated with PWM, where higher PWM rates were observed in herds facing porcine reproductive and respiratory syndrome virus (PRRSV) outbreaks, porcine epidemic diarrhea virus (PEDV) positive, the weeks before and during feed medication, and weeks without using Rotavirus vaccine or Rotavirus feedback. Altogether, these results corroborate that PWM is a multifactorial problem, and a better understanding of the risk factors is essential in developing strategies to improve survival rates. Therefore, this study identified the major risk factors associated with PWM for groups of pigs raised under field conditions, and the results underscore the significance of data analysis in comprehending the unique challenges and opportunities inherent to each system.

Effects of Caffeine and Glucose Supplementation at Birth on Piglet Pre-Weaning Growth, Thermoregulation, and Survival.

Piglet pre-weaning mortality of approximately 15% represents a major economic and welfare concern to the pork industry. Supplementing neonatal piglets with glucose and/or caffeine has the potential to counteract hypoxic stress experienced during parturition and provide an energy substrate, which may improve survival to weaning. This study investigated the effects of caffeine and glucose supplementation at birth, in combination or separately, on piglet growth, thermoregulatory ability, and pre-weaning survival. At birth, 398 piglets were assigned to one of four oral treatments: saline, glucose (300 mg), caffeine (30 mg), or caffeine and glucose combined (30 mg caffeine and 300 mg glucose), dissolved in 6 mL saline. Piglets were tagged at birth, and time taken to reach the udder was recorded. Rectal temperatures were recorded at 4 h and 24 h post-partum, and body weights recorded at birth and 1, 3, and 18 days of age. Colostrum intake was estimated using birth and day 1 weights, and all pre-weaning mortalities were recorded. Treatments did not affect rectal temperature, colostrum intake, or pre-weaning mortality (p > 0.05). Low birth weight piglets (<0.9 kg) treated with caffeine and glucose had increased growth between 1 and 3 days of age (p < 0.05) compared to low birth weight piglets of other treatment groups. Caffeine supplementation alone reduced overall pre-weaning growth in low birth weight piglets compared to all other treatments (p = 0.05). Oral caffeine and glucose had no significant effect on piglet performance except in low birthweight piglets, where it improved growth in the first 3 days of life. Caffeine and glucose supplementation in combination may be beneficial for low birth weight piglets.

Pen Versus Crate: A Comparative Study on the Effects of Different Farrowing Systems on Farrowing Performance, Colostrum Yield and Piglet Preweaning Mortality in Sows under Tropical Conditions.

The present study was performed to determine the farrowing performance of sows, newborn piglet characteristics, colostrum yield, milk yield and piglet preweaning mortality in a free-farrowing pen compared to a conventional farrowing crate system in a tropical environment. A total of 92 sows and 1344 piglets were included in the study. The sows were allocated by parity into two farrowing systems, either a free-farrowing pen (n = 54 sows and 805 piglets) or a crate (n = 38 sows and 539 piglets). Backfat thickness and loin muscle depth of sows at 109.0 ± 3.0 days of gestation were measured. Reproductive performance data including total number of piglets born (TB), number of piglets born alive (BA), percentage of stillborn piglets (SB) and percentage of mummified foetuses (MF) per litter, farrowing duration, piglet expulsion interval, time from onset of farrowing to the last placental expulsion, piglet preweaning mortality rate, percentage of piglets crushed by sows and number of piglets at weaning were analysed. In addition, piglet colostrum intake, colostrum yield, Brix index and milk yield of sows were evaluated. On average, TB, BA, farrowing duration, colostrum yield and milk yield during 3 to 10 and 10 to 17 days of lactation were 14.7 ± 2.8, 12.8 ± 3.1, 213.2 ± 142.2 min, 5.3 ± 1.4 kg, 8.6 ± 1.5 kg, and 10.4 ± 2.2 kg, respectively. Sows kept in the free-farrowing pen tended to produce more colostrum than crated sows (5.5 ± 0.2 vs. 4.9 ± 0.2 kg, p = 0.080). Piglets born in the free-farrowing pen had a higher colostrum intake than those in the crate system (437.0 ± 6.9 and 411.7 ± 8.3 g, p = 0.019). However, the piglet preweaning mortality rate (26.8 ± 2.9 vs. 17.0 ± 3.8, p = 0.045) and the proportion of piglets crushed by sows (13.1 ± 2.1 vs. 5.8 ± 2.7, p = 0.037) in the free-farrowing pen were higher than those in the crate system. Interestingly, in the free-farrowing pen, piglet preweaning mortality rate in sows with high backfat thickness was higher than that in sows with moderate (37.8 ± 5.1% vs. 21.6 ± 3.6%, p = 0.011) and low (21.0 ± 6.2%, p = 0.038) backfat thickness. Moreover, the incidence of crushing in sows with high backfat thickness was higher in the free-farrowing pen than in the crate system (17.6 ± 3.6 vs. 4.0 ± 5.7, p = 0.049), but this difference was not detected for sows with moderate and low backfat thickness (p &gt; 0.05). Milk yield of sows during 3 to 10 days (8.6 ± 0.2 vs. 8.6 ± 2.3, p &gt; 0.05) and 10 to 17 days (10.2 ± 0.3 vs. 10.4 ± 0.4, p &gt; 0.05) did not differ between the two farrowing systems. In conclusion, piglets born in the free-farrowing pen had a higher colostrum intake than those in the crate system. However, the piglet preweaning mortality rate and the proportion of piglets crushed by sows in the free-farrowing pen were higher than in the crate system. Interestingly, a high proportion of piglet preweaning mortality in the free-farrowing system was detected only in sows with high backfat thickness before farrowing but not in those with low and moderate backfat thickness. Therefore, additional management in sows with high backfat thickness (&gt;24 mm) before farrowing should be considered to avoid the crushing of piglets by sows.

251 Effects of Cross-Fostering and Number of Litters Used to Create Cross-Fostered Litters on Piglet Pre-Weaning Mortality and Weaning Weight

Abstract The objective was to determine effects of cross-fostering and number of litters used to create cross-fostered litters on piglet pre-weaning mortality (PWM) and weight. The study was conducted on 2 commercial farrowing facilities using a RCBD (53 blocks; total of 265 litters/3675 piglets). Blocking factors were farrowing day, sow parity, body condition score, functional teat number, and average and CV of piglet birth weight. Treatments involved cross-fostering different percentages of the litter (0% = no cross-fostering; 50% = half cross-fostered, half from the birth sow; 100% = all piglets cross-fostered) and differing number of litters used in cross-fostering. The 5 Treatments were (% fostered/number of litters used): 1) 0%/1 litter; 2) 100%/1 litter; 3) 100%/6+ litters; 4) 50%/4+ litters; 5) 50%/2 litters. Litter sizes at cross-fostering (13 or 14 piglets) were equalized across Treatments within block. Piglets were weighed 24 h after birth (when cross-fostering was carried out) and at weaning (19.2 ± 0.97 d); all PWM was recorded. Data were analyzed using SAS, models accounted for the fixed effect of Treatment and random effects of sow, block, and farm. The 0%/1 litter and 100%/1 litter Treatments were similar (P &amp;gt; 0.05; Table 1) for all measurements, indicating no effect of cross-fostering per se. Litter sizes at 7 and 14 d, and weaning were lower (P ≤ 0.05) for the two 1-litter Treatments compared with the 50%/2 litters Treatment; other Treatments were intermediate. There was no effect (P &amp;gt; 0.05) of Treatment on piglet weight. Pre-weaning mortality was greater (P ≤ 0.05) for the two 1-litter treatments compared with the other 3 Treatments, which were similar (P &amp;gt; 0.05). In conclusion, cross-fostering had no effect on piglet performance, however, PWM was greater for treatments comprised of piglets from a single litter compared with those from several litters.

PSV-20 Effects of Enterid™ in Lactating Sow Diets on Sow and Litter Performance

Abstract A total of 196 sows (parity = 2±1.1; farrowed in 5 groups) were used in this study to evaluate the effects of feeding Enterid™ feed additive (a mixture of prebiotics, probiotics, and flavoring compounds, PMI Additives) on sow and litter performance. On day 109 of gestation, sows were moved to farrowing rooms and assigned to one of two dietary treatments, including: control and control + 0.05% Enterid™. Respective diets were fed to the sows from day 109 of gestation to weaning (weaning age: 19±0.13 day). Sow body weight (BW) and backfat thickness were measured at d 109 of gestation, within 24h after-farrow, and at weaning. Sow feed consumption was recorded daily. Individual pig BW was recorded at birth and weaning. A completely randomized design was used to test the effect of diets and ANOVA was performed with mixed models using MIXED procedure in SAS (SAS 9.4, SAS Inc.). Sows fed Enterid™ numerically had greater weaning body weight (BW; 222 kg vs. 217 kg; P = 0.11) and lost less BW (-1.14 vs. -5.38 kg; P = 0.01) and backfat (+0.5 vs. -1.5 mm, P = 0.02) from farrow to weaning compared to the control. In addition, sows fed Enterid™ numerically had greater total lactation feed intake (127 vs 123 kg; P = 0.13) and ADFI (6.64 vs 6.42 kg; P = 0.17). Enterid™ numerically reduced piglet preweaning mortality by 1% (9.15 vs 10.16%). Data of this study suggests that Enterid™ can provide benefits toward improving performance of sows and reducing mortality of preweaning piglets.

Modeling and Assessing Heat Transfer of Piglet Microclimates

High piglet pre-weaning mortality rates can be attributed to poor creep area microclimate resulting in negative productivity, welfare, and economic consequences. A piglet mechanistic steady-state thermal balance model was developed using previous models and expanded to assess (a) thermal interactions of multiple pigs and (b) conduction heat transfer. The piglet Effective Environment Temperature (EET) equation was also modified to incorporate piglet age (day 0 to 30) and a conduction heat transfer term. Model parameters were validated with empirical data consisting of the thermal component (dry-bulb temperature, Tdb; mean radiant temperature, TMR; airspeed, U; mat underside temperature, Tm) of the microclimate and dimension data of the piglets (i.e., body weight, length, height, width, and calculated surface area). Model results demonstrate that the common microclimate supplemental heat sources (heat mats and heat lamps; HL) can meet the needs of the piglets. The new EET was more consistent for a novel semi-enclosed heated microclimate (SEHM) in comparison to the HL. This demonstrates the benefit of precision technologies over manually adjusted supplemental heat sources. The experimental data and model results suggest further development of an ideal thermal index for piglet microclimates needs to account for variations of piglet health and body condition to be more applicable in industry.

Effect of farrowing pen size on pre-weaning performance of piglets.

Litter sizes in commercial pig production have increased substantially over recent years; however, farrowing pen sizes have generally not changed over the same time period. The objective of this study was to evaluate the effect of farrowing pen size on piglet pre-weaning growth and mortality. Differences in pen size were created by varying the width of pens of the same length, increasing the creep area available to the piglets. The study used a total of 1,786 litters in a randomized complete block design to compare two farrowing pen size treatments (FPS): Standard (pen width 1.52 m) and Increased (pen width 1.68 m). Litter sizes were equalized across treatments (12.9 ± 1.95 piglets) at 24 h after birth using cross-fostering. Litter weights were collected at birth and weaning (21.3 ± 2.08 d); pre-weaning mortality was recorded. The experimental unit was the litter; models for statistical analysis included FPS and replicate. Farrowing pen size had no effect (P > 0.05) on litter size at birth (12.8 and 13.0 for the Standard and Increased FPS, respectively), after cross-fostering (12.9 for both treatments), or at weaning (11.2 and 11.3, respectively). There was no effect (P > 0.05) of FPS on total litter or average piglet weight at birth, after cross-fostering, and at weaning. These results suggest no benefit in piglet performance from increasing the width of farrowing pens. As litter sizes continue to increase in commercial production, further research is warranted to re-evaluate the impact of farrowing pen size on pre-weaning mortality.

92 Effect of Rearing Cross-fostered Piglets in Litters of Differing Within-litter Birth Weight Variation on Pre-weaning Growth and Mortality

Abstract Cross-fostering of piglets is a common commercial practice, however, there is limited information on optimum methods. The objective of this study was to evaluate the effects of within-litter birth weight variation after cross-fostering on piglet pre-weaning mortality (PWM) and growth. A RCBD was used with 47 blocks of 6 litters (total 282 litters/3,948 piglets); blocking factors were farrowing day, sow parity, body condition score, and functional teat number. Piglets were allotted at 24 h after birth according to Birth Weight Category (BWC) [L (&amp;lt; 1.0 kg), M (1.0 to 1.5 kg), or H (1.5 to 2.0 kg)] to 6 Litter Composition (LC) treatments with 14 piglets/litter: Uniform (14 L, M or H); Mixed L+M (7 L, 7 M); Mixed M+H (7 M, 7 H); Mixed L+M+H (3 L, 6 M, 5 H). Piglets were weaned at 18.7 ± 0.64 d and PWM was recorded. Piglet birth and weaning weights were analyzed using PROC MIXED of SAS; PWM were analyzed using PROC GLIMMIX of SAS; models included BWC, LC, the interaction, and sow within block. There were LC by BWC interactions (P &amp;lt; 0.05) for PWM and weaning weights. For L piglets, there was no effect (P &amp;gt; 0.05) of LC on PWM (22.8, 26.7, and 28.4% for Uniform, Mixed L+M, and Mixed L+M+H treatments, respectively). For H piglets, PWM was lower (P &amp;lt; 0.05) in Mixed L+M+H compared to Uniform or Mixed M+H litters (1.7, 9.6, and 5.8%, respectively). For M piglets, PWM was lower (P &amp;lt; 0.05) in Mixed L+M than Uniform or Mixed M+H litters (7.1, 12.2, and 14.6%, respectively); Mixed L+M+H were intermediate (10.0%; P &amp;gt; 0.05). Weaning weights generally followed a similar but opposite pattern for all BWC. In conclusion, increasing the average weight of littermates generally decreased weaning weights and increased PWM within each BWC.

PSIII-1 Effect of Rearing Cross-fostered Piglets in Litters of Differing Size Relative to Sow Functional Teat Number on Pre-weaning Growth and Mortality

Abstract Litter sizes of commercial sows have increased recently, often resulting in the number of piglets exceeding the sow functional teat number. The objective of this study was to determine the effects of litter size after cross-fostering on piglet pre-weaning mortality (PWM) and growth. A RCBD was used with 13 blocks of 3 litters (total 39 litters/561 piglets); blocking factors were farrowing day, sow parity, body condition score, and functional teat number. Three Litter Size treatments (LS) relative to sow functional teat number were compared: Under (2 piglets below); Equal (same number of piglets); Over (2 piglets above). Piglets were weighed 24 h after birth and allotted to LS to create litters with similar gender ratio and average and CV of birth weight. Weaning was at 19.5 ± 0.50 d, weights and PWM were recorded. Piglet weight data were analyzed using PROC MIXED of SAS; PWM data were analyzed using PROC GLIMMIX of SAS. Models included LS and sow within block. Litter sizes averaged 12.1, 14.1, and 16.1 for the Under, Equal, and Over treatments, respectively (P ≤ 0.05). The Under treatment tended (P = 0.07) to have greater weaning weights compared to the Equal and Over treatments (Table 1). The Under treatment had lower (P ≤ 0.05) PWM than the Over treatment, with the Equal treatment being intermediate and not different to the other 2 (P &amp;gt; 0.05; Table 1). In conclusion, reducing litter size after cross-fostering to two piglets below the number of functional teats of the sow decreased PWM and tended to increase weaning weights.

87 Effect of Number of Source Litters Used to Create Cross-fostered Litters on Piglet Pre-weaning Mortality and Weaning Weight

Abstract Sow litter sizes have increased over recent decades, increasing the need for cross-fostering. The objective of this study was to determine the effect of the number of source litters used to create cross-fostered litters on piglet pre-weaning mortality (PWM) and weaning weight. A RCBD was used with 26 blocks of 5 litters (total 130 litters/1820 piglets), all litters consisted of 14 piglets. Blocking factors were farrowing day, sow parity, body condition score, and functional teat number, and the average and CV of piglet birth weight. Five cross-fostering treatments were compared: 0%, 1 source (all piglets remaining on the birth sow); 100%, 1 source (all piglets moved from birth to a different sow); 100%, 6+ sources (piglets from ≥ 6 birth sows used to form a litter on a different sow); 50%, 2 sources (7 piglets remaining with birth sow, 7 from one other sow); 50%, 4+ sources (7 piglets remaining with the birth sow, 7 from ≥ 3 other sows). The single-source litters were selected from those with &amp;gt; 14 piglets at birth, with excess piglets removed. For other treatments, piglets were selected to meet blocking factors. Piglets were weighed 24 h after birth and at weaning (19.5 ± 0.50 d); all PWM was recorded. Weight data were analyzed using PROC MIXED of SAS; PWM data were analyzed using PROC GLIMMIX of SAS. Models included Treatment and sow within block. There was no effect (P &amp;gt; 0.05) of treatment on weaning weights. Pre-weaning mortality was greater (P &amp;lt; 0.05) for the 0%, 1 source compared to the 50%, 2 source treatment, with the others being intermediate and generally not statistically different (Table 1). In conclusion, cross-fostering and/or mixing litters had no effect on weaning weights, but pre-weaning mortality was highest for the non-fostered treatment.

PSVI-2 Rising 10-year Trend in Piglet Pre-weaning Mortality in Breeding Herds Associated with Sow Herd Size and Number of Piglets Born Alive

Abstract The objectives of the present study were to explore the trend in preweaning mortality (PWM) and related measurements such as piglets born alive (PBA), stillborn piglets, herd productivity and herd size in sow herds over a 10-year period; and 2) to examine the relationships between PWM and the related measurements. Herd-level annual data from 2007–2016 for 91 herds in Spain were abstracted from a sow database compiled by a veterinary consultancy firm. The database software automatically calculated herd-level PWM (%) as follows: the total number of piglets born alive to a sow completely weaned during a year (TPBA) minus the total number of piglets weaned by the completely weaned sow during the year divided by TPBA x 100. All the statistical analyses were performed using SAS University Edition. A growth curve model was applied to incorporate correlations for all of the observations arising from the same farm. Herd means of PWM (SD) increased from 11.9 (4.1) % to 14.4 (3.2) %, and mean PBA increased by 1.9 pigs. Mean age of piglet death during lactation increased by 3.8 days, and there was a significant effect of increased year on herd size and the number of piglets weaned per sow per year (PSY; P &amp;lt; 0.05). Higher PWM was associated with more PBA, more stillborn piglets and small herds (lower than the median size: &amp;lt; 570 sows; P &amp;lt; 0.05). Also, as PBA increased from 9 to 14 pigs, PWM in large herds (&amp;gt; 570 sows) increased by only 6.6%, compared with 9.6% in small herds. Furthermore, as PWM decreased from 18 to 8%, herd productivity measured as PSY increased by 2.2 pigs in large herds, but only by 0.6 pigs in small herds. In conclusion, the effect of increased PBA on PWM was alleviated more in large herds than in small herds. Also, the impact of decreased PWM on herd productivity was greater in large herds than in small herds.

Effects of farrowing stall layout and number of heat lamps on sow and piglet behavior

Farrowing stalls are used in the United States swine industry to reduce pre-weaning piglet mortality, enable efficient individual animal management, and decrease facility construction and operating costs. The quantity and quality of space provided for sows and piglets in farrowing stalls are important economic and welfare considerations. To further explore the impacts of farrowing stall space allocation, a large-scale field study was conducted to compare sow and piglet behavior when housed in three farrowing stall layouts (TSL – traditional stall layout, ECSL – expanded creep area stall layout, ESCSL – expanded sow and creep area stall layout) with either one or two heat lamps (1HL and 2HL, respectively). A computer vision system classified posture budgets and behaviors of 322 sows and piglet location for 324 litters. Linear mixed models were developed to compare behavior and piglet pre-weaning mortality metrics between experimental treatments. Results show sows in ESCSL spent more time lying compared to sows in ECSL (p = 0.028) and less time sitting compared to sows in TSL and ECSL (p < 0.01). Sows with the 2HL treatment had an increase in percentage lying (p = 0.017) and a decrease in percentage standing (p = 0.045) compared to sows with the 1HL treatment. Number of piglets, parity, and batch also influenced sow postural behavior (p < 0.05). Sow lying orientation was not impacted by HL treatment. Sow postures and behaviors were influenced by day of lactation (p < 0.001). Piglets with 2HL treatment spent more time in the heated region and less time in the creep and sow regions for all stall layouts on all days of lactation observed (p < 0.001). In the ESCSL, piglets had a greater percentage of time in the sow region compared to ECSL piglets (p < 0.004). Piglets did not spend equal percentages of time between the two creep or two HL regions (p < 0.001), and piglet location was correlated with sow lying orientation for most of the creep regions analyzed (p < 0.01). Increases in piglet pre-weaning mortality were correlated with increases in sow lying (p = 0.027) and decreases in standing (p = 0.025) and feeding (p < 0.001). However, correlations with sow posture were likely due to the impacts of day of lactation (p < 0.001). No correlations were found between piglet location and pre-weaning mortality (p> 0.05). Results can guide producers to consider wider sow areas in farrowing stalls to better meet sow behavioral needs and to include larger heated areas to meet piglet behavioral needs during lactation.

Effect of within-litter birth weight variation after cross-fostering on piglet preweaning growth and mortality.

Cross-fostering is commonly used in commercial swine production to equalize litter sizes and/or adjust piglet birth weights within litters. However, there is limited published information on optimum cross-fostering procedures. This study evaluated the effects of within-litter birth weight variation after cross-fostering (using litters of 14 piglets) on piglet preweaning mortality (PWM) and weaning weight (WW). An RCBD was used (blocking factors were day of farrowing and sow parity, body condition score, and functional teat number) with an incomplete factorial arrangement of the following two treatments: 1) birth weight category (BWC): light (<1.0 kg), medium (1.0 to 1.5 kg), or heavy (1.5 to 2.0 kg); 2) litter composition: uniform, all piglets in the litter of the same BWC [uniform light (14 light piglets); uniform medium (14 medium piglets); uniform heavy (14 heavy piglets)]; mixed, piglets in the litter of two or more BWC [L+M (seven light and seven medium piglets); M+H (seven medium and seven heavy piglets); L+M+H (three light, six medium, and five heavy piglets)]. Piglets were weighed at 24 h after birth and randomly allotted to litter composition treatment from within BWC; all piglets were cross-fostered. There were 47 blocks of six litters (total 282 litters and 3,948 piglets). Weaning weights were collected at 18.7 ± 0.64 d of age; all PWM was recorded. Individual piglet WW and PWM data were analyzed using PROC MIXED and PROC GLIMMIX of SAS, respectively; models included fixed effects of BWC, litter composition, and the interaction, and random effects of sow within the block. There was litter composition by BWC interactions (P ≤ 0.05) for WW and PWM. Within each BWC, WW generally increased and PWM generally decreased as littermate weight decreased. For example, WW was greatest (P ≤ 0.05) for light piglets in uniform light litters, for medium piglets in L+M litters, and for heavy piglets in L+M+H litters. Preweaning mortality was lowest (P ≤ 0.05) for medium piglets in L+M litters, and for heavy piglets in L+M+H litters; however, litter composition had no effect (P > 0.05) on PWM of light piglets. In conclusion, increasing the average birth weight of littermates after cross-fostering generally decreased WW and increased PWM for piglets of all birth weight categories. This implies that the optimum approach to cross-fostering that maximizes piglet preweaning growth and survival is likely to vary depending on the birth weight distribution of the population.

Effect of PRRSV stability on productive parameters in breeding herds of a swine large integrated group in Spain

BackgroundIn breeding herds, porcine reproductive and respiratory syndrome (PRRS) clinically manifests as increased abortions, number of stillbirths, and pre-weaning mortality, and as a direct consequence, results in a decrease of the number of piglets weaned per sow per year. Breeding farm classification according the PRRS virus (PRRSV) status (unstable or stable) is a key control strategy for this disease. The aim of this study was to evaluate the production improvement related to achieving a PRRSV stable status in breeding herds in Spain. For this purpose, epidemiological and productivity data were collected from a systematic PRRSV monitoring program in 35 breeding herds from a large integrated swine group in Spain. A comparative statistical analysis was conducted using four key production indicators (KPI) between different PRRSV status and a generalized linear mixed model: weekly abortions/1000 sows (ABTHS), born-alive rate (BAR), pre-weaning mortality rate (PWMR), and number of weaned piglets per 1000 sows (WPTHS).ResultsFrom the 35 monitored farms during a total period of 58 weeks, we collected 49 to 58 weeks of production data and PRRSV classification status for each study farm. This represented a total of 1997 (741 unstable and 1256 stable) weekly data collected that was eligible for the KPI comparative study. PRRSV stability was associated with significant improvement in BAR (+ 1.10 %, p < 0.001), PWMR (-0.88 %, p < 0.002) and WPTHS (+ 24.52, p < 0.0001).ConclusionsThese results demonstrate for the first time the improved production due to achieving PRRSV stability in breeding herds under field conditions in a European country. Increased number of born-alive piglets and a reduction of piglet pre-weaning mortality represents an increase of 1.28 weaned piglets per sow per year if PRRSV stability was achieved and maintained for one-year period in a breeding farm.

A 10-year trend in piglet pre-weaning mortality in breeding herds associated with sow herd size and number of piglets born alive

BackgroundPiglet pre-weaning mortality (PWM) is one of the biggest problems regarding sow performance and piglet welfare. Recently, PWM has increased in some countries, but it is not known if there are similar increases in other countries, nor whether increased PWM is related to either increased numbers of piglets born alive (PBA) or to sow herd size. So, the objectives of the present study were 1) to explore the trend in PWM in Spanish sow herds over a recent 10-year period, along with related measurements such as PBA, stillborn piglets, herd productivity and herd size; and 2) to examine the relationships between PWM and the related measurements.MethodsHerd-level annual data from 2007 to 2016 for 91 herds in Spain were abstracted from a sow database compiled by a veterinary consultancy firm that asked client producers to mail data files on a regular basis. The database software automatically calculated herd-level PWM (%) as follows: the total number of piglets born alive to a sow completely weaned during a year (TPBA) minus the total number of piglets weaned by the completely weaned sow during the year divided by TPBA × 100. All the statistical analyses were performed by using SAS University Edition. A growth curve model was applied to incorporate correlations for all of the observations arising from the same farm.ResultsOver the 10 years, herd means of PWM (standard deviation) increased from 11.9 (4.1) % to 14.4 (3.2) %, and mean PBA increased by 1.9 pigs. Mean age of piglet death during lactation increased by 3.8 days, and later years were significantly associated with herd size and the number of piglets weaned per sow per year (PSY; P < 0.05). Higher PWM was associated with more PBA, more stillborn piglets and small-to-mid herds (lower than the median size: < 570 sows; P < 0.05). Also, there was a significant interaction between the herd size groups and PBA for PWM (P < 0.05): as PBA increased from 9 to 14 pigs, PWM increased by 9.6% in small-to-mid herds, compared with an increase of only 6.6% in large herds (> 570 sows). Furthermore, as PWM decreased from 18 to 8%, herd productivity measured as PSY increased by 2.2 pigs in large herds, compared with only 0.6 pigs in small-to-mid herds.ConclusionLarge herds were better than small-to-mid herds at alleviating the association between increased PBA and increased PWM. Also, the relationship between decreased PWM and increased herd productivity was improved more in large herds than in small-to-mid herds.

Effect of rearing cross-fostered piglets in litters of either uniform or mixed birth weights on preweaning growth and mortality.

Cross-fostering is a practice commonly used in the swine industry to equalize litter sizes, however, there is limited understanding of the optimum cross-fostering methods that will maximize piglet preweaning growth and survival. This study evaluated the effects of within-litter variation in birth weight after cross-fostering on piglet preweaning mortality (PWM) and weaning weight (WW) using litters of 15 piglets. A hierarchical incomplete block design was used (blocking factors: day of farrowing and sow parity, body condition score, and number of functional teats) with a 3 × 2 factorial arrangement of treatments: 1) Birth Weight Category (BWC): Light (<1.0 kg), Medium (1.0 to 1.5 kg), or Heavy (1.5 to 2.0 kg); 2) Litter Composition: UNIFORM (all 15 piglets in each litter of the same BWC), or MIXED (five piglets in each litter from each BWC, i.e., five Light, five Medium, and five Heavy piglets). At 24 h after birth, piglets were weighed and randomly allotted to litter composition treatments from within BWC. The experimental unit was five piglets of the same BWC; there were three experimental units within each Litter Composition treatment litter. There were 17 blocks, each of six litters (one UNIFORM litter of each BWC; three MIXED litters) and 51 replicates (three replicates per block of six litters) for a total of 102 cross-fostered litters and 1,530 piglets. Piglets were weaned at 19.7 ± 0.46 d of age; WW and PWM were measured. PROC GLIMMIX and MIXED of SAS were used to analyze PWM and WW, respectively. Models included BWC, Litter Composition, the interaction, and replicate within the block. There were BWC by Litter Composition treatment interactions (P ≤ 0.05) for PWM and WW. Preweaning mortality was greater (P ≤ 0.05) for Light piglets in MIXED than UNIFORM litters. In contrast, for Heavy piglets, PWM was greater (P ≤ 0.05) and WW was lower (P ≤ 0.05) in UNIFORM than MIXED litters. Medium piglets had similar (P > 0.05) PWM and WW in UNIFORM and MIXED litters. The results of this study, which involved large litter sizes typical of current commercial production, suggested that for piglet survival to weaning, using cross-fostering to form litters of piglets of similar birth weight was beneficial for light piglets, detrimental for heavy piglets, and neutral for medium piglets.

85 The effect of drying and warming piglets at birth on pre-weaning mortality

Abstract Piglets are susceptible to chilling early after birth, which is a major pre-disposing factor for pre-weaning mortality (PWM). This study evaluated the effect of drying and warming piglets at birth on PWM at a commercial facility. A CRD was used with 802 sows (litters), allotted at start of farrowing to 2 treatments (applied at birth): Control (no treatment); Dried+Warmed (dried with a cellulose-based desiccant and warmed in a heated box for 30 min). Piglets were weighed at birth and weaning; PWM was recorded. The effects of farrowing room temperature on PWM were evaluated by classifying litters as being born under Cool or Warm conditions (&amp;lt; 25° C and ≥ 25°C, respectively). Similarly, effects of birth weight on PWM were evaluated by classifying piglets into 3 Birth Weight Categories (BWC; &amp;lt; 1.0 kg, 1.0-1.5 kg, or &amp;gt; 1.5 kg). PROC GLIMMIX and MIXED of SAS were used to analyze PWM and other data, respectively. Litter was the experimental unit; piglet a subsample of litter. The model included fixed effects of treatment, and farrowing room temperature or BWC as appropriate, and the random effect of piglet within litter. Rectal temperature at 30 min after birth, measured on a sub-sample of 10% of litters, was greater (P &amp;lt; 0.05) for the Dried+Warmed than the Control treatment. There was no effect (P &amp;gt; 0.05) of drying and warming piglets on weaning weight or overall PWM. Additionally, PWM was similar across treatments within each BWC. However, the Dried+Warmed treatment reduced (P &amp;lt; 0.05) PWM compared to the Control under Cool but not Warm farrowing room temperatures. In conclusion, this suggests that drying and warming piglets at birth increases rectal temperature and may be an effective method to reduce piglet PWM under cooler farrowing room temperatures. This research was funded by the National Pork Board.

Effect of RNF4-SacII gene polymorphism on reproductive traits of Landrace × Large White crossbred sows.

The aim of the present study was to investigate whether and to what extent the RNF4-SacII gene polymorphism influences reproduction performances in hyperprolific sow lines. The study involved 101 Landrace x Large White crossbred sows, with 461 records collected on the following reproductive traits: Total Number of piglets Born per litter (TNB), Number of piglets Born Alive per litter (NBA), Number of StillBorn piglets per litter (NSB), piglet Pre-Weaning Mortality (PWM) and Number of piglets at Weaning per litter (NW). The least square method with the GLM procedure in SAS with eight effects was used to pursue the data analysis. Study results revealed that TT homozygotes and TC heterozygotes had a significantly higher (p<.05) NW than CC homozygotes for the life-span performance in all parities and first parity analysed. In the fourth parity analysed, TNB and NBA in TC genotype were significantly higher (p<.05) as compared with TT genotype. Based on the life-span performance, significant effect (p<.05) was recorded for order of parity on TNB, NBA and NW, for farrowing season on TNB and NSB, and for lactation length on PWM. In the second parity, significant effect (p<.05) was recorded for sire of boar on NSB and for gestation length on TNB. Only in the fourth parity, significant effect (p<.05) of RNF4 gene was observed on NBA. There was significant additive effect (p<.05) of the RNF4 gene polymorphism identified on NW in all parities analysed, and significant additive and dominance effects (p<.05) on NSB in the third parity analysed. In conclusion, additional research on related production pig genotypes is necessary to elucidate the effect of RNF4 gene mutation on reproductive traits.

Effect of parity number, year and season farrowing on reproductive performance in Large White pigs

This study examines certain identifiable non-genetic sources of variation (parity number, year and season farrowing) for their effects on Large White sow litter performance traits, such as litter size, mortality and weight of piglets at birth and at weaning. The population used for the present study is from a pig farm managed by Tavriys’ki svyni, LLC, located in Skadovsky district (Kherson Oblast, Ukraine). Reproductive performance records on 280 Large White (LW) sows were used. A total of 633 litters were farrowed from January 2007 to July 2017. The litter records included information on the total number of piglets born (TNB), number of piglets born alive (NBA), number of stillborn piglets (NSB), frequency of stillborn piglets (FSB), average weight of piglets at birth (AWPB), litter size at weaning (NW), piglet pre-weaning mortality (PWM) and average weight of piglets at weaning (AWPW). To determine the effect of parity number, year and month farrowing on reproductive performance traits, the analysis of variance (ANOVA) was used. Results obtained showed significant influence of parity number on most of the reproductive parameters studied, apart from AWPB, PWM and AWPW. The total litter size at birth was the lowest in primiparous sows and in cases second-parity sows, but significantly exceeded the overall average population estimation during the fourth-sixth parities farrowing. The least squares estimates of the mortality rate of piglets at birth were significantly lower than in second parity sows, however they significantly increased in sows at eighth parity. The year of the sow's farrowing had the most significant influence on the weight of piglets at birth and at weaning. Moreover, a clear upward trend can be noted in relation to the weight of piglets at birth, which is accompanied by a gradual increase of the corresponding least squares estimates during 2007-2015. Late summer and early autumn (August-October) are the seasons when the litter size traits in the LW sows consistently show the lowest values, indicating a ‘seasonal infertility period’. Thus, all the analysis performed in the present work shows that in the LW sows, as in other pig breeds, the parity number, year and season farrowing influence the reproductive and developmental processes.

Higher light intensity and mat temperature attract piglets to creep areas in farrowing pens

Loose farrowing pens have been considered as alternatives to crates to enhance sow welfare. A major concern with pen systems is often higher piglet pre-weaning mortality, especially due to crushing by the sow. An optimal management of light and mat surface temperature may promote greater piglet use of the creep, which has been associated with reduced piglet crushing. A total of 108 sows and their piglets were studied in sow welfare and piglet protection pens on a commercial piggery, across two replicates. Sows were randomly assigned to pens arranged within two creep treatments (bright creep: 300 lx v. dark creep: 4 lx), considering mat temperature as a covariate. Twelve sows and their litters in each treatment (24 in total) had their behaviour continuously recorded for 72-h postpartum (pp), and four focal piglets per litter were weighed on the first and third days pp. In situ behaviour observations were performed daily (from 0800 to 1700 h) on all sows and their litters, every 15 min over 72-h pp to record piglet time spent in the creep, latency to enter the creep for the first time, latency for the litter to remain in the creep for at least 10 min, and piglet and sow use of pen areas immediately in front of (A2) and farthest from the creep (A3). Piglets with access to bright creeps spent on average 7.2% more time (P<0.01) in the creeps than piglets in pens with Dark creeps. In addition, for each degree increase in mat temperature, piglets spent on average 2.1% more time (P<0.01) in the creep. Piglets in pens with bright creeps spent less time in A2 (P=0.04) and the least time in A3 (P=0.01). Light or mat temperature did not affect sow use of pen areas or piglet weight gain. Piglets with bright creeps tended (P=0.06) to take longer to enter the creep for the first time after birth, but the latency for 30.0% of the litter to remain clustered for 10 min tended (P=0.08) to be shorter in bright compared to dark creeps. Overall, piglet use of the creep increased with warm mat temperatures and brightness, which should be further investigated as potential strategies to promote piglet safety and reduce crushing in pen farrowing systems.