Piglet Survival Research Articles

Growth intensity and fattening qualities of pigs during changes in feeding types during reproduction and fattening

The article presents the results of studying the dependence of fattening qualities of pigs on the type of feeding during rearing and fattening and its change during these two periods. It is proved that the dynamics of pig growth depended on the type of feeding and its changes. In the first third of the experiment, live weight of piglets with liquid type of feeding was added more intensively. In the second third of the experiment (70–120 days) animals with the same type of feeding were characterized by more intensive growth compared to analogues in which the type of feeding was changed to alternative. In the final third of fattening, this trend persisted. It was determined that the best growth dynamics throughout the experiment was demonstrated by pigs with constant liquid feeding, and the worst was demonstrated by changes in liquid to dry feeding. Animals with constant types of feeding during the experiment grew more intensively compared to their counterparts, in which the type of feeding was changed to alternative. It was found that piglets with liquid type of feeding had during average rearing by 6.1 % higher average daily and absolute and 2.4 % relative gains, 4.4 % higher weight of animals at the end of rearing. Pigs consumed 11.5 % more feed per head per day, but had a 5.1 % worse feed payment in increments and 1.0 % worse piglet survival during the rearing period. It is proved that the change of feeding types from dry to liquid and from liquid to dry negatively affected the growth and fattening qualities of pigs. It was found that during the period of fattening animals with constant type of feeding prevailed analogues with variable type of feeding on the preservation of pigs during fattening by 0.5 %, on average daily gains in this period by 9.0 %, in absolute gains on fattening by 7.3 %. Pigs reached a commodity weight of 120 kg by 7.2 days (4.3 %) faster, ate 4.3 % more feed per day, had a better 2.4 % feed conversion and found an 18.4 % better complex index fattening qualities. The best fattening indicators during the fattening period were pigs with constant liquid type of feeding, while the worst were when changing the liquid type of feeding to dry during fattening. It is proved that for the whole period of research pigs with constant type of feeding had advantages over analogues, in which the type of feeding changed during the experiment on the preservation of animals by 0.5 %, average daily gain of 6.6 %, absolute gain of 6.3 %, ate 4.3 % more feed per day, but had 2.7 % worse feed conversion. The best fattening indicators during the whole period of the experiment were found in pigs with constant liquid type of feeding, and the worst when changing the liquid type of feeding during rearing to dry during fattening. It is proved that the type of feeding affected the growth dynamics, preservation and fattening qualities of pigs of the final hybrid of English origin, that with liquid type of feeding the growth rate of pigs exceeded that of dry analogues fattening qualities. The most significant deterioration in growth occurred with changes in the liquid type of feeding during rearing to the dry type for fattening.

Genetic variation in piglet mortality in outdoor organic production systems

Piglet mortality from farrowing to weaning is a major concern, especially in outdoor organic production systems. This issue might impair animal welfare and generate economic losses for the farmer. In particular, it is difficult to apply management tools that are commonly used for indoor pig production systems to organic or outdoor production systems. Genetics and breeding approaches might be used to improve piglet survival. However, knowledge remains limited on the genetic background underlying survival traits in organic pigs that are born and reared outdoors. Here, we investigated the mortality of piglets from farrowing to weaning in an outdoor organic pig population and suggested genetic strategies to reduce piglet mortality in this production system. The experiment included mortality records of piglets from farrowing to weaning (around 69 days of age). Pedigree-based threshold models were used to analyse the mortality traits of piglets at 0–3 days of age, 4–11 days, and 12 days to weaning. Stillborn piglets were included in the group of piglets that died at 0–3 days of age. We found that the mortality rate from farrowing to weaning was, on average, 19.2%. However, most piglet deaths (79.1%) occurred at 0–11 days of age. As the age of piglets increased, the direct heritability of piglet mortality rose from 0 to 0.04, whereas maternal heritability decreased from 0.03 to a non-significant value. Piglets with higher BW had a lower mortality rate. However, the genetic correlations between maternal effects on piglet mortality and piglet BW were not significant; thus, selection for piglets with higher BW at around 10 days of age, through improving maternal genetics, would not reduce piglet mortality. Piglet mortality increased from sows with increasing number of parities. Crossbreeding also reduced piglet mortality. In conclusion, selection focusing on sow genotype, the use of younger sows, and crossbreeding could contribute to maintain piglet mortality at lower levels in outdoor organic pig production systems.

118 Awardee Talk: An Empirical Model of Essential Amino Acid Requirements in the Pregnant Sow

Abstract Amino acid (AA) requirements are generally considered to be the minimum needed for maximum growth or protein synthesis; however, multiple studies have shown that AA intakes above these requirements improve various body functions such as immune response, gut health, and reproduction. The objective of the current modeling approach was to estimate AA intake in gestation that considered protein synthesis as well as sow reproductive performance and offspring development, potentially increasing piglet growth and survivability. A literature review was conducted to identify studies evaluating the effects of sow AA intake during gestation on protein synthesis, sow body weight, litter size, average piglet birth weight and suckling piglet growth rate. Data from 26 empirical studies from 1989 to 2021 were selected for model development and estimation of arginine, leucine, lysine, methionine, threonine, and valine requirements. To check model accuracy and performance, a validation analysis was conducted by contrasting the model predicted lysine requirements with data from 17 published studies not used in the development of the model. The estimated lysine requirement was approximately 40% greater than the minimum lysine intake required for maximum protein synthesis. Similarly, the ratios of arginine, leucine, methionine, and valine to lysine were on average 1.60, 2.47, 0.41, and 0.79, respectively, which are 6 to 300% greater than, and the ratio of threonine to lysine was similar to, current recommendations. The validation analysis showed that the estimated lysine requirement resulted in the greatest litter size and birth weight. In addition, when compared with lysine intakes that met current recommendations, lysine intake at the estimated requirement improved colostrum and milk quality, stillborn rate, proportion of low birth weight, suckling piglet growth rate, and sow blood urea, among other metabolic variables. In conclusion, at the estimated requirements sow reproductive performance as well as piglet survivability and growth rate are improved.

150 Impact of Prefarrow Feeding Strategy on Farrowing Duration and Piglet Survival

Abstract The objective of the study was to evaluate the impact of prefarrow feeding strategies on sow farrowing duration and percentage of stillborn piglets. Sows (n = 215) were farrowed at a commercial sow farm in eastern North Carolina. Genetics of the sows were PIC. Farrowing rooms were curtain sided with natural ventilation. Sows were randomly allocated to 1 of 3 prefarrow feeding strategies. Upon entering a farrowing stall, sows were fed either 2.27kg in the morning (Control), 1.14kg in the morning and 1.14kg in the evening (TWICE) or 2.27kg in the morning top dressed with 50g of TransRite Sow Ultra (CaCl). Sows started dietary treatments and farrowed, on average, d 112.6 and d 115.6 of gestation, respectively. Data were analyzed in SAS using PROC GLM. Statistical models contained prefarrow feeding strategy and parity as fixed effects and total number born was included as a covariate. Average total number born, number born alive and stillborns were 15.42, 14.16 and 1.26 piglets, respectively. Farrowing duration differed (P < .01) between treatments. Both TWICE and CaCl had shorter (P < .05) farrowing duration than Control sows (4:51 and 5:26 vs. 6:49, respectively). First parity sows had shorter (P < 0.05) farrowing duration than multiparous sows (4:23 vs. 6:08). Sows fed CaCl had a lower (P < 0.05) percentage of stillborns when compared with Control sows (6.1 vs. 9.2%) while TWICE did not differ (P > 0.05) from CaCl or Control (7.3% stillborns). An increase of 1 piglet in total number born increased (P < 0.05) percent stillborns by .24%. Results suggest either TWICE or CaCl could be used to reduce farrowing duration, perhaps reducing the need for farrowing assistance and allowing for improved farm labor efficiency. Funding for this project was provided by the Swine Research and Education Experience through the U.S. Pork Center of Excellence.

246 Awardee Talk: Evaluating the Impact of Essential Fatty Acids in Lactation Diets on Sow and Litter Performance

Abstract Two experiments were conducted to evaluate the effects of supplemental fat sources providing low and high essential fatty acids (EFA) in lactation diets on sow reproductive performance, piglet growth and survivability, and colostrum and milk composition. In Exp. 1, mixed parity sows (n = 91) were allotted to 5 experimental treatments arranged in a 2×2 + 1 factorial. Treatments were corn-soybean meal-based diets that contained no added fat or diets with 3% added fat as either beef tallow or soybean oil starting on d 107 or 112 of gestation. Sows were provided low EFA [linoleic acid (LA) and α-linolenic acid (ALA)] in diets without supplemental fat or with beef tallow or high EFA with soybean oil. Results confirmed that providing fat sources with high EFA can increase colostrum and milk LA and ALA content, regardless of pre-farrow time of diet consumption. However, supplemental fat did not influence litter growth performance (P > 0.05). In Exp. 2, mixed parity sows (n = 3,451) were assigned to 4 corn-soybean meal-wheat-based lactation diets with 0.5 (Control) or 3% choice white grease (CWG), 3% soybean oil (SO), or a combination of 3% soybean oil and 2% choice white grease (Combination) at d 112 of gestation to provide diets with low or high EFA. Lactation ADFI increased (P < 0.05) for sows fed the Combination and CWG diets compared with sows fed the Control or SO diet. Sows fed Combination and SO diets had greater (P < 0.05) LA and ALA intake, LA and ALA in colostrum and milk, litter weaning weights, and litter ADG than sows fed 0.5 or 3% CWG. Sow EFA intake did not affect (P > 0.10) piglet survivability or subsequent sow reproductive performance. In conclusion, increased LA and ALA intake provided by SO during lactation increased overall litter growth and weaning weights but did not affect piglet survivability or subsequent performance.

65 Evaluation of Essential Fatty Acids in Lactating Sow Diets on Sow Reproductive Performance, Colostrum and Milk Composition, and Pre-Weaning Litter Growth and Survivability

Abstract Mixed parity sows (n = 3,451; PIC, Hendersonville, TN) and their litters were used to evaluate the effects of essential fatty acid (EFA) intake on sow reproductive performance, piglet growth and survivability, and colostrum and milk composition. At approximately d 112 of gestation, sows were randomly assigned to 1 of 4 corn-soybean meal-wheat-based lactation diets with 0.5 (Control) or 3% choice white grease (CWG), 3% soybean oil (SO), or a combination of 3% soybean oil and 2% choice white grease (Combination). Thus, sows were provided diets with low EFA [linoleic acid (LA) and α-linolenic acid (ALA)] in diets with CWG or high EFA in diets with SO. Lactation ADFI increased (P < 0.05) for sows fed the Combination and CWG diets compared with sows fed the Control or SO diet. Daily LA and ALA intake of sows fed the Combination and SO diets were greater (P < 0.05) than sows fed 0.5 or 3% CWG. Overall, sows consuming high EFA from the Combination or SO diets produced litters with heavier (P < 0.05) piglet weaning weights and greater (P < 0.05) litter ADG when compared with litters from sows fed diets with low EFA provided through CWG. There was no effect of sow EFA intake on piglet survivability (P > 0.10). Lactation diet EFA concentration did not influence colostrum or milk dry matter, crude protein, or crude fat content (P>0.10). However, LA and ALA content in colostrum and milk at weaning increased (P < 0.05) in response to elevated dietary EFA from SO. There was no evidence for differences (P > 0.10) in subsequent sow reproductive or litter performance due to previous lactation EFA intake. In conclusion, increased LA and ALA intake provided by SO during lactation increased overall litter growth and pig weaning weights but did not affect piglet survivability or subsequent performance.

PSV-18 Time Since Last Meal Until the Onset of Farrowing Affects Survivability of Newborn Piglets

Abstract The present study aimed to investigate whether time since last meal until the onset of farrowing affects sow reproductive performance. The results are based on data records compiled from 8 batches for a total of 660 mixed parity (µ = 3.7) sows from the same commercial farm. All sows were fed standard lactation diets twice a day (7:30 AM and 4:30 PM) 1 week before expected farrowing. Time since last meal until the onset of farrowing and farrowing duration were calculated accordingly. Based on the time from the start of last meal to the onset of farrowing, sows were divided into three groups: 0-3 hours, 3-6 hours and 6-16 hours (212, 220 and 228 sows respectively). Probability of born alive, stillborn and mummified piglets were statistically analyzed by a binomial model in R. Farrowing duration of sow was not affected by time since last meal until the onset of farrowing. However, sows farrowed 3-6 hours after feeding had lowest probability of stillborn piglet compared with sows farrowed 0-3 hour and 6-16 hour after feeding (6% vs 8% and 10%; P < 0.01), greater probability of born alive was also found in sows in 3-6 hour group than the other 2 groups (92% vs 89% and 88%; P < 0.01). The probability of mummified piglet was not affected when comparing the three groups. Time since last meal until the onset of farrowing also showed no effect on litter size or litter birth weight. In conclusion, feeding sows the last meal 3-6 hours before farrowing may help improve live born and decrease stillborn piglets.

122 Timing of Dietary Zinc Additions During Gestation for Improved Piglet Survival

Abstract Gestating sows (n = 267) were used to determine if timing of feeding elevated dietary zinc in a commercial setting would reduce pre-weaning mortality of piglets. Sows from 3 consecutive weekly farrowing groups were assigned randomly within parity to 1 of 3 treatments consisting of: 1) Control: a corn-soybean meal diet containing 125 ppm supplemental Zn supplied by zinc hydroxychloride; 2) Breed-to-Farrow (B-to-F): as Control + 141 ppm supplemental Zn as ZnSO4 (266 ppm total supplemental Zn) fed from 5 d after breeding to farrowing; and 3) Day 110-to-Farrow (D110-to-F): as Control diet fed from breeding to farrowing + 2,715 ppm supplemental Zn as ZnSO4 (2,840 ppm total supplemental Zn) starting on d 110 of gestation until farrowing. The statistical model considered fixed effects of treatment, farrowing group, and the random effect of their interaction. Dietary treatments did not influence number of total pigs born or pigs weaned per litter (Table). No differences were observed for any piglet growth criteria evaluated across treatments (P > 0.05). For B-to-F sows, there was an increase in percent of pigs born alive compared with Control and D110-to-F sows (P = 0.002). Percentage of stillborn pigs tended to decrease for sows assigned to the B-to-F treatment (P = 0.052) compared with Control or D110-to-F sows. Feeding elevated zinc throughout gestation increased (P = 0.015) percentage of low-birth-weight pigs born alive compared with Control sows. Mortality of low-birth-weight piglets did not differ among treatments (P = 0.592). However, a trend for decreasing post-natal mortality (P = 0.065) of normal birth weight pigs was observed for pigs born to sows fed elevated zinc. The incidence of low-birth-weight pigs was higher (P < 0.001) for sows fed the D110-to-F treatment compared with Control sows. Overall, feeding elevated zinc to sows throughout gestation increased the proportion of pigs born alive and marginally increased survival of normal birth weight pigs.

124 Early Microbiome Development for Gut Health: Intrinsic and Extrinsic Drivers

Abstract The gut microbiome, the collection of bacteria, fungi, virus and protozoa that inhabit the pig gastrointestinal tract, is promptly acquired at birth. During this seeding process, maternal and environmental microbial sources have a fundamental role, further modulated by nutritional and management interventions applied to both sow and piglet. Simultaneously, early microbiome seeding has significant impacts on the physiological landscape of the piglet gastrointestinal tract. In this talk, we will address the importance of diverse intrinsic and extrinsic factors, including nutrition, environment and sow physiology, in shaping early microbiome colonization and specific gut health traits in young pigs. Specifically, we propose that early microbiome development, including strategies for its manipulation, could potentially impact piglet survivability, immune function, pathogen susceptibility, digestion, absorption and overall well-being. We propose that, although some of these microbiome-mediated effects may be transient, others can be long lasting, possibly affecting health and productive performance along the life course. We propose that a microbiome lens could potentially contribute to better understanding health and performance in young pigs, by bridging basic and applied nutrition research.

Effect of Dexamethasone and Route of Administration on Sow Farrowing Behaviours, Piglet Delivery and Litter Performance.

Simple SummaryThe pain experienced during labor is one that is shared universally. When sows experience the pain of labor for the first time, the levels of discomfort can be so stressful that they lash out aggressively at their piglets. Sows new to the birthing experience may also have problems with delivery or resist nursing the litter for extended periods of time. To help younger sows during and after delivery, we treated a group with dexamethasone, a strong anti-inflammatory treatment. It was predicted that this anti-inflammatory would be able to provide some relief from the inflammatory pain associated with labor and help younger sows with their birthing processes and nursing of their litter. As a hormone that can easily pass through cell walls, it was also predicted that dexamethasone could pass directly through the vaginal membrane of a sow for a non-injectable treatment alternative.The inflammatory pain and stress some crated sows experience during farrowing has attendant risks of piglet-directed aggression, reduced teat exposure and hindered post-partum recovery. To counter this, the steroidal anti-inflammatory compound, dexamethasone, can be administered. To measure the potential for mucosal absorption as an alternative to injection, the permeability of porcine vaginal mucosa to dexamethasone was demonstrated using Franz cell diffusion. These studies found dexamethasone treatment diffused through vaginal mucosa at a constant rate, with 52.37 ± 5.54% permeation in 6 h. To examine in vivo effects on farrowing outcomes, dexamethasone was administered to gilts and parity one sows on the day of expected farrowing. We hypothesized that it would provide relief from farrowing discomfort and reduce behaviours threatening piglet survival. Sows were randomly assigned to receive dexamethasone as an intramuscular injection (n = 23); dexamethasone applied topically into the vagina (n = 20), or to receive no dexamethasone (n = 23). Sows (n = 66) and piglets (n = 593) were monitored for performance indicators during farrowing and early lactation. A subset of sows (n = 24) was also video monitored continuously over 24 h for behaviours associated with pain, postural changes and piglet interactions. No differences were observed between treatment for farrowing performance, piglet survival or behavioural changes for sows experiencing their first or second farrowing (p > 0.05), rejecting the hypothesis that corticosteroid administration will improve sow farrowing performance. This investigation did, however, show that dexamethasone can permeate through porcine vaginal mucosa and so can be administered as a non-injectable treatment.

The Effect of Lift Crates on Piglet Survival Rate and Sow Stress Level during Farrowing.

Simple SummaryIn intensive farms, the mortality of newborn piglets during farrowing is a critical aspect that represents a significant cause of economic loss in pig production, and the deaths, representing 5–25% of newborn piglets, depend mainly on starvation and crushing. In the present study, we aimed to determine the effect of lift farrowing crates on piglet mortality by crushing and on sow welfare. Eighty-four sows of the same genetics were observed over three sessions for one year. Twenty-eight sows per session were randomly assigned to a room equipped with conventional crates or lift crates. No primiparous sows were considered in the study to avoid sows unexperienced with the dynamics of lift crates. The farm’s veterinarian assessed the number of crushed piglets within 48 h, 72 h, and at weaning. Hair cortisol concentration (HCC) was measured at the entry and the exit from farrowing to evaluate stress level variation. Feet diseases and backfat thickness were evaluated to assess sows’ potential diseases induced by lift crates and metabolic problems. The results show that the number of crushed piglets per sow was higher in the conventional crate rooms than the lift crate ones. Mean values of HCC variation in sows during farrowing were significantly different in the two housing systems and higher for the lift crate-housed sows. No significant differences were detected for backfat variation and feet disease scoring. In conclusion, sows housed in the lift crates evidenced an increase in hair cortisol values during farrowing, probably reflecting a higher stress status induced by the lift crate.In the present study, we aimed to determine the effect of lift farrowing crates on piglet mortality by crushing and on sow welfare. Eighty-four sows were considered in the one-year experiment in three monitoring sessions. In each session, 14 sows were housed in a room with conventional crates (CC), and 14 sows were lodged in a room equipped with lift crates (LC). The sows, of the same genetics, with parity ranging from 2 to 9, were randomly distributed in CC and LC rooms. No primiparous sows were considered in the study to avoid sows unexperienced with the dynamics of lift crates. The numbers of crushed piglets, assessed by the farm’s veterinarian, within 48 h, 72 h, and at weaning (28th day), were recorded. Hair cortisol concentration (HCC) was measured upon entry and exit from farrowing to evaluate stress level variation. Feet diseases and backfat thickness were evaluated to assess sows’ potential diseases induced by lift crates and metabolic problems. The results show that the number of crushed piglets per sow was higher in the CC rooms than in the LC rooms in the first two days after delivery (0.39 vs. 0.15, p < 0.05) and up to weaning (0.50 vs. 0.37; p < 0.05). Mean values of HCC variation in sows during farrowing were significantly different in the two housing systems and higher for the LC sows (0.53 pg/mg vs. 0.22 pg/mg; p < 0.05). No significant differences were detected for backfat variation and feet disease scoring between LC and CC sows. In conclusion, LC sows evidenced an increase in hair cortisol values during farrowing, probably caused by a higher stress status induced by the lift crate, along with the benefit of the higher survival rate of piglets before weaning.

JAKOS´ C ENERGETYCZNA, IMMUNOLOGICZNA I AMINOKWASOWA SIARY MACIORY – PRZEGL ˛AD

Along the increasing number of live born piglets in a litter, which reduce the newborn live weight, plays the colostrum nutritional quality an essential role to the survival of newborn piglets. Concentration of colostrum nutrients is affected with several factors from which the time from the start of parturition has the greatest impact. On the second place is nutrition of pregnant sows. A lot of scientific articles were published with the goal to describe sow's colostrum nutrients. In this review we would bring closer look on the sow's colostrum, where the concentration of energy, immunoglobulins and amino acids are the main determinants for successful survive of piglets first days of life.

Piglet Morphology: Indicators of Neonatal Viability?

Simple SummaryEarly identification of poor-performing and non-viable piglets is important for effective interventions. Weight has been the consistently used indicator of likely survival in commercial production. We found that piglet survival increased with increasing abdominal circumference (girth) and crown to rump length. When a piglet was proportionately long and wide, they were more likely to be heavier at 24 h and survive until weaning, unless they were a small piglet. Small piglets that were disproportionate were more likely to survive than the proportionate small piglets, especially when they consumed more than 200 g of colostrum. We suggest that the girth and length of the piglet should be used when making production decisions for small piglets.The morphological measures, crown-to-rump length (CR), and abdominal circumference (AC) have been suggested to be as good, if not better, than birth weight for predicting piglet performance. We explored the relationships between CR and AC, and piglet weights at birth and 24 h, to investigate their predictive value for piglet survival. Piglet weight and AC at birth and 24 h, and CR at 24 h were recorded for 373 piglets born to 31 sows. Morphological measures were categorised into two levels for weight and three levels for AC and CR. Further, AC and CR groupings were concatenated to create a new variable (PigProp) to describe the proportionality of piglet morphology. Proportionate piglets had equal CR and AC levels, and disproportionate piglets had contrasting levels. Birth AC was a good predictor of colostrum intake (p < 0.001) when accounting for birth weight, but 24 h weight and PigProp were good indicators of actual colostrum intake (p < 0.001 for both). The significant interaction of colostrum and PigProp showed that within the smaller piglet groups, those who had greater than 200 g of colostrum had higher 24 h weight and survival (p < 0.001 both). As expected, as body weight and colostrum intake increased, so did weight change to d 21 (P = 0.03 and trend at p = 0.1, respectively). A similar pattern was seen with increasing PigProp group (p < 0.001); however, piglets from the disproportionate group 1,3 had the greatest observed weight change (5.15 ± 0.06 kg). Our data show morphological measures may be more predictive of piglet viability in terms of both performance and survival than weight and there may be subgroups that have higher than expected chances of survival.

Heritability and genetic correlation estimates of semen production traits with litter traits and pork production traits in purebred Duroc pigs.

We estimated heritabilities of semen production traits and their genetic correlations with litter traits and pork production traits in purebred Duroc pigs. Semen production traits were semen volume, sperm concentration, proportion of morphologically normal sperms, total number of sperm, and total number of morphologically normal sperm. Litter traits at farrowing were total number born, number born alive, number stillborn, total litter weight at birth, mean litter weight at birth, and piglet survival rate at birth. Litter traits at weaning were litter size at weaning, total litter weight at weaning, mean litter weight at weaning, and piglet survival rate from birth to weaning. Pork production traits were average daily gain, backfat thickness, and loin muscle area. We analyzed 45,913 semen collection records of 896 boars, 6,950 farrowing performance records of 1,400 sows, 2,237 weaning performance records of 586 sows, and individual growth performance records of 9,550 animals measured at approximately 5 mo of age. Heritabilities were estimated using a single-trait animal model. Genetic correlations were estimated using a 2-trait animal model. Estimated heritabilities of semen production traits ranged from 0.20 for sperm concentration to 0.29 for semen volume and were equal to or higher than those of litter traits, ranging from 0.06 for number stillborn and piglet survival rate at birth to 0.25 for mean litter weight at birth, but lower than those of pork production traits, ranging from 0.50 for average daily gain to 0.63 for backfat thickness. In many cases, the absolute values of estimated genetic correlations between semen production traits and other traits were smaller than 0.3. These estimated genetic parameters provide useful information for establishing a comprehensive pig breeding scheme.

Development of a Novel Vaginal Drug Delivery System to Control Time of Farrowing and Allow Supervision of Piglet Delivery.

The swine industry has evolved significantly in the recent decades, but this has come at considerable expense to piglet survival. Breeding sows for greater prolificacy has been accompanied by a greater proportion of piglets being born underweight, of lower vigor, and higher susceptibility to early mortality. Inducing sows to farrow during working hours has the potential to increase piglet survivability, but non-therapeutic injectable products are often discouraged on farms. We aimed to design and develop a novel vaginal drug delivery system (NVDDS) that could reliably trigger luteolysis and induce parturition. To achieve this, two vaginal tablets containing the luteolytic agent cloprostenol were formulated to be inserted together: one would release constituents immediately on insertion (immediate release; IR) and the other would release cloprostenol in a controlled manner (controlled release; CR). The two formulations (IR and CR) were evaluated for drug release, swelling and bio-adhesion in conditions simulating the sow vaginal environment. The IR tablet released the drug completely for 5 min whereas the CR tablet took 5 h to release 50% of the drug. Furthermore, the release kinetics were evaluated by fitting the dissolution profiles into different mathematical models. Both IR and CR tablets were best fitted by the Makoid–Banakar model which assumes release by summation of different mechanisms. The performance of the optimized formulations was studied in vivo with 161 Large White x Landrace sows of varying parity (0–5). The sows were assigned to five groups. Group 1 (SI) received a single vulval injection of cloprostenol at 0700 h (n = 32), group 2 (SDI) received the same dose split in two parts, at 0700h and 1300h (n = 33). Group 3 (IRT) animals were administered an IR tablet at 0700h (n = 32), while group 4 (IRCRT) received both IR and CR tablets at 0700 h (n = 33). Group 5 was untreated and served as a control (n = 32). The interval to farrowing was longer (p < 0.001) for controls than for treated sows, but there were no differences among cloprostenol treatments for timing of farrowing. The finding confirms the efficacy of the NVDDS for induction of farrowing in sows.

Digestive efficiency traits in growing pigs are genetically correlated with sow litter traits in the Large White breed

Digestive efficiency traits are promising selection criteria to improve feed efficiency in pigs. However, the genetic relationships between digestive efficiency and sow reproductive traits are mostly unknown and need to be estimated. In this study, reproductive traits were available for 61 601 litters recorded on 21 719 Large White purebred sows. The traits were comprised of the number of born alive (NBA) and the number of weaned piglets (NWP), the number of stillbirths (NSB) and piglet mortality during suckling (PM). For a subset of 32518 litters, the mean (MBW) and CV of piglet birth weights (CVBW) were deduced from individual piglet weights as well as the proportion of piglets weighing less than 1 kg (PPL1K). Growth and feed efficiency traits were available for 4 643 Large White male pigs related to sows with reproductive performances. They comprised average daily gain (ADG), daily feed intake (DFI) and feed conversion ratio (FCR). A subset of 1 391 pigs had predictions for digestibility coefficients (DC) of energy, organic matter and nitrogen obtained by analysing faecal samples with near-infrared spectrometry. Estimated heritabilities were low for NBA, NSB, NWP and PM (0.08 ± 0.01 to 0.11 ± 0.01) and low to moderate for litter weight characteristics (0.14 ± 0.02 to 0.38 ± 0.01). Heritability estimates were moderate to high for ADG, DFI and FCR (0.37 ± 0.04 to 0.54 ± 0.05) and moderate for DC traits (0.26 ± 0.06 to 0.38 ± 0.07). Genetic correlations were low between ADG, or alternatively FCR, and reproductive traits. They were significantly different from zero with MBW (0.19 ± 0.06 with ADG and −0.15 ± 0.06 with FCR) and PPL1K (−0.19 ± 0.07 with ADG and 0.18 ± 0.07 with FCR). All genetic correlations between DFI and reproductive traits were low and not significantly different from zero. Genetic correlations between DC traits and NBA were significantly different from zero for DC of organic matter and energy (<−0.25 ± 0.11). DC traits were moderately correlated with MBW (>0.30 ± 0.11), CVBW (<−0.36 ± 0.11) and PPL1K (<−0.37 ± 0.11) at the genetic level. Genetic correlations between DC traits and PM were significantly negative and hence favourable (<−0.38 ± 0.12). Finally, genetic correlations between DC traits and NWP were close to zero. These results suggested that sows closely related to growing pigs with the best digestive efficiency would produce heavier and more homogeneous piglets, with slightly smaller litter sizes at birth but better survival. Hence, there is usable genetic variation in DC that could be exploited to define new selection strategies in maternal lines aiming at improving not only feed efficiency but also piglet survival.

Correlations of gestational hemoglobin level, placental trace elements content, and reproductive performances in pregnant sows.

The iron status of sows has a great influence on reproductive performance. Iron deficiency reduces reproductive performance and newborn piglet survival rate of sow. The hemoglobin is a potential predictor for the iron status of sows and is convenient for rapid detection in pig farms. However, the relationship between iron status, hemoglobin, placental trace elements, and reproductive performance remains unclear. In this study, the hemoglobin and reproductive performance of more than 500 sows with first to sixth parities at different gestation stages (25, 55, 75, 95, and 110 d of gestation) in two large-scale sow farms were collected, and the content of placental Fe, Zn, Mn, and Cu was analyzed. The results show that hemoglobin levels of sows during pregnancy (days 75, 95, and 110) decreased significantly (P < 0.001). As the parity increases, the hemoglobin levels of sows at days 25 and 55 of gestation and placental mineral element contents including Fe, Zn, Mn, and Cu at delivery decreased (P < 0.05), while the litter size, birth alive, and litter weights increased gradually (P < 0.001). Furthermore, hemoglobin during pregnancy had a negative linear correlation with litter weight and average weight (P < 0.05), and higher hemoglobin at day 25 of gestation may reduce the number of stillbirths (P = 0.05), but higher hemoglobin at day 110 of gestation may tend to be a benefit for the birth (P = 0.01). And there was a significant positive linear correlation between hemoglobin at day 110 of gestation and placental Fe and Mn levels (P = 0.002, P = 0.013). There was also a significant positive linear correlation among Fe, Zn, Mn, and Cu in the placenta (P < 0.001). The levels of Fe, Zn, and Mn in the placental at delivery were positively related to the average weight of the fetus (P = 0.048, P = 0.027, P = 0.047), and placental Cu was linearly correlated with litter size (P = 0.029). Our research revealed that the requirements for iron during gestation were varied in different gestation periods and parities. The feeds should be adjusted according to the gestation periods, parities, or iron status to meet the iron requirements of sows and fetal pigs.

The application of new breeding technology based on gene editing in pig industry - A review.

Genome/gene-editing (GE) techniques, characterized by a low technological barrier, high efficiency, and broad application among organisms, are now being employed not only in medical science but also in agriculture/veterinary science. Different engineered CRISPR/Cas9s have been identified to expand the application of this technology. In pig production, GE is a precise new breeding technology (NBT), and promising outcomes in improving economic traits, such as growth, lean or healthy meat production, animal welfare, and disease resistance, have already been documented and reviewed. These promising achievements in porcine gene editing, including the Myostatin gene knockout (KO) in indigenous breeds to improve lean meat production, the uncoupling protein 1 (UCP1) gene knock-in to enhance piglet thermogenesis and survival under cold stress, the generation of GGTA1 and CMP-N-glycolylneuraminic acid hydroxylase (CMAH) gene double KO (dKO) pigs to produce healthy red meat, and the KO or deletion of exon 7 of the CD163 gene to confer resistance to porcine reproductive and respiratory syndrome virus infection, are described in the present article. Other related approaches for such purposes are also discussed. The current trend of global regulations or legislation for GE organisms is that they are exempted from classification as genetically modified organisms (GMOs) if no exogenes are integrated into the genome, according to product-based and not process-based methods. Moreover, an updated case study in the EU showed that current GMO legislation is not fit for purpose in term of NBTs, which contribute to the objectives of the EU’s Green Deal and biodiversity strategies and even meet the United Nations’ sustainable development goals for a more resilient and sustainable agri-food system. The GE pigs generated via NBT will be exempted from classification as GMOs, and their global valorization and commercialization can be foreseen.

Disentangling the behavioural and fibre influences of nesting enrichment for sows on piglet survival

The pork industry is willing to adopt practices that improve the welfare of pigs, but these practices should be evaluated appropriately to ensure success for all stakeholders. Nest-building is a highly conserved, innate behaviour that, despite many years of domestication, still exists in commercial sows. The behaviour is inhibited because of confinement within a crate and the absence of appropriate materials. Allowing the sow to perform some aspects of nesting will enhance welfare, as well as offspring survival through improved farrowing ease, reduced risky posture changes, and increased maternal bonding and colostrum/milk access. The aim of this review was to summarise outcomes from nesting investigations that utlise different substrates on piglet survival. The most commonly studied nesting enrichment material is straw, and it can be argued that straw has the most consistent and positive influence on piglet survival. However, in addition to using it to build a nest, sows will consume large volumes of straw, which increases dietary fibre intake. Fibre improves gastrointestinal health, energy release and satiety, all of which have been shown to offer similar benefits to piglet survival as allowing the sow to nest. So, to argue that straw is the most appropriate nesting substrate when using piglet survival as a benchmark is flawed. There may be an opportunity to exploit nesting materials other than straw that are easier for the industry to adopt in combination with high fibre peri-parturient diets, and such strategies should be considered.

Evaluation of Essential Fatty Acids in Lactating Sow Diets on Sow Reproductive Performance, Colostrum and Milk Composition, and Piglet Survivability

A total of 3,451 mixed parity sows and their litters were used to evaluate the effects of essential fatty acid intake on sow reproductive performance, piglet growth and survivability, and colostrum and milk composition. At approximately d 112 of gestation, sows were blocked by parity within farrowing room and randomly assigned to 1 of 4 experimental treatments. Lactation diets were corn-soybean meal-wheat-based and included 0.5 (Control) or 3% choice white grease (CWG), 3% soybean oil (SO), or a combination of 3% soybean oil and 2% choice white grease (Combination). Thus, sows were provided diets with low essential fatty acid (EFA; as linoleic [LA] and α-linolenic acid [ALA]) in diets with choice white grease or high EFA in diets with soybean oil. Prior to farrowing, sows were provided 4 lb/d of their assigned lactation diet and then allowed ad libitum access after parturition. Overall lactation ADFI increased (P < 0.001) when sows were fed the Combination and CWG treatments compared to sows fed the Control or diet with 3% SO. Regardless of differences among ADFI, daily LA and ALA intake of sows assigned to the Combination and SO treatments were greater (P < 0.001) than sows fed diets with lower EFA provided as CWG. There was no effect of sow EFA intake on piglet survivability from birth to 24 h or from 24 h to weaning (P > 0.10). Overall, sows consuming high EFA provided in the Combination and SO diets produced litters with greater (P < 0.05) litter gain and litter ADG during the lactation period and heavier (P < 0.001) piglet weaning weights when compared to litters from sows fed diets with low EFA provided through CWG. Lactation diet EFA composition did not influence colostrum or milk dry matter, crude protein, or crude fat content (P > 0.10). However, LA and ALA content in both colostrum and milk at weaning increased (P < 0.05) in response to increased EFA levels in diets that contained SO. There was no evidence for differences (P > 0.10) in wean-to-estrus interval, percentage of sows bred by d 7, percentage of sows bred by d 12, farrowing rate, or subsequent farrowing performance due to sow lactation EFA intake. In conclusion, increased LA and ALA intake during the lactation period from soybean oil addition increased overall litter growth and average weaning weights of pigs but did not affect piglet survivability or subsequent reproductive performance of sows.