An association analysis of sow parity,live-weight and back-fat depth as indicators of sow productivity

Understanding how critical sow live-weight and back-fat depth during gestation are in ensuring optimum sow productivity is important. The objective of this study was to quantify the association between sow parity, live-weight and back-fat depth during gestation with subsequent sow reproductive performance. Records of 1058 sows and 13 827 piglets from 10 trials on two research farms between the years 2005 and 2015 were analysed. Sows ranged from parity 1 to 6 with the number of sows per parity distributed as follows: 232, 277, 180, 131, 132 and 106, respectively. Variables that were analysed included total born (TB), born alive (BA), piglet birth weight (BtWT), pre-weaning mortality (PWM), piglet wean weight (WnWT), number of piglets weaned (Wn), wean to service interval (WSI), piglets born alive in subsequent farrowing and sow lactation feed intake. Calculated variables included the within-litter CV in birth weight (LtV), pre-weaning growth rate per litter (PWG), total litter gain (TLG), lactation efficiency and litter size reared after cross-fostering. Data were analysed using linear mixed models accounting for covariance among records. Third and fourth parity sows had more (P<0.05) TB, BA and heavier BtWT compared with gilts and parity 6 sow contemporaries. Parities 2 and 3 sows weaned more (P<0.05) piglets than older sows. These piglets had heavier (P<0.05) birth weights than those from gilt litters. LtV and PWM were greater (P<0.01) in litters born to parity 5 sows than those born to younger sows. Sow live-weight and back-fat depth at service, days 25 and 50 of gestation were not associated with TB, BA, BtWT, LtV, PWG, WnWT or lactation efficiency (P>0.05). Heavier sow live-weight throughout gestation was associated with an increase in PWM (P<0.01) and reduced Wn and lactation feed intake (P<0.05). Deeper back-fat in late gestation was associated with fewer (P<0.05) BA but heavier (P<0.05) BtWT, whereas deeper back-fat depth throughout gestation was associated with reduced (P<0.01) lactation feed intake. Sow back-fat depth was not associated with LtV, PWG, TLG, WSI or piglets born alive in subsequent farrowing (P>0.05). In conclusion, this study showed that sow parity, live-weight and back-fat depth can be used as indicators of reproductive performance. In addition, this study also provides validation for future development of a benchmarking tool to monitor and improve the productivity of modern sow herd.     

Second litter syndrome in Iberian pig breed: factors influencing the performance

Second litter syndrome (SLS) consists of a loss of prolificacy in the second parity (P2), when a sow presents the same or lower results for litter size than in the first parity (P1). This syndrome has been reported for modern prolific breeds but has not been studied for rustic breeds. The objectives of this study are to determine how and to what degree Iberian sows (a low productivity breed recently raised on intensive farms) are affected by SLS; to establish a target and reference levels; and to assess the factors influencing the performance. Analysed data correspond to 66 Spanish farms with a total of 126 140 Iberian sows. The average Iberian sow prolificacy in P1 was 8.91 total born (TB) and 8.47 born alive (BA) piglets, whereas in P2, it decreased by ?0.05 TB and ?0.01 BA piglets, suggesting some general incidence of SLS. At the sow level, 56.63% did not improve prolificacy in terms of BA piglets in P2, and 16.98% had a clear decrease in prolificacy, losing ≥3 BA piglets in P2. Within herds, a mean of 57.75% of sows showed SLS, with an evident decrease in the number of BA piglets in P2. The plausible target for the Iberian farm’s prolificacy comes from the quartile of farms with the lowest percentage of SLS sows within the farms with the highest prolificacy between P1 and P2 (mean of 8.77 BA). So, in this subset of farms (N = 17), 47.3% of sows improved their prolificacy in P2 (i.e. did not show SLS). Hence, half the sows could be expected to show SLS even on farms with a good performance. Finally, this study brings out the main factors reducing P2 prolificacy through SLS in the Iberian breed: later age at first farrowing, long first lactation length, medium weaning to conception interval and large litter size in P1. In conclusion, improving the reproductive performance of Iberian farms requires reducing the percentage of sows with SLS, paying special attention to those risk factors. The knowledge derived from this study can provide references for comparing and establishing objectives of performance on Iberian sow farms which can be used for other robust breeds.     

Dietary supplementation with maize distillers dried grains with solubles during late gestation and lactation: Effects on sow and litter performance,and on colostrum and milk composition

The objectives of this study were to determine the effects of maize distillers dried grains with solubles (DDGS) during late gestation and lactation on sow and piglet performance, and on colostrum and milk composition. Thirty-six second- and third-parity (2.43 parity) sows (Yorkshire) were allotted to 1 of 3 groups and fed diets containing 0 (control), 200 or 400 g DDGS/kg during the last 20 d of gestation and throughout a 21 d of lactation. Experimental diets contained 12.9 MJ metabolizable energy/kg and 9.7 g lysine/kg. The colostrum and milk samples were obtained on d 0 (farrowing) and d 21 (weaning). There were no differences (P>0.05) in the sows’ average gestation lengths, weaning-to-estrus interval, average daily feed intake, and the lactation backfat and body weight change between dietary treatments. There were no dietary effects (P>0.05) of DDGS on the numbers of total, born alive piglets, average birth weights, piglets per litter at weaning or piglets average daily gain during lactation. No differences (P>0.05) were observed in total solids, protein, fat and lactose among the sows fed the DDGS diets compared with the control. The composition of total solids and protein of sows colostrum and milk were higher at farrowing (d 0) than at weaning (d 21) (P<0.001). However, the fat and lactose content of sows colostrum and milk were increased (P<0.001) from d 0 (farrowing) to d 21 (weaning). In conclusion, the results suggest that 400 g DDGS/kg (87 g lysine/kg) supplemented with 5.2 g lysine/kg included in late gestation and lactation diets is sufficient to replace all the dietary soybean meal without significantly affecting sow and litter performance or colostrum and milk composition.     

Short Communication: effect of positive handling of sows on litter performance and pre-weaning piglet mortality

Fear and environmental stressors may negatively affect the welfare of farm animals such as pigs. The present study investigated the effects of music and positive handling on reproductive performance of sows (n = 1014; parity 1 to 8) from a commercial pig farm practicing a batch farrowing system. Every 2 weeks, 56 sows were moved from the gestation unit to conventional-crated farrowing houses 1 week prior to expected farrowing. Treated (T; n = 299) and control (C; n = 715) sows were included in the study. In the farrowing houses, auditory enrichment (music from a radio) was provided to sows of T groups daily from 0600 to 1800 h until the end of lactation. Until the day of farrowing, T sows were additionally subjected, for 15 s per day per sow, to continuous back scratching by one member of farm staff. Litter performance and piglet mortality were recorded and analysed between T and C sows using linear mixed regression models. The number of liveborn piglets (C 13.85 v. T 13.26) and liveborn corrected for fostering (C 13.85 v. T 13.43) was significantly higher (P < 0.05) in C groups compared to the T groups. The number of stillborn piglets was 0.60 and 0.72 in T and C groups, respectively (P > 0.05). With regard to piglet mortality, a linear mixed regression model showed a significant overall effect of treatment in reducing piglet mortality (P < 0.01). Yet, the effect of treatment varied according to litter size (number of liveborn piglets) with a diminishing treatment effect in sows with a high litter size (P < 0.01). Pre-weaning survival was improved in the current study by the combined effect of daily back scratching of sows prior to farrowing and providing music to sows and piglets during lactation. Further research is needed to assess the separate effects of both interventions.     

Reproductive performance of purebred landrace and Yorkshire sows in Thailand with special reference to seasonal influence and parity number

The purpose of this study was to analyze reproductive performance in purebred Landrace and Yorkshire sows with special reference to seasonal influence and parity number, under tropical conditions where day length is almost constant throughout the year. Data from three purebred sow herds in Thailand during the period from 1993 to 1996 were analyzed. The two breeds were present in all three herds. The analysis comprised records of 3848 Landrace sow litters and 2033 Yorkshire sow litters. The statistical models included the fixed effects of month, year, parity, breed of the sow, herd, and two-way interactions of breed-parity, breed-herd, breed-month, breed-year, parity-month, month-herd, year-herd and month-year. The random effect of sow within breed was included in all models. Analysis of covariance was performed to analyze the effect of temperature, humidity and heat index on number of total born per litter (NTB), weaning to first service interval (WSI) and farrowing rate (FR). Landrace sows had significantly higher NTB (0.6 piglets), number of live born per litter (0.5 piglets), and average birth weight (0.13 kg) than Yorkshire sows (P<0.001). Farrowing rate was 3.9% higher in Landrace sows than in Yorkshire sows (P<0.01). However, Yorkshire sows had significantly shorter WSI (P<0.001) and significantly higher proportion of sows served within 7 days after weaning (P<0.01) than Landrace sows. No breed differences were found in number of stillborn per litter and weaning to conception interval. Parity had significant effect on all reproductive parameters analyzed. Number of total born and live born per litter was significantly lower for sows farrowing during the rainy season than in other seasons. Farrowing rate was low for sows mated during the hot and rainy season. Weaning to service interval and WSI7 were prolonged for sows weaned during the hot and rainy season. Reproductive performance was significantly unfavorably influenced by elevated temperature and heat index after mating (NTB and FR) or during lactation (WSI).     

Plane of nutrition during gestation affects reproductive performance and retention rate of hyperprolific sows under commercial conditions

Defining a maternal plane of nutrition during gestation is pivotal for improving sow productivity and the cost-effectiveness of feeding. The benefits of increasing the amount of feed during late gestation have been controversial. The objective of this study was to investigate the effects of different planes of nutrition during gestation on reproductive performance of hyperprolific sows and pre-weaning litter performance. One hundred and thirty-five gestating sows were randomly assigned to one of three planes of nutrition throughout parities three and four (P4), as follows: Req – plane designed to meet requirements of prolific sows (2.3 kg per day from day 1 to 21; 1.8 kg per day from day 22 to 75; 2.3 kg per day from day 76 to farrowing); Bump – plane designed as the Req, with increased feed intake during late gestation (3.0 kg per day from day 91 to farrowing); and Maintenance – plane designed to closely meet maintenance requirements of sows (1.8 kg per day from day 1 to farrowing). All treatments were fed the same gestation diet (2.50 MCal NE/kg; 0.67% SID Lysine; 15.17% CP). Sow biometrical parameters at farrowing and at weaning, and litter characteristics were recorded. Also, blood samples were collected for pre- and post-prandial serum glucose and plasma insulin, as well as triglycerides, calcium, and phosphorus analyses. Culling, stratified by cause, and retention rates were recorded in all treatments for each parity. Over two parities, Bump sows had higher weight gain and, at P4, had a higher number of piglets born alive (P < 0.05). Bump sows lost more weight between the end of gestation and weaning over two parities (P < 0.05). Maintenance sows showed reduced body condition score with a higher percentage of piglets removed throughout lactation (due to inappetence and inability to reach the udder) at P4 (P = 0.03). Pre- and post-prandial glucose levels were higher in Bump sows, as well as post-prandial insulin and phosphorus levels at P4 (P < 0.05). Bump sows also showed increased plasma triglycerides compared to the other treatments (P = 0.03). Retention rate was reduced in Maintenance compared to Bump and Req sows at parity 5 (P = 0.02). Taken together, our results indicate that higher feed intake allowance during late gestation may improve the sow’s nutritional status triggering positive results on litter size of hyperprolific sows (e.g., more than 17 total born). However, body condition score must be carefully evaluated to prevent excessive weight gain during successive parities.     

Animal board invited review: Factors affecting the early growth and development of gilt progeny compared to sow progeny

Progeny born to primiparous sows farrowing their first litter, often called gilt progeny (GP), are typically characterised by their poorer overall production performance than progeny from multiparous sows (sow progeny; SP). Gilt progeny consistently grow slower, are born and weaned lighter, and have higher postweaning illness and mortality rates than SP. Collectively, their poorer performance culminates in a long time to reach market weight and, ultimately, reduced revenue. Due to the high replacement rates of sows, the primiparous sow and her progeny represent a large proportion of the herd resulting in a significant loss for the pig industry. While the reasons for poorer performance are complex and multifaceted, they may largely be attributed to the immature age at which gilts are often mated and the significant impact of this on their metabolism during gestation and lactation. As a result, this can have negative consequences on the piglet itself. To improve GP performance, it is crucial to understand the biological basis for differences between GP and SP. The purpose of this review is to summarise published literature investigating differences in growth performance and health status between GP and SP. It also examines the primiparous sow during gestation and lactation and how the young sow must support her own growth while supporting the metabolic demands of her pregnancy and the growth and development of her litter. Finally, the underlying physiology of GP is discussed in terms of growth and development in utero, the neonatal period, and the early development of the gastrointestinal tract. The present review concludes that there are a number of interplaying factors relating to the anatomy and physiology of the primiparous sow and of GP themselves. The studies presented herein strongly suggest that poor support of piglet growth in utero and reduced colostrum and milk production and consumption are largely responsible for the underperformance of GP. It is therefore recommended that future management strategies focus on supporting the primiparous sow during gestation and lactation, increasing the preweaning growth of GP to improve their ability to cope with the stressors of weaning, selection of reproductive traits such as uterine capacity to improve birth weights and ultimately GP performance, and finally, increase the longevity of sows to reduce the proportion of GP entering the herd.     

Genetic parameters for haemoglobin levels in sows and piglets as well as sow reproductive performance and piglet survival

Genetic parameters were estimated for haemoglobin (Hb) levels in sows and piglets as well as sow reproductive performance and piglet survival. Reproductive traits were available between 2005 and 2014 for 7857 litters from 1029 Large White and 858 Landrace sows. In 2012 and 2013, Hb levels, sow BW and sow back fat depth were measured on 348 sows with 529 litters 5 days prior to farrowing. In addition, Hb levels were available for 1127 one-day-old piglets from 383 litters (a maximum of three piglets per litter) of 277 sows with Hb levels. The average Hb levels in sows (sow Hb), their litters (litter Hb, based on average Hb of three piglets) and individual piglets (piglet Hb) were 112 ± 12.6 g/l, 103 ± 15.3 g/l and 105 ± 21.7 g/l, respectively. Heritabilities for Hb levels were 0.09 ± 0.07 for sow Hb, 0.19 ± 0.11 for litter Hb and 0.08 ± 0.05 for piglet Hb. Estimates for the permanent environment effect of sows were 0.09 ± 0.09 for sow Hb, 0.11 ± 0.12 for litter Hb and 0.12 ± 0.03 for piglet Hb. In comparison, heritabilities for both number of stillborn piglets and pre-weaning survival were lower (0.05 ± 0.01 and 0.04 ± 0.01). Sow BW had no significant heritability, while sow back fat depth was lowly heritable (0.10 ± 0.08). Positive genetic correlations were found between sow Hb and litter Hb (0.64 ± 0.47) and between litter Hb and sow back fat depth (0.71 ± 0.53). Higher litter Hb was genetically associated with lower number of stillborn piglets (−0.78 ± 0.35) and higher pre-weaning survival (0.28 ± 0.33). Negative genetic correlations between sow Hb and average piglet birth weight of the litter (−0.60 ± 0.34) and between piglet Hb and birth weight of individual piglets (−0.37 ± 0.32) indicate that selection for heavier piglets may reduce Hb levels in sows and piglets. Similarly, selection for larger litter size will reduce average piglet birth weight (r_g: −0.40 ± 0.12) and pre-weaning survival (−0.57 ± 0.13) and may lead to lower litter Hb (−0.48 ± 0.27). This study shows promising first results for the use of Hb levels as a selection criterion in pig breeding programs, and selection for higher Hb levels may improve piglet survival and limit further reduction in Hb levels in sows and piglets due to selection for larger and heavier litters.     

Unraveling the actual background of second litter syndrome in pigs: based on Large White data

Second litter syndrome (SLS) in sows is when fertility performance is lower in the second parity than in the first parity. The causes of SLS have been associated with lactation weight loss, premature first insemination, short lactation length, short weaning to insemination interval, season, and farm of farrowing. There is little known about the genetic background of SLS or if it is a real biological problem or just a statistical issue. Thus, we aimed to evaluate risk factors, investigate genetic background of SLS, and estimate the probability of SLS existing due to the statistical properties of the trait. The records of 246 799 litters (total number born, TNB) from 46 218 Large White sows were used. A total of 15 398 sows had SLS. Two traits were defined: first a binominal trait if a sow had SLS or not (biSLS) and second a continuous trait (Range) created by subtracting the total number of piglets born in the first parity (TNB1) from the piglets born in the second parity (TNB2). Lactation length, farm, and season of the farrowing had significant effects on SLS traits when tested as fixed effects in the genetic model. These effects are farm management-related factors. The age at first insemination and weaning to insemination interval were significant only for other reproduction traits (e.g., TNB1, TNB2, litter weight in parity 1 and 2). The heritability of biSLS was 0.05 (on observed scale), whereas heritability of Range was 0.03. To verify the existence of SLS data with records of 50 000 sows and 9 parities was simulated. The simulations showed that the average expected frequency of SLS across all the parities was 0.49 (±0.05) while the observed frequency in the actual data was 0.46 (±0.04). We compared this to SLS frequencies in 67 farms and only 2 farms had more piglets born in the first parity compared to the second. Therefore, on the individual sow level SLS is likely due to statistical properties of the trait, whereas on the farm level SLS is likely due to farm management. Thus, SLS should not be considered an abnormality nor a syndrome if on average the herd litter size in parity 2 is larger than in parity 1.     

Nurse sow strategies in the domestic pig: I. Consequences for selected measures of sow welfare

Management strategies are needed to optimise the number of piglets weaned from hyper-prolific sows. Nurse sow strategies involve transferring supernumerary new-born piglets onto a sow whose own piglets are either weaned or fostered onto another sow. Such ‘nurse sows’ have extended lactations spent in farrowing crates, which could have negative implications for their welfare. This study used 47 sows, 20 of which farrowed large litters and had their biggest piglets fostered onto nurse sows which were either 1 week (2STEP7, n=9) or 3 weeks into lactation (1STEP21, n=10). Sows from which piglets were removed (R) were either left with the remainder of the litter intact (I) (remain intact (RI) sows, n=10), or had their litters equalised (E) for birth weight using piglets of the same age from non-experimental sows (remain equalised (RE) sows, n=9). Piglets from 2STEP7 were fostered onto another nurse sow which was 3 weeks into lactation (2STEP21, n=9). Back-fat thickness was measured at entry to the farrowing house, at fostering (nurse sows only) and weaning. Sows were scored for ease of locomotion and skin and claw lesions at entry to the farrowing house and weaning. Salivary cortisol samples were collected and tear staining was scored at 0900 h weekly from entry until weaning. Saliva samples were also taken at fostering. Data were analysed using GLMs with appropriate random and repeated factors, or non-parametric tests were applied where appropriate. Back-fat thickness decreased between entry and weaning for all sows (F_1,42=26.59, P<0.001) and tended to differ between treatments (F_4,16=2.91; P=0.06). At weaning RI sows had lower limb lesion scores than 2STEP7 and RE sows (χ²₄=10.8, P<0.05). No treatment effects were detected on salivary cortisol concentrations (P>0.05) and all nurse sows had a higher salivary cortisol concentration at fostering, compared with the other days (F_10,426=3.47; P<0.05). Acute effects of fostering differed between nurse sow treatments (F_2,113=3.45, P<0.05); 2STEP7 sows had a higher salivary cortisol concentration than 1STEP21 and 2STEP21 sows on the day of fostering. 2STEP7 sows had a higher salivary cortisol concentration at fostering, compared with 1STEP21 and 2STEP21 sows. Tear staining scores were not influenced by treatment (P>0.05). In conclusion, no difference was detected between nurse sows and non-nurse sows in body condition or severity of lesions. Although some nurse sows experienced stress at fostering, no long-term effect of the nurse sow strategies was detected on stress levels compared with sows that raised their own litter.     

Variability and repeatability in gestation length related to litter performance in female pigs on commercial farms

Forecasting gestation length (GL) in sows enables producers to be prepared to provide assistance at farrowing, or for timely treatment to induce parturition. The objectives of the present study were to determine GL across parities, the repeatability and correlation of the GL, and associations of GL with the three litter size variables (total pigs born, pigs born alive, and dead piglets) and longevity. This study was conducted on 94 farms and encompassed 66,254 farrowing records of 13,715 sows born during 1999. Variance components and correlation analyses were used to determine the repeatability and the correlations of GL. Mixed-effects models were used to analyze associations of GL with litter size variables and longevity. The mean of GL across parities was from 115.2 to 115.4 d. The proportions of GL 114, 115, and 116 d for all farrowing events were 19.2, 30.8, and 22.2%, respectively. The GL between parities were correlated (0.40/=117 d (P<0.01). Sows with GL相似文献   

Shortening sow restraint period during lactation improves production and decreases hair cortisol concentrations in sows and their piglets

Food animal welfare is an issue of great concern, as society has a responsibility for animals under human care. Pork is the most consumed meat worldwide, with more than a billion pigs being slaughtered globally every year. Still, in most countries, sows are restrained in farrowing crates throughout lactation. In these crates, sows are confined with bars to an area that is just slightly larger than their body. Thus, moving and turning around, grooming, or expressing other natural behaviors are typically impossible. In this study, we utilized a simple and practical modification of conventional farrowing crates to designed farrowing pens, by removable confinement bars, which provide the flexibility to change the housing system from one to another. Our objective was to examine the parameters of production and hair cortisol concentrations after different restraint periods during lactation. Analyses included data from 77 sows and their 997 piglets. Sows were housed in farrowing crates, but the confinement bars were removed after different periods, from 3 days post-farrowing to full restraint. For certain analyses, sows were grouped into Short or Long Restraint groups (3–10 days vs 13–24 days, respectively). Multiple linear regression revealed that for any additional day in restraint of the sows, piglets' weaning rate decreases by 0.4% (P < 0.05). Moreover, the total number of weaned piglets per litter was higher in the Short Restraint group as compared to the Long Restraint group (10.4 ± 0.3 vs 9.7 ± 0.3, respectively; P < 0.05). Accordingly, total litter weight on the weaning day tended to be higher in the Short Restraint group (68.8 ± 2.2 vs 64.9 ± 1.8 kg; P = 0.1210). The requirement for medical treatments during lactation (e.g., antibiotics, NSAID) tended to be less frequent in the Short Restraint group (Sows: 21.9% vs 40%; P = 0.1219. Piglets: 2.4% vs 17.1%; P = 0.0609). Hair cortisol as a marker for chronic stress during lactation decreased when the restraint period was shortened in both sows and piglets. Our analysis revealed that sows' hair cortisol is a significant mediator between the restraint of the sow and its piglets' hair cortisol (Sobel test; P < 0.05). For every day of sows' restraint, sows' hair cortisol increased by 0.5 pg/mg, and for any additional unit of sows' hair cortisol, piglets' hair cortisol increased by 0.36 pg/mg. In conclusion, sustainable swine farming management can be beneficial for both animals and farmers; limiting sow restraint during lactation is expected to reduce stress, enhance welfare and production, and potentially improve the economics of swine operations.     

The Effects of Dietary Supplementation with Chromium Picolinate throughout Gestation on Productive Performance, Cr Concentration, Serum Parameters, and Colostrum Composition in Sows

The objective of this study was to determine the effects of supplemental chromium as chromium picolinate (CrPic) on productive performance, chromium (Cr) concentration, serum parameters, and colostrum composition in sows. Thirty Yorkshire sows were bred with semen from a pool of Landrace boars. The sows were equally grouped and treated with either a diet containing 0 (control) or 400 ppb dietary Cr supplementation throughout gestation. The sows received the same basal diet based on corn-DDGS meal. Supplemental CrPic increased (P?<?0.05) the sow body mass gain from the insemination to the day 110 of gestation in sows. No differences (P?>?0.50) were observed in the gestation interval, sow mass, and backfat at insemination, after farrowing, at weaning and lactation loss. The number of piglets born alive, piglets per litter at weaning, and litter weaned mass were increased (P?<?0.05) for those supplemented with CrPic compared with the control. However, the total number of piglets born, total born litter mass, average piglet birth body mass, born alive litter mass, and average born alive piglet mass did not differ among the treatments (P?>?0.05). The placental masses of sows were similar among treatments (P?>?0.05). Dietary supplementation with CrPic throughout gestation in sows showed increased (P?<?0.01) concentration of Cr in the colostrum or serum at days 70 and 110. Compared with the control group, dietary supplementation with CrPic throughout gestation in sows decreased (P?<?0.05) the serum insulin concentration, the glucose or serum urea nitrogen concentration at days 70 and 110. However, no differences (P?>?0.05) were observed in total protein concentration among treatments. No differences (P?>?0.05) were observed in total solids, protein, fat or lactose among sows fed the diets supplemented with CrPic compared with the control. This exciting finding provides evidence for an increase in mass gain and live-born piglets in sows supplemented with CrPic throughout gestation.     

Farrowing rates and litter size following transfer of vitrified porcine embryos into a commercial swine herd

The objective was to determine farrowing rates and litter sizes that could be achieved in a typical farm-to-farm porcine embryo transfer program using vitrified blastocysts that were zona pellucida intact when cryopreserved. The embryos were transferred surgically on-farm into recipient sows that were managed throughout gestation and farrowing under the same conditions as other sows in the herd. Twenty recipient sows (mean parity 2.1) received a total of 568 embryos; seven received 203 embryos derived from donor sows, five received 139 embryos from gilts and eight received a mixture of 161 embryos from sows and 65 from gilts. Sixteen sows (80%) were confirmed pregnant at approximately 35 days gestation, 15 farrowed at full term (farrowing rate 75%). One sow died during gestation (with a total of 18 fetuses in utero). A total of 123 piglets were born (mean, 8.2), of which 115 were born alive (mean, 7.7). Of the 568 embryos transferred to all 20 sows, 21.6% resulted in piglets born and 29.0% survived to produce piglets in sows that farrowed. There were no significant differences in embryo survival among sow, gilt or mixed sow and gilt embryos. The ratio of males to females was 71/52 and the mean birth weight was 1.6 kg (range 0.6-2.6 kg). In conclusion, vitrified zona pellucida intact embryos can be used to transfer genetic material from farm-to-farm with acceptable reproductive performance.     

Estimation of genetic trends from 1977 to 1998 for farrowing characteristics in the French Large White breed using frozen semen

The objective of the study was to estimate genetic trends from 1977 to 1998 in the French Large White (LW) breed for stillbirth and associated traits measured at farrowing using frozen semen. Two groups of pigs (G77 and G98) were obtained by inseminating LW sows with semen from LW boars born either in 1977 or in 1998. A second generation was produced by inter se mating in each group. Farrowing was thoroughly supervised through both direct observations and video recording all long farrowing on a total of 137 first- and second-parity litters produced by sows from this second generation (68 G77 and 69 G98 litters, respectively). Measurements included birth time, weight and birth characteristics (including orientation, presence of cyanosis or oedema, membrane obstruction, umbilical cord length/content) of each piglet, as well as sow traits (weight and backfat thickness, farrowing duration, litter size and within-litter variation of weights at birth). The data were analysed using linear or generalised linear mixed models, according to the definition of the trait (continuous or binary data). The importance of several effects to piglet probability of stillbirth was then quantified by computing the reduction of variance associated with the addition of each effect in the model. Litter size did not significantly differ in first parity, but was higher in G98 second-parity sows: the differences for global (including pre partum dead piglets) and total numbers of piglets born per litter were +2.3 ± 1.1 and +1.3 ± 0.6, respectively. G98 sows also had a higher number of stillbirths in both parities (+0.7 ± 0.3 stillborn per litter). Piglets from G98 litters were heavier at birth (+130 ± 40 g for birth weight adjusted for litter size), without any increase in within-litter heterogeneity of birth weight. No significant difference was detected between G77 and G88 groups for farrowing length and the distribution of time interval between piglet births. G98 stillborn piglets had longer and more often empty umbilical cords at birth. G98 piglets born alive also had more often umbilical nodes than G77 piglets. These characteristics were considered as indicators of increased farrowing difficulties and risk of hypoxia at birth in G98 pigs. Time of birth of each piglet, sow fatness at farrowing and time of first placenta expulsion were the main factors of variation of the piglet's probability of stillbirth.     

Climatic effects on sow fertility and piglet survival under influence of a moderate climate

Although the climate in Germany is moderate, heat stress conditions may occur during summer months. However, it is unknown to what extent sow fertility and piglet survival are affected under moderate climatic conditions in indoor systems. Therefore, this study estimated effects of temperature and temperature–humidity index (THI) on sow fertility and piglet survival under practical husbandry conditions. Temperature and relative humidity were recorded in six piglet-producing farms in Lower Saxony, Germany, from July 2011 to August 2012. Based on that, the THI was calculated. In one farrowing, waiting and servicing unit of each farm two data loggers were installed. Reproductive parameters of 8279 successful inseminations and 10 369 litters including total number of piglets born, liveborn, stillborn and weaned piglets as well as pre-weaning mortality were evaluated. The effects of temperature and THI on reproductive parameters were estimated for varying periods after breeding and before and after farrowing, respectively. Average daily temperature across all units ranged from 15.6°C to 29.0°C, and average THI from 62.4 to 75.1. Season and parity significantly affected total number of piglets born, number of liveborn, stillborn and weaned piglets (P<0.001). The number of piglets born increased with rising temperature and THI in the 1^st week post breeding. Higher temperatures and THI values before farrowing resulted in a reduced number of liveborn piglets. Elevated temperature and THI values after farrowing were associated with a greater number of weaned piglets. The pre-weaning mortality significantly decreased with increasing temperature and THI values after farrowing (P<0.05). In conclusion, temperature and THI affected the reproductive performance of the sows and the survival of the piglets in different ways. While increased climatic values at the time of breeding positively affected the total number of piglets born, increased values at the time of farrowing had negative impacts on the reproductive performance of the sows. Piglets benefited from higher temperature and THI values after farrowing.     

Effect of dietary fat or starch supply during gestation and/or lactation on the performance of sows, piglets' survival and on the performance of progeny after weaning

Two trials were carried out to compare the effects of fat or starch inclusion in sow's diet on sow and litter performance. In each trial, sows were assigned to one of two treatments. In trial 1, the sows were fed diets containing either soybean oil (5%, treatment GL5) or cornstarch (11.3%, GL0) from day 35 of gestation to weaning. Daily net energy and nutrient allowance were equalised during gestation. In trial 2, the same treatments were applied only after farrowing (treatments L5 and L0, respectively). Within each trial, a batch of piglets was studied until slaughter. In trial 1, adipose cell development and total lipid content were determined on some pigs at weaning (n = 6/treatment) and at slaughter in dorsal subcutaneous adipose tissue (n = 13/group at least) and in muscle (n = 46/group at least). Piglets' birth weight was not affected by treatment in trial 1. Survival rates at birth and after 24 h of life were higher in treatment GL5 (4.0% v. 7.5% stillborn piglets in GL0 treatment, P < 0.05; 8.7% v. 12.6% of piglets alive at 24 h of age died in treatment GL0, P = 0.06). Subsequently, overall survival rate until weaning was higher in treatment GL5 (81.4% v. 75.7% of total born piglets, P = 0.03), but litter size at weaning was not significantly affected (11.3). Litter growth rate before weaning was increased when a fat-enriched diet was provided during gestation and lactation (+140 g/day per litter; P < 0.01) and to a lower extent when provided only after farrowing (+90 g/day; P < 0.05). Energy supply through fat did not decrease the mobilisation of the sow's body reserve and backfat thickness loss was even higher with treatment GL5 (P < 0.05). After weaning, pigs' average daily gain, feed : gain ratio and carcass lean content were not affected by the energy source supplied before and/or after farrowing. At weaning, the number of adipose cells in the dorsal subcutaneous adipose tissue and in the Longissimus dorsi muscle was higher in the GL5 pigs. Muscle lipid content at weaning did not differ between treatments, but it was higher at slaughter, around 110 kg, in the GL5 pigs (3.46% v. 2.58%, P < 0.001).     

Effect of birth litter size, birth parity number, growth rate, backfat thickness and age at first mating of gilts on their reproductive performance as sows

The present study was performed to evaluate retrospectively the influence of birth litter size, birth parity number, performance test parameters (growth rate from birth to 100kg body weight and backfat thickness at 100kg body weight) and age at first mating (AFM) of gilts on their reproductive performance as sows. Traits analysed included remating rate in gilts (RRG), litter size, weaning-to-first-service interval (WSI), remating rate in sows and farrowing rate (FR). Data were collected from 11 Swedish Landrace (L) and 8 Swedish Yorkshire (Y) nucleus herds and included 20712 farrowing records from sow parities 1-5. Sows that farrowed for the first time during 1993-1997, having complete records of performance test and AFM, were followed up to investigate their subsequent reproductive performance until their last farrowing in 1999. Analysis of variance and multiple regression were applied to continuous data. Logistic regression was applied to categorical data. The analyses were based on the same animals and the records were split into six groups of females, i.e. gilts, primiparous sows, and sows in parities 2-5, respectively. Each additional piglet in the litter in which the gilt was born was associated with an increase of her own litter size of between 0.07 and 0.1 piglets per litter (P<0.001). Gilts born from sow parity 1 had a longer WSI as primiparous sows compared with gilts born from sow parity 4 (0.3 days; P<0.05) or parity 5 (0.4 days; P<0.01). Gilts with a higher growth rate of up to 100kg body weight had a larger litter size (all parities 1-5; P<0.05), shorter WSI (all parities 1-5; P<0.05) and higher FR (parities 2 and 5; P<0.05) than gilts with a lower growth rate. Gilts with a high backfat thickness at 100kg body weight had a shorter WSI as primiparous sows (P<0.001) compared with low backfat gilts, and 0.1 piglets per litter more as second parity sows (P<0.01). A 10 day increase in AFM resulted in an increase in litter size of about 0.1 piglet for primiparous sows (P<0.001) and a decrease (P<0.05) for sow parities 4 and 5.     

Body weight loss during lactation and its influence on weaning-to-service interval and ovulation rate in Landrace and Yorkshire sows in the tropical environment of Thailand

The aim of this study was to investigate the ovulation rate and the weaning-to-service interval (WSI) of sows in relation to their body weight loss during lactation in tropical climatic conditions. Effect of lactation length (LL), number of total born piglets, number of live born piglets, litter birth weight, average piglet birth weight, number of pigs weaned, litter weaning weight and average pig weaned weight on sow weight loss during lactation were also studied. This study was conducted in two commercial purebred sow herds (A, B) in the central part of Thailand from August to December 1997. The herds had both Landrace (L) and Yorkshire (Y) sows. The 123 sows (55 L and 68 Y) in herd A and 153 sows (95 L and 58 Y) in herd B, parity 1-4, were weighed within 4 days after farrowing and at weaning. Lactation length, litter size at birth and at weaning, litter weight at birth and at weaning, and WSI were recorded for each of these sows. In herd A, 52 sows (20 L and 32 Y) were examined once by laparoscopy between days 8 and 14 after AI-service. These sows had farrowed at least seven piglets in the previous parturition. The numbers of corpora lutea (CL) in both ovaries were counted, and were assumed to equal the ovulation rate. L-sows had significantly (P < 0.05) higher relative weight loss during lactation (RWL) than Y-sows. The RWL increased by 0.7% for each extra pig weaned. When LL increased by 1 day, within the interval of 17-34 days, RWL decreased by 0.6%. Sows with a high weight loss had significantly (P < 0.05) longer WSI than sows with medium or low weight loss. Weight loss had a significant (P < 0.05) effect on WSI in parity 1 and 2 sows. Y-sows had more CL than L-sows (15.7 versus 14.0) (P < 0.05). RWL, parity and regression on lactation length had no significant effect on number of CL. In conclusion, sows with higher number of pigs weaned lose more weight. Under the restricted feeding regime applied, high weight loss during lactation prolongs WSI in parity 1 and 2 sows, but has no influence on the ovulation rate at first oestrus after weaning. The ovulation rate is higher in Yorkshire than in Landrace sows. The ovulation rate is independent of parity.     

Genetic aspects regarding piglet losses and the maternal behaviour of sows. Part 2. Genetic relationship between maternal behaviour in sows and piglet mortality

The aim of the study was to analyse the genetic background of different traits to characterise the maternal behaviour of sows and to evaluate the relationship to different causes of piglet losses - increasing piglet survival due to higher maternal abilities of the sow. A total of 1538 purebred litters from 943 German Landrace sows in the year 2004 were available for data analysis. Around 13 971 individually earmarked piglets were included in the analyses. Maternal abilities were characterised through the sow's reaction to the separation from her litter during the first 24 h after farrowing, and on day 21 of lactation, the reaction towards the playback of a piglet's distress call and the reaction towards an unknown noise (music). In 1220 of these litters, the sows were also scored for aggressiveness in the group when regrouped before entering the farrowing crates. To describe fertility, the number of piglets born alive, stillborn piglets, number of piglets born in total and the individual birth weight were utilised. Different causes of piglet losses were evaluated as binary traits of the dam with survival rate, different definitions for crushing by the sow, being underweight and runts. The heritability for being aggressive in the group was h2 = 0.32 and for the behaviour traits during lactation, the heritabilities ranged from h2 = 0.06 to 0.14. The genetic correlations showed that more-reactive sows had fewer piglet losses.