Genetic determination of individual birth weight, litter weight and litter size in Mukota pigs

Genetic parameters for individual birth weight (IBWT), total number of pigs born (NBT), number of pigs born alive (NBA), number of pigs born dead (NBD) and litter weight at birth (LBWT) were estimated using 1961 Mukota pigs kept at the University of Zimbabwe Farm, Harare, Zimbabwe. Variance components were estimated for IBWT based on a direct-maternal genetic effects model. The genetic relationships among NBT, NBA, NBD and LBWT were assessed using a multi-trait direct effects model. For LBWT, the direct, maternal and common environmental litter proportions on the phenotypic variance were 0.090, 0.033 and 0.009, respectively. After adjustment of IBWT for NBA, phenotypic fractions were 0.091, 0.034 and 0.011 for direct, maternal and litter effects. The correlation between the direct and maternal genetic effects of IBWT was − 0.354 and − 0.295, with and without adjustment for NBT. Heritabilities for NBT, NBA, NBD and LBWT were 0.020, 0.030, 0.088 and 0.196, respectively. Differences in the maternal heritability and the heritability for LBWT, a trait of the dam, are different due to accumulation of observations per litter. Maternal genetic effects are, therefore, of less importance than in highly selected European breeds.     

Influence of piglet birth weight on postnatal growth performance, tissue lipogenic capacity and muscle histological traits at market weight

High fecundity of sows induces a large within-litter variation in piglet birth weight. This study aimed to determine whether piglet birth weight influenced growth performance, tissue lipogenic capacity and muscle characteristics at slaughter. A total of 19 piglets were assigned to either light birth weight group (LBW: 0.80-1.10 kg, n=9) or heavy birth weight group (HBW: 1.75-2.05 kg, n=10). Light birth weight was associated significantly with reduced average daily gain during suckling and post-weaning periods only. At slaughter (102±0.6 kg), LBW pigs were 12 days older than HBW littermates (P<0.01). Plasma IGF-I concentration was reduced by 24% (P<0.05) in LBW pigs compared to HBW pigs. Subcutaneous fat depth, tissue lipid content and lipogenic capacity did not differ between groups. Fiber mean cross-sectional area was increased by 14% in semitendinosus, and by 20% in longissimus and rhomboideus muscles, respectively (P<0.05), in LBW pigs compared with HBW pigs. Total fiber number was reduced in both semitendinosus (−13%) and rhomboideus muscles (−20%, P<0.10) of LBW pigs compared with HBW pigs. Whether such histological modifications influence the sensory quality of pork remains to be established.     

Within-litter variation of birth weight in hyperprolific Czech Large White sows and its relation to litter size traits, stillborn piglets and losses until weaning

Data from about 2900 litters (approximately 40,000 piglets) originating from 1063 Czech Large White hyperprolific sows were analyzed. The phenotypic and genetic relations between litter size traits, piglet mortality during farrowing and from birth to weaning and several statistics referring to the distribution of the birth weight within litter were analyzed. All genetic parameters were estimated from multi-trait animal models including the following factors: mating type (natural service or insemination), parity, linear and quadratic regression on age at first farrowing (1st litter) or farrowing interval (2nd and subsequent litters), herd-year-season effect and additive-genetic effect of the sow. The phenotypic correlations of the mean birth weight with the total number of piglets born and piglets born alive were − 0.30. Traits describing the variability of the birth weight within litter (range, variance, standard deviation, coefficient of variation) were mostly positively correlated with litter size. A statistically significant phenotypic correlation (− 0.09 to − 0.15) between mean birth weight and losses at birth and from birth to weaning was found. The heritability for the number of piglets born, piglets born alive and piglets weaned was around 0.15. The number of stillborn piglets had only a very low heritability less than 0.05, whereas the heritability for losses from birth to weaning was 0.13. The heritabilities of the mean, minimal and maximal birth weight were 0.16, 0.10 and 0.10, respectively. The heritability for all statistics and measures referring to the variability of the birth weight within litter was very low and did never exceed the value of 0.05. An increase in litter size was shown to be genetically connected with a decrease in the mean piglet birth weight and an increase in the within-litter variability of birth weight. Selection on litter size should be accompanied by selection on mortality traits and/or birth-weight traits. Losses from birth to weaning and the minimal birth weight in the litter were proposed as potential traits for a selection against piglet mortality.     

Genetic homogenisation of birth weight in rabbits: Indirect selection response for uterine horn characteristics

A divergent selection experiment on within-litter homogeneity of birth weight in rabbits was carried out at the INRA experimental farm at Auzeville. The two lines were created by selecting breeding does and bucks from the female strain AGP22 bred at the Grimaud Frères Sélection Company. This involved a new model incorporating a genotypic value for the mean of individual birth weight and a genotypic value for the environmental variance. This new “trait” was modelled in the usual infinitesimal framework, giving estimated breeding values for environmental variability. There was a favourable selection response with a significant difference in within-litter standard deviation of birth weight between the lines selected for increasing (HOM) or decreasing (HET) homogeneity. At the end of the third generation, 31 females from the HOM line and 33 from the HET line were sacrificed to collect the uterine horns and measure their initial length (L1) and their length after elongation with a weight of 50 g (L2) and then 70 g (L3). The length in the homogeneous line was significantly greater, whatever the weight (L1: + 1.3 cm, P = 0.02; L2:  + 2.8 cm P < 0.001; L3:  + 4.2 cm, P < 0.001). The absolute and the relative elongations were significantly higher in the HOM line. There was no significant effect of the line on the number of ova shed, the weight of the ovary, or the weight of the uterine horns. It is concluded that the divergence between lines for the within-litter homogeneity of birth weight is at least partly due to the characteristics of the genital tract, i.e. the length and capacity for elongation of the uterine horn.     

Birth weight,birth type and pre-weaning survivability of West African Dwarf goats raised in the Dangme West District of the Greater Accra Region of Ghana

A study was conducted on 441 West African Dwarf goat (WADG) kids born from September 1999 to August 2002 at three locations in the Dangme West District of the Greater Accra Region in Ghana to determine the effect of environmental factors on birth weight, birth type and pre-weaning survivability. The overall mean birth weight was 1.32 ± 0.01 kg. Birth weights were similar (p >0.05) between single births (1.43 ± 0.04 kg) and twins (1.34 ± 0.03 kg), but singles were significantly heavier (p < 0.05) than triplets (1.24 ± 0.05 kg). Kids born in the major wet season recorded the best mean birth weight (1.37 ± 0.04 kg). Sex, parity of does, and year of birth of kids had no significant (p > 0.05) effect on birth weight. Mean litter size was 1.93 ± 0.03. Does that kidded in the dry season had a significantly (p < 0.05) higher litter size (2.05 ± 0.06) than those that kidded in the minor wet season (1.80 ± 0.10). Litter size of first-parity kids was significantly smaller (p < 0.05) than in subsequent parities. Litter size dropped significantly (p < 0.05) from year 2 (2.03 ± 0.07) to year 3 (1.83 ± 0.07). Pre-weaning survivability was 79.1% and season of kidding had a significant (p < 0.05) effect on survivability. Survivability of quadruplets (61.8%) was significantly (p < 0.05) lower than in the other birth types.     

Influence of birth order,birth weight,colostrum and serum immunoglobulin G on neonatal piglet survival

Background

Intake of colostrum after birth is essential to stimulate intestinal growth and function, and to provide systemic immunological protection via absorption of Immunoglobulin G (IgG). The birth order and weight of 745 piglets (from 75 litters) were recorded during a one-week period of farrowing. Only pigs weighing greater than 0.68 kg birth weight were chosen for the trial. Sow colostrum was collected during parturition, and piglets were bled between 48 and 72 hours post-birth. Piglet serum IgG and colostral IgG concentrations were determined by radial immunodiffusion.

Results

Sow parity had a significant (P < 0.001) effect on sow colostral IgG concentration, being 5% higher in multiparous females. Sow colostral IgG concentration explained 6% and piglet birth order accounted for another 4% of the variation observed in piglet serum IgG concentration (P < 0.05); however, birth weight had no detectable effect. Piglet serum IgG concentration had both a linear (P < 0.05) and quadratic effect (P < 0.05) on % survival. Piglets with 1,000 mg/dl serum IgG or less (n=24) had a 67% survival; whereas, piglets with IgG concentrations between 2250 to 2500 mg/dl (n=247) had a 91% survival. Birth order had no detectable effect on survival, but birth weight had a positive linear effect (P < 0.05). Piglets weighing 0.9 kg (n = 107) at birth had a 68% survival rate, and those weighing 1.6 kg (n = 158) had an 89% survival.

Conclusion

We found that the combination of sow colostrum IgG concentration and birth order can account for 10% of the variation of piglet serum IgG concentration and that piglets with less than 1,000 mg/dl IgG serum concentration and weight of 0.9 kg at birth had low survival rate when compared to their larger siblings. The effective management of colostrum uptake in neonatal piglets in the first 24 hrs post-birth may potentially improve survival from birth to weaning.     

Comparison of sow farrowing characteristics between a Chinese breed and three French breeds

Sow farrowing characteristics, including litter size, stillbirth, kinetics of births and piglet weight traits, were compared in 4 populations: Meishan (MS), Large White (LW), Duroc × Large White (DU × LW) and Laconie (LA). The kinetics of births was characterised by farrowing duration (FD), birth interval (BI), and farrowing irregularity, estimated by the standard deviation of BI (SDBI). The within-litter distribution of piglet birth weights was described by different traits including the mean (MBW) and standard deviation (SDBW) of birth weight. Additional characteristics of the sow were also analysed: weight at farrowing (SWF), gestation length (GEST), and birth assistance (BA). The data set included 47 MS, 605 LW, 55 DU × LW and 160 LA litters. For analyses, multivariate methods were used, including principal component analyses (PCA) and multiple factorial analyses (MFA). These methods allowed the relative importance of between-breed and within-breed variability of the correlation structure to be estimated and the homogeneity between populations (by comparison of the 4 breed correlation structures) to be investigated. Though most of the variability was observed within-breed (97%), between-breed variation appeared to be highly significant (P < 0.0001). This variation was essentially due to the Meishan breed departing from others, because of the lower weight at farrowing and, to a lesser extent, to the lower number of stillbirths and lower piglet mean and standard deviation in birth weight. Litter size did not contribute much to the variability between breeds. The rather strong correlations related to between-breed structures (r > 0.70) indicated that the correlation pattern was similar among breeds. Stillbirth was independent from litter size and appeared as closely associated with farrowing duration in the French breeds.     

Relationships among steroid hormone levels in newborn piglets,birth weight,placental weight,vitality of offspring and litter size

Blood estrone sulfate (E₁S), estrone (E₁), estradiol (E₂) and progesterone (P₄) in newborn piglets were measured to clarify the relationships among birth and placental weight, vitality of offspring and litter size. First, the association between vital status (normal, weak and stillborn) from 165 newborn piglets of 18 litters and steroid concentrations; second, steroid concentrations from 152 newborn normal piglets and litter size; and third, steroid content in fetal placenta from 50 newborn normal piglets of six litters and litter size, were investigated. In the normal group, the birth and placental weight were significantly higher than those in the other groups. Blood E₁S levels in the stillborn group were significantly lower, whereas E₁, E₂ and P₄ were significantly higher compared to the normal group. Blood and placental E₁S levels in the small litter group were significantly higher than those in the other groups. However, there was no significant difference among the three litter size groups in the levels of steroid hormones in maternal blood. These results indicate that vitality of newborn piglets is related to E₁S concentration of neonate, to birth weight and placental weight. However, steroid hormone concentrations of newborn piglets were greatly affected by the number of littermates.     

Results of four generations of a canalising selection for rabbit birth weight

A divergent selection experiment based on the homogeneity of birth weight in rabbit was carried out at the INRA experimental farm of Auzeville. The two lines were created by selecting breeding does and bucks from the female strain AGP22 bred at the Grimaud Frères Sélection company for environmental variability of birth weight. This involved a new model incorporating a genotypic value for the mean and a genotypic value for the environmental variance. There was a selection response with a significant difference in the within-litter standard deviation of birth weight between the lines after four generations of selection (6.93 g vs. 8.13 g). The mortality of kits at birth and from birth to weaning was lower in the “homogeneous” line than in the “heterogeneous” line (16.6% vs. 18.6% and 17.7% vs. 32.7%, respectively). The litter size at weaning was higher in the “homogeneous” line (7.22 vs. 5.39). The selection on the homogeneity of birth weight had no significant influence on the other traits. It was concluded that selection for reduced environmental variance of birth weight improved young rabbit survival without reducing the mean of birth weight.     

Genetic parameters for individual birth and weaning weight and for litter size of Large White pigs

Data from a French experimental herd recorded between 1990 and 1997 were used to estimate genetic parameters for individual birth and weaning weight, as well as litter size of Large White pigs using restricted maximum likelihood (REML) methodology applied to a multivariate animal model. In addition to fixed effects the model included random common environment of litter, direct and maternal additive genetic effects. The data consisted of 1928 litters including individual weight observations from 18 151 animals for birth weight and from 15 360 animals for weaning weight with 5% of animals transferred to a nurse. Estimates of direct and maternal heritability and proportion of the common environmental variance for birth weight were 0.02, 0.21 and 0.11, respectively. The corresponding values for weaning weight were 0.08, 0.16 and 0.23 and for litter size 0.22, 0.02 and 0.06, respectively. The direct and the maternal genetic correlations between birth and weaning weight were positive (0.59 and 0.76). Weak positive (negative) genetic correlations between direct effects on weight traits and maternal effects on birth weight (weaning weight) were found. Negative correlations were found between direct genetic effect for litter size and maternal genetic effects on all three traits. The negative relationship between litter size and individual weight requires a combined selection for litter size and weight.     

Effect of piglet birth weight on body weight,growth, backfat,and longissimus muscle area of commercial market swine

The objective of this study was to estimate the effect of piglet birth weight on future BW, growth, backfat, and longissimus muscle area of pigs in a commercial U.S. production system. Pigs (n = 5727) at a commercial farm were individually weighed and identified within 24 h of birth. Weights were collected prior to weaning (n = 4108), after finisher placement (n = 3439), and 7 (n = 1622) and 16 (n = 1586) weeks into finishing; hot carcass weight was also collected (n = 1693). Average daily gain during lactation, nursery, finishing, and overall (birth to 16 weeks into finishing) was calculated. During BW collection 16 weeks into finishing, real-time ultrasound backfat thickness and longissimus muscle area were measured. Sex × birth weight (linear and quadratic) interactions were observed for BW at weaning and finisher placement and daily gain during pre-weaning and nursery. Linear birth weight × cross foster interactions were observed for weaning weight and pre-weaning gain. Linear and quadratic effects of birth weight on BW at weaning, finisher placement, 7 and 16 weeks into finishing, and hot carcass weight and average daily gain during pre-weaning, nursery, finishing, and total were observed. For all measures of BW and average daily gain, as birth weight increased subsequent BW and average daily gain increased at a decreasing rate; however, for the sex × birth weight (linear and quadratic) interactions, heavier birth weight barrows were lighter and grew slower than gilts of comparable birth weight. Worth noting, the birth weight × sex interactions described very few pigs in the extreme portion of the birth weight distribution. For birth weight × cross foster interactions, non-cross fostered pigs were increasingly heavier and faster growing as birth weight increased compared to cross fostered pigs. Heavier birth weight pigs tended to have increased backfat depth (P = 0.07). Linear and quadratic effects of birth weight on longissimus muscle area were observed; as birth weight increased muscling increased at a decreasing rate. Regardless of interactions or period of production, increased birth weight resulted in heavier future BW, faster daily gain along with larger longissimus muscle area prior to harvest. In all instances the magnitude of the negative effect of birth weight increased as birth weight decreased.     

Genetic analyses of piglet survival and individual birth weight on first generation data of a selection experiment for piglet survival under outdoor conditions

Genetic parameters of piglet survival traits and birth weight were estimated on the first generation data of a selection experiment aimed at improving piglet survival using a multiple trait linear and threshold model. Data on 5293 piglets for survival at birth, at day one after birth and during the entire nursing period, as well as individual birth weight and litter size, were recorded in an outdoor production system. Genetic effects of piglet survival traits and birth weight were estimated based on threshold and Gaussian models, respectively, using a Bayesian approach. The statistical model included as fixed effects selection group, parity, gender, fostering, gestation length and month of farrowing and, alternatively, an adjustment for litter size. Direct genetic effects (i.e. the piglet's genetic potential) for piglet survival and birth weight were estimated separately, whereas maternal genetic and environmental effects could only be estimated for the given data structure in a combined litter effect. Posterior means of heritabilities for direct genetic effects of survival at birth, at first day after birth and the entire nursing period, as well as birth weight, were 0.08, 0.07, 0.08 and 0.20, respectively. Genetic correlations among survival traits were in the range of 0.29 to 0.40 and indicate that these traits were mainly attributable to different genetic effects. Genetic correlations between direct effects of survival traits and birth weight ranged between 0.18 and 0.23 and were reduced when weights of stillborn piglets were omitted in the analysis or the traits were adjusted for litter size. The magnitudes of direct genetic effects of survival traits are substantially higher than estimates in the literature, which may indicate that these traits have a higher genetic influence under outdoor conditions. The use of birth weight in the multiple trait estimation provided important information for the estimation of survival traits due to its favourable genetic correlations with survival, its high heritability and its high information content as a continuously measured trait.     

Influence of birth weight and nutrient supply before and after weaning on the performance of rabbit does to age of the first mating

The objective of the study was to determine the effect of birth weight and the influence of nutrient supply during nursing and after weaning on the performance of suckling and growing rabbits (n = 182). The experiment was set-up using a 3 × 2 × 2 factorial arrangement. Newborn female rabbits were divided on the basis of their birth weight in 3 classes: low /L/ = 35–45 g, medium /M/ = 53–58 g and high /H/ = 65–70 g. Half of the litters were nursed by one (O) doe and the other half by two does (T). Kits were weaned at 3 weeks of age. From the age of 4 weeks half of the rabbits were fed ad libitum (AL), while the other half were reared on a restricted feeding regime (R) corresponding to 80–85% of the ad libitum feed intake level.Birth weight had a significant effect on the body weight up to the end of the experiment (18 weeks of age). H kits attained higher body weight at all ages (3772 g at 18 weeks of age compared to 3565 g and 3373 g for L and M rabbits, respectively). Significant differences were found in feed intake between 3 and 15 weeks of age, in feed conversion between 9 and 12 weeks of age and in weight gain between 3 and 4 and 12 and 15 weeks of age, in the majority of cases in favour of the H rabbits.Nursing by one or two does exerted the most pronounced effect on the body weight. T kits had significantly higher body weight than O kits up to 15 weeks of age (3306 vs. 3108 g). Differences in feed intake, feed conversion and body weight were only periodically demonstrable between the groups O and T.The feeding regime exerted a significant influence on the feed intake, weight gain and body weight of kits. Significant differences in the feed conversion were found, however, only between 15 and 18 weeks of age. Although AL rabbits achieved better feed conversion at all ages except the period between 9 and 12 weeks of age.It seems that the three factors (birth weight, number of nursing does and feeding regime), especially the feed restriction, could influence the production of does.     

Genetic parameters for individual birth and weaning weight and for litter size of Large White pigs

Data from a French experimental herd recorded between 1990 and 1997 were used to estimate genetic parameters for individual birth and weaning weight, as well as litter size of Large White pigs using restricted maximum likelihood (REML) methodology applied to a multivariate animal model. In addition to fixed effects the model included random common environment of litter, direct and maternal additive genetic effects. The data consisted of 1928 litters including individual weight observations from 18151 animals for birth weight and from 15360 animals for weaning weight with 5% of animals transferred to a nurse. Estimates of direct and maternal heritability and proportion of the common environmental variance for birth weight were 0.02, 0.21 and 0.11, respectively. The corresponding values for weaning weight were 0.08, 0.16 and 0.23 and for litter size 0.22, 0.02 and 0.06, respectively. The direct and the maternal genetic correlations between birth and weaning weight were positive (0.59 and 0.76). Weak positive (negative) genetic correlations between direct effects on weight traits and maternal effects on birth weight (weaning weight) were found. Negative correlations were found between direct genetic effect for litter size and maternal genetic effects on all three traits. The negative relationship between litter size and individual weight requires a combined selection for litter size and weight.     

Compensatory feeding during early gestation for sows with a high weight loss after a summer lactation increased piglet birth weight but reduced litter size

Sows mated in summer produce a greater proportion of born-light piglets (<1.1 kg) which contributes to increased carcass fatness in the progeny population. The reasons for the low birth weight of these piglets remain unclear, and there have been few successful mitigation strategies identified. We hypothesized that: 1) the low birth weight of progeny born to sows mated in summer may be associated with weight loss during the previous summer lactation; and 2) increasing early gestation feed allowance for the sows with high lactational weight loss in summer can help weight recovery and improve progeny birth weight. Sows were classified as having either low (av. 1%) or high (av. 7%) lactational weight loss in their summer lactation. All the sows with low lactational weight loss (LLStd) and half of the sows with high lactational weight loss received a standard gestation feeding regime (HLStd) (2.6 kg/d; day 0–30 gestation), whereas the rest of the sows with high lactational weight loss received a compensatory feed allowance (HLComp) (3.5 kg/d; day 0–30 gestation). A comparison of LLStd (n = 75) versus HLStd sows (n = 78) showed that this magnitude of weight loss over summer lactation did not affect the average piglet or litter birth weight, but such results may be influenced by the higher litter size (P = 0.030) observed in LLStd sows. A comparison of HLStd versus HLComp (n = 81) sows showed that the compensatory feeding increased (P = 0.021) weight gain of gestating sows by 6 kg, increased (P = 0.009) average piglet birth weight by 0.12 kg, tended to reduce (P = 0.054) the percentage of born-light piglets from 23.5% to 17.1% but reduced the litter size by 1.4 (P = 0.014). A subgroup of progeny stratified as born-light (0.8–1.1 kg) or -normal (1.3–1.7 kg) from each sow treatment were monitored for growth performance from weaning until 100 kg weight. The growth performance and carcass backfat of progeny were not affected by sow treatments. Born-light progeny had lower feed intake, lower growth rate, higher G:F, and higher carcass backfat than born-normal progeny (all P < 0.05). In summary, compensatory feeding from day 0 to 30 gestation in the sows with high weight loss during summer lactation reduced the percentage of born-light progeny at the cost of a lower litter size, which should improve growth rate and carcass leanness in the progeny population born to sows with high lactational weight loss.     

Interactions between the associations of parity, lactation length, and weaning-to-conception interval with subsequent litter size in swine herds using early weaning

Sixteen farms having an average lactation length between 14.9 and 18.9 days were selected based upon producers' willingness to keep records of production and lactation feed intake. Data contained 9162 subsequent litter-size records abstracted from computerized production information-system files and lactation feed-intake records. Two-way interactions between the associations of parity and lactation length, and parity and weaning-to-conception interval with subsequent litter size were found in the same statistical model. Subsequent litter size did not increase in parities 1 and 2 as lactation length increased – but subsequent litter size in sows of parities 3–6 increased. In only parity 1, sows with weaning-to-conception interval 6–12 days produced 0.5 fewer pigs at subsequent farrowing than those with weaning-to-conception interval 1–5 days. However, in multiparous sows, no difference in subsequent litter size was found between weaning-to-conception intervals 1–5 and 6–12 days.     

Genetic control of the environmental variance for birth weight in seven generations of a divergent selection experiment in mice

Data from seven generations of a divergent selection experiment designed for environmental variability of birth weight were analysed to estimate genetic parameters and to explore signs of selection response. A total of 10 783 birth weight records from 638 females and 1127 litters in combination with 10 007 pedigree records were used. Each record of birth weight was assigned to the mother of the pup in a heteroscedastic model, and after seven generations of selection, evidence of success in the selection process was shown. A Bayesian analysis showed that success of the selection process started from the first generation for birth weight and from the second generation for its environmental variability. Genetic parameters were estimated across generations. However, only from the third generation onwards were the records useful to consider the results to be reliable. The results showed a consistent positive and low genetic correlation between the birth weight trait and its environmental variability, which could allow an independent selection process. This study has demonstrated that the genetic control of the birth weight environmental variability is possible in mice. Nevertheless, before the results are applied directly in farm animals, it would be worth confirming any other implications on other important traits, such as robustness, longevity and welfare.     

Effect of early gestation feeding, birth weight, and gender of progeny on muscle fiber characteristics of pigs at slaughter

Maternal nutrition and progeny birth weight affect muscle fiber development in the pig, thereby influencing early postnatal growth rate. The objective of the study was to determine the extent to which growth, morphometric characteristics, and area and distribution of slow-oxidative (SO), fast oxidative-glycolytic (FOG), and fast glycolytic (FG) fibers of three muscles (LM = longissimus muscle; RF = rectus femoris; ST = semitendinosus) of slaughter pigs were affected by DE intake level during the first 50 d of gestation. Multiparous Swiss Large White sows were assigned randomly to one of three energy intake treatments: 1) fed 2.8 kg/d of a standard diet (STD; n = 6) containing 10.7 MJ DE/kg; 2) fed 2.8 kg/d of a low-energy diet (LE; n = 5) containing 6.6 MJ DE/kg; or 3) fed 4.0 kg/d of a standard diet (HE; n = 5) containing 10.7 MJ DE/kg (as-fed basis). Sows were subjected to energy intake treatments for the first 50 d of gestation; however, from d 51 to parturition, sows received 2.8 kg/d of the standard diet, and the amount of feed offered each sow during lactation was adjusted according to the litter size. Sows farrowed normally and pig birth weights were recorded. Based on birth weight, the two lightest (1.27 kg; Lt) and two heaviest (1.76 kg; Hvy) barrows and gilts from the 16 litters (n = 64) were selected at weaning and were offered a fixed amount of feed (170 g x BW(0.569)/d) from 25 to 105 kg BW. Regardless of the birth weight, progeny from HE sows grew slower (P < 0.05) during lactation and the growing-finishing period, had a lower (P < 0.05) gain-to-feed ratios, and had higher (P < 0.05) percentages of adipose tissue than pigs born from LE sows. The ST was shorter (P = 0.03) in Lt than in Hvy pigs, and the ST of gilts was heavier (P = 0.01) and had a larger (P = 0.01) girth than the ST of barrows. Overall mean fiber area tended to be larger (P < or = 0.11) in the LM and light portion of the ST of Lt than in Hvy pigs, and was larger (P = 0.03) in the ST of gilts than barrows. The ST of progeny from LE sows had fewer (P < 0.10) FG fibers, which was compensated by either more (P < 0.05) FOG in the light portion of the ST, or more (P < 0.10) SO fibers in the dark portion, and these differences were more pronounced in Lt pigs than in Hvy pigs. Overall, maternal feeding regimen affected muscle fiber type distribution, whereas birth weight and gender affected muscle fiber area.