Production and reproduetive traits in Danish Landrace (LD) and Large White (LW) swine were analysed by restricted maximum likelihood methods to obtain heritabilities as well as genetic and phenotypic correlations. Production traits were: age, backfat thickness (BT), muscle depth (MD) and the ratio BT/MD, adjusted to Standard bodyweight of 85 kg. Reproduction traits were: number of pigs born (NB) and number of pigs weaned (NW) per sow and parity. Heritabilities for age, BT, MD and BT/MD were 0.60, 0.44, 0.51 and 0.42 for LD and 0.36, 0.44, 0.37 and 0.45 for LW, respectively. Genetic correlations between age and BT were-0.22 in LD and-0.44 in LW. The genetic correlation between age and MD was close to zero in both breeds. Genetic correlation between BT and MD were-0.36 and-0.25 in LD and LW, respectively. Heritabilities for NB were 0.25 in LD and 0.13 in LW while heritabilities for NW were close to zero in both breeds. Genetic correlation between NB and NW was 0.46 and 0.70 in LD and LW, respectively. Zusammenfassung Titel der Arbeit: Genetische Parameter von Produktions-und Reproduktionsmerkmalen bei Schweinen der Rassen Danish Large White und Landrasse untersucht in einem Betrieb in Griechenland Heritabilitäten sowie phänotypische und genetische Korrelationen einiger Produktions-und Reproduktions-merkmale bei Schweinen der Rassen Danish Large White (LW) und Landrasse (LD) wurden mit Restricted Maximum Likelihood Methoden geschätzt. Folgende Produktionsmerkmale wurden untersucht: Alter, Rückenspeckdicke (BT), Muskeldicke (MD) und das BT/MD Verhältnis, korrigiert auf ein konstantes Körpergewicht von 85 kg. Folgende Reproduktionsmerkmale wurden untersucht: Wurfgrösse bei der Geburt (NB) und beim Absetzen (NW). Bei den LD-Schweinen wurden Heritabilitätswerte von 0,60 ftlr das Alter, 0,44 flir die BT, 0,51 ftlr die MD und 0,42 ftlr das BT/MD Verhältnis geschätzt. Die entsprechenden Werte bei den LW-Schweinen waren 0,36 für das Alter, 0,44 für die BT, 0,37 für die MD und 0,45 für das BT/MD Verhältnis. Die geschätzte genetische Korrelation zwischen dem Alter und der BT betrug-0,22 bei den LD-und-0,44 bei den LW-Schweinen, während die entsprechende Korrelation zwischen dem Alter und der MD in beiden Rassen nahe Null lag. Die geschätzte genetische Korrelation zwischen der BT and der MD betrug-0,36 bei den LD-und-0,25 bei den LW-Schweinen. Die Heritabilitätswerte für die NB betrug 0,25 bei den LD-und 0,13 bei den LW-Schweinen, während die entsprechenden Werte für die NW bei beiden Rassen gleich Null waren. Zwischen der NB und der NW wurde eine genetische Korrelation von 0,46 bei den LD-und von 0,70 bei den LW-Schweinen ermittelt.

The objective of this study was to investigate the importance of maternal genetic effects on postweaning performance traits of Yorkshire, Landrace, Duroc, and Hampshire breeds of swine. Data consisted of performance test records collected in a commercial swine operation from 1992 to 1999. Boars from 60% of the litters were culled at weaning based on a combination of maternal and performance indexes that differed by breed. Remaining boars and all females were grown to 100 d of age. At this time all pigs were weighed (WT100) and selected for testing using recalculated breed-specific indexes (n = 15,594, 55,497, 12,267, and 9,782 for Landrace, Yorkshire, Duroc, and Hampshire, respectively). All pigs were weighed at the end of the 77-d test, and backfat (BF) and loin eye area (LEA) were measured over the 12th rib by ultrasound. Average daily feed intake was calculated for boars, and ADG was calculated for all animals. Genetic parameters were estimated for each breed and trait using multiple-trait DFREML procedures. Fixed effects were contemporary groups and either initial or final test age as a covariate. Four models were examined. Model 1 included only the additive genetic effect of the animal. Model 2 added the common litter environmental effect; Model 3 added the maternal genetic value assumed to be uncorrelated with additive genetic effects. Model 4 was the same as Model 3 with additive and maternal genetic effects assumed to be correlated. All models were two-trait models with WT100 as the second trait. Ratios of likelihoods were used to compare models. Maternal effects were important (P < 0.05) for WT100, ADG, ADFI, LEA, and BF in Landrace; for WT100, ADG, LEA, and BF in Yorkshire; for WT100 and ADG in Duroc, and for WT100 in Hampshire. Estimates of heritabilities for direct additive effects using the appropriate model for ADG, ADFI, LEA, and BF were 0.28, 0.34, 0.48, and 0.63 for Landrace; 0.26, 0.31, 0.39, and 0.65 for Yorkshire; 0.14, 0.20, 0.26, and 0.35 for Duroc; and 0.17, 0.23, 0.25, and 0.31 for Hampshire, respectively. Heritability estimates for maternal genetic effects for ADG, ADFI, LEA, and BF were 0.02, 0.05, 0.06, and 0.07 for Landrace and 0.02, 0, 0.04, and 0.06 for Yorkshire, respectively. They were zero for all traits except ADG (0.03) in Duroc and for all traits in Hampshire. Maternal effects may need to be considered in genetic evaluation of performance traits in some breeds of swine.

Knowledge of the relationships between absolute growth rate (AGR), relative growth rate (RGR) and feed conversion (FCONV) of bulls in postweaning feedlot performance tests can give cattle producers important information for selecting superior sires. Weight gain and FCONV data that were collected during 16 yr were analyzed from 393 Angus and 340 Hereford bulls by 26 and 27 sires, respectively, that were individually fed in 140-d tests. Sire variance and covariance components were used to obtain heritability (h2) estimates for AGR, RGR and FCONV and the genetic correlations (rg) and phenotypic correlations (rp) among these traits. Respective mean AGR, RGR and FCONV were 1.27 +/- .14 kg/d, .4378 +/- .0395%/d and 7.32 +/- .58 kg/kg for the Angus and 1.28 +/- .12 kg/d, .4552 +/- .0388%/d and 6.56 +/- .46 kg/kg for the Hereford bulls. Estimates of h2 were similar for AGR and RGR in both Angus (.36 +/- .11 and .22 +/- .09) and Hereford (.33 +/- .11 and .20 +/- .09) bulls. The h2 estimates for FCONV were .14 +/- .07 for Angus and .13 +/- .08 for Herefords. For the Angus and Hereford bulls, respectively, rg were .86 +/- .09 and .86 +/- .13 between AGR and RGR, -.84 +/- .38 and -.74 +/- .49 between AGR and FCONV and -.84 +/- .49 and -.61 +/- .64 between RGR and FCONV. The rp were .80 +/- .03 and .68 +/- .04 between AGR and RGR, -.58 +/- .05 and -.51 +/- .05 between AGR and FCONV and -.71 +/- .04 and -.73 +/- .04 between RGR and FCONV for the Angus and Hereford bulls, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

A study was conducted using 3 groups of gestating gilts and sows (n = 98) to determine the effects of Pichia guilliermondii (Pg), a whole cellinactivated yeast product (CitriStim; ADM Alliance Nutrition), on performance and immune parameters of dams and litters. Within 24 h of breeding, gilts and sows were allotted to 1 of 3 treatments consisting of a control (SC) diet or SC diet supplemented with 0.1 (S1) or 0.2% (S2) Pg. Dietary treatments were maintained through lactation. Colostrum and milk (day 14) samples were collected for IgA, IgG, and IgM analysis. Blood samples were collected from sows on day 110 of gestation (group 3 only), while at weaning for all 3 groups, and from piglets at 14 d of age for peripheral white blood cell counts and serum IgA, IgG, and IgM analysis. Inclusion of Pg resulted in an increase in number born alive as the level of Pg increased (12.49, 13.33, and 13.43 born alive per litter for SC, S1, and S2, respectively; linear effect [LS], P = 0.003). Additionally, the percentage of piglets weighing less than 0.9 kg at birth was reduced in sows provided Pg at 0.1% or 0.2% compared with control (LS, P = 0.006). Sows receiving Pg during gestation and lactation also weaned a greater number of piglets (10.31, 10.55, and 10.60 weaned per litter in control, 0.1% and 0.2% Pg, respectively; LS, P = 0.02). However, percent preweaning mortality was 17.58%, 19.38%, and 19.61% for control, 0.1%, and 0.2% Pg, respectively (LS, P = 0.02). There were no differences in gestation BW gain, farrowing (days 110 to 48 h postfarrowing) or lactation (day 110 to weaning) BW loss, number of mummies or stillborn, or piglets' individual birth or weaning weight. On day 110 of gestation, the neutrophil concentration (quadratic effect [QS], P = 0.03) and neutrophil:lymphocyte ratio (QS, P = 0.04) in peripheral blood were greater in S1 than SC, with S2 being intermediate. At weaning there was a linear increase in neutrophil concentration (P = 0.03), neutrophil:lymphocyte ratio (P = 0.01), and percentage of neutrophils in the leukocyte population (P = 0.01) as level of Pg increased in sow diets. In conclusion, Pg inclusion in sow diets linearly increased total number born alive and weaned, with no change in average birth or weaning weight, and decreased the number of lightweight pigs at birth. However, inclusion of Pg had no effect on immune parameters measured in milk, colostrum, or day 14 piglet serum, but increased the peripheral blood neutrophil concentration of gilts and sows.