Effects of Direct Additive and Direct Dominance on Litter Traits in Crossbred Sows between Danish Yorkshire and Danish Landrace Pigs in Vietnam

Background: The objectives of this study were to estimate the effects of direct additive and dominance on litter traits and to predict the reproduction of un-tested crossbred sows between Danish Yorkshire (Y) and Danish Landrace (L) pigs in Vietnam. Methods: Litter traits data were obtained between 2014 and 2017 in Binh Thang and Khang Minh An breeding farms, with 671 litters of crossbred sows crossed from 1,308 litters of purebred Yorkshire and Landrace sows. Result: In F1 sows, heterosis was manifested in all traits with 6.7-6.4% for TNB; 5.4-6.2% for NBA; 4.4-4.8% for NW and 5.7-6.0% for AWW traits. Additionally, direct dominance was the most positive effect on litter traits in crossbred sows. In rotational crossbred sows of L (YL) and L (LY), while the value of litter traits remarkably decreased in comparison with F1 groups, it was a noticeably higher than that of the purebred sows by 1.4-3.0%. In un-tested crossbred groups of Y (YL) and Y (LY), predicted values for litter traits were equal in tested crossbred groups of L (YL) and L (LY) and lower than F1 crossbred sows.

PSXII-12 Partitioning direct and maternal genetic effects into additive and non-additive components for growth and maternal traits in Yorkshire pigs

This study investigates how much direct and maternal non-additive genetic effects contribute to growth and maternal traits in swine. We analyzed a sample of 19,475 genotyped Yorkshire pigs from Acuity Ag Solutions, LLC (Carlyle, IL). Approximately 50K SNPs were kept after quality control, and missing genotypes were then imputed using findhap.f90. The genotypes were used to construct genomic relationship matrices (GRMs) corresponding to additive (A), dominance (D), and additive-by-additive epistasis (E) effects for both direct and maternal effects. The GRMs were subsequently employed as covariance structure matrices in a linear mixed model consisting of eight random components, namely three direct genetic effects (Ad, Dd, and Ed), three maternal genetic effects (Am, Dm, and Em), maternal environmental effect, and common litter environmental effect. We estimated these variance components (VCs) for six growth traits (birth weight, average daily gain, back fat, and loin area) and six maternal traits of a sow (total number of piglets born, number of piglets born alive, average weight of piglets at birth, average weight of piglets weaned) using REML in MMAP (https://mmap.github.io/). As shown in Table 1, we found significant (P< 0.05) direct dominance and epistasis VCs for all six growth traits. Additionally, direct epistasis effects explained a larger proportion of phenotypic variation than direct dominance for all growth traits (0.04–0.12 vs. 0.01–0.04). In contrast, direct non-additive VCs were not significant for any maternal trait except for epistasis in average weight of piglets weaned. As for maternal non-additive effects, we only discovered significant additive VC in birth weight and average daily gain and significant epistasis VC in back fat (P< 0.05). Other maternal genetic VCs were largely negligible. In summary, direct dominance and epistasis effects play a prominent role in growth traits of Yorkshire pigs.

Evaluation of beef cattle genotypes and estimation of direct and maternal genetic effects in a tropical environment. 3. Fertility and calf survival traits

Data from a crossbreeding experiment were analysed to compare various breeds in a tropical environment. Data included male fertility [scrotal circumference at yearling age (YSC) and at 18 months of age (FSC)], female fertility [calving success (CS) and days to calving (DTC)], and calf survival [survival of calf up to 1 week after birth (WKS) and up to weaning (PWS)] traits. Male fertility traits were analysed as traits of the progeny generation, whereas female fertility and calf survival traits were analysed as traits of the dam (parental generation). Tropically adapted British breed bulls and taurine crossbreds (British × Sanga) had higher YSC and FSC than Zebu and its crosses when adjusted for their body weights. Large negative direct and maternal additive effects on scrotal circumference for Zebu relative to the British breed also suggested reduced scrotal circumference and fertility in Zebu and Zebu-derived crosses. Direct dominance effects for YSC and FSC were only significant when an adjustment for body weight was not included in the model, emphasising that the heterosis observed was only due to the increased body weight. In general, CS was higher in non-lactating cows and maiden heifers than in lactating cows. The advantage to crossbred genotypes was more pronounced in lactating cows. Among lactating purebreds, CS was significantly (P < 0.05) higher in Belmont Adaptaur (Hereford–Shorthorn, HS) than in Belmont Red (AX), Belmont Brahman cross (BX), and Brahman (Bh). Lactating crossbreds with a common dam breed of HS, AX, BX, and Bh had 19, 33, 21, and 14% greater CS than their respective purebreds. Boran-sired crossbred dams had higher CS than Brahman-sired crossbreds, indicating higher fertility levels of Borans. Significant direct dominance effect for CS in lactating taurine–indicine crosses and in non-lactating taurine–taurine crosses signifies the importance of use of appropriate breed crosses in improving female fertility. Significantly negative (desirable) direct dominance effects for DTC in indicine–indicine and taurine–indicine crosses suggest an advantage from crossbreeding in achieving early calvings. High mortalities were recorded in calves born to HS dams from matings with Brahman bulls due to dystocia. This resulted in low WKS and PWS for HS dam breeds. All additive and dominance effects for calf survival traits were non-significant except for the direct dominance effect in taurine–indicine crosses for PWS. Moderate percentage heterosis estimates in lactating cows for CS and desirable, significant, but low percentage heterosis estimates for DTC were observed. Percentage heterosis estimates for calf survival traits were low and non-significant.

PARALLEL ALGORITHMS FOR SOME DOMINANCE PROBLEMS BASED ON THE PRAM MODEL

Two parallel geometric algorithms based on the idea of point domination are presented. The first algorithm solves the d-dimensional isothetic rectangles intersection counting problem of input size N/2d, where d>1 and N is a multiple of 2d, in O( log d−1 N) time and O(N log N) space. The second algorithm solves the direct dominance reporting problem for a set of N points in the plane in O( log N+J) time and O(N log N) space, where J denotes the maximum of the number of direct dominances reported by any single point in the set. Both algorithms make use of the EREW PRAM (Exclusive Read Exclusive Write Parallel Random Access Machine) consisting of O(N) processors as the computational model.

Lurin Valley, Peru: Early Intermediate Period Settlement Development

The relationships between the social development in the upper Lurin valley and an expanding Early Intermediate period Lima state are examined. Internally, population growth and irrigation complexity progress together in the Lurin. Warfare, although not directly caused by population expansion, may function to regulate population. With irrigation and population expansion, a local social stratification originates but political control remains highly dispersed. A centralized control is only initiated by the external introduction of direct dominance by the Lima state.