Unfavorable Genetic Correlations Research Articles

Genetic correlations between disease resistance, vaccine-induced side effects and harvest body weight in Atlantic salmon ( Salmo salar)

The objective of this study was to estimate the genetic correlations between vaccine-induced side effects, disease resistance and growth in Atlantic salmon. This was obtained using data from four independent sib groups from each of 144 to 279 families of the same year-class from SalmoBreed AS. Resistance to furunculosis was recorded as survival of unvaccinated (FUR, 279 families) and vaccinated (FUR-V, 150 families) presmolts in two separate challenge tests, while resistance to infectious salmon anemia (ISA) was recorded as survival in a third challenge test with unvaccinated presmolt (ISA, 279 families). Vaccine-induced side effects and growth (body weight at harvest) of vaccinated fish was evaluated on the fourth sample 12 months after sea transfer (SW12, 144 families). The genetic correlations of vaccine-induced side effects with resistance to furunculosis (of both vaccinated and unvaccinated fish) and ISA (unvaccinated fish) and with growth were not significantly different from zero. Therefore, selection for one of these traits is not expected to result in large unfavorable correlated response in the other traits. However, a low, albeit significant, unfavorable genetic correlation was found for growth with resistance to furunculosis in vaccinated fish (FUR-V), while that with unvaccinated fish (FUR) was not significantly different from zero. This may indicate that the best responders to vaccination may direct more resources into immunological reactions which, in accordance to resource reallocation theory, may leave fewer resources for growth.

Genetic and Economic Analysis for the Relationship between Udder Health and Milk Production Traits in Friesian Cows

A total of 4,752 monthly lactation records of Friesian cows during the period from 2000 to 2005 were used to estimate genetic parameters and to determine the effect of udder health on milk production traits. Three milk production traits were studied: 305- day milk yield (305-dMY), 305-day fat yield (305-dFY) and 305-day protein yield (305-dPY). Four udder health traits were studied: somatic cell count (SCC), mastitis (MAST), udder health status (UDHS) with 10 categories and udder quarter infection (UDQI) with 7 categories. Mixed model least square analysis was used to estimate the fixed effects of month and year of calving and parity (P) on different studied traits. Sire and dam within sire were included in the model as random effects. Data were analyzed using Multi-trait Derivative Free Restricted Maximum Likelihood methodology (MTDFREML) to estimate genetic parameters. Unadjusted means of 305-dMY, 305-dFY, 305-dPY and SCC were 3,936, 121, 90 kg and 453,000 cells/ml, respectively. Increasing SCC from 300,000 to 2,000,000 cells/ml increased UDQI from 5.51 to 23.2%. Losses in monthly and lactationally milk yields per cow ranged from 17 to 93 and from 135 to 991 kg, respectively. The corresponding losses in monthly and lactationally milk yields return per cow at the same level of SCC ranged from 29.8 to 163 and from 236 to 1,734 Egyptian pounds, respectively. Heritability estimates of 305-dMY, 305-dFY, 305-dPY, SCC, MAST, UDHS, UDQI were 0.31±0.4, 0.33±0.03, 0.35±0.05, 0.23±0.02, 0.14±0.02, 0.13±0.03, and 0.09±0.01, respectively. All milk production traits showed slightly unfavorable negative phenotypic and genetic correlations with SCC, MAST, UDHS and UDQI. There were positive and high genetic correlations between SCC and each of MAST (0.85±0.7), UDHS (0.87±0.10) and UDQI (0.77±0.06) and between MAST and each of UDHS (0.91±0.11) and UDQI (0.83±0.07). It could be concluded that the economic losses from mastitis and high SCC are considerable. The high genetic correlation between SCC and clinical mastitis (CM) suggest that the selection for lower SCC would help to reduce or eliminate the undesirable correlated responses of clinical mastitis associated with selection for increasing milk yield. Additionally, it is recommended also that if direct information on under health traits

Histocompatibility genes and Somatic Cell Count (SCC) in Italian Holstein Friesian

Mastitis is a dairy cattle disease leading to great economic losses in milk production, management costs and veterinary treatments. This character generally shows an unfavourable genetic correlation with milk production. However, genetic factors influencing mastitis susceptibility independent from those influencing milk production could exist. Therefore, it should be possible to select at the same time against mastitis and for high milk production. The “somatic cell count” (SCC) can be used for selection against mastitis due to high genetic correlation with mastitis (Weller et al., 1992), higher heritability than clinical mastitis, lower costs for data collection and data availability at national level with an objective measurement. Genetic evaluation for “somatic cell count” has been recently officially introduced also in Italy for Holstein Friesian........

Molecular characterization of a long range haplotype affecting protein yield and mastitis susceptibility in Norwegian Red cattle

BackgroundPrevious fine mapping studies in Norwegian Red cattle (NRC) in the region 86-90.4 Mb on Bos taurus chromosome 6 (BTA6) has revealed a quantitative trait locus (QTL) for protein yield (PY) around 88 Mb and a QTL for clinical mastitis (CM) around 90 Mb. The close proximity of these QTLs may partly explain the unfavorable genetic correlation between these two traits in NRC. A long range haplotype covering this region was introduced into the NRC population through the importation of a Holstein-Friesian bull (1606 Frasse) from Sweden in the 1970s. It has been suggested that this haplotype has a favorable effect on milk protein content but an unfavorable effect on mastitis susceptibility. Selective breeding for milk production traits is likely to have increased the frequency of this haplotype in the NRC population.ResultsAssociation mapping for PY and CM in NRC was performed using genotypes from 556 SNPs throughout the region 86-97 Mb on BTA6 and daughter-yield-deviations (DYDs) from 2601 bulls made available from the Norwegian dairy herd recording system. Highest test scores for PY were found for single-nucleotide polymorphisms (SNPs) within and surrounding the genes CSN2 and CSN1S2, coding for the β-casein and αS2-casein proteins. High coverage re-sequencing by high throughput sequencing technology enabled molecular characterization of a long range haplotype from 1606 Frasse encompassing these two genes. Haplotype analysis of a large number of descendants from this bull indicated that the haplotype was not markedly disrupted by recombination in this region. The haplotype was associated with both increased milk protein content and increased susceptibility to mastitis, which might explain parts of the observed genetic correlation between PY and CM in NRC. Plausible causal polymorphisms affecting PY were detected in the promoter region and in the 5'-flanking UTR of CSN1S2. These polymorphisms could affect transcription or translation of CSN1S2 and thereby affect the amount of αS2-casein in milk.Highest test scores for CM were found in the region 89-91 Mb on BTA6, very close to a cluster of genes coding for CXC chemokines. Expression levels of some of these CXC chemokines have previously been shown to increase in bovine mammary gland cell lines after exposure to bacterial cell wall components.ConclusionMolecular characterization of the long range haplotype from the Holstein-Friesian bull 1606 Frasse, imported into NRC in the 1970s, revealed polymorphisms that could affect transcription or translation of the casein gene CSN1S2. Sires with this haplotype had daughters with significantly elevated milk protein content and selection for milk production traits is likely to have increased the frequency of this haplotype in the NRC population. The haplotype was also associated with increased mastitis susceptibility, which might explain parts of the genetic correlation between PY and CM in NRC.

Genetic Variation of Stem Forking in Loblolly Pine

Abstract Forking defects were studied in loblolly pine (Pinus taeda L.) in 6-year-old genetic tests from the second cycle of breeding in the North Carolina State University Cooperative Tree Improvement Program. Data were available from 268 test series (each with two 6-parent half-diallel mating designs, with 12 parents, 30 crosses, and 144 progeny per cross) over six geographic regions. A subset of 123 series with average forking between 20 and 80% was used for genetic analysis. Forking differed significantly among regions, with the highest in the Upper Gulf Coastal Plain (24%) and the lowest in the Georgia-Florida Coastal Plain (12%). The individual-tree heritabilities were low (0.06), but the half-sib (0.76), narrow-sense full-sib (0.59), and broad-sense full-sib (0.71) family-mean heritabilities were moderately high. This result suggests that forking is partially under genetic control at the family level, but at the individual tree level, it is mostly determined by the environment. Genetic gain was estimated for half-sib family selection with a selection differential of 20%. Gain ranged from 12 to 23% reduction in forking across different regions. A weak unfavorable genetic correlation (0.18) was found between forking and height, suggesting that selection for growth alone will negatively affect forking in loblolly pine. A favorable genetic correlation (0.33) was found between forking and straightness.

The impact of genetic selection for increased milk yield on the welfare of dairy cows

AbstractMilk yield per cow has more than doubled in the previous 40 years and many cows now produce more than 20,000 kg of milk per lactation. The increase in production should be viewed with concern because: i) the increase in milk yield has been accompanied by declining fertility, increasing leg and metabolic problems and declining longevity; ii) there are unfavourable genetic correlations between milk yield and fertility, mastitis and other production diseases, indicating that deterioration in fertility and health is largely a consequence of selection for increased milk yield; and iii) high disease incidence, reduced fertility, decreased longevity and modification of normal behaviour are indicative of substantial decline in cow welfare. Improving welfare is important as good welfare is regarded by the public as indicative of sustainable systems and good product quality and may also be economically beneficial. Expansion of the Profitable Lifetime Index used in the UK to include mastitis resistance and fertility could increase economic response to selection by up to 80%, compared with selection for milk production alone. In the last 10 years, several breeding organisations in Europe and North America followed the example of Nordic Countries and have included improving fertility and reducing incidence of mastitis in their breeding objectives, but these efforts are still timid. A multi-trait selection programme in which improving health, fertility and other welfare traits are included in the breeding objective, and appropriately weighted relative to production traits, should be adopted by all breeding organisations motivated in their goal of improving welfare.

Genetic analysis of reproductive performance in Landrace sows and its correlation to piglet growth

The aim of this study was to investigate the reproductive performance of sows, including the interval from weaning to service after 1st litter and litter size in the following (2nd) parity, as well as the direct and maternal genetic effects of piglet growth on these reproduction traits. Data on 15 946 Norwegian Landrace sows' 1st and 2nd parity, and on 106,962 piglets born in 11,323 1st parity litters were included in the analyses. In total, five traits were analysed. Weaning-to-service interval was based on a 1- to 7-day interval (WSI7) or a transformed 1- to 50-day interval (WSI50). A third reproduction trait was total number of piglets born in 2nd parity (NBTnext). Piglet weight was included in the analyses, either as average piglet weight in the litter at 3 weeks of age (meanW3) or as individual piglet weight gain during the first 3 weeks of life (IWG03). Genetic parameters were estimated with animal models, including both direct and maternal effects for IWG03. Heritability estimates for WSI7, WSI50 and NBTnext were 0.08, 0.03 and 0.09 respectively. For meanW3, the heritability estimate was 0.21. For IWG03, the direct and maternal heritability estimates were 0.15 and 0.10 respectively. Negative and unfavourable genetic correlations were estimated between meanW3 and NBTnext ( r g = − 0.37), and between IWG03 maternal and NBTnext ( r g = − 0.39). The ability to raise fast growing, heavy piglets seems to have an unfavorable effect on total number born in next litter but not on the weaning-to-service interval.

Relationships of subjectively assessed wool and conformation traits with objectively measured wool and live weight traits in the Tygerhoek Merino flock

Records of the Tygerhoek Merino resource flock were used to estimate genetic, phenotypic and environmental parameters between subjective wool and conformation traits with objective wool and live weight traits. The database contained records of 4 495 animals, the progeny of 449 sires and 1 831 dams, and born from 1989 to 2004. On the genetic level (rg) live weight was favourably related to regularity of crimp (ROC) (0.20), woolly face score (WFS) (0.21), general head conformation (GEN) (0.67), conformation of the hind legs (HOCKS) (0.36), conformation of the front legs (FQ) (0.42), topline (TOPL) (0.25) and total fold score (TOT). Estimates of rg were favourable for clean yield with wool quality (QUAL) (0.30), wool colour (COL) (0.45), wool oil (OIL) (-0.44), staple formation (STAPL), belly and points (BANDP) (0.24), face cover score (FCS) (0.18), GEN (0.25), HOCKS (0.19), TOT (-0.26) and FQ (0.18). Clean fleece weight (CFW) was favourable correlated `to QUAL (0.18), STAPL (0.39), BANDP (0.48) and GEN (0.23). Staple length was favourably related to COL (0.16), BANDP (0.40) and WFS (0.16) and negatively related to OIL (-0.33). Staple strength was favourable correlated to ROC (0.33) and FQ (0.39). Fibre diameter was favourable correlated with QUAL (-0.32), ROC (-0.28), FCS (-0.32), pastern score (PS) (-0.16) and TOPL (-0.18). Coefficient of variation of fibre diameter (CVFD) was favourably correlated with QUAL (-0.50), ROC (-0.73), HOCKS (-0.17), FQ (-0.33) and TOPL (-0.25). In contrast, unfavourable correlations occurred for SS with TOT (0.25), for FD with STAPL (0.59), BANDP (0.37), HOCKS (0.13) and TOT (0.13). Other unfavourable genetic correlations were between CFW and TOT (0.28) and between CVFD and STAPL (0.49). The results showed that selection for LW and objective wool traits will not seriously compromise subjective wool and conformation traits, barring a few exceptions.

Genetic Parameters of Growth Traits and Wood Density in Eucalyptus grandis Progenies Planted in Argentina

Abstract To determine the genetic parameters of growth traits and wood density (estimated by Pilodyn penetration) in a population of Eucalyptus grandis formed by families from 11 seed origins in NE Queensland, Australia and a local land race, 8.5-year-old progenies established in three sites in NE Argentina were evaluated. Local trees exhibited higher growth rate at two sites and better stem form, but also deeper Pilodyn penetration, at all sites; thus, there is potential to infuse new genetic variation into the current breeding population in the region. A significant amount of genetic variation was found for all traits assessed, with growth traits [diameter (DBH), height (HT) and volume (VOL)] showing different genetic structure and degree of genetic control as compared to stem straightness (FORM), bark thickness (BARK) and Pilodyn penetration (PILO). The effect of origin was negligible for growth traits while it was important for the other traits, so it should be considered in the selection strategy; in addition, individual heritability for growth traits (0.11-0.16 in the combined analyses) was generally lower than for the other traits (0.20-0.35). Genetic correlations between sites for all traits were high enough to indicate that genotype-environment interaction would not affect the selection program by using a single breeding population for this region. Genetic correlations between growth traits were high (rg > 0.80), and negligible between these and FORM; the only unfavorable genetic correlation was between PILO and BARK (rg = -0.44). Age-age correlations for growth traits and FORM were very high (rg > 0.90). Results suggest that all traits evaluated could be handled in a breeding program, either independently or combined, without negative correlated effects. Early selection for growth traits and stem form is also possible, with major savings in time.

Genetic variation and relationships to growth traits for microfibril angle, wood density and modulus of elasticity in a Picea abies clonal trial in southern Sweden

Genetic variation in wood density, microfibril angle (MFA), wood stiffness (MOE), height, diameter and volume was investigated in a 26-year-old Norway spruce [(Picea abies (L.) Karst.] clonal trial in southern Sweden. Wood quality measurements were performed on 10 mm increment cores using SilviScan. For MFA, mean values of annual rings showed the highest value (30°) at ring 2 counting from the pith, followed by a steep decrease and a gradual stabilization around ring 12 at approximately 14°. MOE showed a monotonic increase from 5 GPa to 14 GPa when moving from pith to bark. High broad-sense heritability values were found for wood density (0.48), MFA (0.41) and MOE (0.50). All growth traits displayed heritability values of similar magnitudes as reported in earlier studies. The generally high age–age correlations between different sections of the wood cores suggested that early selection for wood quality traits would be successful. Owing to unfavorable genetic correlations between volume and MOE, the correlated response indicated that selection for volume only at age 10 would result in a 0.27% decrease in weighted MOE at age 26 for every 1% increase in volume.

Characterization of a QTL region affecting clinical mastitis and protein yield on BTA6

Quantitative trait loci affecting clinical mastitis were detected and fine mapped to a narrow region on bovine chromosome 6 in the Norwegian Red cattle population. The region includes the casein gene cluster and several candidate genes thought to influence clinical mastitis. The most significant results were found for SNPs within the Mucin 7 gene. This gene encodes an antimicrobial peptide and constitutes part of the first line of defence for the mucosal immune system. Detection of long haplotypes extending several Mb may indicate that artificial selection has influenced the haplotype structures in the region. A search for selection sweeps supports this observation and coincides with association results found both by single SNP and haplotype analyses. Our analyses identified haplotypes carrying quantitative trait loci alleles associated with high protein yield and simultaneously fewer incidences of clinical mastitis. The fact that such haplotypes are found in relative high frequencies in Norwegian Red may reflect the combined breeding goal that is characterized by selection for both milk production and disease resistance. The identification of these haplotypes raises the possibility of overcoming the unfavourable genetic correlation between these traits through haplotype-assisted selection.

Phenotypic and genetic relationships of common health disorders with milk and fat yield persistencies from producer-recorded health data and test-day yields

The objective of this study was to investigate phenotypic and genetic relationships of common health disorders in dairy cows with milk (PMY) and fat (PFY) yield persistencies. Health and production data from 398 commercial dairy herds were used. Disease traits were defined in binary form for individual lactations considering mastitis only during the first 100 d in milk (MAST1), only after 100 d in milk (MAST2), and at any stage of lactation (MAST), and reproductive disorders (REPRO), metabolic disorders (METAB), and lameness (LAME). The persistencies were defined to be uncorrelated with 305-d yields. Impact of the diseases on PMY and PFY were investigated separately in first (FL) and later (LL) lactations. Phenotypic associations of PMY and PFY with likelihood of diseases in current and subsequent lactations were examined using odds ratios from a logistic regression model. Linear-threshold sire-maternal grandsire models were used to estimate genetic correlations of displaced abomasums (DA), ketosis (KET), metritis (MET), MAST, MAST1, and MAST2 with PMY and PFY across parities. Metabolic diseases and REPRO had significantly positive relationships with PMY and PFY in both FL and LL. Significantly greater PMY and PFY were associated with MAST1 in LL. Significantly lower PMY and PFY were related to MAST2 in both FL and LL, whereas cows affected by MAST had significantly less persistent lactations. Incidence of MAST and MAST2 decreased with increasing PMY and PFY in the present and previous lactation. Heritability of disease incidences were 0.03 (DA), 0.01 (KET), 0.10 (MAST), 0.02 to 0.05 (MAST1), 0.02 (MAST2), and 0.04 to 0.10 (MET). Displaced abomasum, KET, MAST, MAST1, and MET had unfavorable genetic correlations of 0.35, 0.46, 0.17, 0.02, and 0.27 with PMY, and 0.16, 0.21, 0.07, 0.06, and 0.12 with PFY, respectively. Favorable genetic correlations were found for MAST2 with PMY (−0.24) and PFY (−0.04). Results suggest that diseases in early lactation increase persistency of milk and fat yield. Selection for greater lactation persistency must consider these antagonistic relationships.

Genetic analysis of reproduction traits and their relationship with conformation traits in Holstein cows

The main objectives of the present study were to examine genetic aspects of fertility traits and their relationships with type traits in Iranian Holstein cows. Fertility traits included calving interval (CI), days from calving to first insemination (DFS), days open (DO), and gestation length (GL). Type traits were stature (ST), body depth (BD), fore-udder attachment (FU), rear-udder height (RU), udder depth (UD), rump width (RW), and angularity (AG). Fertility traits were analyzed using data files containing up to 26,147 records in parities 1 to 8 which were collected from 1980 to 2004. Data on type traits included 3274 records on first lactation cows. An animal model restricted maximum likelihood method was used to estimate (co)variance components. Heritability estimates for fertility traits were low and ranged from 0.04 ± 0.01 (DFS) to 0.07 ± 0.013 (CI) and 0.07 ± 0.002 (GL). Repeatabilities for these traits were estimated to vary from 0.06 (DFS) to 0.12 (GL). Genetic correlations between fertility traits were close to zero. Estimated heritabilities for type traits, except for RU, were moderate and ranged from 0.20 ± 0.047 (FU) to 0.38 ± 0.04 (RW). Genetic correlations between fertility and type traits ranged from zero (DO with ST and FU) to 0.79 (DFS with BD). This study showed that despite the low heritabilities, there was exploitable genetic variance in fertility traits. It showed that body volume traits including BD and AG as well as RW and UD had unfavorable genetic correlations with CI, DFS, and GL. However, these relationships can be used for indirect selection of dairy cows for fertility traits.

Genetic correlations among juvenile wood quality and growth traits and implications for selection strategy in Pinus radiata D. Don

• Juvenile wood quality in Pinus radiata is affected by factors such as low density, stiffness, and high microfibril angle, spiral grain, and shrinkage. Adverse genetic correlations between growth and wood quality traits remain as one of the main constraints in radiata pine advanced generation selection breeding program. • Juvenile wood property data for this study were available from two progeny tests aged 7 and 6 y. We estimated the genetic correlations between stiffness, density, microfibril angle, spiral grain, shrinkage in the juvenile core and DBH growth in radiata pine, and) to evaluated various selection scenarios to deal with multiple objective traits. • Negative genetic correlations were found for modulus of elasticity (MoE) and density with microfibril angle, spiral grain, shrinkage, and DBH. We observed low to moderate unfavourable genetic correlations between all wood quality traits and DBH growth. • These low to moderate genetic correlations suggest that there may be some genotypes which have high DBH growth performance while also having high wood stiffness and density, and that the adverse correlation between DBH and MoE may not entirely prohibit the improvement of both traits. Results indicate that, in the short term, the optimal strategy is index selection using economic weights for breeding objective traits (MAI and stiffness) in radiata pine. • In the long-term, simultaneously purging of the adverse genetic correlation and optimizing index selection may be the best selection strategy in multiple-trait selection breeding programs with adverse genetic correlations.

Genetic correlations between reproduction of crossbred ewes and the growth and carcass performance of their progeny

Genetic correlations were estimated between first cross ewe reproduction traits and growth and carcass traits of their second cross lamb progeny. The 2460 crossbred ewes were progeny of 74 maternal breed sires and mainly Merino dams. The ewes had 3 joinings to terminal sire rams with 6824 joining records resulting in 9002 lambs born and 7176 lambs slaughtered. The ewe reproduction traits included: fertility, litter size, ewe rearing ability or lamb survival, number of lambs born (NLBj) and weaned (NLWj) per ewe joined, with traits reflecting ewe productivity being total litter weight weaned (TWWj) per ewe joined and the component trait average lamb weaning weight in the litter (AWW). The lamb growth traits included weight of the lambs at birth (BWT), weaning (WWT) and post weaning (PWWT) as well as growth rate pre and post weaning. The lamb carcass traits included hot carcass weight (HCWT), dressing yield (DRESS%), fat depth (FatGR, FatC), eye muscle depth (EMD) and area (EMA) and meat quality traits (colour and pH). The genetic correlations were estimated by bivariate mixed models using ASReml. The genetic correlations between the composite reproduction traits of the ewes and the post-weaning growth rate of their lambs were high (0.67 for NLBj and 0.65 for NLWj). There were moderate positive correlations between NLWj and WWT (0.36), PWWT (0.49) and pre weaning growth (0.36) and NLBj with PWWT (0.31). BWT was negatively correlated with litter size (−0.34) and positively with ewe rearing ability (0.38). Most of the other genetic correlations were smaller than their standard errors which generally ranged from 0.2 to 0.3. The genetic correlations for HCWT with all the ewe reproduction traits were positive and moderate (0.29–0.53) and high with the ewe productivity traits that included weight of lambs (TWWj 0.98 and AWW 0.96). The genetic correlations among the other traits were variable and had high standard errors, generally ranging from 0.1 to 0.5. However there were generally negative and unfavourable genetic correlations between the reproduction traits and DRESS% and meat colour L*, whereas those with carcass fat (FatC and FatGR) were generally negative and favourable.

Genetic parameters of direct and ratio traits from field and station tests of pigs

Abstract. Genetic parameters of several growth and carcass traits were estimated for the Hungarian Large White (HLW) and Hungarian Landrace (HL) pig breeds. The objective of the analysis was to compare the direct (days on station test, consumed feed, valuable cuts and age) and ratio/composite (net daily gain, feed conversion, proportion of valuable cuts, lean meat percentage and average daily gain and meat quality score) traits, which were collected in the course of station and field tests. The analysis was based on the national database (1997–2003) using univariate and bivariate animal models. Estimated heritabilities for station test traits ranged between 0.34–0.69 (except for meat quality score, where the heritability was low (0.10, 0.15 for HLW and HL, respectively) and exceeded that of the field test traits (0.18–0.23). Relative importance of random litter effects was low for the station test traits (0.01–0.29) but moderate for the field test traits (0.20–0.48). The unfavourable genetic correlation between lean meat percentage and meat quality score (−0.28, −0.44 for HLW and LW, respectively) is worth mentioning. In both performance tests the direct and ratio test counterparts showed similar heritabilities and their genetic correlation were close to unity (0.74–0.95). Based on these results selection on either the direct or on the ratio traits would possibly result similar selection response.

Genetic parameters for measures of energetic efficiency of bulls and their relationships with carcass traits of field progeny in Japanese Black cattle1

Records on 514 bulls from the sire population born from 1978 to 2004, and on 22,099 of their field progeny born from 1997 to 2003 with available pedigree information (total number = 124,458) were used to estimate genetic parameters for feed intake and energy efficiency traits of bulls and their relationships with carcass traits of field progeny. Feed intake and energetic efficiency traits were daily feed intake, TDN intake, feed conversion ratio (FCR), TDN conversion ratio (TDNCR), residual feed intake (RFI), partial efficiency of growth, relative growth rate, and Kleiber ratio. Progeny carcass traits were carcass weight (CWT), yield estimate, ribeye area, rib thickness, subcutaneous fat thickness (SFT), marbling score (MSR), meat color standard (MCS), fat color standard (FCS), and meat quality grade. All measures of feed intake and energetic efficiency were moderately heritable (ranged from 0.24 to 0.49), except for partial efficiency of growth and relative growth rate, which were high (0.58) and low (0.14), respectively. The phenotypic and genetic correlations between FCR and TDNCR were >or=0.93. Selection for Kleiber ratio will improve all of the energetic efficiency traits with no effect on feed intake measures (daily feed intake and TDN intake). The genetic correlations of FCR, TDNCR, and RFI of bulls with most of the carcass traits of their field progeny were favorable (ranged from -0.24 to -0.72), except with fat color standard (no correlation), MCS, and SFT. Positive (unfavorable) genetic correlations of MCS with FCR, TDNCR, and RFI (0.79, 0.70, and 0.51, respectively) were found. The SFT was negatively genetically correlated with FCR and TDNCR (-0.32 and -0.20, respectively); however, the genetic correlation between RFI and SFT was not significantly different from zero (r(g) = -0.08 +/- 0.12). Favorable correlated responses in CWT, yield estimate, ribeye area, rib thickness, MSR, and meat quality grade would be predicted for selection against any measure of energetic efficiency. The correlated responses in CWT and MSR of progeny were greater for selection against RFI than for selection against any other energetic efficiency trait. Results of this study indicate that RFI should be preferred over other measures of energetic efficiency to include in selection programs.

Genetic associations of sow longevity with age at first farrowing, number of piglets weaned, and wean to insemination interval in the Finnish Landrace swine population1

The objective of the study was to estimate genetic parameters for length of productive life (LPL), and determine its genetic correlation with age at first farrowing (AFF), number of piglets weaned at first farrowing (NW), and first wean-to-insemination interval (W2I) in the Finnish Landrace swine population. Data from the Finnish national litter recording scheme were utilized to estimate the genetics of LPL, and genetic associations between LPL, AFF, NW, and W2I. Data from the Finnish Landrace sow records were utilized from farms that farrowed more than 20 gilts annually from 2000 through 2005. The data set included information from 11,222 sows, all of which had AFF and NW information available. The sows producing the records evaluated were daughters of 1,267 sires, and there were 3,684 animals in the pedigree when all of the sires were traced back to founder animals. All data were obtained from FABA Breeding (Vantaa, Finland). Multivariate Bayesian analysis of Gaussian, right censored Gaussian, and categorical traits was utilized to estimate (co)variance parameters of LPL, AFF, NW, and W2I of the sow. From these traits, AFF and NW were treated as Gaussian, LPL as right-censored Gaussian, and W2I as categorical traits. Estimated posterior means of heritabilities were 0.22, 0.16, 0.09, and 0.08 for LPL, AFF, NW, and W2I, respectively. A relatively large proportion of variance due to farm-year interaction was observed (posterior means of f(2) ranged between 0.03 and 0.26). The LPL was moderately genetically correlated with NW and AFF (posterior means were -0.20 and 0.36, respectively), whereas no clear association was found between W2I and LPL. Favorable genetic correlations between AFF and W2I and between NW and W2I were also observed. Additionally, an unfavorable genetic correlation between AFF and NW was observed in the present data set. Because LPL is genetically associated with other economically important prolificacy traits, it should be included in a multiple trait swine breeding value estimation system.

Genetic parameters for carcass and meat quality traits and their relationships to liveweight and wool production in hogget Merino rams

Genetic parameters for carcass and meat quality traits of about 18-month-old Merino rams (n = 5870), the progeny of 543 sires from three research resource flocks, were estimated. The estimates of heritability for hot carcass weight (HCW) and the various fat and muscle dimension measurements were moderate and ranged from 0.20 to 0.37. The brightness of meat (colour L*, 0.18 +/- 0.03 standard error) and meat pH (0.22 +/- 0.03) also had moderate estimates of heritability, although meat relative redness (colour a*, 0.10 +/- 0.03) and relative yellowness (colour b*, 0.10 +/- 0.03) were lower. Heritability estimates for live weights were moderate and ranged from 0.29 to 0.41 with significant permanent maternal environmental effects (0.13 to 0.10). The heritability estimates for the hogget wool traits were moderate to high and ranged from 0.27 to 0.60. The ultrasound measurements of fat depth (FATUS) and eye muscle depth (EMDUS) on live animals were highly genetically correlated with the corresponding carcass measurements (0.69 +/- 0.09 FATC and 0.77 +/- 0.07 EMD). Carcass tissue depth (FATGR) had moderate to low genetic correlations with carcass muscle measurements [0.18 +/- 0.10 EMD and 0.05 +/- 0.10 eye muscle area (EMA)], while those with FATC were negative. The genetic correlation between EMD and eye muscle width (EMW) was 0.41 +/- 0.08, while EMA was highly correlated with EMD (0.89 +/- 0.0) and EMW (0.78 +/- 0.04). The genetic correlations for muscle colour with muscle measurements were moderately negative, while those with fat measurements were close to zero. Meat pH was positively correlated with muscle measurements (0.14 to 0.17) and negatively correlated with fat measurements (-0.06 to -0.18). EMDUS also showed a similar pattern of correlations to EMD with meat quality indicator traits, although FATUS had positive correlations with these traits which were generally smaller than their standard error. The genetic correlations among the meat colour traits were high and positive while those with meat pH were high and negative, which were all in the favourable direction. Generally, phenotypic correlations were similar or slightly lower than the corresponding genetic correlations. There were generally small to moderate negative genetic correlations between clean fleece weight (CFW) and carcass fat traits while those with muscle traits were close to zero. As the Merino is already a relatively lean breed, this implies that particular attention should be given to this relationship in Merino breeding programmes to prevent the reduction of fat reserves as a correlated response to selection for increased fleece weight. The ultrasound scan traits generally showed a similar pattern to the corresponding carcass fat and muscle traits. There was a small unfavourable genetic correlation between CFW and meat pH (0.19 +/- 0.07).

Genetic Variation and Breeding Potential of Phytate and Inorganic Phosphorus in a Maize Population

Seed P is predominantly bound in the organic compound phytate, which makes the bioavailability of P low for monogastric animals fed maize (Zea mays L.)‐based diets. Decreasing phytate and increasing inorganic P (Pi, an available form of P) concentrations in maize grain would be desirable to help ameliorate environmental problems associated with high P in feces. Our objective was to investigate the potential of improving the P profile of maize grain through breeding and selection. Ninety S1 families from the BS31 population were evaluated at two locations for phytate, Pi, and other grain quality and agronomic traits. Phytate concentrations ranged from 1.98 to 2.46 g kg−1, and the broad‐sense heritability (H) was relatively low (0.60). Both genetic variance and H (0.84) were much greater for Pi Few unfavorable genetic correlations were observed between either Pi or phytate and other key economic traits. Also, selection differentials of multiple trait indices indicated that the P profile of maize grain and grain yield and moisture could be improved simultaneously. Many cycles of selection will be needed, however, to reach desirable phytate and Pi concentrations, especially when selecting for multiple traits. Regardless, our results are encouraging given that the families evaluated were related S1 families and the number of families was relatively small.