Estimated breeding values and association mapping for persistency and total milk yield using natural cubic smoothing splines

BackgroundFor dairy producers, a reliable description of lactation curves is a valuable tool for management and selection. From a breeding and production viewpoint, milk yield persistency and total milk yield are important traits. Understanding the genetic drivers for the phenotypic variation of both these traits could provide a means for improving these traits in commercial production.MethodsIt has been shown that Natural Cubic Smoothing Splines (NCSS) can model the features of lactation curves with greater flexibility than the traditional parametric methods. NCSS were used to model the sire effect on the lactation curves of cows. The sire solutions for persistency and total milk yield were derived using NCSS and a whole-genome approach based on a hierarchical model was developed for a large association study using single nucleotide polymorphisms (SNP).ResultsEstimated sire breeding values (EBV) for persistency and milk yield were calculated using NCSS. Persistency EBV were correlated with peak yield but not with total milk yield. Several SNP were found to be associated with both traits and these were used to identify candidate genes for further investigation.ConclusionNCSS can be used to estimate EBV for lactation persistency and total milk yield, which in turn can be used in whole-genome association studies.Klara L. Verbyla and Arunas P. Verbyl

Genotype by Environment Variance Heterogeneity in a Two-Stage Analysis

The analysis of a series of crop variety trials often proceeds using a mixed model in which the data are the combined means from individual trials. The residual variation for this model consists of genotype by environment (G.E) interactions and within trial error variation. The latter is regarded as known from the analyses of individual trials, and any associated heterogeneity can be accounted for in the overall mixed model by the use of weights. The G.E interactions may also have non-constant variance, and since the variances themselves are often of interest, we propose that heterogeneity arising from these sources be accommodated by modelling the G.E variances as a log-linear function of explanatory variables. We present a residual maximum likelihood estimation method, and develop a diagnostic technique for detecting dependence. The approach is demonstrated using a large unbalanced set of crop variety testing data. The methodology is easily generalised to residual variance modellin..

Effect of postinfection application of phosphorous (phosphonic) acid on the incidence and sporulation of Plasmopara viticola on grapevine

Phosphorous acid (H3P03) applied at 1.2 gIL up to 12 days after infection reduced the incidence and severity of Plasmopara vitieola. When applied up to 13 days after infection, H3P03 reduced sporulation. In some experiments, the postinfection activity of H3P03 was better than metalaxyl, while in other experiments it was less effective. Both fungicides applied after infection reduced the incidence and severity of disease on leaves and flower clusters, indicating that postinfection applications should reduce the production of inoculum and the consequent spread of disease within a vineyard. In most cases, the addition of copper oxychloride did not affect the efficacy of H3P03

Effects of relocation on production in caged layers

1. Two experiments were conducted to determine the effects on laying performance of relocating caged hens at 30, 42 and 54 weeks of age. 2. In experiment 1 with hens caged individually, treatment groups comprised relocated hens given 5 new neighbours and hens not relocated but given 0, 2 or 4 new neighbours. 3. In experiment 2 with hens housed two per cage, treatment groups comprised relocation with or without that hen which shared the cage before the move. 4. In both experiments relocated hens laid fewer eggs in the week following social reorganisation. 5. Relocated hens in experiment 1 ate less food in the week following the shift at 42 weeks of age than did hens not moved. In experiment 2 in which all hens were moved, food consumption was not affected

A survey of the cadmium concentration in kidney, liver and muscle of Aough Australian cattle

A survey to assess the extent of cadmium accumulation in South Australian cattle was undertaken in 1989–91. Of the 8635 cattle sampled, about 12% of the kidney samples and 1% of the liver samples contained cadmium concentrations above the maximum permitted concentration for human consumption of 2.5 mg/kg wet weight for kidney and 1.25 mg/kg wet weight for liver. None of the 262 muscle samples assayed contained cadmium concentrations above the maximum permitted concentration of 0.2 mg/kg wet weight. There was a significant effect of location, gender and season on the extent of non-compliance. Of the regions examined, non-compliance rates for Kangaroo Island, Lower Eyre, South East and Lower Central were significantly higher than for the other regions. In general, non-compliance rates were higher in female cattle than in male cattle, increased with age and were lowest in spring. After adjustment for these factors, non-compliance rates were similar across farm types, namely dairy, beef and feedlot. Although there was a significant correlation between cadmium concentrations in liver and in whole kidney, the confidence limit was considered excessive, rendering liver cadmium values an unreliable predictor of cadmium values in kidney

comparison of total tuber yields from inner and guard rows used in potato (Solanum tuberosum L.) fertiliser experiments

Total tuber yields were compared for inner and outer (guard) rows from 4 phosphorus (P) and 3 nitrogen (N) field experiments conducted during 1985-86 in South Australia, and from 5 N and 2 potassium (K) field experiments conducted during 1985-86 and 1987-88 in Tasmania. All fertiliser treatments were banded along the rows, either at planting or part at planting and the remainder sidedressed after emergence. The inter-row spacings were in the range 76-86 cm and the cultivars used were Kennebec, Coliban and Russet Burbank. Analysis showed that at only 1 of the 14 sites (site 6 in South Australia) was the mean total tuber yield for the inner 2 rows significantly (

The use of synthetic gonadotropin releasing hormone treatment in the collection of sheep embryos

Gonadotropin releasing hormone (GnRH) treatment was examined as a means of improving the efficacy of embryo collection in the sheep following intrauterine insemination of frozen-thawed semen. In summary, treatment consistently improved fertilization rates and the number of fertilized ova collected per ewe was enhanced compared with untreated ewes. The yield of fertilized ova in ewes treated with follicle stimulating hormone (FSH) was maximized by administering GnRH 36 h after progestagen treatment; 24 h was the preferred time in ewes treated with pregnant mare serum gonadotropin (PMSG). There was a significant (P \u3c 0.001) increase in the percentage of unfertilized ova in the former treatment when GnRH was given at 24 h. An examination of the time of insemination (0, 6, 12 and 18 h before the median time of ovulation) indicated that fertilization rates were highest when inseminationo ccurred at 6 h in both GnRH-treatede wes and in untreated ewes. In GnRH-treated ewes, the recovery of ova was lowest when insemination occurred at the time of ovulation. The number of motile frozen-thawed spermatozoa required for fertilizat n treatment was estimated to be approximately 20 x +? following 10 per uterine horn. GnRH-treatment also improved the yield of fertilized ova in sheep that were naturally mated, although this yield was lower than that obtained with intrauterine insemination of frozen-thawed semen. It is concluded that fertilization failure, a major problem in sheep embryo collection, can be eliminated through judicious use of GnRH treatment and properly timed intrauterine insemination