Production characters of straightbred, F1 and F2 cows: birth and weaning characters of terminal-cross calves

Records of 2,449 births and 2,120 weanings of terminal-cross calves were used to characterize maternal productivity of first- and second-generation cows from a diallel of Angus, Brahman, Hereford, Holstein and Jersey when mated to third-breed sires. Third- and later-parity cows were randomly assigned after each parturition to Charolais and Red Poll bulls in multiple-sire pastures. Calves were weaned at approximately 7 mo of age; males were not castrated. A mixed model was assumed for data analysis. Effects included in the model were breed-type of dam, cow within breed-type of dam (random), breed of sire of calf, season of record, year of record, age of dam group, sex of calf and age of calf (covariate). Age of dam groups were 4- and 5-yr-olds, 6- and 7-yr-olds, 8-, 9- and 10-yr-olds, and those greater than 10 yr of age. Dependent variables were calf weight, shoulder width and hip width at birth, weaning weight, weaning height and survival to weaning. Holstein and Holstein crosses tended to produce the largest calves at birth and weaning. Among straightbred dams, the smallest calves were born to Brahman, whereas Hereford weaned the smallest calves. Brahman-Jersey dams produced the smallest calves at birth among crossbreds; Angus-Hereford cows weaned the smallest calves. Average maternal heterosis estimates for birth weight were small and non-significant. Calves of F1 crossbred dams were 17.4 kg heavier (P less than .01) and 1.70 cm taller (P less than .01) at weaning than calves of first-generation straightbred dams.(ABSTRACT TRUNCATED AT 250 WORDS)     

Positive association between a glutathione‐S‐transferase polymorphism and lymphoma in dogs

Glutathione‐S‐transferase enzymes (GSTs) play an important role in the detoxification of environmental carcinogens. Defective GST genotypes are over‐represented in human cancers; in particular, low activity GSTT1 genotypes are risk factors for non‐Hodgkin lymphoma. We hypothesized that defective GSTT1 genotypes would be associated with lymphoma risk in dogs. To address this, we resequenced the exons, splice junctions, and 3′‐UTR of canine GSTT1 in dogs with lymphoma (n = 93) and age‐matched unaffected dogs (n = 86). Of 27 canine GSTT1 variants identified, the I2+28 G>A was significantly associated with lymphoma [odds ratio (OR) 6.26, 95% confidence interval (CI), 1.77–22.2], with the AA genotype found in 18.3% of affected dogs but only 3.5% of controls (P = 0.002). This intronic variant was predicted to perturb GSTT1 mRNA splicing, and may increase lymphoma risk by impairing detoxification of environmental chemicals. Confirmation of this finding in a larger population of dogs may support the inclusion of GSTT1 genotyping in epidemiologic studies of canine lymphoma risk.     

Production, nitrogen and carbon balance of maize-based forage systems

Nitrogen (N) and carbon (C) surplus can be used as indicators of an agroecosystems’ ability to maintain soil fertility. Maize is the key crop of intensive forage systems in northern Italy, and large amounts of manure are often supplied to this crop. Different maize-based cropping systems and manure managements were compared in this paper. The following were assessed, using the results of an 11-year experiment: crop production and N uptakes; C and N surpluses; soil C and N contents. The treatments were maize for silage (Ms), maize for grain (Mg), double annual crop rotation maize–Italian ryegrass (Mr), and rotation maize–grass ley (Ml). Five fertilization management systems were adopted: 0N control, and bovine slurry and farmyard manure supplied at two levels, ranging from 215 to 385 kg ha⁻¹ of total N.

The dry-matter production of Mr was significantly higher than those of the other systems. The response of maize to fertilization was similar in all the cropping systems, except for Mr, for which the crop showed a high reactivity to N input at both fertilizer levels. Soil reserves were rapidly consumed in the unfertilized treatment of Mr, whereas the high productivity potential of this cropping system was exerted in fertilized plots. The introduction of a ley in rotation with maize reduced the system's DM production, due to the low yield potential of grass compared to that of maize, reduced the system response to fertilization, and diminished the exploitation of organic N at high fertilization rates. Cumulated N surplus caused an enrichment of the soil N pool size: 43% of excess N was retained by the soil. The relationship between the cumulated C surplus and the soil C pool size indicated that 26–27% was retained by the soil. Crop residues of the Mg system were less effective in building up the soil C pool than other C sources. Both slurry and farmyard manure exerted a positive effect on the soil C and N retention. When farmyard manure was used, 18% of C and 45% of surplus N were incorporated into the soil organic matter (SOM). Slurry also built up the SOM content, resulting in 9% of C and 24% of N surplus.     

Reductive detoxification of the acetophenone skeleton of the carnation phytoanticipin by Fusarium oxysporum f.sp. dianthi

The skeleton of the carnation phytoanticipin, acetophenone, was detoxified by Fusarium oxysporum f.sp. dianthi , the main fungal parasite of carnation. This process consisted of the reduction to ethanol of the acetyl group, leading to the formation of phenylethanol, which has lower fungitoxic activity than the parent molecule. The conversion took place through the activity of an adaptive fungal oxidoreductase, which was NADH-dependent and was released by the fungus as two enzymatic forms within the culture substrate in the presence of acetophenone. Reduction was stereospecific and gave rise to only one of the two possible enantiomeric forms.