Gossypol toxicity in preruminant calves

SUMMARY Twenty-four of 57 calves fed a diet containing 33% cotton seed meal (CSM) died between 7 and 15 weeks of age. Initial deaths were not accompanied by premonitory signs, but after CSM withdrawal most calves developed rough coats, anorexia, weakness, ascites and subcutaneous oedema. Those that died had large volumes of serous fluid in the body cavities, hard livers of ‘nutmeg’ appearance, and pulmonary congestion. Histopathologically the livers showed periacinar necrosis in acute cases and periacinar fibrosis in chronic cases. Lungs from several calves had oedema, haemosiderosis and fibrosis in some pulmonary vessels. Atrophy of myocardial fibres was present in most cases. The concentration of free gossypol in the diet was 100 to 220 mg/kg. Ante-mortem and post-mortem findings supported a diagnosis of gossypol poisoning. The deaths continued for 4 weeks after withdrawal of CSM from the diet.     

The use of ultrasonography in the reproductive evaluation of boars

The objective was to study the use of ultrasound as a complementary test in the breeding soundness evaluation in male pigs and study the pattern of echogenicity of the testicular parenchyma in boars of different racial groups. Twenty‐six adult boars from four different racial groups were used, 10 from the Piau breed (group 1), four from the commercial and finishing group (group 2), six Pietrain breed (group 3) and six from the Duroc breed (group 4). All animals were evaluated for breeding soundness evaluation and the ultrasound examination of the testicles. The groups of animals that were evaluated showed no difference in the main semen parameters that were evaluated, except for the sperm volume, concentration of the ejaculated sperm and the supravital staining; the lowest figures were for the animals from the Piau breed (group 1). In relation to the testicular biometrics, Duroc animals (group 4) had a greater scrotal width compared to the other groups. But when we assessed the intensity of pixels of the testicles, there was a difference between groups. The groups 2 (finishing animals), 3 (Pietrain) and 4 had no difference between themselves. Group 3 had greater pixel intensity in relation to group 1. Of the 26 animals studied, five showed an abnormality during ultrasound evaluation, like hydrocele, hyperechoic mass in the testicular parenchyma, cyst in the head of the epididymis and the presence of fluid in the head and tail of the epididymis. The various animal groups studied did not differ in the principal reproductive parameters evaluated, showing that despite the great variability of reproductive traits between breeds and within the same breed, the breeding soundness evaluation, the more complete it is, is essential for the selection of breeders and the ultrasonography of the reproductive system becomes an important addition in this examination.     

Molecular markers for improving control of soil-borne pathogen <Emphasis Type="Italic">Fusarium oxysporum</Emphasis> in sugar beet

Fusarium spp. cause severe damage in many agricultural crops, including sugar beet, with Fusarium oxysporum historically being considered as the most damaging of all species. Sugar beet needs to be protected from this class of soil-borne pathogens in order to ensure an optimal sugar yield in the field. Genetic control of the disease is crucial in managing these pathogens. Identification of single nucleotide polymorphism (SNP) markers linked to resistance can be a powerful tool for the introgression of valuable genes needed to develop Fusarium-resistant varieties. A candidate gene approach was carried out to identify SNP markers linked to putative Fusarium resistance sources in sugar beet. Five resistant analogue genes (RGAs) were screened by means of high resolution melting (HRM) analysis in a set of sugar beet lines, considered as resistant and susceptible to Fusarium oxysporum. HRM polymorphisms were observed in 80% of amplicons. Two HRM polymorphisms were significantly associated with Fusarium resistance (P < 0.05). The amplicons that showed association were sequenced and two SNPs were identified. The association was further validated on 96 susceptible and 96 resistant plants using competitive allele-specific PCR (KASPar) technology. The selected SNPs could be used for marker-assisted breeding of Fusarium resistance in sugar beet.     

Modelling the impact of within-storm variability of rainfall on the loading of solutes to preferential flow pathways

Rainfall variability within a storm can have a significant impact on the amount of chemical transported by surface runoff and preferential flow. Previously, studies have evaluated only a few slowly varying rainfall patterns and related sorption capacities. We use a bounded random cascade approach to generate 50 000 realizations of realistic rainfall intensity patterns within a single storm event (96 minutes duration, mean intensity of 18.75 mm hour^?1) to explore the effects on the partitioning of rainfall and linearly sorbing solutes between fast preferential flow (loading) and slow flow in the soil matrix for a silt loam and a sandy clay. Loading and infiltration are modelled by a near‐surface mixing model and Green–Ampt infiltration. The statistical properties of loading were evaluated from these simulations. For this storm the mean total of resident solute mixing from the soil to preferential flow reached a maximum for a retardation factor R ～ 5. Much smaller loadings occurred for more weakly sorbing and more strongly sorbing solutes. The variability of loading tended to decrease with increasing R. Ensemble averaged rainfall patterns were derived which related to the magnitude of loading. The patterns of rainfall generating large preferential flows did not necessarily lead to large solute loading. Early peaking, mid‐storm peaking and late peaking rainfall contributed to large solute loadings, depending upon soil and chemical properties. These patterns result from a balance between the amount of preferential flow generated and the amount of solute available when preferential flow is triggered. The results suggest that the use of R as a measure of the mobility of resident solutes depends on the flow pathway considered. In addition, characterization of flux distributions in soil with weakly sorbing, resident tracers, may underestimate the potential for rapid transport of strongly sorbing solutes subject to natural variations in rainfall.     

Repeated grading of weed abundance and multivariate methods to improve the efficacy of on-farm weed control trials

We evaluated whether new information could be drawn from additional data collection and unconventional statistical analyses of an on-farm trial. First, we compared a conventional sampling method using a biomass estimate of weed abundance to repeated visual assessment of the percentage ground cover of weeds. The biomass was sampled once after the treatment, whereas the ground cover was repeatedly sampled once before weed control plus several occasions after weed control. Second, we contrasted the outcomes from analysis of variance ( anova ), taking samples from a single point in time with repeated measures (rm) anova and a multivariate method. As the outcomes and conclusions drawn were relatively similar, we conclude that the ground cover estimate of weed abundance was as reliable as the biomass estimate. The rm anova enabled us to follow the temporal trend in response to treatments in the most abundant species, including possible initial differences. Multivariate analysis went even further, by clearly displaying species-wise responses and treatment selectivity.     

Blood content of broiler chicken carcases prepared by different slaughter methods

Two trials using broiler chickens were undertaken to determine if variations in commercial slaughter techniques affected either the appearance or the residual blood content of the carcases produced. In the first trial groups of broilers were either stunned (55, 80 or 105 volts), electrocuted (240 volts) or anaesthetised and the subsequent bleed-out volumes after one, two, three and four minutes exsanguination were measured. The method of slaughter made no difference to the amount of blood lost after venesection. Haemoglobin content of the pectoral muscle was used to measure residual blood and was uniformly low in all groups (0.7 to 0.16 mg haemoglobin/g of muscle). In the second trial groups of chickens were either stunned and bled out, electrocuted, electrocuted and bled out, decapitated or halal killed before processing. The edible portions of the carcases were minced and the average haemoglobin content for each group was 0.19, 0.36, 0.22, 0.17 and 0.17 mg/g of soft tissue. The appearance of chickens that were stunned and bled out was the same as that of chickens that were electrocuted and bled out. The authors conclude that killing chickens by electrocution before exsanguination does not adversely affect the carcase appearance. Furthermore, electrocution ensures that broiler chickens are humanely slaughtered.