Treatment with Gonadotropin Releasing-Hormone in Prepubertal Gilts at Two Different Ages

To study the effect of GnRH in prepubertal gilts, seven crossbred gilts were treated with saline solution and 250 fig GnRH. In connection with saline and GnRH treatments blood was sampled every 15 min for 4 h, thereafter every 30 min for 2 h and every 60 min for 3 h, and finally every 3 h for 6 days. The ovaries were inspected by laparo-scopy just before and 6 days after GnRH treatment. The first GnRH treatment was undertaken when the gilts had a mean age of 141 days and mean body weight of 66 kg. One gilt was in prooestrus at this treatment. In the other 6 gilts the mean LH level was around 0.5 μg/l during a 4 h period after the saline injection. After the GnRH treatment a LH peak was seen with a mean duration of 4 h and a mean maximum level of 9.2 ± 2.07 μg/1. None of the gilts ovulated or showed oestrus within a week after GnRH treatment, which was confirmed by laparoscopy. The seventh gilt which was in prooestrus had high levels of oestradiol-17β (> 40 pmol/1) at GnRH treatment and no LH peak was seen during a 4 h period after treatment.Two gilts which had not shown oestrus at an age of 173 days and a mean body weight of 93 kg were treated a second time with 250 μg GnRH. The LH peak had a duration of 4 h and a mean maximum level of 5.3 ± 3.04 μg/l. Neither of these 2 gilts showed oestrus or ovulated within a week after GnRH injection. It was concluded that a single injection of GnRH results in a LH peak but is not enough to stimulate ovulation or oestrus in prepubertal gilts at a mean age either of 141 or 173 days.Key words: GnRH-treatment, prepubertal gilts, LH, oestradiol-17β     

Chemical Composition of Barley Cultivars Fractionated by Weighing,Pneumatic Classification,Sieving, and Sorting on a Specific Gravity Table

Five different barley cultivars, including covered and naked samples containing low, normal, or high-amylose starches were fractionated by weighing, pneumatic classification, sieving, or sorting on a specific gravity table, and analyzed for content of starch, protein, ash, and β-glucan. For ash content, almost no variation could be found between different fractions. Protein content was minimum in the intermediate fractions for all cultivars when sorted by weighing. For the other fractionation methods, the differences in protein content were small. A tendency for decreasing content of starch with increasing grain mass and size could be seen when fractionating grains by weighing and sieving, respectively. The clearest trend was seen in differences in β-glucan content for all cultivars and all methods used. The main interpretation of our results is, however, that the chemical composition within the cultivars studied is very similar for all fractions, and that the differences between the unfractionated barley samples are larger.     

Climate change,human impacts,and the resilience of coral reefs

The diversity, frequency, and scale of human impacts on coral reefs are increasing to the extent that reefs are threatened globally. Projected increases in carbon dioxide and temperature over the next 50 years exceed the conditions under which coral reefs have flourished over the past half-million years. However, reefs will change rather than disappear entirely, with some species already showing far greater tolerance to climate change and coral bleaching than others. International integration of management strategies that support reef resilience need to be vigorously implemented, and complemented by strong policy decisions to reduce the rate of global warming.     

Subclinical characteristics of the wasting pig syndrome

The plasma concentrations of cortisol and corticosteroid-binding globulin and the adrenal synthesis capacity of cortisol were analysed in 10-week-old healthy and age-matched wasting or unthrifty pigs. Crypt cell multiplication, villus height and intestinal mucosal alkaline phosphatase (ALP) activity were also investigated. Furthermore, the effect of amperozide, a psychotropic drug with specific effects on emotional behaviour, was analysed for its effect on plasma ALP activity and villus height. Although the wasting pigs exhibited an increased cortisol synthesis capacity, there was a decreased plasma concentration of cortisol in these pigs. Furthermore, the plasma cortisol binding capacity was found to be significantly lowered in wasting pigs. There was also a reduced crypt cell proliferation, a reduced villus height and a decreased ALP activity in the ileal mucosa. Treatment with amperozide resulted in a normalisation of plasma ALP activity in unthrifty pigs, indicating a stimulation of body growth. The results indicate that the growth depression of wasting pigs is most probably a chronic stress syndrome caused by the inability of these animals to cope with the events following weaning and mixing.     

Physiological and genetic characterisation of some new Aphanomyces strains isolated from freshwater crayfish

Five Aphanomyces strains were isolated during suspected outbreaks of crayfish disease in Spain and Italy. Genetic and physiological evidence show that the strains isolated from the freshwater crayfish Procambarus clarkii and Pacifastacus leniusculus, do not fit into any previously identified group of Aphanomyces astaci and are not capable of killing crayfish following standardised experimental infection. RAPD-PCR and ITS sequencing analysis show a high degree of similarity between the new isolates, while they are clearly different from the A. astaci reference strains. They do, however, possess some properties, which are commonly associated with parasitic species such as repeated zoospore emergence and the lack of sexual reproduction. The five isolates share some physiological properties i.e. a high growth rate, and germination in response to nutrients and, in contrast to A. astaci, they do not express chitinase constitutively during growth or sporulation. Until their taxonomic status is fully elucidated we suggest that the new isolates be given the tentative species name Aphanomyces repetans.     

Social effects and boar taint: significance for production of slaughter boars (Sus scrofa)

A study was conducted to elucidate the effects of social factors on the concentrations of boar taint substances, androstenone and skatole, in boars. The factors included dominance (social rank) and the effects of strongly tainted animals on other members of the group. Four successive replicates of 100 pigs (50 boars + 50 gilts) with an average live weight of 24 kg were randomly allocated to 10 pens of 10. Data for this study were collected during the period of 67 to 114 kg of live weight and included the repetitive recording of agonistic behavior during competitive feeding; blood sampling for determination of plasma androstenone, skatole and testosterone in boars; feces sampling for determination of skatole content; and collection of bulbourethral glands in boars, and uteri plus ovaries in gilts at slaughter, for the assessment of sexual maturity. Results show an influence of social rank on plasma concentrations of androstenone (P = .0001) and testosterone (P = .0001), the weight of the bulbourethral glands (P = .0001), and plasma skatole (P = .02). Pens were classified according to the pig with the highest concentration of androstenone in the pen into high, medium, and low maximum pens. In pens with high maximum concentrations of androstenone, the second-highest androstenone concentration (P = .0001), and the average concentration (P = .0003) in the pen were higher than those in pens with medium or low maximum concentrations of androstenone. Mean aggression level was also higher (P = .02), but pens with high maximum aggression level did not have higher mean androstenone concentration. Rank effect on androstenone was more important than aggression effect. Neither maximum androstenone concentration nor maximum aggression level in a pen was related to the pen mean stage of sexual maturity in either sex. No influences of rank, aggression, or aggression received were found on the feces skatole level, and no pheromonal communicative function was demonstrated for skatole. High androstenone concentrations did not have a suppressive effect on androstenone concentrations in other males of the group; on the contrary, the levels were increased. This may be due to a stimulating effect of androstenone and, possibly, mating activity. Consequently, in the production of boars for slaughter, strongly tainted animals should be avoided or removed and mating activity minimized. This could be facilitated by, for instance, slaughtering before sexual maturity or separate rearing of the sexes.     

The Hereditary 'Short Tail' Sperm Defect - A New Reproductive Problem in Yorkshire Boars

This study describes a new sperm defect in Yorkshire boars. The length of the sperm tail is markedly reduced, resulting in a total immotility in all spermatozoa. At transmission electron microscopy level, the morphology of the midpiece microtubular components area is seriously affected. This boar sperm defect differs from the ‘tail stump’ defect observed in bulls, the tails being longer in most spermatozoa than those found in affected bulls. Therefore, the term ‘short tail’ sperm defect is more adequate. The authors observed the first case in 1987. In 1998, this defect became a noteworthy reproductive problem, when it was observed in nine boars intended for breeding. In one litter, three littermates were affected with the ‘short tail’ sperm defect. At the present time the authors believe that the defect is recessively inherited.