In vitro Evaluation of the Quality and Fertilizing Capacity of Boar Semen Frozen in 0.25 ml straws

Twenty-two boar ejaculates were frozen in 0.25 ml straws using a controlled cooling rate, then evaluated in vitro in order to assess: (i) the extent to which a range of semen evaluation parameters accurately characterize sperm quality, (ii) the value of quality assessment in the characterization of long-term sperm survival and fertility and (iii) the suitability of the cryopreservation protocol used for yielding semen with good quality and fertilizing capacity. Motility with or without caffeine, plasma membrane integrity (PMI) evaluated with both propidium iodide (PI) and Hoechst 33258, and acrosome morphology were studied, the ejaculates being then classified into five quality groups. A thermoresistance test and a homologous in vitro fertilization test were applied to selected ejaculates of these groups. Caffeine-stimulated motility and PMI evaluated with PI provided better estimations of semen quality than the other tests of motility, PMI, or acrosome morphology, but this quality assessment could not reveal differences in fertilizing capacity or thermoresistance among ejaculates. Over 43% spermatozoa survived cryopreservation in 19 of the 22 ejaculates, with inter-boar and inter-ejaculate variability in the freezing success being observed. The fertilizing capacity, however, was seriously affected by the process regardless of the semen quality. It is concluded that caffeine-stimulated motility and PMI evaluated with PI give accurate information on sperm quality, but important aspects to the valuation of semen such as thermoresistance and fertilizing capacity are not revealed by this quality study. Moreover, the approach of selecting suitable protocols of cryopreservation does not appear to be sufficient for guaranteeing systematically good quality and fertilizing capacity in the frozen-thawed semen.     

Market stress-associated changes in serum complement activity in feeder calves.

Classical hemolytic complement (C) of calves was analyzed during a protocol designed to imitate the usual market handling of feeder calves from the southeastern United States. Serum C concentrations of the calves (n = 100 x 4 years) were evaluated on their farm of origin, on arrival at an auction market, on arrival at a feedyard, and during their first 4 weeks in the feedyard. Complement concentrations (measured in CH50 units) were typically lowest at the farm of origin and highest when the calves entered the auction market 28 to 133 days later. Serum C concentrations decreased after the calves encountered the severe stresses of being in the auction market for 7 days, 24-hour truck transport (1,932 km) to the feedyard, and the first 7 days in the feedyard. The C concentrations recovered after 21 to 28 days in the feedyard. Steers had significantly (P less than or equal to 0.05) lower C concentrations than did heifers in 3 of 4 years at the farm of origin, and in 2 of 4 years at the auction market. Morbid calves had significantly (P less than or equal to 0.05) lower C values than did healthy calves on day 7 in the feedyard in 3 of 4 years. There were significant differences in C concentrations of calves from different farms of origin in each of the 4 years. There was no significant difference in C concentrations of calves that were vaccinated vs those not vaccinated with Pasteurella haemolytica.     

Oxfendazole pulse release intraruminal devices and bovine parasitic bronchitis: comparison of two control strategies in a field experiment

Lungworm-infected seeder calves were used on two 1.41 ha paddocks to ensure that groups of 11 susceptible trial calves would be exposed to heavy early season challenge with Dictyocaulus viviparus. This produced conditions for an artificially severe test of two control strategies. The first employed a front-loaded oxfendazole pulse release bolus, ie, an intraruminal device which released one therapeutic anthelmintic dose immediately and five subsequent pulses at approximately three-weekly intervals. These front-loaded boluses were given to five of 11 calves on one paddock as soon as parasitic bronchitis had become clinically obvious (34 days after turnout) while the remaining six calves were kept as untreated controls. Clinical signs quickly subsided in the treated animals and no further respiratory problems occurred despite continued exposure to reinfection. The other control strategy involved the administration at turnout of an oxfendazole pulse release device which released the first of five anthelmintic doses approximately three weeks after administration, to all 11 calves on the other paddock. This strategy was almost completely successful in preventing patent infections from establishing and reduced the infectivity of the pasture in August and September by 94.1 per cent as shown by tracer calf studies. The calves treated at turnout performed better than the calves treated with the front-loaded boluses for most of the season and had an average weight-gain advantage of 20.4 kg at housing (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

Pheromone-mediated mating disruption in the millet stem borer, Coniesta ignefusalis (Lepidoptera: Pyralidae)

The millet stem borer, Coniesta ignefusalis Hampson (Lepidoptera: Pyralidae), is a major pest of pearl millet in the Sahelian region of Africa. The female sex pheromone has been identified and synthesised, and previous research had shown that the synthetic pheromone could cause high levels of reproductive communication disruption in small plots when released at rates of 640 mg/ha/day, using PVC resin formulation renewed every seven days to maintain efficiency. In the present research, in experiments in farmers’ fields in Niger, 86.8% (SE = 2.6%) communication disruption was achieved when polyethylene vials loaded with 0.5 mg pheromone at 400 dispensers/ha were used and replaced every 21 days. Polyethylene vials loaded with 80 mg pheromone gave uniform, zero-order release at approximately 0.05 mg/day at 27 °C. Experiments carried out on replicated 0.5 ha plots in farmers’ fields in Niger using a single application of these dispensers at 400 dispensers/ha resulted in at least 99% suppression of pheromone trap catches of male C. ignefusalis moths in treated plots relative to numbers in untreated plots for up to 3 months. However, sampling the central portions of these plots before and after harvest showed no significant differences in infestation, damage or yield loss between plots treated with pheromone and untreated plots. This may have been because of small plot size and the immigration of mated female moths into the treated plots which negated any reduction of mating of females within the treated plots. Comparisons of numbers of male C. ignefusalis moths in traps baited with the standard 0.5 mg monitoring lures and those baited with the 80 mg disruption dispensers showed catches in the latter were only 10-20% of those in the former; indicating high level communication disruptions in traps with high dose dispensers. Implications of using insect synthetic pheromones in the development of integrated management of C. ignefusalis in pearl millet cropping systems in the Sahel are discussed.     

Effects of insecticides applied to control cucumber beetles (Coleoptera: Chrysomelidae) on watermelon yields

Foliar insecticides applied to control the striped and spotted cucumber beetles, Acalymma vittatum (Fab.) and Diabrotica undecimpunctata howardi Barber, on watermelon, Citrullus lanatus, were of little or no value in three studies conducted in two locations over 2 years. However, an at-planting application of the systemic, soil insecticide carbofuran resulted in higher early yields, although the differences were not statistically significant in small plots. In 1991, large plots comparing carbofuran-treated watermelons with untreated watermelons in two commercial fields showed large and statistically significant increases in melon yield when carbofuran was applied, especially in early yield. Studies in 1992 and 1993 showed that the application of carbofuran at planting stimulated root and shoot growth after transplating and increased yields when compared with untreated plots, plots treated with methyl bromide, or another soil insecticide, terbufos. These studies suggest that carbofuran may be acting as a growth stimulant, as well as an insecticide.     

Effect of oral L-carnitine on its concentration in the plasma of yearling Thoroughbred horses

After an oral dose of 10 g of L-carnitine the plasma concentrations of free and total carnitine increased in five yearling thoroughbred horses, reaching a peak two to four hours after administration, but in two horses there was no increase. In the five which responded, the mean (+/- sd) peak increase in total carnitine concentration was 15.1 +/- 6.9 mumol/litre from a predose mean of 18.8 +/- 3.4 mumol/litre, and the mean peak increase in free carnitine concentration was 13.5 +/- 3.1 mumol/litre from a pre-dose mean concentration of 12.5 +/- 2.2 mumol/litre. These changes were similar to those observed previously in a group of adult thoroughbred horses given 10 g of L-carnitine. There was no consistent pattern of change in the concentration of acetylcarnitine in the seven yearling horses.     

Extraction and Activation of Wheat Polyphenol Oxidase by Detergents: Biochemistry and Applications

Polyphenol oxidases (PPOs) from several plant species, including wheat, have been implicated in undesirable brown discolorations of food products. It has been demonstrated that these enzymes are often present in a latent form or are membrane‐associated, necessitating detergent or other treatments to obtain fully active preparations. Here, the influence of different detergents on wheat meal and flour PPOs was investigated. Extraction in presence of 50 mM SDS led to a 5‐ to 15‐fold increase in PPO activity, making quantitative assays in flour from low‐PPO lines more robust. Among a series of additional nonionic, anionic, and cationic detergents tested, only n ‐lauroylsarcosine increased extractable PPO activity to a degree comparable to that of SDS. Additional experiments suggested that a large fraction of wheat meal PPOs may be membrane‐associated and that SDS is able to activate PPOs extracted from high‐activity but not from low‐activity wheat lines. PPO activities assayed after SDS extraction of meal and flour were highly correlated with each other and with activity determined in whole (intact) kernels in absence of SDS. Correlation coefficients between PPO activities measured with all these methods and noodle brightness were about equal, indicating that activities assayed after SDS extraction are useful for germplasm screening and quality prediction.