A modified technique for flushing ova from the sheep uterus

Abstract

Extract

Sheep ova are normally obtained from the reproductive tract using the flushing techniques described by Hunter et al. (1955) Cumming, I. A. and McDonald, M. F. 1967. The production of ova by New Zealand Romney ewes following hormonal stimulation. N.Z. Jl agric. Res., 10: 226–236. [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]. Oviduct flushes, in the writers' experience, give a higher recovery of ova than uterine flushes, but they result in more adhesions of the tract, which can cause infertility. Consequently, the development of satisfactory uterine flushing techniques appears necessary before ova can be recovered repeatedly from superior ewes. This paper describes such a technique.     

Dietary zinc concentration and lipopolysaccharide injection affect circulating trace minerals,acute phase protein response,and behavior as evaluated by an ear-tag–based accelerometer in beef steers

To assess plasma trace mineral (TM) concentrations, the acute phase protein response, and behavior in response to a lipopolysaccharide (LPS) challenge, 96 Angus cross steers (average initial body weight [BW]: 285 ± 14.4 kg) were sorted into two groups by BW (heavy and light; n = 48/group), fitted with an ear-tag–based accelerometer (CowManager SensOor; Agis, Harmelen, Netherlands), and stagger started 14 d apart. Consecutive day BW was recorded to start the 24-d trial (days −1 and 0). Dietary treatments began on day 0: common diet with either 30 (Zn30) or 100 (Zn100) mg supplemental Zn/kg DM (ZnSO₄). On day 17, steers received one of the following injection treatments intravenously to complete the 2 × 3 factorial: 1) SALINE (~2–3 mL of physiological saline), 2) LOWLPS: 0.25 µg LPS/kg BW, or 3) HIGHLPS: 0.375 µg LPS/kg BW. Blood, rectal temperature (RT), and BW were recorded on day 16 (−24 h relative to injection), and BW was used to assign injection treatment. Approximately 6, 24 (day 18), and 48 (day 19) h after treatment, BW, RT, and blood were collected, and final BW recorded on day 24. Data were analyzed in Proc Mixed of SAS with fixed effects of diet, injection, diet × injection; for BW, RT, dry matter intake (DMI), plasma TM, and haptoglobin-repeated measures analysis were used to evaluate effects over time. Area under the curve analysis determined by GraphPad Prism was used for analysis of accelerometer data. Body weight was unaffected by diet or injection (P ≥ 0.16), but there was an injection × time effect for DMI and RT (P < 0.05), where DMI decreased in both LPS treatments on day 16, but recovered by day 17, and RT was increased in LPS treatments 6 h post-injection. Steers receiving LPS spent less time highly active and eating than SALINE (P < 0.01). Steers in HIGHLPS spent lesser time ruminating, followed by LOWLPS and then SALINE (P < 0.001). An injection × time effect (P < 0.001) for plasma Zn showed decreased concentrations within 6 h of injection and remained decreased through 24 h before recovering by 48 h. A tendency for a diet × time effect (P = 0.06) on plasma Zn suggests plasma Zn repletion occurred at a greater rate in Zn100 compared to Zn30. These results suggest that increased supplemental Zn may alter the rate of recovery of Zn status from an acute inflammatory event. Additionally, ear-tag–based accelerometers used in this study were effective at detecting sickness behavior in feedlot steers, and rumination may be more sensitive than other variables.     

Effect of virginiamycin supplementation on the performance of young grazing cattle

Three experiments have been conducted to study the effect of virginiamycin in young grazing-bulls (Experiment 1) and heifers (Experiments 2 and 3). Rotational grazing on permanent grassland was practised and animals were supplemented with 1 kg dried sugarbeet pulp per head daily. Control groups did not receive virginiamycin via the supplement, while it was incorporated at 120, 300 and 200 mg kg⁻¹ for the treatment groups in Experiments 1 to 3 respectively.
Average daily liveweight gain was significantly increased from 0·59 to 0·72 kg in Experiment 1 and from 0·73 to 0·81 kg in Experiment 3, but was not affected in Experiment 2 (0·51 vs 0·55 kg). Virginiamycin also increased liveweight gain per ha by 12, 7 and 13%, respectively, for the three experiments. Grazed area per animal was not enlarged to the same extent as the calculated daily energy allowances, which may suggest an improved digestibility and/or rumen fermentation.     

Carbon kinetics of milk formation in Holstein cows in late lactation

Carbon transfer to milk in Holstein cows in late lactation was measured by introducing changes in the natural stable carbon isotope composition of the feed. Six Holstein cows in mid-lactation were placed on a diet naturally low in 13C (-25.0% vs Pee Dee belemnite [PDB] an international carbon isotope standard), based on alfalfa-barley, and six others were placed on a diet naturally enriched in 13C (-11.5% vs PDB), based on corn. After a 7-wk equilibration period on these diets, three cows were switched from alfalfa-barley to corn, and three were switched from corn to alfalfa-barley. The three other cows in each group served as controls. 13C/12C ratios were measured in daily morning milk samples during the week before and for 6 wk after the changes in diet. After the diets had been switched, milk isotope ratios rapidly approached the isotopic composition of the new diet, indicating rapid transfer of dietary carbon into milk. The data were consistent with a model whereby milk was synthesized from a single precursor pool that responded rapidly to dietary perturbation. The milk precursor pool had a half-life of approximately .9 d and had a mass of approximately 7 kg of carbon, which was renewed daily by the entry of 5 kg of digestible dietary carbon.     

Spatial and temporal analysis of coffee wilt disease caused by Fusarium xylarioides in Coffea canephora

Coffee wilt disease (CWD) caused by Fusarium xylarioides, considered to be a soil-inhabiting fungus, is endemic in several African countries, affecting commercially important coffee species and causing serious economic losses. Coffee wilt disease development in naturally infected Coffea canephora fields at the Coffee Research Institute in Uganda was assessed from April 2001 to March 2006 to generate information about temporal and spatial spread of the disease. Maps of diseased trees were also generated from the data. Semi-variance analysis was performed on the data to show the spatio-temporal structure of disease. Host influence on the spatio-temporal structure was deduced from the distribution pattern of diseased and healthy trees and analysis of variance. Results show that the temporal disease epidemic progress was slow. The disease was found to spread from initial infections to healthy neighbouring trees, resulting in an aggregated pattern. An infected tree could infect up to three healthy trees away, in any direction. Disease foci formed and expanded with time, coalescing but punctuated in spots planted with resistant hosts. There were varying levels of susceptibility among host genotypes, affecting the rates and levels of epidemic development. The implications of the findings to the control of CWD are discussed.     

Variation in Occurrence of Dematiaceous Hyphomycetes on Forage Bermudagrass over Years, Sampling Times, and Locations

ABSTRACT Leaf samples of forage bermudagrass with symptoms of infection by species of Bipolaris, Curvularia, and Exserohilum (dematiaceous hyphomycetes) were collected from three swine waste application sites in Mississippi at eight sampling times during each of 3 years. Samples were assayed for pathogens by observing sporulation on plated leaf tissue. Among 3,600 leaves assayed, eight species of the three genera were observed. Features and criteria for the practical identification of species on plated leaf samples are described. Sporulation by dematiaceous hyphomycetes was observed on 97% of leaves; a single pathogen was observed on 20% and two to five pathogens were observed on 77% of leaves. Distributions of leaves among classes with one to five pathogens per leaf, for sites within years, always differed significantly (P = 0.01) from a Poisson distribution and usually included fewer leaves than expected with four or five pathogens. Significant (P = 0.05) variation in frequencies of occurrence of pathogens among 72 samples of 50 leaves each was attributed to pathogen species, sampling times, and species-time interactions. Exserohilum rostratum, Curvularia lunata, and Bipolaris cynodontis were the most frequent pathogens across years and sites; B. spicifera and C. geniculata were intermediate; and B. hawaiiensis, B. sorokiniana, and B. stenospila were least frequent. For the five most common pathogens, significant differences in frequency among locations were commonplace. Six pathogens exhibited significant (P = 0.05) positive and negative correlations with others in overall frequencies of occurrence across years, sampling times, and sites. However, chi(2) tests of dual occurrence indicated that interactions between specific pairs of pathogens in or on leaves are not likely to be major causes for overall frequency correlations. Results indicate that dematiaceous hyphomycetes typically infect forage bermudagrass on swine waste application sites in complexes rather than as individual species; that E. rostratum, C. lunata, and B. cynodontis are the predominant pathogens; and that frequencies of pathogens often differ significantly between locations.     

Computerized apparatus for measuring dynamic flavor release from liquid food matrices

A fully computer-controlled apparatus was designed. It combines a glass reactor with a temperature-controlled hood, in which headspace volatiles are captured. Flavored liquids can be introduced into the reactor and exposed to conditions of temperature, air flow, shear rate, and saliva flow as they occur in the mouth. As the reactor is completely filled before measurements are started, creation of headspace just before sampling start prevents untimely flavor release resulting in real time data. In the first 30 s of flavor release the concentrations of the volatiles can be measured up to four times by on-line sampling of the dynamic headspace, followed by off-line trapping of the samples on corresponding Tenax traps and analysis using GC-TDS-FID. Flavor compounds from different chemical classes were dissolved in water to achieve concentrations typically present in food (micrograms to milligrams per liter). Most of the compounds showed constant release rates, and the summed quantities of each volatile of three 10 s time intervals correlated linearly with time. The entire method of measurement including sample preparation, release, sampling, trapping, thermodesorption, and GC analysis showed good sensitivity [nanograms (10 s)(-1)] and reproducibility (mean coefficient of variation = 7.2%).     

Resistance to benzimidazole and macrocyclic lactone anthelmintics in cattle nematodes in Argentina

In April 2003, persistent scouring and ill-thrift that was reported in calves form an intensive beef rearing operation in central Argentina despite treatments with benzimidazole and ivermectin. In order to conduct a controlled faecal egg count reduction test on this herd, 40 calves 5-8-months-old were selected on the basis that they had a nematode eggs per gram (epg) of faeces count greater than 150. Animals were divided into four groups (1-4) of 10 calves. Calves of groups 1-3 were treated, respectively, with subcutaneous injection of ivermectin (200 mcg/kg), ricobendazole (4 mg/kg) and levamisole (7.5 mg/kg), while calves of group 4 remained as untreated controls. The egg count reductions carried out 10 days later were lower than 15% in calves treated with ivermectin and ricobendazole, but 100% in animals receiving levamisole. Pooled post-treatment faecal cultures showed larval percentages of 92 and 95 for Haemonchus and 8 and 5 for Cooperia in the faeces of calves treated with ivermectin and ricobendazole, respectively. This is the first reported case of Haemonchus parasiting cattle showing simultaneous resistance to avermectins and benzimidazole type anthelmintics.