Origin of the equine middle latency auditory evoked potential

Recordings of the middle latency of the auditory evoked potential (MLAEP) were made in eight conscious ponies. These traces were compared to those made under halothane anaesthesia with and without paralysis of the skeletal muscles. Recordings were also made from percutaneous electrodes placed along the neck with the same stimulus used for the auditory evoked potentials. The results of these experiments were used to deduce the origin of latencies in the auditory evoked potential occurring between 10 and 25 ms after the stimulus. The MLAEP was found to contain two positive peaks between the latencies of 10 and 25 ms. The first of these two peaks was not abolished by halothane anaesthesia or muscle paralysis. The second of these two peaks was abolished by halothane anaesthesia in all but one animal. In this animal the second peak was abolished by muscle paralysis. No peaks of corresponding latency were recorded from the percutaneous electrodes except from one electrode position at the caudal neck in one pony. The first peak of the middle latency auditory evoked potential seen in conscious ponies appeared to be of central nervous orign. The second peak appeared to be of muscular origin, possibly from the external auditory muscles. The second peak may be analogous to the post-auricular waveform described in man.     

Pre-hospital low-volume resuscitation with hemoglobin-glutamer-200 (Hb-200) in a canine hemorrhagic shock model

The Bowen Technique is a unique hands‐on therapy developed by Tom Bowen of Australia in the 1950s–60s and adapted for use in animals by Carol Bennett in 1997. It consists of a specific sequence of gentle, precise rolling moves done with thumb and fingers over muscle and tendon edges, across the direction of tension. A short waiting period follows each set of moves. Definitive mechanism(s) of action remains to be identified; however, autonomic nervous system modulation (heart rate variability studies) has been documented in humans. The technique has also been reported effective for back, hip, neck, and shoulder pain in human studies. Five geriatric dogs (13–16 years old) of various breeds were presented in a case series at a small animal clinic for primary complaints of stiffness, poor ambulation, and difficulty lying down/getting up. Four had hindlimb proprioceptive deficits; three had arthritic changes to coxofemoral joints and/or lumbar spine; three showed active indicators of pain (chronic pacing/panting; irritability; social withdrawal). All were on NSAID and/or nutritional therapy with unsatisfactory results. One dog had acupuncture weekly for over 1 year but no longer tolerated the needles. Treatment consisted of Animal Bowen at weekly or biweekly intervals. Three dogs were pain scored [0–10; average starting score 6.7 ± 0.6 (mean ± S.D.); range 6–7] by owner before and after treatment. All five dogs showed significant positive changes in attitude, and four had notable improvement in ease of ambulation, after the first treatment. Improvement was progressive over treatment course. Average post‐treatment score was 2.3 ± 2.1 (0, 3, 4); average pain score reduction was 4.3 ± 1.5 (range 3–6) after two to six treatments for the three dogs scored. One dog had complete resolution of hindlimb lameness of 5 years duration after three sessions. Animal Bowen, used alone or in conjunction with standard analgesics and other treatments, can be an effective therapy for chronic musculoskeletal conditions in dogs.     

Comparison of a competitive inhibition ELISA and the card agglutination test for detection of antibodies to Anaplasma marginale and Anaplasma centrale in cattle

OBJECTIVE: To compare a recently developed recombinant MSP-5 competitive inhibition ELISA with a card agglutination test for detection of antibodies to Anaplasma marginale and Anaplasma centrale in Australian cattle. MATERIALS AND METHODS: The ELISA was compared with the card agglutination test using 208 sera from cattle in Anaplasma-free herds, 86 sera from cattle experimentally infected with A marginale or A centrale and 757 sera from cattle in areas endemic for A marginale. RESULTS: The specificity of the ELISA, based on testing 208 sera from cattle in Anaplasma-free areas, was 99.5%, and the sensitivities for detection of antibodies to A marginale and A centrale in sera from the experimentally infected cattle were 98.0% and 100%, respectively. For the same sets of sera, the specificity of the card agglutination test was 98.6% and the sensitivities for detection of antibodies to A marginale and A centrale were 98.0% and 100%, respectively. For the 757 sera collected from cattle in areas endemic for A marginale, the agreement between the ELISA and the card agglutination test depended on the positive threshold selected for the ELISA. The maximum achievable agreement was 91.5% (kappa = 0.73; 95% confidence interval 0.66, 0.79). CONCLUSION: We conclude that the competitive inhibition ELISA is a useful alternative to the card agglutination test for detection of A marginale or A centrale infection in cattle. The assay should be particularly useful for epidemiological applications such as prevalence studies and control programs.     

Use of a Piezo Drill for Intracytoplasmic Sperm Injection into Cattle Oocytes Activated with Ionomycin Associated with Roscovitine

Intracytoplasmic sperm injection (ICSI) consists of the introduction, by micromanipulation, of a single sperm into the cytoplasm of a mature egg. This technique is particularly advantageous when only a few sperm are available for fertilization, representing an important tool in preserving genetic material, especially from poorly fertile males. The results from ICSI in cattle are very often unsatisfactory and difficult to reproduce. Thus, the goal of this study was to evaluate the effect of the use of a Piezo drill (PD) and oocyte activation with ionomycin + roscovitine (I + R) during ICSI in cattle oocytes. After in vitro maturation (24 h), cumulus complex oocytes were divided into four groups: G1 – the ICSI was performed without the use of a PD and the oocyte was activated with I + R; G2 – the ICSI was performed with the use of the PD and activation with I + R; G3 – the ICSI was performed with the use of the PD, but without activation and G4 – parthenogenetic control, treated with I + R, but without sperm injection. The presumptive zygotes were cultured for 7 days and evaluated on day 3 for cleavage rate and on day 7 for blastocyst formation. Embryo production by standard in vitro fertilization in the laboratory was 78% for cleavage (117/150) and 35% for blastocyst formation (41/150). The cleavage rates obtained in G1, G2 and G4 were similar (66.7%, 71.6% and 66.3%, respectively), demonstrating the beneficial effect of oocyte activation. However, in G3, despite the presence of the sperm and the electric stimulation of a PD, the cleavage rates were significantly lower (17.5%) compared with the groups that used chemical activation, even in the absence of sperm (G4). Despite the beneficial effects of activation, this stimulus alone, or in the absence of the PD, was not sufficient for adequate morulae formation (13.4%, 37.9%, 0.0% and 13.5% for G1, G2, G3 and G4, respectively). Only in G2, when the PD was used followed by artificial activation, blastocysts were obtained (14.7%). These results indicate that cattle oocytes must be activated after ICSI to produce viable embryos.     

Effects of rotation, stubble retention and cultivation on take-all and eyespot of wheat in northeastern Victoria, Australia

The effects of different rotations and methods of seed-bed preparation on take-all (Gaeumannomyces graminis var. tritici) (Ggt) and eyespot (Tapesia yallundae; anomorph Pseudocercosporella herpotrichoides) of wheat (Triticum aestivum) were investigated in 1984–1986 in a long-term field experiment (established in 1981), on a fine sandy-clay loam in northeastern Victoria. One treatment, representing the conventional practice, involved burning stubble from the preceding crop followed by four passes with a scarifier in the autumn before sowing wheat each year. Other treatments were direct drilled each year (sown without prior cultivation) and included two stubble treatments (retained or burnt) in either continuously cropped wheat or in lupin (Lupinus angustifolius)-wheat rotations.

High levels of take-all and eyespot developed in the continuously cropped wheat (up to 79% and 66% plants affected, respectively). On the other hand, the incidence of plants with either disease was very low or negligible in wheat that was preceded by lupins. In continuous wheat the incidence of plants with Ggt lesions were up to two times higher in the conventionally cultivated treatment (14% 74% and 79% plants affected in 1984, 1985 and 1986, respectively) than in direct drilled treatment (5%, 36% and 39% plants affected, respectively). Generally, the incidence of plants with Ggt lesions and the severity of root symptoms in direct drilled wheat did not differ significantly between the two stubble treatments.

The incidence of eyespot in direct drilled wheat was exacerbated by the retention of wheat stubble on the uncultivated plots (3%, 46% and 66% plants affected in 1984, 1985, and 1986, respectively) but was reduced by burning the stubble (4%, 19% and 33% plants affected in 1984, 1985, 1986, respectively). However, cultivating soil after burning stubble resulted in more plants with eyespot (14%, 39% and 46% plants affected in 1984, 1985 and 1986, respectively) than did burning stubble alone, and in one year the incidence of affected plants in the cultivated treatment was as high as in wheat direct drilled into stubble. The incidence of eyespot was positively correlated (r=0.85, 0.84 and 0.61 in 1984, 1985 and 1986, respectively) with the incidence of lodged tillers. The incidence of lodging was, generally, highest each year in wheat sown directly into wheat stubble and was reduced by burning wheat stubble or by cropping wheat after lupins.

Wojnowicia graminis was frequently isolated, as was Tapesia yallundae, from eyespot lesions suggesting that perhaps not all symptoms of lodging in Victoria can be attributed to Tapesia yallundae.     

Assessing the usefulness of B‐mode and colour Doppler sonography,and measurements of circulating progesterone concentrations for determining ovarian responses in superovulated ewes

The main goal of this study was to assess the usefulness of two imaging modalities, namely the B‐mode and colour Doppler sonography, and serum progesterone (P₄) concentrations for determining the ovarian response in superovulated ewes. Twenty‐four sexually mature Santa Inês ewes underwent the superovulatory treatment consisting of eight injections of porcine FSH (total dose of 200 or 133 or 100 mg; n  =  8 ewes/total dose) given at 12‐hr intervals and initiated 48 hr before CIDR ^® (Pfizer Inc., Auckland, New Zealand) removal. Six days after natural mating, the ovaries of all donor ewes were visualized and examined with transrectal ultrasonography and then with videolaparoscopy to identify and enumerate corpora lutea (CL ) and luteinized unovulated follicles (LUF s). Jugular blood samples were collected just prior to ovarian examinations. The total number of CL (r  =  .78 and 0.83, p  <  .0001) and LUF s (r  =  .74 and 0.90, p  <  .0001) enumerated using the B‐mode and colour Doppler ultrasonographic technique, respectively, were correlated with that ascertained by videolaparoscopy. Circulating concentrations of P₄ were related directly to the number of healthy CL (r  =  .73, p  =  .0002) and inversely to the number of prematurely regressing CL (r  = ?.46, p  =  .03), but the accuracy of predicting the number of short‐lived CL with serum P₄ concentrations was very poor. The present results indicate that ultrasonographic imaging and serum P₄ measurements on the day of embryo recovery are useful indicators of total/normal CL numbers and both ultrasonographic techniques can be used to quantify LUF s in superovulated ewes.