Successful,repeated non-surgical collection of blastocysts from virgin and repeat breeder heifers

A total of 55 non-surgical collections, 7 days after spontaneous heat, was made in 19 heifers. Recovery rate was 57% (17/30) from 10 repeat breeder heifers and 72% (18/25) from 9 virgin heifers, this difference was not significant. Fertilization rate in both groups was 94%. The eggs were always recovered in the first 100 ml of flushing medium. Mean lengths of oestrous cycle after non-surgical collection were, respectively, 16.9 and 18.1 days in repeat breeder and virgin heifers. This difference was not significant. However, the cycle in which the first collection was made was significantly shorter (P<.005) than the cycle immediately before the collections. Only 61% of possible eggs were non-surgically collected from 4 superovulated repeat breeder cows and no further eggs were found after slaughter, one to two hours later.     

A method for preparation of chromosomes from bovine zygotes and blastocysts

A simple technique for making chromosome preparations from zygotes and early blastocysts is described. The morphological features of blastocysts and total number of cells greatly influence the quality of the preparation.     

Treatment of dogs with oral melanoma by hypofractionated radiation therapy and platinum-based chemotherapy (1987-1997)

This retrospective study in 39 dogs with incompletely resected oral melanoma examined the efficacy of hypofractionated radiation therapy and platinum-containing chemotherapy. All dogs were completely staged, with the majority of dogs classified as stage 1. Dogs received 6 weekly fractions of 6-gray (Gy) megavoltage irradiation with a cobalt-60 unit or a 4-MeV (megaelectron volts) linear accelerator. Dogs received cisplatin (10-30 mg/m2 IV) or carboplatin (90 mg/m2 IV) chemotherapy 60 minutes before radiation delivery. Durations of local control, metastasis-free survival time, and overall survival time were recorded. By the Kaplan-Meier method, 15% of the dogs had local recurrence within a median time of 139 days. Fifty-one percent of the dogs developed metastatic disease within a median time of 311 days (range, 24-2, 163 days). Median survival time for all 39 dogs was 363 days. The combined use of chemotherapy and radiation therapy in this protocol provided local control consistent with previous studies. Low-dose chemotherapy was used with the intent of enhancing radiation therapy for the local control of an incompletely excised tumor. Survival times were longer than previously reported for dogs with oral malignant melanoma. Additional studies are required to determine whether these results were due to the effects of chemotherapy on microscopic disease or the enhanced local control provided by chemoradiation therapy.     

Field testing the influence of sperm competition based on sperm mobility in breeder turkey toms

1. Commercial reproduction of turkeys relies on pooling of semen from multiple males for inseminations. Understanding how sperm characteristics influence paternity under commercial breeding conditions is important to improving production efficiency. 2. The objective of this study was to evaluate progeny production of individual toms following commercial practices of pooling semen to determine if sperm mobility influences progeny production in field conditions. 3. A total of 104 toms were evaluated for sperm mobility. A subset of 10 toms were housed together and semen was collected, pooled and used to inseminate hens (n = 28). Hens were inseminated at 30 weeks of age and weekly thereafter. 4. Ejaculates from each tom were evaluated on two separate days for sperm mobility. Semen from each tom was diluted and layered upon 6% (wt/vol) Accudenz solution. The sperm suspension was incubated at 41 degrees C for 5 min and absorbance was measured with a spectrophotometer. 5. Toms were ranked by absorbance and categorised as high or low if mobility score was +/- 1 SD from the flock mean (average). 6. For parentage determination, DNA was extracted from tom, hen and poult blood. Poult parentage (n = 276) was determined at one day of age or at 14 weeks by analysis of marker genotypes that were generated by polymerase chain reaction (PCR) amplification of genomic DNA with selected microsatellite markers. 7. Sperm mobility differed across males with absorbance values ranging from 0.147 to 0.366. 8. Findings demonstrate differences in poult production among individual toms when semen from multiple males was pooled and inseminated. Toms classified as high, average and low produced 55, 41 and 4% of the offspring, respectively. 9. It appears that sperm mobility is a trait that influences sperm competition among toms under field conditions where sperm numbers inseminated from individual toms are not controlled or constant and that toms with low sperm mobility produce few offspring.     

Bovine and ovine mycoplasmal arthritis and synovitis (abstract)

The pathology of mycoplasmal gonitis in a Friesian cow aged 15 months, and polyarthritis in a 3-week-old East Friesian sheep was described. Both stifle joints of the cow, which was 1/63 calves that developed polyarthritis after being fed milk contaminated with Mycoplasma mycoides mycoides large colony type (MmmLC), were distended with yellow flocculent fluid. The capsular and synovial tissues and their associated tendon sheaths were greatly thickened due to chronic active fibrinopurulent inflammation with ulceration of synovial membranes and progressive organisation of the exudate by granulation tissue and fibrosis. Nodular aggregates of lymphocytes and plasma cells studded the membrane. Articular surfaces were unremarkable. Mycoides cluster organisms were demonstrated on polymerase chain reaction (PCR) analysis of the joint tissues and these were confirmed on culture as MmmLC. The lamb was the offspring of an agalactic ewe whose progeny of the previous 3 years developed polyarthritis. The carpal and hock joints had periarticular nodular swellings and there was mild haemarthrosis of all appendicular skeletal joints. Lesions were characterised as subacute active fibrinopurulent synovitis and periarthritis with haemorrhage. Articular surfaces were normal. Joint tissue was positive by PCR for the mycoides cluster of organisms. Mycoplasma was not isolated in culture.