Sheep, mice, cattle, goats and pigs have all been cloned by transfer of a donor cell nucleus into an enucleated ovum, and now we add the successful cloning of a cat (Felis domesticus) to this list. However, this cloning technology may not be readily extendable to other mammalian species if our understanding of their reproductive processes is limited or if there are species-specific obstacles.

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The objective of the present study was to determine differences in time of detection of pregnancy between heifers and cows and the interval after insemination at which the maximum sensitivity and negative predictive value of transrectal ultrasonography were obtained. One-thousand-four-hundred transrectal ultrasonographies (TRUS-1; 1,079 in cows and 321 in heifers) were performed using a 5-MHz linear-array transducer. The cattle were randomly assigned to have TRUS performed once between days 24 and 30 (estrus=day 0) in cows or between days 21 and 27 in heifers. Every TRUS diagnosis was subsequently compared with a second TRUS diagnosis (TRUS-2), performed 3-8 days later, after day 30 (range 31-38) for cows and after day 27 (range 28-35) for heifers. The sensitivity and specificity between cows and heifers for the common days of TRUS (from 24 to 27) were compared. In cows, sensitivity increased gradually from 74.5% at day 24 to 100% at day 29 (P<0.01). Specificity increased from days 24-25 and reached a plateau of 96.6% on day 26 (P<0.01). In heifers, sensitivity increased from 50% at day 21 to 100% at day 26 (P<0.01). Specificity increased from 87.5% at day 21 and remained steady at 94% starting on day 23 (P>0.05). The sensitivity for cows and heifers was 89.2 and 96.8%, respectively (P<0.05) and the specificity was 93.0 and 93.4% (P>0.05). In this study, heifers were diagnosed pregnant earlier than cows, and the maximum sensitivity and negative predictive value were obtained 3 days earlier in heifers than cows (days 26 and 29, respectively).

Summary. Background: Large animal models that accurately mimic human hemophilia A (HA) are in great demand for developing and testing novel therapies to treat HA. Objectives: To re-establish a line of sheep exhibiting a spontaneous bleeding disorder closely mimicking severe human HA, fully characterize their clinical presentation, and define the molecular basis for disease. Patients/methods: Sequential reproductive manipulations were performed with cryopreserved semen from a deceased affected ram. The resultant animals were examined for hematologic parameters, clinical symptoms, and responsiveness to human FVIII (hFVIII). The full coding region of sheep FVIII mRNA was sequenced to identify the genetic lesion. Results and conclusions: The combined reproductive technologies yielded 36 carriers and 8 affected animals. The latter had almost non-existent levels of FVIII:C and extremely prolonged aPTT, with otherwise normal hematologic parameters. These animals exhibited bleeding from the umbilical cord, prolonged tail and nail cuticle bleeding time, and multiple episodes of severe spontaneous bleeding, including hemarthroses, muscle hematomas and hematuria, all of which responded to hFVIII. Inhibitors of hFVIII were detected in four treated animals, further establishing the preclinical value of this model. Sequencing identified a premature stop codon and frame-shift in exon 14, providing a molecular explanation for HA. Given the decades of experience using sheep to study both normal physiology and a wide array of diseases and the high homology between human and sheep FVIII, this new model will enable a better understanding of HA and facilitate the development and testing of novel treatments that can directly translate to HA patients.

To increase the basic understanding of killer whale (Orcinus orca) reproductive physiology necessary for the development of artificial breeding programs, we utilized radioimmunoassays (RIA) to detect urinary immunoreactive steroid metabolites (pregnanediol-3~-glucuronide [PdG] and estrone-conjugates [EC]) and gonadotropins (luteinizing hormone [LH] and follicle-stimulating hormone [FSH]) in urine samples from six female killer whales. Urine samples were collected from the whales by voluntary presentation behavior over a 2-to 4-year period. All urinary hormone values were corrected for intersample urine concentration variations by indexing with creatinine. Daily urine samples from four whales were collected during two conceptions and 18 complete estrous cycles. LH, FSH, EC, and PdG immunoreactive levels were determined and combined with observed copulatory activity in five cycles, including two conceptive cycles from two whales. Mean luteal phase lengths ranged from 9.7 to 19.2 days. Mean follicular phase lengths ranged from 6.5 to 16.8 days. Mean estrous cycle lengths based on the first detectable PdG levels were 41.6 2 6.72 S.E.M. days. After PdG nadir, immunoreactive FSH levels showed a bimodal pattern with the first peak being greater in size, and both preceding a follicular phase EC increase. LH levels > the 95% confidence interval of the mean were considered significant. Combined LH immunoreactive values from whales 2 and 6 during two and three estrous cycles, respectively, had significant LH peak concentrations on day minus 2. These significant LH peaks were assumed to represent the preovulatory LH surge. Eight copulations during two conceptive cycles were observed between whales 2 and 6 and a breeding male. Six of these copulations (3 with each female whale) occurred within 72 hours of the beginning or the end of the presumptive preovulatory LH surge. Estrous activity was seen throughout the year for the herd. However, individuals had varying periods of anestrus that could not be linked to environmental, social, or nutritional influences. The whales that were reproductively successful had anestrus intervals that were usually influenced by gestation, postparturient period, or lactation. The information obtained during this research enhances the foundation for future artificial reproductive management techniques. 0 1993 Wiley-Liss, Inc.