Validation of a gauze sponge sampling methodology to detect Tritrichomonas foetus by real-time PCR.

Bovine trichomoniasis is a concern for the cattle industry. Advances in testing systems have increased the ability to detect the disease in bulls. However, the greatest limitation is proper collection of an adequate sample. The low repeatability observed with most sample collection techniques can cause false-negative results. The aim of our study was to validate a sample collection technique that increases diagnostic sensitivity and is easier and safer to collect than preputial scraping. Commercial bulls (n = 111) of unknown infection status were sampled for detection of Tritrichomonas foetus using 2 different collection methods: 1) preputial scraping with a dry insemination pipette and 2) penile sponging with a 16-ply gauze sponge. Preputial scraping samples were collected by vigorously scraping preputial and penile mucosa using a rigid insemination pipette while applying negative pressure with a syringe. Penile sponge samples were obtained by swabbing the penile and preputial mucosa with a gauze sponge during full extension of the penis. All samples were processed using a commercial medium and submitted under similar conditions for PCR testing. Positive PCR results were detected in 37 of 111 (33%) bulls using the preputial scraping technique; however, 39 of 111 (35%) were positive using the penile sponging technique. The Newton-Raphson algorithm predicted that the sensitivity of the preputial scraping method was 0.919 (95% CI: 0.689-0.983) and the sensitivity of the penile sponging was 0.949 (95% CI: 0.818-0.987). These data indicate that the penile sponging technique is a reliable alternative to the preputial scraping method.

Embryo Transfer (Techniques, Donors, and Recipients).

Commercial embryo transfer has evolved as an art and as a science since the early 1970s. Today's multiple ovulation embryo transfer is a widely used reproductive tool on many farms and is performed by veterinarians throughout the world. Propagation of the female genomes of select donors, through embryo transfer, has allowed a rapid progression of genetic gain in many breeds, much like what happened with artificial insemination since the 1940s. Advancement of this technology is migrating to in vitro fertilization technology today, allowing a higher volume of offspring to be produced with sex selection in the laboratory.

Effects of label-dose permethrin administration in yearling beef cattle: I. Reproductive function and embryo quality of superovulated heifers.

The objective was to study the effects of a commercial pyrethroid-based pour-on product, permethrin, on reproductive performance in superovulated beef heifers by assessing steroid biosynthesis and embryo quality. Nonpregnant, yearling beef heifers (n = 10; 418 ± 33 kg; 5.5 ± 0.2 body conditioning scores) were assigned by body weight and breed to either (1) saline control or (2) permethrin pour-on administered at label dose (PYR). Superovulation was achieved on all heifers using a timed, 17-day, CIDR-based protocol with GnRH and PGF2α and decreasing total dosage of 240-mg FSH administered twice daily for 4 days. Heifers were artificially inseminated twice (at onset of estrus and 12 hours later) by same technician with frozen semen from single bull collection. To determine short- and long-term effects of permethrin on embryo quality and steroid biosynthesis, superovulation was initiated twice with collection of embryos occurring at 17 and 51 days after treatment. Embryos were recovered 6.5 days after first artificial insemination via nonsurgical flush and were evaluated by International Embryo Transfer Society standards. Blood was collected at standing estrus and day of embryo recovery. Estradiol (E2) and progesterone (P4) concentrations were analyzed via RIA. MIXED and GLIMMIX procedures of SAS were used to analyze continuous and categorical data, respectively. Heifer per flush was the experimental unit. Total embryos recovered did not differ because of treatment (P = 0.30), but did decrease in flush 2 compared with flush 1 (P = 0.02). Quality grade, total transferable quality embryos, and overall flush success did not differ because of treatment (P ≥ 0.16). However, transferable quality embryos were decreased in flush 2 compared with flush 1 (P = 0.05). Total unfertilized oocytes were greater in saline control (P = 0.04). The PYR heifers tended to have less total P4 (P = 0.15) and P4 per CL (P = 0.06) at recovery. E2 per ovulated follicle and E2 per total ovarian structure was greater in flush 2 (P ≤ 0.03) but did not differ because of treatment (P ≥ 0.23). In summary, these data indicate that permethrin administration at label dose in superovulated beef heifers has a tendency to reduce P4, but embryo quality is not affected.

Effects of label-dose permethrin administration in yearling beef cattle: I. Bull reproductive function and testicular histopathology.

Pyrethroid administration to a wide variety of laboratory animals has been shown to cause detrimental effects on male fertility, including sperm quality, by means of endocrine disruption. The objective of this experiment was to study the effects of a commercial, permethrin-containing pour-on product on reproductive variables and testicular histopathology of yearling beef bulls. Black Angus bulls (n = 60; aged 369 ± 17 days; 511 ± 33 kg; 6.2 ± 0.5 body condition scores) were assigned to either (1) saline control (CON) or (2) permethrin pour-on administered at label dose (PYR). Blood samples were collected, and industry standard breeding soundness examinations (BSE), via electroejaculation, were performed on all bulls at 5 days before and 14 days after treatment. Progressive sperm motility and eosin-nigrosin-stained sperm were analyzed using high-power phase-contrast microscopy. Plasma testosterone concentrations were analyzed via radioimmunoassay. Bulls were slaughtered at 34 days, and one testicle per bull was randomly collected for histologic examination. Change in sperm motility between BSEs was not different because of treatment; sperm morphology however improved across treatments, but PYR bulls had less improvement in percent of head (P < 0.001) sperm abnormalities compared to CON, resulting in less improvement of primary abnormalities (P = 0.04). Nonetheless, morphological differences did not change the overall outcome for satisfactory breeder status. Change in testosterone concentration did not differ because of treatment. Histopathologic examination identified that testicular degeneration and tubule diameter did not differ as a result of treatment. It should be noted, however, that degeneration score (higher score having more degeneration) was positively correlated with primary abnormalities (P < 0.01; r = 0.35) and negatively correlated with normal sperm cells (P < 0.001; r = -0.43). In summary, these data indicate that a single use of permethrin at label dose in yearling Angus bulls results in minimal detrimental effects on sperm morphology but not to a degree that impacts the ability of bulls to pass a standard BSE.