The objective was to evaluate the effect of 2 doses of PGF(2alpha) injected early postpartum on uterine involution, serum concentration of acute phase proteins at 12 d postpartum, and fertility in Holstein cows with acute puerperal metritis. Only cows diagnosed with retained fetal membranes and metritis and treated with ceftiofur hydrochloride for 5 d were used in the study. Two hundred cows were assigned randomly to be treated (n = 100) or to serve as controls (n = 100). Treatment consisted of 2 i.m. injections of PGF(2alpha) 8 h apart on d 8 postpartum. A subsample of 90 cows was selected randomly (45 treated cows; 45 controls) to evaluate uterine diameter using ultrasonography, uterine score, and serum concentrations of acute phase proteins at 12 d postpartum. The outcome variable for all cows was conception rate at first service. Postpartum, primiparous, treated cows had smaller uterine diameters and lower uterine scores than controls. Cows with a uterine diameter <5.1 cm at 12 d postpartum were 5.5 times more likely to conceive at first service than cows with larger uterine horn diameter. Treatment significantly reduced the concentrations of serum alpha1-acid glycoprotein. Within primiparous cows, treatment also increased conception at first service by 17%. It was concluded that 2 doses of PGF(2alpha) 8 h apart at 8 d postpartum in primiparous cows with acute puerperal metritis decreased the diameter of uterine horns and serum concentration of alpha1-acid glycoprotein at 12 d postpartum and increased the conception rate at first service.

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We developed a method to evaluate bovine sperm membranes in normal (1G) and simulated microgravity (Sim-µG). Bovine spermatozoa are used as a model system because they have cellular membranes analogous to those of other cell types, and yet are much simpler because they have no cytoplasm and do not participate in DNA transcription or mRNA translation. They can be cultured as single cells and are easily evaluated for membrane characteristics using flow cytometry. These features make the mammalian spermatozoon a useful model for exploring the principles of membrane structure/function in the presence of a variety of environmental challenges such as simulated microgravity. Cryopreserved, washed beef bull sperm (4-8 × 106 mL −1 ) were incubated under non-capacitating conditions (modified glucose-free Tyrode's medium containing low bicarbonate, HEPES buffer, pyruvate and 3 mg mL −1 BSA V; 23 • C in air), and these spermatozoa remained alive for 24-48 h at 1G. To simulate µG, spermatozoa were incubated under the same conditions, in a HARV 10 rotating wall vessel (RWV, Synthecon, Inc, Houston,TX, USA) at 9 rpms. Spermatozoa were incubated in 1G and Sim-µG environments for 2.5-4.5 h and subsequently exposed to 0, 60 or 80 µg mL −1 LC for 0, 4, 8, 12, 16 and 20 min. Three fluorochrome combinations were used as probes at each [LC]/time point: (1) propidium Iodide (dead status) + SYBR 14 (live status);(2) PI + FITC-PSA (acrosome reactions [ARs]); (3) PI + MitoTracker Deep Red (mitochondrial activity). Approximately 1 million spermatozoa from 3 bulls were evaluated over 4 days. Data were acquired on a FACSVantage SE flow cytometer, and initially analyzed (quality control) using the bundled FACSVantage SE software package (Cell Quest, BD BioSciences, San Jose, CA, USA). This provided graphics of simple cell relations (fluorescence v. LC exposure time). For further statistical analysis, and incorporation of non-parametric statistical tools (including pattern recognition using Support Vector Machines), the data were processed using a collection of Perl scripts and C programs. Results: Live/dead status: When Sim-µG + 60 µg mL −1 LC sperm were compared to 1G + 60 µg mL −1 LC, and 80 µg mL −1 LC sperm, their profiles were more similar to the 1G 80 µg mL −1 LC profiles. AR status: the Sim-µG + 60 µg mL −1 LC profiles were similar to the 1G + 60 µg mL −1 LC profiles. Mitochondrial Status: the Sim-µG + 60 µg mL −1 LC profiles were more similar to 1G + 80 µg mL −1 LC profiles. Summary: although Sim-µG sperm lost their motility within 3 h, they were alive. Cell profiles indicate that Sim-µG sperm nuclear membranes are less stable and their mitochondria are less functional than the 1G controls, but their acrosomes are intact indicating that fertilizing potential may remain. Additional experiments are needed to determine the time course for Sim-µG, induced changes, and whether Sim-µG sperm can penetrate eggs.

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