Multivariate analysis of factors associated with calving interval and calving rate in dairy cows.

We collected data on reproductive events of cows (n = 2116) that included dates of calving, first service, last artificial insemination before pregnancy examination, pregnancy examination, abortion, diagnosis of cystic ovary, and treatment with prostaglandin. We used multivariate analysis to evaluate the relationship between the interval from insemination to pregnancy examination and the length of calving interval, adjusting for other factors affecting the calving interval. The effect of the interval from insemination to pregnancy examination on calving rate was estimated using logistic regression analysis.

The repeatability and effect of season on seminal characteristics and computer-aided sperm analysis in the stallion.

The within-stallion repeatability and effect of season on sperm movement characteristics, determined by computer-aided sperm analysis (CASA), were compared with those of other seminal characteristics. The computer-aided determinations of sperm movement were more repeatable than the seminal characteristics of gel-free volume and sperm cell concentration based on coefficients of variation obtained from the analysis of multiple ejaculates from the same stallions. A significant (P<0.

Association between the preovulatory luteinizing hormone surge and the early ultrasonographic detection of pregnancy and fetal heartbeats in beagle dogs.

The size of the gestational sac and embryonic mass as well as the embryonic heartbeat were examined ultrasonographically from Day 16 to 25 of pregnancy in 15 beagle bitches, using a 7.5 MHz transducer. Results were more consistent when gestational age was based on the day of the preovulatory luteinizing hormone (LH) surge than on the day of first breeding.

Variation in glycogen and mucins in the equine uterus related to physiologic and pathologic conditions.

Histochemical stains were applied to six equine uterine biopsies representative of the physiologic breeding season, Spring and Fall transition, and Winter anestrus periods. These were compared with uterine biopsies from six mares with intrauterine urine pooling, eight mares used to study the uterine response to indwelling catheterization, and necropsy specimens from four pregnant mares at approximately 60 or 100 d of gestation. Alcian blue staining at pH 2.

The flehmen response of bulls and cows.

The response of dairy bulls to the urine of cows in various stages of the reproductive cycle was quantified by presenting 200 ml of urine in a stainless steel bowl to the stanchioned bulls for 10 min. Estrous mucus was also presented in the same manner. Sniffs, nose licks and flehmen responses were recorded.

A spectrophotometric procedure for the determination of objective measurements of equine spermatozoan motility.

A spectrophotometric procedure was developed and evaluated for the objective measurement of equine spermatozoan motility. A 100 mul sample of a sperm suspension, prepared by the removal of seminal plasma, was layered under a column of optically clear medium in a specially designed spectrophotometric cuvette maintained at 37 degrees C. Changes in light transmittance above the interface of the sperm suspension and medium were recorded on chart paper.

Rate-amplitude correlation from single-channel records. A hidden structure in ion channel gating kinetics?

Lifetime probability density functions from single-channel recording are usually assumed to follow a multiexponential form. The amplitudes and rate constants for each exponential component are presumed to be independent. We have explored this assumption and have found a correlation between the amplitudes and the rate constants in certain cases.

Survival of equine embryos transferred to normal and subfertile mares.

To test the hypothesis that an abnormal uterine environment was a cause of early embryonic loss in subfertile mares, morphologically normal embryos were transferred to normal mares (n = 20) and subfertile mares (n = 20), and embryo survival rates were compared. Embryos were recovered nonsurgically at Days 7 to 8 postovulation and transferred surgically to normal and subfertile mares that had ovulated on the same day or within 2 d after a donor. Survival of transferred embryos was monitored by ultrasonography of the recipient mare's uterus from Day 9 through Day 28 postovulation.

Pregnancy rates at Days 2 and 14 and estimated embryonic loss rates prior to day 14 in normal and subfertile mares.

Pregnancy rates at Days 2 and 14 postovulation were determined for 15 normal mares and 15 subfertile mares. Embryonic loss rates were estimated by the difference in the Day 2 and Day 14 pregnancy rates. Mares were artificially inseminated with the pooled ejaculates from three stallions, and the embryonic vesicle was detected with ultrasonography at Days 9, 10, 12 and 14.

A Field Topic Current Concepts in Brucellosis.

Brucellosis continues to be a very devastating disease in the United States and throughout the world. In dairy herds, spread of the disease often results in severe milk losses due to the necessary slaughter of infected animals. Many herds have been depopulated because herd owners have not followed management recommendations to control the spread of infection.