Time of ovulation was determined for Holstein cows (n = 51) for estruses occurring spontaneously (n = 33) or those induced by PGF2 alpha (n = 86). Ultrasound examination of ovaries was conducted 42 to 49 d postpartum, followed by administration of 25 mg of PGF2 alpha if a corpus luteum was observed. In the absence of a corpus luteum, ovaries were reexamined weekly, and PGF2 alpha was administered upon observation of the presence of a corpus luteum. Onset of estrus was determined by HeatWatch, an electronic pressure-sensing system that recorded each mount associated with estrus. To determine ovulation in relation to first detected mount, ultrasound examinations were conducted at 12, 20, and 24 h after the initial mount and then every 2 h until 40 h. Cows were assigned randomly to receive one of two treatments: 1) the cow received 25 mg of PGF2 alpha 8 to 13 d later or 2) the cow was allowed to cycle spontaneously and then was switched to alternate treatment at a third cycle. The mean estrus period, determined from mounting activity recorded by HeatWatch, consisted of 10.1 mounts over 9.5 h (6.0 mounts were > or = 2 s) for a total 24.1 s of mounting activity. Estrus characteristics were extremely variable and were not different for estruses induced by PGF2 alpha or for those occurring spontaneously. Mean ovulation time relative to first mount was 27.6 +/- 5.4 h and was not different between spontaneous and induced estruses. Knowing the time of ovulation in reference to the first mount of estrus and being able to identify the first mount consistently and accurately with the HeatWatch system allows for accurate timing of AI.

Using 1 market-available activity monitor, 3 experiments were conducted in dairy cows to determine timing of ovulation, compare within-herd conception risk of cows inseminated based on activity monitors versus timed artificial insemination (AI), and determine conception risk of cows inseminated at various intervals after achieving an activity threshold. In experiment 1, ovaries were scanned every 3h by transrectal ultrasonography to determine the time of ovulation beginning 14 ± 0.5 h after the achieved activity threshold (n=132) or first standing event (n=59), or both (n=59). Progesterone at the first ovarian scan (0.1 ± 0.01 ng/mL) and ovarian structures [1 or 2 preovulatory-sized follicles (16.5 ± 0.2 mm)] confirmed that 88.6% of cows identified by activity were in estrus. The remaining 15 cows (11.4%) with a corpus luteum and elevated progesterone concentration (5.3 ± 0.5 ng/mL) were classified as false positives. The average interval from first standing event to ovulation (n=59) differed slightly from the interval after the achieved threshold (26.4 ± 0.7 vs. 24.6 ± 0.7 h, respectively). In 97 cows fitted with activity monitors, that interval was 25.7 ± 0.4 h. In experiment 2, the conception risk in 394 cows in 1 herd fitted with activity monitors was compared with that of 413 cows submitted to a timed AI program through 3 AI services. Days to first AI were reduced in cows fitted with activity monitors, and conception risk after activity threshold was less than that for timed AI at first service because of differing days in milk at first AI. Both median and mean days to pregnancy, however, were reduced in activity-group cows by 10 and 24 d, respectively, compared with timed AI cows. In experiment 3, 4,019 cows in 19 herds were inseminated after achieving the activity threshold. Conception risk was determined for cows inseminated at various intervals after the achieved activity threshold. A curvilinear conception risk curve peaked at 47.9% for primiparous cows inseminated between 13 and 16 h, whereas conception risk in multiparous cows was steady at 34% through 12 h and decreased thereafter. These experiments demonstrate that time of ovulation after activity threshold closely resembles the time of ovulation after first standing estrus. Time of insemination up to 12h after the activity threshold produced similar conception risks for multiparous cows, whereas intervals shorter than 13 and greater than 16 h in primiparous cows seemed to compromise their conception risk. Although conception risk may not be improved at individual inseminations after achieving an activity threshold, the rate of achieving pregnancy is hastened. Activity monitors can accurately predict ovulation and time of AI.

Observing cows in estrus and inseminating them at the optimum time are necessary steps for effective reproductive management of a dairy herd. However, larger herd sizes can lead to reproductive inefficiency and decreased profits on dairy farms. Synchronization of estrus behavior through pharmacological control has been used to improve reproductive efficiency. Methods of synchronizing estrus were originally devised to decrease the time spent detecting estrus; however, systematic breeding programs are now being used for convenience and efficiency in reproductive management. Systematic breeding programs provide an organized approach for administering artificial insemination (AI) at first service. Moreover, reproductive management is based on a methodical approach for the entire herd rather than for the individual cow. Targeted Breeding (Pharmacia-Upjohn, Kalamazoo, MI) consists of a series of three PGF2 alpha injections at 14-d intervals. For convenience, injections are usually given one day a week to all cows that surpass the specified target date. The PGF2 alpha injections may be continued until detection of estrus and AI or fixed-time AI. Ovsynch consists of a GnRH injection at a random stage of the estrous cycle, followed by PGF2 alpha 7 d later, a second GnRH injection 36 to 48 h after PGF2 alpha, and timed AI. Research has shown that both Ovsynch and Targeted Breeding can improve reproductive performance over that of traditional programs.

Nine hundred and twenty Holstein cows from 16 commercial dairy herds to evaluate three systematic breeding protocols: 14-d PGF2alpha, timed artificial insemination (AI), and GnRH-PGF2alpha, relative to AI following estrus detection without hormone intervention. The timed AI protocol involved GnRH, followed by PGF2alpha 7 d later and GnRH again 2 d after PGF2alpha, with AI 6 to 18 h after the second GnRH. The GnRH-PGF2alpha protocol consisted of GnRH followed by PGF2alpha 7 d later. Eight herds relied on visual observation to detect estrus, and eight herds utilized the HeatWatch estrus detection system. The average interval to first postpartum AI was shortest for the timed AI protocol (77.1 d) followed by the 14-d PGF2alpha protocol (81.6 d). There was no difference in days to first AI between the control (86.1 d) and GnRH-PGF2alpha (89.5 d) protocols. Percent pregnant per first AI did not differ among control (45.6%), 14-d PGF2alpha (43.7%), or GnRH-PGF2alpha (44.0%) protocols, but all protocols had a higher percent pregnant per first AI than the timed AI protocol (30.1%). Response to the GnRH-PGF2alpha protocol was limited because 44.0% of the cows submitted to the protocol were not detected in estrus < or = 10 d post-PGF2, administration and had an interval to first AI of 103.8 d. Cumulative percent pregnant by 120 d postpartum did not differ between control cows (53.1%) and hormonally treated cows (50.6%). Visual observation herds had a shorter interval to first postpartum AI (82.8 d) than the HeatWatch herds (84.8 d), with a higher overall rate of estrus detection across all protocols (75.3 and 67.6%, respectively).

To evaluate the prognostic significance of clinical as well as histological disease features at the time of diagnosis, an immunohistochemical and morphometric study was performed on bone marrow trephine biopsies in 130 patients with Ph(1+)-CML. For identification of all cell elements of the megakaryocytopoiesis we used the monoclonal antibody CD61 (Y2/51) and for the macrophages, the recently characterized antibody PG-M1. Density of argyrophilic fibers was determined per fat cell-free marrow area. Based on a multivariate analysis-derived risk model, the reproducibility of the prognostic score described by Sokal and co-workers was tested, particularly with regard to histological variables. Additionally, we calculated the disease-specific loss in life expectancy. Our prognostic model (Cox model) consisted of the variables: age, spleen size, peripheral erythro-normoblasts, pseudo-Gaucher cells, and fiber density. To assess the validity of this new CML score, a receiver-operating curve (ROC) of sensitivity and specificity was constructed. The improved prognostic efficiency of this newly developed risk model in predicting death within 3 years after diagnosis of CML was demonstrated in comparison with generally accepted staging systems. Immunohistochemistry revealed that not the total number of macrophages, but only the subfraction of pseudo-Gaucher cells exerted a significant impact on survival. Furthermore, it was feasible to calculate the number of atypical micromegakaryocytes and pro- and megakaryoblasts. This abnormal and immature cell population showed a significant correlation with fiber density and prognosis. Finally, the practical value of the Hannover classification was tested. This histological classification enabled a discrimination between two groups with different survival patterns, i.e., granulocyte and/or megakaryocyte-rich subtypes versus subtypes with increase in reticulin and collagen fibers.