Lactating dairy cows in four lots were observed for sexual behavior for 6 mo. One freemartin heifer in each lot was implanted with testosterone propionate and estradiol benzoate to aid in detection of estrus. Blood samples were obtained from androgenized heifers every other week for determination of serum testosterone. The addition of an androgenized heifer to each lot increased the number of mounts and attempts to mount cows, both overall and within observation periods. Thus, the likelihood of detecting a cow in estrus was increased with the addition of the androgenized heifers. Greatest benefit was seen when one or two cows were simultaneously in estrus in each lot. Observational data and serum progesterone concentration of mounted cows indicated that androgenized heifers were selectively mounting open cows displaying estrus, whereas the remaining nonandrogenized cows were less selective with their mounting activity. Serum testosterone increased after heifers were implanted, but testosterone was not related to the proportion of sexual activity. Duration of sexual activity by the implanted heifers was approximately 90 d.

Fifteen lactating Holstein cows were used in a trial designed to evaluate the effectiveness of intrauterine inoculation (challenge) of Actinomycespyogenes (A) alone or in combination with Fusobacteriumnecrophorum (F) and Bacteroidesmelaninogenicus (B) to induce pyometra. Cows were assigned to one of five groups: A (n = 3), AB (n = 3), AF (n = 3), ABF (n = 3) or C (control, broth medium alone; n = 3). All cows exhibited estrus 12 or 13 d prior to challenge (Day 0=first day of challenge). During the prechallenge period, the reproductive tract of each cow was palpated per rectum and uterine fluid aspirates for culture and uterine biopsies were also obtained. All cows received an intravenous injection of 5,000 IU of human chorionic gonadotropin (hCG; Day 5) and an intrauterine infusion of 40 ml of 0.7% iodine solution (Day 1). Cows were then inoculated on Days 0, 1 and 2 of the experiment. Sequential palpations of the reproductive tracts, samples of uterine fluid for culture and uterine biopsies were performed for a total of 30 d after the first inoculation. A cow was diagnosed as having pyometra when purulent uterine fluid and a corpus luteum were detected by palpation per rectum. The number of cows that developed pyometra in Group A was 2 of 3, in Group AB 3 of 3, in Group AF 3 of 3, in Group ABF 3 of 3 and in Group C 0 of 3. Cows with pyometra did not exhibit estrus. In 7 of 11 cows, pyometra persisted for more than 21 d. In cows that developed pyometra, the same species of bacteria infused into the uterus were usually recovered one or more times during the postchallenge period. When clinical pyometra was diagnosed, histologic endometritis was invariably present. Histologic endometritis and concurrent isolation of A. pyogenes alone or A. pyogenes with gram-negative anaerobic bacteria occurred in 91.7% of samples during the postchallenge period. Regardless of bacterial treatment, gram-negative anaerobic bacteria were frequently isolated with A. pyogenes during this period.

Concentrations of serum thyroxine (T4) and 3,5,3'-triiodothyronine (T3) were determined after the administration of freshly reconstituted thyrotropin-releasing hormone (TRH), reconstituted TRH that had been previously frozen, or thyrotropin (TSH) to 10 mature dogs (6 Greyhounds and 4 mixed-breed dogs). Thyrotropin-releasing hormone (0.1 mg/kg) or TSH (5 U/dog) was administered IV; venous blood samples were collected before and 6 hours after administration of TRH or TSH. Concentrations of the T4 and T3 were similar (P greater than 0.05) in serum after administration of freshly reconstituted or previously frozen TRH, indicating that TRH can be frozen at -20 C for at least 1 week without a loss in potency. Concentrations of T4, but not T3, were higher after the administration of TSH than they were after the administration of TRH (P less than 0.01). Concentrations of T4 increased at least 3-fold in all 10 dogs given TSH, whereas a 3-fold increase occurred in 7 of 10 dogs given freshly reconstituted or previously frozen TRH. Concentrations of T4 did not double in 1 dog given freshly reconstituted TRH and in 1 dog given previously frozen TRH. Concentrations of T3 doubled in 5 of 10, 2 of 10, and 5 of 10 dogs given TSH, freshly reconstituted TRH, or previously frozen TRH, respectively. Results suggested that concentrations of serum T4 are higher 6 hours after the administration of TSH than after administration of TRH, using dosage regimens of 5 U of TSH/dog or 0.1 mg of TRH/kg.(ABSTRACT TRUNCATED AT 250 WORDS)

Experiments were conducted to determine digestibility of wet corn gluten feed in sheep and effect of wet corn gluten feed on DM intake, milk production, and milk composition by dairy cows. In Trial 1, six wethers were fed wet corn gluten feed at maintenance and ad libitum for determination of nutrient digestibility by the conventional 7-d total collection technique. The sheep ate 1.32 times maintenance at ad libitum intake and no significant differences were found in digestibility due to intake. Digestibilities of DM, organic matter, energy, CP, ether extract, ADF, NDF, and hemicellulose averaged 70.3, 73.0, 73.7, 78.3, 72.8, 51.4, 58.1, and 60.4%, respectively. Mean total digestible nutrients for both treatments was 70.3. In Trial 2, 12 Holstein cows in mid to late lactation were allotted to a 4 x 4 Latin square design. Cows were fed a total mixed ration twice daily. Wet corn gluten feed was fed at 0 (control), 10, 20, and 30% of the total ration DM. There were no significant treatment effects on DM intake, milk yield, or milk composition. Dry matter intake (kg/d), milk production (kg/d), and percent milk fat were 21.4, 22.9, and 3.71, respectively, for control; 21.4, 23.0, and 3.80 for the 10%; 21.0, 23.1, and 3.71 for the 20%; and 21.0, 23.2, and 3.89 for the 30% wet corn gluten feed.

Detection of estrus is the most costly factor contributing to reproductive efficiency in dairy cattle (1, 2, 3). In Colorado alone, the potential economic loss from poor detection of estrus to the dairy industry is from $123 to $205 per cow per year (4). The use of teaser animals as an aid in the detection of estrus has generally been proved advantageous (5). Teaser animals are usually surgically altered intact males or androgenized females. The use of an intact male although surgically altered does not eliminate the potential of venereal disease transmission. In addition, the cost of surgical altering and time lost until the teaser animal can be used must be considered. Androgenizing heifers has proven effective. The accepted procedure has been intramuscular injections of 200 mg of testosterone every other day for 20 days plus biweekly boostering with testosterone injections (5, 6, 7). A simpler approach would be to use an implant containing testosterone to get a longer duration of activity in the androgenized heifer. This presentation will detail the preliminary results on the use of this procedure.

At the University of Utrecht, the Netherlands, an effective technique has been developed for complete bovine fetotomy.1 With many cows in dystocia, not all of the cuts involved in the Utrecht fetotomy are necessary. In addition, the placement of the wire over previously cut surfaces is difficult. Thus, modifications of the Utrecht method of fetotomy were made in an effort to reduce fetal size with fewer cuts and to improve the ease of wire placement. In addition, delivery is usually easier if a means is created for gas to escape from the cavities of the emphysematous fetus.

Blood was collected from 6 adult bitches (3 pregnant and 3 nonpregnant) daily for 59 days after the onset of diestrus, and serum progesterone concentrations were determined. The bitches were hysterectomized at various times during diestrus [diestrus day (DD) 5, 15, or 25] to determine whether the uterus has a role in maintaining luteal function in the pregnant or nonpregnant bitch. Concentrations of serum luteinizing hormone (LH) were also measured to determine whether LH concentrations decrease when luteal function abates (experiment 1). All 6 bitches in experiment 1 had progesterone concentrations greater than 1.0 ng/ml during the 2-month period, indicating that neither the pregnant nor nonpregnant uterus was necessary for maintaining luteal function in the bitch. Concentrations of LH appeared to increase in the serum of 5 of the 6 bitches when progesterone concentrations were declining, indicating that cessation of luteal function does not appear to result from a lack of LH. Blood was collected from the 6 bitches used in experiment 1 twice weekly during the 2nd diestrus after hysterectomy (experiment 2) to determine whether alterations in luteal function that might be observed during experiment 1 were due to some aspect of the surgical procedure, rather than to absence of a uterus. Progesterone concentrations in the serum were lower (P less than 0.05) during the 10 days after surgery in the 2 bitches hysterectomized on DD 5 than in the 4 bitches remaining intact during this period (experiment 1).(ABSTRACT TRUNCATED AT 250 WORDS)

In an effort to clarify the pathogenesis of pyometra, 20 cows with retained fetal membranes and 20 without, but with contemporary calving dates were studied. They were palpated and their uteri were subjected to sample collections for bacteriologic cultural examinations twice weekly for 4 weeks. Blood samples were obtained each day and evaluated for serum progesterone concentration. Three cows without and 3 with retained fetal membranes developed pyometra during the study, resulting in 3 groups designated control (CON), cows with retained fetal membranes (RFM), and cows with pyometra (PYO). Bacterial isolations occurred less frequently in the CON group than in the PYO and RFM groups. Growth patterns of bacteria also varied between groups. Coliform and incidental bacteria disappeared from the uterus of the PYO group by the end of the 3rd week. In contrast, heavy growth of Corynebacterium pyogenes and gram-negative anaerobic bacteria developed during this same period in the PYO group. In cows with pyometra, the significant persistent pathogenic bacteria recovered were C pyogenes and gram-negative anaerobic bacteria, especially Fusobacterium necrophorum and Bacteroides melaninogenicus. Anaerobic bacteria were isolated simultaneously with C pyogenes in most cows of the PYO group, but less often in CON and RFM groups, and highest growth levels were present near the time of ovulation. Clinically, pyometra usually developed about 10 days after observation of concurrent ovulation and high growth levels of C pyogenes and gram-negative anaerobic bacteria. A hypothesis is presented for development of pyometra in the cow.

Equilibrium, double-antibody radioimmunoassay (RIA) procedures were validated to measure concentrations of prostaglandin (PG) F2 alpha, and E2 in canine plasma and endometrium. The procedure for measuring PGF2 alpha or PGE2 used [125I]PGF2 alpha or [3H]PGE2, respectively, as radiolabeled antigens. Specificity was demonstrated by determining the relative potency of selected PG. Relative potencies were calculated by dividing the mass of PGF2 alpha or PGE2 producing 50% inhibition of maximum bound tubes (Bo) by the quantity of test PG producing 50% inhibition in the same assay. Only PGF1 alpha and PGE1 had relative potencies of greater than 1.0% in the PGF2 alpha and PGE2 RIA, respectively. To assess the accuracy of the 2 assay systems, known amounts of authentic hormone were added to plasma, tissue, or 0.05M phosphate-buffered saline solution containing 0.1% gelatin (gel-PBSS). When increasing amounts of PGF2 alpha or PGE2 were added to plasma, tissue, or gel-PBSS, concentrations of PG assayed from extracted or extracted plus chromatographed samples were similar. Additionally, PGF1 alpha or PGE1 was not detected in canine plasma or tissue; therefore, extraction was the only purification needed before analysis of PGF2 alpha or PGE2. The intra-assay precision of 10 assay replicates for a low (70% Bo) and high (27% Bo) sample was 16.0% and 6.7% (coefficient of variation), respectively, for the PGF2 alpha assay. The intra-assay precision of 3 assay replicates for a low (80% Bo) and high (32% Bo) sample was 7.6% and 4.4%, respectively, for the PGE2 assay.(ABSTRACT TRUNCATED AT 250 WORDS)

Serum testosterone concentrations in samples collected daily from 6 bitches for at least 60 days before the onset of diestrus were determined by radioimmunoassay. Mean serum concentrations (+/- SEM) of testosterone ranged from 31 +/- 11 to 141 +/- 63 pg/ml during late anestrus. Mean testosterone concentrations during proestrus ranged from 106 +/- 29 to 239 +/- 113 pg/ml, with the highest concentration (526 +/- 225 pg/ml) occurring the day of the preovulatory surge of luteinizing hormone. Although the ovaries may be sites of production during late anestrus, proestrus, estrus, and early diestrus, further investigation is necessary to determine whether testosterone has an important physiologic or endocrinologic function in the bitch (ie, sexual behavior, vaginal hypertrophy, and luteinizing hormone surge).

A modification of the "Utrecht technique" for complete bovine fetotomy was developed. In cranial presentation, the first step is decapitation, then oblique indirect section through the neck and thorax to remove 1 forelimb with a small part of the thoracic wall. This is followed by thoracic and abdominal evisceration. The final step is direct oblique section of the fetal pelvis or, alternatively, deep detruncation followed by bisection of the pelvis. In caudal presentation, the first step is removal of a hindlimb, then abdominal and thoracic evisceration, followed by thoracic detruncation and oblique section for removal of 1 forelimb and most of the remaining thorax. The neck and remaining forelimb are removed together to complete the procedure.

Five hundred thirty-four naturally bred Holstein dairy cows from two Colorado dairies were examined perrectum between 21 and 36 days after calving. Alternate cows in each herd received either 25 mg PGF-2 alpha or no treatment at the time of initial examination. No differences were found in days open or pregnancy rates between groups (P>0.25).

Risk factors associated with pyometra were studied in 4 confinement managed dry-lot dairies in Colorado. The incidence of pyometra for the 3-year study was 7.0%. The first risk factor to enter the step-wise logistic regression model was “lactation number”. Cows in their first lactation were at lesser risk of developing pyometra (P<0.001) than cows in all other lactations. The second and final variable to enter the logistic regression model was “dairy farm”. Cows on 1 of the dairy farms were at lesser risk of pyometra than the other herds, (P<0.005), after adjusting for the lactation number of the cows. There was no statistical association for year or season with the incidence of pyometra; however, the probability of three consecutive spring seasons having the greatest frequency of pyometra was 0.0045.

Two studies were conducted to evaluate the concentration of serum progesterone in pyometritic cows and relate it to palpation of ovarian structures perrectum. In Trial 1, serum samples from 34 pyometritic cows were assayed for progesterone. Mean serum progesterone concentrations were 6.8 ± 0.7 ng/ml. In Trial 2, each of 54 pyometritic cows was paired with a control cow on the basis of days post partum (18–50 days). Mean concentration of progesterone was 9.7 ± 1.0 ng/ml for the pyometritic cows and 5.7 ± 0.8 ng/ml in control cows (P<0.005). Progesterone concentration was greater (P<0.005) in both groups of cows with palpable corpora lutea (CLs). Ninety-six percent of the pyometritic cows had palpable CLs compared to 57% of the control group. Comparing serum progesterone only in cows with a palpable CL, the mean concentration was still greater (P<0.005) in the pyometritic group (10.6 ± 1.0 ng/ml) than the control group (6.6 ± 1.0 ng/ml). Compatability of rectal palpation findings and concentrations of serum progesterone were 92.6% for the pyometritic group and 72.2% for the control group. Progesterone concentration increased (P<0.05) by increased days post partum in Trial 2 (n=54) but not in Trial 1 (n=23). In both Trials 1 and 2, uterine size due to pyometra increased (P<0.05) with increased days post partum. No other associations were found.

Trichomoniasis is a veneral disease of cattle caused by Tritrichomonasfetus (T. Fetus). Its clinical signs are repeat breeding at both regular and irregular intervals and, occasionally, abortion. These are easy to observe in dairy cattle. However, in beef cattle on western ranges, the first indication of a problem is usually finding over 20-40% of the cows open at the time of fall pregnancy check. By this time the significant economic damage has already been done. Treatment efforts need to be directed primarily toward the infected bull rather than the cow because of the self limiting nature of the disease in cows. When trichomoniasis is diagnosed in dairy herds, it can be controlled most effectively by AI. However, in some herds, management levels may be inadequate to have a successful AI program. In these, natural breeding programs must be tailored to eliminate the infection.

Concentrations of estradiol, progesterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH) and prolactin in serum from 6 bitches bled daily for at least 45 days before the onset of proestrus, during proestrus and estrus were determined by radioimmunoassay. Mean concentrations of estradiol in serum were high early in the sampling period (20 to 46 pg/ml) and appeared to decrease prior to the onset of proestrus (8 to 19 pg/ml). There were sporadic increases in serum concentrations of LH throughout the sampling period in each bitch. Five of the 6 bitches sampled had increased serum concentrations of LH following the low mean concentration of estradiol just before the onset of proestrus. Mean concentrations of FSH were highest during anestrus (240 to 294 ng/ml) and near the time of the preovulatory surge of LH (297 ng/ml) and were lowest during proestrus (131 to 200 ng/ml). The mean concentration of progesterone for the 6 bitches remained at less than 1.0 ng/ml throughout late anestrus, but increased to greater than 1.0 ng/ml the day of the maximum mean concentration of LH (preovulatory LH surge). Mean concentrations of prolactin were variable throughout the sampling period and demonstrated no consistent pattern among bitches. The results of the current investigation suggest that neither the canine ovary nor pituitary are quiescent during anestrus. The bitch appears to have sufficient FSH present during anestrus for follicular growth. Serum concentrations of LH appear to increase prior to the onset of proestrus when concentrations of estradiol are lowest, possibly inducing a new follicular phase. Progesterone and prolactin do not appear to be involved in the termination of anestrus in the bitch.

Serum concentrations of chloramphenicol were determined after oral doses (55 mg/kg body weight) were administered to 7-9 day old Holstein-Friesian calves. Chloramphenicol in an oral solution produced greater serum concentrations than did an equivalent dose of chloramphenicol in capsules (P less than 0.005). A second dose of each formulation administered 12 h after the first dose elevated serum chloramphenicol concentrations significantly (P less than 0.001). The average serum chloramphenicol concentration exceeded 5 micrograms/ml of serum 1 h after administration of the solution compared with 4 h for the capsules. Average serum chloramphenicol concentration was greater than 5 micrograms/ml for at least 12 h after the dose was administered for both formulations. Of the eight calves receiving repeat doses of chloramphenicol, seven (87.5%) developed diarrhea in 76 +/- 8.6 h. Six of the eight calves (75%) died during or shortly after the period of chloramphenicol administration.

One hundred-fifty-two dairy cows affected with pyometra were treated either with cloprostenol (CLP) or with estradiol cypionate (ECP). The cows which failed to respond within 7-10 days were re-treated with the same drug used in the first treatment. Half of the cows which responded to these treatments received intrauterine infusions with 50 cc nitrofurazone solution. After two treatments, 72 (94.9%) of 79 cows in the CLP group had evacuated the purulent exudate from their uteri whereas only 57 (78.1%) of 73 cows in the ECP group had responded (P<0.005). Treatment-to-breeding and treatment-to-conception intervals were not different between the ECP and CLP groups. The number of services/conception was not different up to the 4th service (3.16 vs 3.57, respectively, P>0.1). Eight (9.3%) of 86 CLP treated and 3 (5.1%) of 59 ECP treated cows had recurrence of pyometra (P>0.1). Incidence of follicular cysts within 30 days after treatment was 16.4% (13 79 ) and 7.0% (4 57 ) among CLP and ECP groups, respectively (P>0.1). Two of 106 CLP (1.9%) and 5 of 107 ECP treatments (4.7%) were associated with subsequent perimetritis and adhesions. Intrauterine infusion of nitrofurazone increased the number of services/ conception (3.57 vs 2.21, P<0.01). Cloprostenol was superior to ECP as an initial treatment of bovine pyometra. Intrauterine infusion of nitrofurazone following evacuation of the uterus appeared not to be effective in prevention of relapses and had a negative effect on conception rates.