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Biomedical subjects

R H Foote

Publications and source records attributed to R H Foote.

At least 163 records · Page 9Linked to original sources
PubMed1982

Behavioral characteristics of beef steers administered estradiol, testosterone and dihydrotestosterone.

Twelve beef steers ranging in age from 6 to 8 mo were randomly assigned to one of four steroid treatment groups so the ability of each hormone to stimulate sexual and(or) agonistic behavior could be assessed. The steers received im injections of either 200 mg of testosterone (T), 200 micrograms of estradiol-17 beta (E2), 200 mg of dihydrotestosterone (DHT) or sesame oil vehicle as control (C), every other day for 10 d. During these 10 d, behavior was studied for 60 min at 0600, 1200, 1800 and 2400 h. Peak activity occurred during the first half of the experiment with maximum behavioral expression observed at the 2400-h observation period. Estradiol was most effective in stimulating eight of the 13 behaviors studied. These included: sniffs received, sniffs given, successful mounts, chin rests given, chin rests received, stands to be mounted, refusals to stand and head butts received. Testosterone was most effective in stimulating Flehmen lip curls, attempted mounts and head butts given. Testosterone significantly increased activity in seven other categories over that of controls. Dihydrotestosterone was never the most effective steroid. It was capable of stimulating several of the behaviors studied above that of controls, but reduced mounting activity of steers. In view of the major responses observed with E2 and the aromatizable androgen, T, these data are interpreted as an indication that E2 plays a significant direct role in sexual behavior in the male bovine.

Aggression↗
PubMed1982

Milk progesterone concentration and production in superovulated Holstein cows.

Six Holstein cows in a commercial herd (three superovulated and three controls) and eight Holstein cows superovulated a total of 12 times in an experimental herd were studied. Superovulation was induced primarily by treatment with follicle stimulating hormone and prostaglandin F2 alpha. Milk was weighed twice daily for 30 days following treatment in the commercial herd with no effect on production. Milk samples were saved on Monday, Wednesday, and Friday to determine progesterone content. Last milk at mid-cycle averaged 8.2 ng/ml of progesterone for the cows in the experimental herd, and 7 days after superovulation they averaged 52.6 +/- 10.2 ng/ml (mean +/- standard error) of progesterone. The correlation with number of embryos recovered was .86. Therefore, milk progesterone may be useful in monitoring superovulatory response. Also, injection of prostaglandin F2 alpha into superovulated cows 9 days after a previous injection did not initiate a new estrous cycle, a fact accurately monitored by milk progesterone determinations.

Animals↗
PubMed1982

Electronic probe measurements of cervico-vaginal mucus for detection of ovulation in dairy cows: sanitation, clinical observations and microflora.

An electronic vaginal probe with a sanitizing carrier unit has been designed to measure changes in the electrical resistance of cervico-vaginal mucus in the cow. Over 400 cows and heifers have been probed during the period prior to breeding. When 33 heifers and cows were probed 2-3X per day for 30 days, mild irritation of the vaginal mucosa developed during the luteal phase. In all other studies no grossly detectable lesions or other complications resulting from probing were observed either in experimental herds or in farmer herds where breeding tests were conducted. Fertility of probed cows was equal to cows inseminated when estrus was detected visually. Weekly culture of microorganisms from cervico-vaginal mucus collected from three cows probed 3X per week for 22 days resulted in no detectable change in the population of microorganisms. The number of isolates each successive week was 11, 8, 8 and 5, respectively. The sanitary procedures followed appeared to prevent introduction of organisms of any consequence, as judged by the decreasing number of isolates during the probing sequence.

Animals↗
PubMed1981

Decreased motility of bull spermatozoa caused by Mycoplasma bovigenitalium.

Mycoplasma bovigenitalium mixed with bull semen in egg yolk-citrate buffer and held at 5 C caused a highly significant time- and dose-dependent depression in sperm motility. Mycoplasma adhered to a majority of spermatozoa, principally to the acrosome, but also the the midpiece and tail. This may reflect the basis for a naturally observed condition in young bulls in which genital mycoplasmosis is associated with low sperm motility.

Animals↗
PubMed1981

Influence of bovine cervical mucus samples and storage conditions on sperm migration in vitro.

In vitro sperm migration assays were performed using bovine spermatozoa and cervical mucus. Experiments were designed to test the effects of storage temperature, method of storage, duration of storage, and source of cervical mucus. Significant variation in migration of spermatozoa was due both to differences in mucus samples and to short-term mucus storage at temperatures ranging from ambient to -196 degrees C. The parallel-orienting effect of cervical mucus on migrating sperm was shown to be a major factor in quantitative assays based upon migration distance. Thus, comparisons of migration among different specimens of semen likely will be biased unless the tests are run simultaneously. Implications of these results are discussed relative to the performance of quantitative sperm migration assays in the clinical or research laboratory.

Animals↗
PubMed1981

Polyacrylamide as a substitute for cervical mucus in sperm migration tests.

A synthetic migration medium for capillary sperm migration studies was developed. Parallel sperm migration in 1.8% polyacrylamide cross-linked with 0.042% N,N'-methylene bis acrylamide was similar to sperm migration in bovine cervical mucus. Bull spermatozoa varying widely in migration distances in bovine cervical mucus maintained similar relative migration distances in this synthetic medium. The advantages of the synthetic medium are its availability in large quantities, its uniformity, and its stability. There was no change in parallel sperm migration distances in the synthetic medium stored at 4 degrees C for up to 4 months. Use of this synthetic medium for human or bovine sperm migration studies would appear to overcome problems associated with the variability of cervical mucus.

Acrylamides↗
PubMed1980

Maturation of rabbit follicular oocytes in a defined medium of varied osmolality.

Rabbit oocytes from follicles greater than or equal to 1 mm in diameter were cultured for 18 h in a defined medium with osmolality adjusted in 20 mosmol increments from 230 to 350 mosmol by altering only the NaCl concentration. Adjustment, based upon determination of the osmolality of the medium, was necessary because a difference existed between calculated and achieved osmolality in this complex solution. The proportions of oocytes which matured to meiosis II with polar body formation were 64, 68, 64 and 65% in media of 250, 270, 290 and 310 mosmol, respectively.

Animals↗
PubMed1980

Effects of two simulated semen culling programs on predicted fertility in an artificially inseminated cow population.

Two semen culling programs designed to improve fertility of semen used in an artificial insemination program were compared. First inseminations and return service data on cows inseminated with semen from 21 Holstein bulls during 1 yr were studied. The culling of less fertile ejaculates within bulls, based on any available semen quality test or combination of tests, would bring about less than a 1% increase in nonreturn rate if 40 to 50% of ejaculates were called. If all semen from the 19% low fertility bulls were culled, this would entail culling 22% of the semen used to inseminate the population and would achieve an improvement of 1% in overall fertility. This could be done with no loss in predicted difference for milk yield of bulls used. Culling of bulls is a functionally simpler and less expensive program than is testing and culling ejaculates within bulls, but this requires that fertility of bulls be known and that it will not change substantially from predicted.

Animals↗
PubMed1979

Estrous cycle patterns in cattle monitored by electrical resistance and milk progesterone.

An electronic probe with parallel stainless steel electrodes was designed to measure changes in electrical resistance in the anterior vagina associated with increased cervical mucus secretion at estrus. Three groups of Holsteins were probed, and a sample of residual milk after milking was taken for progesterone assay every 2nd day for 28 to 40 days. Group I consisted of 29 cycling virgin heifers, Group II consisted of 24 lactating cows in the Cornell herd, and Group III consisted of 62 lactating cows in three commercial herds. Lactating cows were 26 or more days postpartum when sampling began. In Group I, 77% of the measurements at the ventral surface of the anterior vagina were lowest on the day of estrus and correlated well with days KaMaR Heatmount Detectors were triggered or chalk was erased. In Groups II and III, average electrical resistance also was minimal at estrus and was correlated .92 to .99 with average milk progesterone during the 4 days preceding and including estrus. The electronic probe appears to enable one to detect which cows are cycling normally and to aid in determining when to expect estrus.

Animals↗
PubMed1979

Pregnancy rate in dairy cows inseminated on the basis of electronic probe measurements.

A new vaginal probe with two pairs of parallel electrodes 90 degrees apart was designed with a switching arrangement so that electrical resistance (ohms) of the dorsal and the ventral areas of the anterior vagina could be monitored separately during the estrous cycle. Three inseminators probed cows during February--April, 1977, in nine herds in stanchion barn housing. Cows not seen in estrus by 40 to 60 dyas after calving were probed every 3rd day. At each dairyman's option normal cows with a low porbe reading were inseminated. Controls consisted of cows seen in estrus by the dairyman and reported for insemination in the routine manner. The diagnosed pregnancy rate for 86 first service controls was 49% versus 52% for 58 cows not seen in estrus, but identified by low probe readings. Cows varied in electrical resistance at breeding, but the fact that pregnancy rates were equivalent in the two groups is interpreted to mean that the probe was as effective in identifying cows suitable for insemination as was visual observation of estrus by dairymen.

Animals↗
PubMed1979

Growth and reproductive development in freemartins hormonally treated from 1 to 79 weeks of age.

Postnatal growth, steroid hormone profiles and response to steroid hormone treatment were studied in 18 freemartins and one normal female born co-twin with a bull. They were either treated postnatally with testosterone or estrone at one week of age, or left untreated until 50 weeks of age when they received silastic implants calculated to release either 12.9 microgram of estrone or 2.6 microgram of estradiol per day per kg of body weight. Later a dihydrotestosterone-treated group was added. Reproductive development was studied by palpation per rectum and by examination when animals were slaughtered at 79 weeks of age. Treated animals grew slightly faster than untreated animals. Testosterone in untreated freemartins averaged 76 and 87 pg/ml of blood plasma during weeks 1 to 48 and 52 to 56. Corresponding values for those animals with small testosterone implants (weeks 1 to 48) and with larger implants (weeks 52 to 56) were 130 and 272 pg/ml. Estrone and estradiol values appeared to fluctuate between 10 and 50 pg/ml but values are uncertain because they were below the sensitivity of the assay then available. Thus, circulating steroid hormone concentrations were similar to those reported for castrates. Testosterone stimulated clitoral development prenatally and postnatally. None of the treatments influenced vaginal depth, which averaged 4.0, 9.0 and 10.9 cm at 1, 24 and 52 weeks of age. Vaginal depth at birth was not a reliable indicator of freemartinism. Androgen may have inhibited udder development, whereas estrogen appeared to be stimulatory. The reproductive organs of the freemartin were characterized by differences in underdevelopment and the general presence of seminal vesicles. The latter structures, plus clitoral development at birth in 3 animals and postnatal response of the clitoris to testosterone is interpreted to indicate that the presence of androgens is one factor in abnormal development. Otherwise, gross morphology of the reproductive tract was not related to hormone treatment, postnatal gonadal histology, endocrinology or lymphocyte chromosomal karyotypes.

Animals↗
PubMed1978

Monitoring of plasma and milk progesterone for evaluation of postpartum estrous cycles and early pregnancy in mares.

Plasma and milk progesterone concentrations in 13 mares were determined 3 times a week for 5 months, beginning at parturition. The estrous cycle was divided into 2 phases. Estrus was considered to occur when the plasma progesterone concentration was less than 1 ng/ml, with diestrus occurring when plasma progesterone content was greater than or equal to 1 ng/ml. Based on this classification, the period of estrus averaged 8.9 days, diestrus averaged 13.9 days, and the estrous cycle averaged 22.8 days. During estrus, the progesterone concentration in plasma averaged 0.4 ng/ml and in milk averaged 2.2 ng/ml. During diestrus corresponding values were 6.8 and 6.9 ng/ml. In the early pregnant mare, the average progesterone concentration was 5.4 ng/ml for plasma and 4.7 ng/ml for milk. The progesterone pattern was similar in milk and in blood plasma, and the correlation between 362 paired values was 0.7 (P less than 0.01). It was concluded that the estrous cycle of the mare can be mapped accurately by measuring plasma or milk progesterone content at 2- to 3-day intervals. A breeding program based on monitoring blood progesterone was outlined.

Animals↗
PubMed1978

The anatomy of the reproductive system in male Dutch rabbits (Oryctolagus cuniculus) with special emphasis on the accessory sex glands.

The morphology and microscopic anatomy of the reproductive organs and colliculus seminalis of the male rabbit are described and illustrated. Special attention is given to the accessory sex glands, because not all have been accurately identified previously. The terminology suggested for the accessory glands (with other terms commonly used in the literature in parentheses) follows: glandula vesicularis (glandula seminalis, vesicular seminalis), proprostata (glandula vesicularis, coagulating gland, prostata), prostata, paraprostata (glandula Cowperi superior), glandula bulbourethralis (glandula Cowperi inferior). The English equivalents are vesicular, proprostate, prostate, paraprostate and bulbourethral glands. Organs were obtained from 39 adult Dutch-belted rabbits that averaged 2,023 g in bodyweight. Organ weights (means and standard deviations) were as follows: testis, 2.035 +/- 0.529 g; caput epididymidis, 0.264 +/- 0.087 g; corpus epididymidis, 0.046 +/- 0.019 g; cauda epididymidis, 0.398 +/- 0.123 g; proximal part of the ductus deferens, 0.098 +/- 0.026 g; ampulla of the ductus deferens, 0.177 +/- 0.069 g; vesicular gland, 0.529 +/- 1.169 g; proprostate gland, 0.633 +/- 0.304 g; prostate gland, 0.411 +/- 0.181 g; paraprostate gland, 0.040 +/- 0.019 g; bulbourethral gland, 0.390 +/- 0.133 g; and epididymal fat pad, 0.545 +/- 0.339 g. Correlations among organ weights were calculated and interrelationships among them and bodyweight are discussed.

Animals↗
PubMed1978

Behavioral characteristics of freemartins administered estradiol, estrone, testosterone, and dihydrotestosterone.

Eighteen genetic females born co-twin with males and diagnosed as being sterile intersexes (freemartins) were studied from birth to 79 weeks of age. Testosterone (T) and estrone (EI) were administered in Silastic capsules of two groups from birth to 50 weeks of age and other animals were left untreated. At 50 weeks the two treated groups had larger implants installed and the untreated animals were assigned to a new estrone (EII) and estradiol (E2) treatment. Later a dihydrotestosterone (DHT) group was formed in comparison with new E2 and testosterone propionate-enanthate (TP-TE) groups, plus untreated controls. Vulvar interest, Flehmen lip curl, mounting, and agonistic behavior were recorded daily for 30 min while animals were allowed social interaction. Agonistic behavior, interest in the genital area, and mounting were induced or stimulated by T, TP-TE, and E2, but not by DHT or estrone (EI or EII). Also, only animals in the T, TP-TE, and E2 groups induced to mount displayed the standing type of behavioral estrus. Flehmen lip curl was stimulated only by T or TP-TE. The evidence is interpreted to indicate that T, per se, evokes the lip curl, but it probably stimulates other responses at the neural level by conversion to E2. Also, the freemartin response, the response of castrates to steroid hormones, and current knowledge of circulating steroid hormones in male and female cattle could be interpreted to indicate that the neural tissue responsible for sexual behavior in both sexes of this species may respond similarly in several respects.

Agonistic Behavior↗