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Biomedical subjects

R H Foote

Publications and source records attributed to R H Foote.

At least 181 records · Page 10Linked to original sources
PubMed1978

Sources of variation of semen output.

Data from 5033 ejaculates during 1 yr from 55 mature Holstein bulls were analyzed to determine the effects of ejaculate number, days between ejaculates, month of the year, solunar periods, and sires on spermatozoal output and seminal characteristics. First ejaculates contained 49.7% more sperm and 40.8% more sperm per ml than second ejaculates. Increasing the interval between collections from 2 to 6+ days resulted in 45.9% more sperm per ejaculate, 31.0% more sperm per ml. and 14.0% greater volume. However, daily sperm output was highest when bulls were ejaculated most frequently. Lowest semen output was in February and March, associated with a decrease in sperm per ml. Highest semen output was in April and June, associated with the highest concentration of sperm per ml. Solunar periods had no effect on any measure of semen output. The concentration of sperm per ml varied more than the volume per ejaculate and had the largest influence on variation in total sperm harvested per ejaculate. Frequency of ejaculation was a major factor in total sperm harvested per bull per year.

Animals↗
PubMed1978

Embryonic mortality in dairy cows estimated by nonreturns to service, estrus, and cyclic milk progesterone patterns.

Cyclic patterns of progesterone in milk were studied in 262 Holstein cows. Milk progesterone data were obtained from 153 cows for at least 75 days after conception as indicated by continuous high progesterone concentrations in milk for 28 days or more following artificial insemination. Cycling was reinitiated in 11 of these cows between 28 and 75 days after breeding, for an estimated 7.2% rate of embryo-fetal mortality. This was considerably less than a corresponding rate of 22.7% estimated for this herd by the delayed returns to estrus (28 to 75 days). In 350,180 cows inseminated with semen from Holstein bulls the estimated embryo-fetal mortality by the same delayed return to service method was 12.5%. Biases in this latter method of estimation are discussed.

Animals↗
PubMed1978

Release rate of testosterone and estrogens from polydimethylsiloxane implants for extended periods in vivo compared with loss in vitro.

Release rates of testosterone, estrone, and estradiol placed in chambers made from polydimethylsiloxane (PDS) tubing (Dow Corning "Silastic," 3.35 mm ID x 4.65 mm OD) were studied in 14 freemartin cattle with minimal or non-detectable endogenous hormone secretion, and in 0.9% saline:methanol (1:1) baths shaken at 38 degree C. Eighty-seven implants, varying in length from 2 to 10 cm, were placed in 14 animals for 27 to 235 days. The average release rates +/- standard errors, in microgram/cm/day, were testosterone, 55.9 +/- 2.4, estrone, 12.6 +/- 1.8, and estradiol, 11.1 +/- 1.1. A relatively constant release rate was found over the period of time studied and sufficient steroid remained for potential release over periods exceeding 1 year. The dose of hormone delivered was sufficient to increase mounting activity in testosterone-treated animals and estrual activity in those receiving estrogens. Corresponding release rates in vitro for four 10-cm implants containing either testosterone, estrone, or estradiol were 94.3 +/- 1.9, 15.5 +/- 0.7, and 12.7 +/- 0.6 microgram/cm/day, respectively. The general magnitude of release rate in animals could be predicted from laboratory tests.

Animals↗
PubMed1978

Factors influencing the quantity and quality of semen harvested from bulls, rams, boars and stallions.

Several inherited conditions associated with testicular defects, abnormal spermatogenesis and morphologically abnormal sperm have been found. These usually are controlled by single gene pairs. A notable exception is testicular size, with heritability in young bulls ranging from .42 to .88. Testicular size directly affects sperm output potential. The major contributor to variation in semen quality is the environment. Environmental effects may be temporary or permanent. Permanent effects occurring during prenatal and prepubertal periods and temporary or permanent factors acting after spermatogenesis is initiated can alter semen quality. Semen quality improves during the first few months after puberty and declines in old age. Malnutrition and the ingestion of toxic materials can have a major effect on testicular development and spermatogenesis, but the reproductive system has considerable regenerative capacity unless the dietary deficiencies are severe and prolonged. Elevated testicular temperatures resulting from incomplete descent of the testes (cryptorchidism), high environmental temperatures or inflammation are detrimental to spermatogenesis in all scrotal mammals. Cold temperatures appear to be innocuous unless actual freezing of tissue occurs. During periods of decreasing daylight semen quality declines in stallions and improves in seasonally breeding sheep. The time required to form and transport sperm in bulls, rams, boars and stallions is about 64, 56, 47 and 59 days. Therefore, a considerable potential lag may exist between a testicular event responsible for a change in semen quality and the time that this change is evident in ejaculated semen. Conditions imposed at the time of semen collection such as frequency of ejaculation, degree of sexual preparation and type of semen collection may influence the quality of semen harvested. Finally, certain semen characteristics are more variable than others and investigators should utilize suitable existing data to design the most effective least-cost experiments.

Animals↗
PubMed1977

Embryo mortality and altered uterine luminal proteins in progesterone-treated rabbits.

This study was undertaken to elucidate the location, time, and nature of embryo mortality induced by preovulatory progesteron administration. Progesterone was injected into rabbits on days -2, -1, and 0 (the day of mating) at doses of 0.5, 1.0, and 1.0 mg, respectively. Normal fertilization rates resulted, but embryonic death occurred by day 4. Embryos residing in progesterone-treated does for up to 3 days survived normally when transferred to normal recipients, whereas day 4 embryos from treated does exhibited a reduced ability to implant. Uterine fluid (UF) protein pattern was examined on days 1 to 7 after mating. Total UF protein levels were significantly greater in treated animals on day 4 than in controls. Uteroglobin secretion was significantly advanced in the treated animals by day 3. Examination of the time of the arrival of embryos into the uterus revealed a delay in the progesterone-treated rabbits. This delay, coupled with the earlier secretion of uteroglobin in the treated rabbits, indicated a possible asynchrony of approximately 1 day between embryo arrival in the uterus and certain uterine proteins. To determine whether UF could be etiologically implicated in the progesterone-induced embryonic death, embryonic development in vitro and in vivo was examined after exposure to UF collected at different gestational stages. More normal day 3 morulae placed in UF from day 3 control and day 2 progesterone-treated rabbits developed than similar morulae placed in UF from day 2 controls and day 3 progesterone-treated does. Hence, partial physiologic synchrony was achieved. This was interpreted to mean that "asynchronous" UF can be embryotoxic. Infertility was transient. Ability of the does to produce young at a pregnancy immediately following a progesterone-treated pregnancy was not impaired.

Albumins↗
PubMed1977

Sex-chromosome ratios in cattle and their relationship to reproductive development in freemartins.

Nineteen "female" Holstein-Friesian calves born co-twin with a bull were purchased shortly after birth. One subsequently was judged to be a normal female with 0% XY (100% XX) karyotypes in cultures of blood lymphocytes. However, one typical freemartin also had 0% XY (100% XX) Karyotypes in 300 cells when examined at three ages. Overall, 18 freemartins examined at 1, 24, and 52 weeks of age averaged 60.7%, 57.9%, and 55.5% XY cells, respectively (P greater than 0.05). No systematic relationship was found between the proportion of XY cells and the abnormalities of the reproductive organs, as judged by vaginal depth and clitoral development at 1, 24, and 52 weeks, and examination of the reproductive organs per rectum at 54 weeks of age. The clitoris of untreated freemartins and those treated with estrone or estradiol postnatally did not enlarge. Testosterone treatment caused enlargement. None of the hormones affected vaginal depth. These studies provide convincing evidence that the blood lymphocyte XX:XY karyotype ratio (1) is not related to the degree of masculinization and (2) is stabile in the postnatal freemartin. Thirdly, the freemartin reproductive organs do not respond to common sex-steroid hormones postnatally other than the clitoral response to testosterone.

Animals↗
PubMed1977

Seminal quality, spermatozoal outpost, and testicular changes in growing Holstein bulls.

Nine Holstein bulls, initially between the ages of 17 and 22 mo, awaiting proofs in artificial breeding, were ejaculated each summer for 3 yr, and 8 and 7 survivors for 4 and 5 yr, respectively, to study changes in the same group of bulls and determine the predictive value of early measurements. Semen was collected twice a day, 2 days per wk, for 4 wk. Bulls differed in testicular size, consistency, ejaculate volume, total spermatozoal output, percentage of unstained spermatozoa and abnormal spermatozoa, and in several storage and freezing tests. The largest yearly effects were on testis size and consistency, ejaculate volume, and total output of spermatozoa. The latter increased per bull from 28.3 X 10(9) per wk at 17 to 22 mo of age to 40.9 X 10(9) per wk 4 yr later, representing a high output of spermatozoa with a total of only 20 min of intensive sexual preparation per wk. The correlation between testis size and spermatozoal output was .72. Testicular consistency was indicative of semen quality measured simultaneously as judged by correlations with spermatozoal characteristics ranging from .61 to .95. These characteristics are believed to be representative of those Holstein bulls in artificial breeding which are ejaculated frequently.

Animals↗
PubMed1977

Development of and fluid accumulation in mammary glands of freemartins administered estradiol, estrone, or testosterone..

Eighteen Holstein freemartins acquired at 1 wk of age were assigned to a control and to four treatment groups, but only two of the groups received hormone the first 50 wk. Testosterone administered for the first 50 wk appeared to inhibit teat growth whereas estrone stimulated teat and udder length. At 50 wk of age, implants releasing daily approximately 12.9 microgram of testosterone, 2.9 microgram of estrone, or 2.6 microgram of estradiol-17beta per kg of body weight were implanted for 6 wk. One of three testosterone-treated and 9 of 11 estrogen-treated animals exhibited increased udder development associated with fluid accumulation. The 10 animals with fluid accumulation in the udders were milked once 39 days after implanting. The fluid contained 15.0% total solids, 4.1% fat, and 7.0% protein, values which are between those for normal milk and colostrum. These studies support the concept that administration of low concentrations of estrogens alone, released continuously from implants, were capable of stimulating fluid secretion in mammary glands of animals that had no detectable gonadal luteal tissue.

Animals↗
PubMed1977

Effects of package, extender, and light on stored frozen bull spermatozoa.

Spermatozoa were analyzed when fresh, freshly frozen, and stored at --196 C for 6 and 18 mo after processing in egg yolk-citrate and Promine-D extender with varying exposure to light and packaging in straws or glass ampules. Over all treatments there were decreases with time in spermatozoal motility, oxygen uptake, and cellular glutamic oxaloacetic transaminase due to freezing-thawing. Percent progressive motility decreased from spermatozoa freshly frozen (36.5%) to those stored for 6 mo (33.6%). Oxygen uptake in freshly frozen samples was 8.4 microliter per 10(8) cells per h. In frozen semen stored for 6 and 18 mo corresponding values were 12.2 and 8.3 microliter. Packaging methods did not have a significant effect on oxygen uptake, but package interacted with storage. Egg yolk-citrate extender supported greater progressive spermatoal motility than did promine-D. Extender interacted with storage for all criteria. Visible light radiation reduced progressive spermatozoal motility from 40.2 to 38.0% and oxygen uptake from 11.8 to 10.8 microliter per 10(8) cells per h. Light interacted with storage time. Correlations between all criteria and storage times were not important practically.

Animals↗
PubMed1976

Spermagglutinin titers and their relationship to fertility in isoimmunized female rabbits.

The sera from 48 female rabbits immunized by a series of multiple intradermal injections of washed epididymal, washed ejaculated, and beta-amylase-treated rabbit spermatozoa in complete adjuvant were examined for spermagglutinins by the Kibrick gel agglutination test and a slight modification of the Shulman capillary agglutination test. Control animals receiving the adjuvant or saline usually had no positive titers. All three antigenic preparations produced similar titers, positive at dilutions as high as 8192-fold with Kibrick test and 256-fold with the Shulman test. Maximal titer development was reached 4 to 6 weeks after starting the immunization, and positive sera were obtained from some does for 25 weeks. The correlation coefficients between positive titers obtained by the two tests were r = 0.91 during the first 10 weeks and 0.41 at 15 to 25 weeks after immunization.

Animals↗