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Biomedical subjects

R H Foote

Publications and source records attributed to R H Foote.

At least 199 records · Page 11Linked to original sources
PubMed1976

Relationship of testicular weight to age and scrotal circumference of Holstein bulls.

Testicular weights were recorded for 250 Holstein bulls ranging in age from 19 to 189 mo. The multiple regression equation that best described the relationship between paired-testes weight and age of bull was Y = -368.8 + 952.2 LOG X - 180.3 (log X)2, where Y is paired-testes weight in g and X is bull age in mo. Correlations between these two variables were .86 for 24 bulls less than or equal to 60 mo of age and .60 for 23 greater than 60 mo of age. A linear regression equation for 47 bulls was Y = -645.5 + 34.0 X, where Y is paired-testes weight in g and X is scrotal circumference in cm measured within 1 mo of slaughter. The correlation coefficient was .79. Differences in testicular weights of bulls of similar ages were large. These should be taken into account by measuring scrotal circumference and selecting young bulls with larger testes and superior spermatozoal producing capabilities.

Age Factors↗
PubMed1976

Detection of estrus in dairy cows by electrical measurements of vaginal mucus and by milk progesterone.

Electrical resistance (ohms) of mucus were analyzed in 20 postpartum Holstein cows by use of a probe inserted into the anterior vagina every other day for 30 days. Composite milk samples were taken on the same day, and progesterone was determined by radioimmunoassay. Cows were observed twice daily for standing estrus and reproductive organs palpated weekly per rectum (rectal palpation). Fifteen cows which were cycling showed increasing progesterone 6 to 7 days after the onset of estrus with values of 8.1 to 10.0 ng progesterone/ml milk on days 10 to 17. Concentrations had declined rapidly 2 days before onset of the next estrus. Progesterone in milk was affected by cow and by day of the cycle. Electrical resistance followed a similar cyclical pattern, but variability was large and only cows differed. The correlation between milk progesterone and mucus resistance was .22. Progesterone concentrations for four cows with follicular cysts fluctuated randomly with a mean of 2.6 ng/ml. Mean resistance of vaginal mucus was 44 omega for both cycling and cystic cows, indicating that a single measurement of electrical resistance every 2nd day was unreliable in distinguishing physiological states. One cow had high progesterone in milk on days 19 to 25 and was diagnosed pregnant by rectal palpation 3 wk later. Cows were not seen in estrus 28% of the time when milk progesterone and rectal palpation indicated they were in the follicular phase of the estrous cycle and were cycling.

Animals↗
PubMed1976

Testosterone and libido in holstein bulls of various ages.

Testosterone was measured by radio-immunoassay in the blood plasma collected from 197 and 195 Holstein bulls in the spring and fall seasons, respectively. Bulls ranged in age from 8 mo to 13.5 yr. The average value for spring was 8.0 ng/ml, higher than the value of 5.7 ng/ml in the fall. Also, there was a tendency for testosterone to increase with age of the bulls up to 6 to 7 yr. The concentration of circulating testosterone was unrelated to libido or semen quality.

Age Factors↗
PubMed1976

Fertility of bull semen frozen with beta-amylase, beta-glucuronidase, and catalase.

"Capacitase," a product combining beta-amylase and beta-glucuronidase, was compatible with survival of bull spermatozoa frozen in whole milk-glycerol extender at final concentrations per ml of 0, 5, 10, and 20 mug of beta-amylase combined with 0, 75, 150, and 300 units of beta-glucuronidase, respectively. Bull semen was frozen in whole milk-glycerol extender containing the three lower concentrations of enzymes tested in the previous trial and used to inseminate 9057 first-service cows within 4 mo of freezing. The 60- to 90-day percent nonreturns were 74.6, 75.6, and 75.0. The same treatments plus a fourth one containing 10 mug of catalase per ml were fertility tested in another trial. Insemination of 16,842 cows resulted in 75.6, 74.1, 74.6, and 74.2% nonreturns. In this trial semen was held immersed in liquid nitrogen and distributed for immediate use each mo for 6 mo. There was no change in fertility during 6 mo of continuous storage at --196 C. Under the conditions tested neither catalase nor beta-amylase with beta-glucuronidase enhanced fertility of frozen bull semen.

Amylases↗
PubMed1976

Survival and fertility of antibiotic-treated bovine spermatozoa.

Motility of spermatozoa stored at 5 C with up to 1000 units or mug of chloramphenicol, polymyxin, kanamycin, tylosin, ampicillin, lincomycin, spectinomycin, erythromycin, novabiocin, or terramycin per ml of extender was compared to that with penicillin plus dihydrostreptomycin. Novabiocin and terramycin were toxic, but other antibiotic treatments had no effect. However, erythromycin and tylosin, as well as colymycin, depressed motility of frozen thawed spermatozoa. Spermatozoal motility was equivalent, following freezing in ampules or straws. All of the antibiotics which were non-toxic when added singly to frozen semen were also not harmful to frozen spermatozoa when as much as 2000 units or mug were added per ml of extender containing penicillin and dihydrostreptomycin. The addition of 1000 units or mug of ampicillin, chloramphenicol, kanamycin, lincomycin, polymyxin, or spectinomycin per ml of extender containing 750 units penicillin and 750 mug dihydrostreptomycin per ml did not influence the fertility of frozen spermatozoa in a field test involving 19,663 first inseminations.

Animals↗
PubMed1975

Lipid deficient extender for bovine spermatozoa: its development and use in measuring freezing-induced lipid loss.

To facilitate the measurement of lipid losses from spermatozoa due to freezing, three low-lipid seminal extenders containing lactose, bovine serum albumin, or soybean protein were evaluated as potential cryoprotectants. All extenders were formulated to have an osmotic pressure within the range of 270 to 330 mosmol and a pH of 6.8 to 7.0. Soybean protein (Promine-D) maintained the highest post-thaw motility of spermatozoa with similar survival for spermatozoa frozen in ampules and straws. The extender derived from testing several components consisted of Tris(hydroxymethyl) aminomethane (245 mM), and citric acid monohydrate (78mM), as the buffering compounds; and fructose (69 mM), glycerol (7% vol/vol), and Promine-D (1.5% wt/vol). Post-thaw sperm motility of approximately 40% was not different from the Tris-egg yolk control. Fertility of fresh rabbit semen treated with the extender was normal. After freeze-thawing, protected spermatozoa contained more lipid (1.61 versus 1.20 mug/10-6 sperm) and lost less glutamic oxaloacetic transaminase enzyme (102 versus 108 Karmen units) than when Promine-D was not incorporated. However, even with protection by soybean protein, spermatozoa lipid content decreased from 2.43 to 1.61 mug/10-6 sperm after one freeze-thawing. The lipid status of spermatozoa frozen and thawed in conventional bull seminal extenders containing large amounts of lipids is unknown.

Animals↗
PubMed1975

Estrus detection and estrus detection aids.

There is no substitute for good management. Each animal should be identified carefully. The herds man should know all signs of estrus or impending estrus. In addition, for visual detection of estrus to be highly effective, sufficient time must be taken at least twice a day to catch animals with a short estrus period. Presently there are two visual aids to estrus detection which provide potential 24-h surveillance. One aid is a pressure sensitive device mounted on the back of each cow which can be triggered when the cow stands for mounting. The second one is a marking device worn by sexually aggressive animals which will stripe with colored ink the back of estrous animals as the marker animal mounts and dismounts. Both devices are effective when used properly. Other tests of changes in cervical mucus, vaginal characteristics, temperature, blood flow, and hormone changes in blood and milk are either not suffciently reliable or else simple enough yet to be practical aids for routine detection of estrus in dairy cattle. Milk progesterone can assist in characterizing problem cows.

Animals↗
PubMed1975

Milk progesterone in postpartum and pregnant cows as a monitor of reproductive status.

Milk samples were analyzed for progesterone content by a petroleum ehter extraction and competitive protein binding assay validated for milk. In one experiment, 11 cows were sampled twice daily for 24 days beginning with an observed estrus 15 to 45 days postpartum, and again 19, 21, 23, and 25 days after breeding. Progesterone values during the estrous cycle paralleled those for blood plasma but were slightly higher at estrus (1.49 ng/ml milk) and maximum (9 ng/ml) on days 11 to 16 of the estrous cycle. After breeding, cows later diagnosed pregnant averaged 7.12 ng/ml while those later found to be nonpregnant averaged 2.36 ng/ml. All diagnoses of pregnancy were correct. In a separate experiment there was no difference between milk from front and rear quarters, but progesterone was highest in last milk, intermediate in composite milk, and lowest in first milk.

Animals↗