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Biomedical subjects

J A Pennington

Publications and source records attributed to J A Pennington.

At least 37 records · Page 2Linked to original sources
PubMed1987

Molybdenum, nickel, cobalt, vanadium, and strontium in total diets.

The 234 foods from a 1984 collection of the Food and Drug Administration's Total Diet Study were analyzed for the trace elements molybdenum, nickel, cobalt, vanadium, and strontium by plasma emission spectrometry. Daily intakes of these elements were then estimated for eight age-sex groups on the basis of results from national food consumption surveys. The contribution of food commodity groups to the daily intake of the five elements and the distribution of the elements in the 234 foods were also determined. Results from this study were compared with those reported earlier from other laboratories.

Adolescent↗
PubMed1986

Influence of feeding time and diet on time of parturition in multiparous ewes.

Three hundred three pregnant ewes were randomly allotted to treatments in a 2 (diet) X 2 (feeding time) factorial arrangement 10 d before the first lambs were due in two lambing seasons to study the effect of time of feeding and diet on time of lambing. Behavioral activities were observed to determine if there was a relationship to time of parturition. All ewes were fed .5 kg ground whole corn per day plus either: alfalfa hay fed at 2200 each day, alfalfa hay fed at 1000 each day, alfalfa haylage fed at 2200 each day or alfalfa haylage fed at 1000 each day. Lambing data from 1983 and 1984 were combined across years because no treatment X year interactions (P greater than .05) were detected. Average time of day for lambing did not differ (P greater than .05) among treatments. In general, no differences due to treatments were observed in lambing time or behavioral activities studied. When data were pooled across treatments, two peak lambing times were observed. These peak times for lambing were from 0300 to 0700 (22.1%) and from 1500 to 1900 (22.5%). During these two 4-h periods (8 h total) 44.6% of the ewes gave birth.

Animal Husbandry↗
PubMed1986

Relationships of sexual activities in estrous cows to different frequencies of observation and pedometer measurements.

Sexual activities were observed continuously for 120 h in Holstein dairy cows during moderate climate. Pedometer measurements of motor activity were correlated with total activities initiated, total activities received, mounts received, and time in estrus. Twelve of 14 individual sexual activities also were correlated on a within-cow basis with pedometer-measured increases in motor activity; disoriented mounts and licking front were not correlated to pedometer increases. Although observations of four 1-h and four or six 30-min observations accounted for greater variation, pedometer increases in activity accounted for as much variation in total sexual activities as periodic observations of 30 min or 1 h for 1 to 3 X /d. Combining periodic observations with pedometer measurements resulted in greater coefficients of determination for analyses of sexual activities than with each individual factor. Sexual activities and pedometer increases also were correlated positively with body condition score and day postpartum, and they were correlated negatively with milk production and body weight change since calving. Although mounting and total sexual activities were shifted significantly from expected on a quartile basis, shifts were probably not of practical significance and provided little evidence for more frequent occurrence of estrous activity during nocturnal periods. Rather, the most marked decrease in mounting and total sexual activities occurred at milking and feeding times, indicating that dairy farmers should be more concerned with disruptions of activities by management practices rather than nocturnal occurrence of estrus.

Animals↗
PubMed1986

Mineral content of foods and total diets: the Selected Minerals in Foods Survey, 1982 to 1984.

The 234 foods of the FDA's Total Diet Study were collected four times per year form mid-1982 to mid-1984 and analyzed for 11 essential minerals. Daily intakes of the minerals were estimated for eight age-sex groups of the U.S. population. Levels of calcium, magnesium, iron, zinc, copper, and manganese were low (less than 80% of the RDA or below the low end of the Estimated Safe and Adequate Daily Dietary Intake range) for some or all age-sex groups. Those most at risk of low intakes were young children, teenage girls, adult women, and older women. Non-discretionary sodium intake exceeded the upper Estimated Safe and Adequate Daily Dietary Intake range for two age-sex groups, and iodine was considerably above the RDA for all age-sex groups. Levels of potassium, phosphorus, and selenium were adequate for all groups.

Diet Surveys↗
PubMed1985

Prolactin in bovine milk near the time of calving and its relationship to premature induction of lactogenesis.

Twenty-three primiparous heifers and pluriparous cows were milked once daily beginning 3 to 10 days before parturition. Retrospectively, they were divided into groups representing either successful or unsuccessful premature induction of lactogenesis, depending on milk production prior to calving. Successfully induced animals had prepartum milk yields greater than 4 kg/milking and unsuccessful animals yielded less. Ten of 23 animals satisfied the criterion for successful premature induction at 2.6 +/- .4 days before calving and 3.6 +/- .8 days after first milking and had peak prepartum yields of 7.9 +/- .7 kg/milking. Total number of prepartum days milked did not differ between successful and unsuccessful groups. Greater milk yield prepartum was significantly associated with higher milk prolactin concentration on days -6 to -4. Heifers had less milk yield than cows but did not differ in milk prolactin concentration or in total prolactin per milking. Premature induction of lactogenesis did not confer significant lactational benefits for more than 1 day postpartum or over the first 35 days postpartum. Premature induction of lactogenesis as a result of prepartum milking did not, as hypothesized, decrease the ability of mammary secretions to accumulate prolactin in large amounts. All groups rapidly lost this ability after parturition, suggesting that the hormonal environment of late pregnancy may promote the transfer of prolactin from blood into milk when there is regular removal of prepartum milk.

Animals↗
PubMed1985

Comparison of pregnancy diagnosis by milk progesterone on day 21 and day 24 postbreeding: field study in dairy cattle.

Milk samples collected at 21 and 24 d after breeding were used to diagnose cows as pregnant, questionable, or not pregnant with high, intermediate, or low progesterone in the milk. Total agreement of pregnancy diagnosis in cows by milk progesterone at 21 d postbreeding and diagnosis by return to estrus or palpation of reproductive organs was 85.8% (77.4% on pregnant progesterone diagnosis and 97.2% on not pregnant progesterone diagnosis). Total agreement of diagnosis by progesterone at 24 d postbreeding and diagnosis by estrus or palpation was 88.4% (83.5% on pregnant progesterone diagnosis and 95.3% on not pregnant progesterone diagnosis). Although total accuracy of cows diagnosed both pregnant and not pregnant by milk progesterone on d 24 postbreeding was greater than diagnosis on d 21 postbreeding when cows in estrus by d 24 were deleted from the data, other comparisons for effect of day on accuracy of diagnosis were not different. Total accuracy of diagnosis on d 24 was not increased by using milk progesterone on both d 21 and 24. Samples collected on the day of breeding indicated that 18 of 960 (1.9%) had intermediate or high progesterone. Fourteen (1.5%) additional cows had progesterone above levels expected for a cow in estrus.

Animals↗
PubMed1985

Sexual activity of Holstein cows: seasonal effects.

Continuous observations of Holstein dairy cows during natural and prostaglandin-induced estrus were conducted to determine effects of cold and hot weather on the degree and pattern of sexual activities, circadian profile of activities, and location of activities. Mounts with pelvic thrusts and mounts plus 12 other estrous-related activities for 73 cows were monitored for 96 h in cold weather and 120 h in hot weather. Eleven cows in hot weather with more than one mount were in estrus longer with less intensity of mounting than 16 cows in cold weather; climate did not affect mounts received or total activities initiated per cow. Number of cows in standing estrus affected mounts received per cow, total activities received per cow, and time in estrus but not activities initiated per animal. Two estrual cows in cold weather and 6 cows in hot weather received less than 2 mounts. Cows in cold weather had more (28%) total estrous activity as mounting activity than cows in hot weather (14%); cows in hot weather interacted more by rubbing and licking than cows in cold weather. Cows in cold weather had more mounting activity from 0600 to 1759 h (73%) than from 1800 to 0559 h (27%) and had more mounts from 1200 to 1759 h than cows in hot weather. During both cold and hot weather, sexual activities decreased at milking time. In the freestall housing with drylot, 80% of the mounting activity in both climates occurred in an outdoor drylot and feed manger area, which had best footing. These data indicate that climate affected mounting and total sexual activity of lactating dairy cows.

Animals↗
PubMed1984

Selected minerals in foods surveys, 1974 to 1981/82.

The levels of 11 essential minerals in food commodity groups and total diets of adult males, infants, and toddlers were summarized from the Selected Minerals in Foods Survey, Fiscal Years (FY) 1974 through mid-1982, of the Food and Drug Administration (FDA) to evaluate the sources and adequacy of those minerals in the diets. The three diets were adequate in calcium, phosphorus, magnesium, potassium, manganese, and selenium; low in copper; and elevated in sodium and iodine. Iron was adequate in adult male but not in infant or toddler diets, and zinc was adequate in infant but somewhat low in adult male and toddler diets. Dairy products; meat, fish, and poultry; grain and cereal products; and fruits and vegetables were the major sources of the 11 minerals. Some statistically significant differences in mineral levels were found among years for total diets and food commodity groups. Regression analysis indicated several linear trends in the mineral content of food commodity groups but no linear trends in the mineral levels of total diets. FDA continues to monitor the levels of minerals in food and diets through the revised Total Diet Study program, which began in mid-FY82.

Adult↗
PubMed1983

Efficacy of gonadotropin-releasing hormone administered at the time of artificial insemination of heifers and postpartum and repeat breeder dairy cows.

The efficacy of gonadotropin releasing hormone (GnRH) on the fertility of dairy heifers and postpartum cows was studied. In one study, 300 cows were assigned randomly to 1 treatment from a 2 X 2 design, and 2 ml of 0.15M saline solution or 100 micrograms of GnRH was given IM on postpartum day (PPD) 14 and at the time of 1st postpartum breeding. In a 2nd study, repeat breeder cows (n = 346) were given saline solution or GnRH at the time of the 3rd breeding. In a 3rd study, heifers (n = 185) were given saline solution or GnRH at 1st breeding. Animals were observed for repeat estrus, and pregnancy diagnoses were made by rectal palpation 45 to 60 days after breeding. Conception rates were 15% to 18% higher for cows given GnRH, whether at PPD 14 or at the first postpartum breeding. When GnRH was given at the first breeding, conception rates were significantly higher (P less than 0.05). Conception rates for repeat breeder cows given GnRH were 25% higher than those in controls (P less than 0.005). Conception rates for heifers did not differ between treatments.

Animals↗
PubMed1983

Revision of the Total Diet Study food list and diets.

The foods and diets of FDA's Total Diet Study have been revised according to current food consumption patterns. A representative subset of 234 foods, selected from aggregated NFCS and NHANES II data, is collected and analyzed by the Kansas City Field Office Laboratory for 11 essential minerals and more than 120 chemical contaminants. The daily intake by weight of these 234 foods has been extrapolated to represent 100% of the usual diet for eight age-sex groups. These extrapolated food intakes will be used to assess daily contaminant and mineral intakes. The revised food list and diets will be used until the results of another national food consumption survey show the necessity to further revise the diets for the Total Diet Study Program.

Adolescent↗
PubMed1983

Total diet study: determination of iodine intake by neutron activation analysis.

Composite food samples from adult, infant, and toddler market baskets of the Food and Drug Administration's (FDA) Total Diet Study for Fiscal Year 1980 were analyzed for iodine by neutron activation analysis (NAA) at the FDA NAA laboratory at the National Bureau of Standards. The mean iodine content of the total diets was 412, 397, and 410 micrograms, per day for adult (2,900 kcal per day), infant, and toddler diets, respectively. These intakes correspond with 275%, 882%, and 586% of the adult, infant, and toddler Recommended Dietary Allowances, respectively. Dairy products and iodate-containing breads were major dietary sources of iodine. The iodine values for total diets reported here, determined by NAA, are from 11% to 15% higher than those determined by colorimetric analysis at FDA's Kansas City Field Office Laboratory.

Adolescent↗
PubMed1982

Milk progesterone for pregnancy diagnosis in dairy goats.

Factors affecting progesterone concentration in milk of lactating dairy goats and use of this milk for pregnancy diagnosis were studied. Radioimmunoassay was used to assay progesterone in milk. Mean milk progesterone (ng/ml) +/- standard errors of 6 pregnant does for first, composite, and last milk were 9.9 +/- 2.0, 18.2 +/- 3.5, and 21.7 +/- 4.1. Correlation between milk fat and progesterone in composite milk was low (.11). Composite milk samples from 4 nonpregnant does were obtained daily throughout the estrous cycle. Milk progesterone (ng/ml) was 1 to 2 at estrus, rose to 5 to 12 within 2 to 5 days, reached a plateau at 15 to 25 in the middle of the estrous cycle, and then dropped to low concentrations again at 3 to 5 days before the next estrus. Milk progesterone also was used to diagnose pregnancy in 72 does. Forty-two does were diagnosed pregnant by high progesterone; 36 of these does later produced kids, and 5 other does aborted in various stages of pregnancy. Of 21 does diagnosed not pregnant with low progesterone, 19 does were not pregnant by either return to estrus or lack of parturition in the spring. All three incorrectly diagnosed does were problem breeders. Nine does with intermediate milk progesterone were classified questionable. Milk progesterone can be used to provide an early indication of the pregnancy status of does.

Animals↗
PubMed1981

Influences on progesterone concentration in bovine milk.

Factors affecting progesterone concentrations in milk of lactating dairy cows were studied and discussed as they pertained to pregnancy diagnosis. Adding a preservative to milk allowed storage at room temperature for 10 days with no effect on progesterone analysis. Progesterone content in first, composite, and last milk was associated with fat content, although correlation between progesterone concentration in composite milk and fat percentage was low. Variation was considerable in individual samples for each of the milk fractions. Day of the estrous cycle was the most important factor affecting progesterone concentration in milk from cycling cows. Samples for pregnancy diagnosis by milk progesterone should be collected near the time that nonpregnant cows are expected to return to estrus. Progesterone concentration in milk from pregnant cows remained high throughout gestation with progesterone concentrations similar to those in the luteal phase of the estrous cycle.

Animals↗
PubMed1976

Prenancy diagnosis in dairy cattle by progesterone concentration in milk.

Concentration of progesterone in whole milk was used to diagnose pregnancy in lactating dairy cows. Milk samples were taken 21 to 22 days postbreeding and analyzed for progesterone by radioimmunoassay. Progesterone in milk greater than 11 ng/ml, 8 to 11 ng/ml, and less than 8 ng/ml was used classify animals as pregnant, questionable, and not pregnant. In this classification for 123 cows, 67 were classified pregnant, 7 questionable, and 49 not pregnant. A comparison of progesterone diagnosis with actual calving results showed agreement of 73 and 98% for the cows classified as pregnant and not pregnant. Thirteen of 19 animals, in which there were discrepancies between diagnoses by milk progesterone and calving results, were not detected in estrus within 30 days after breeding. One animal classified not pregnant by milk progesterone was pregnant.

Animals↗
PubMed1975

Effects of intraruminal and intra-abomasal additions of cod-liver oil on milk fat production in the cow.

Four Holstein cows were used in a modified switchback design to show the effect on milk-fat synthesis of (1) control diet, (2) 29.23, 3.92, 6.48, 30.65, 3.44 control diet plus 255 g/day of cod-liver oil in rumen, and (3) control diet plus 225 g/day of cod-liver oil in abomasum. Mean milk yield (kg/day), fat production (kg/day), and milk-fat percentage were (1) 21.87, .79, 3.63; (2) 22.99, .70, 3.05; and (3) 23.02, .75, 3.28. Compared to the post-treatment control period, only one cow decreased in milk-fat percentage on 3 while all cows decreased in milk-fat percentage on 2. Proportions of carbons 16:0, 16:1, 18:0, 18:1, 18:2, and trans-monoene fatty acids of the milk fat were (1) 30.31, 3.24, 10.15, 30.48, 2.59, 7.91; (2) 26.37; and (3) 26.30, 3.72, 10.56, 30.10, 2.96, 9.84. Proportions of rumen volatile fatty acids were not significantly affected by treatment. Proportions of carbons 16:0, 18:0, 18:1, 18:2, and 18:3 fatty acids in the rumen ingesta were (1) 17.28, 47.92, 21.71, 10.59, 2.46; (2) 19.55, 25.90, 37.21, 11.97, 5.39; and (3) 16.90, 50.80, 19.66, 9.11, and 3.23. Fatty acid composition of blood-serum phospholipids were affected by treatment.

Abomasum↗
PubMedDate not supplied

Aluminium content of foods and diets.

Literature data on the aluminium content of individual foods have been compiled, summarized and presented by food groups. The contribution of aluminium from food preparation and cooking utensils and from food additives is discussed. Literature data on the daily intake of aluminium are summarized, and the contribution of food groups to daily aluminium intake is estimated. The major sources of dietary aluminium include several with aluminium additives (grain products, processed cheese and salt) and several that are naturally high in aluminium (tea, herbs and spices). The aluminium that may migrate from aluminium utensils is probably not a major or consistent source of this element. Daily intakes of aluminium, as reported prior to 1980, were 18-36 mg per day. More recent data, which are probably more accurate, indicate intakes of 9 mg per day for teenage and adult females and 12-14 mg per day for teenage and adult males.

Aluminum↗
PubMedDate not supplied

Silicon in foods and diets.

Information on the silicon content of foods and diets is summarized from published literature, and the silicon content of US diets is calculated based on the Food and Drug Administration's Total Diet Study model and literature values for silicon in foods. Silicon levels tend to be higher in foods derived from plants than in foods from animal sources. Foods highest in silicon include grains, especially oats, barley and some rice fractions. Average daily intakes of silicon probably range from about 20 to 50 mg/day with the lower values for animal-based diets and the higher values for plant-based diets. The silicon content of adult US diets, based on the Total Diet Study model, is 19 mg/day for women and 40 mg/day for men.

Animals↗