PubMed Health⌕ Search

Biomedical subjects

J W Lauderdale

Publications and source records attributed to J W Lauderdale.

At least 19 recordsLinked to original sources
PubMed2003

A dose-response study of melengestrol acetate on feedlot performance and carcass characteristics of beef steers.

The dose response of melengestrol acetate (MGA) on ADG (kg/d) and gain efficiency (gain/DMI, g/kg) was estimated in beef steers fed a finishing diet under commercial feedlot conditions. Melengestrol acetate is not approved for use in steers as a feed additive. The study design was five blocks of four pens (each pen was assigned a dose of MGA) with 166 to 200 steers per pen. Melengestrol acetate was fed to steers at 0 (n = 899, five pens), 0.1 (n = 900, five pens), 0.2 (n = 899, five pens), and 0.4 (n = 900, five pens) mg of MGA/steer daily. Pens within a block were slaughtered on the same day. Blocks 1 through 5 were fed MGA for 123, 122, 116, 124, and 138 d, respectively. The experimental unit was a pen of steers, and blocking was based on source of steers. The ADG was 1.81, 1.85, 1.80, and 1.83 kg/d for steers fed 0, 0.1, 0.2, and 0.4 mg MGA per day, respectively. For ADG, the dose was significant, but neither linear nor quadratic effects were significant. Compared with steers of the control group, ADG was greater for steers fed 0.1 mg MGA (P < 0.01). Feed efficiencies were 170, 173, 171, and 172 g/kg for steers fed 0, 0.1, 0.2, and 0.4 mg MGA/d, respectively; however, no effects of dose (P = 0.19) or linear (P = 0.21) or quadratic (P > 0.60) effects were observed. There was no evidence for either positive or negative effects of MGA on DMI, hot carcass weight, dressing percent, quality grade, yield grade, back fat thickness, marbling score, longissimus muscle area, and incidence of dark cutter carcasses in response to feeding MGA to steers at doses of 0.1, 0.2, and 0.4 mg daily. The incidence of buller behavior (0.43 to 1.11%) was low and did not permit an accurate test of the clinical observations that feeding MGA to steers decreases the occurrence of buller steers. Melengestrol acetate fed to finishing beef steers produced small improvements in growth performance (ADG, 2.2%) at the 0.1 mg MGA dose, but none of the doses examined produced improvement in carcass quality or yield grade measurements.

Animals↗
PubMed1999

What is the pharmaceutical industry doing, and what does the pharmaceutical industry want from animal science departments?

Perceived contemporary issues are 1) food safety and food healthfulness, 2) environment, 3) sustainability, 4) biotechnology, 5) animal well-being, 6) animals as food, and 7) research funding. Food safety is the paramount contemporary issue, and environment and sustainability issues can be considered as a single issue. Biotechnology, animal well-being, and animals as food are addressed in this paper as separate issues, but they can be considered as components of food safety and healthfulness. The pharmaceutical industry addresses these issues by providing safe and effective products to the livestock industry. These products are used to treat and prevent disease and to increase livestock production efficiency. These products contribute to a safe food supply, enhance protection of the environment, and increase the sustainability of animal agriculture through increased efficiency of livestock production. The pharmaceutical industry wants the following from animal science departments: 1) students skilled in deductive and inductive thinking and communicating to peers and the public; 2) regional research on food safety, such as irradiation, steaming of carcasses, E. coli contamination, antibiotic resistance, production facilities, and carcass contamination; 3) improved research to identify the food values of animal products and effective communication of that research to the public; 4) research on topics having the greatest potential to increase efficiency of animal production consistent with a positive impact on the environment and sustainability of animal production; 5) leadership in developing and using technologies such as biotechnology, not only as descriptors of biological processes, but as technologies to test hypotheses leading to new understandings of biology; 6) research on animal well-being and production facilities that foster animal well-being; 7) research and education on ethical and moral aspects of animals as food through encouragement of one or more staff members to become effective animal science department spokespersons; and 8) active participation in activities such as FAIR 95, Federation of Animal Science Societies, and multidepartmental and(or) interdisciplinary programs.

Animal Husbandry↗
PubMed1996

Industry's responsibility to the consumer.

The responsibility of industry to the consumer is to provide products derived from biotechnology that are effective as labeled and safe for their intended use on animals, plants and in the environment. Moreover, food products from the animals and plants receiving the drugs or chemicals must be safe for human consumption. To fulfill these responsibilities, industry must provide an accurate label for the drug or chemical, ensure drug or chemical product consistency so that every batch of the drug or chemical is similar to every other batch, complete studies to document that the drug or chemical is safe for use in the animal or on the plant, complete studies designed to provide data to ensure that the food derived from the use of the drug or chemical is safe for human consumption and complete studies to document that the drug or chemical is safe for use in the environment. The process of requiring data to be derived from sound experimental science, completion of the studies under scrutiny by regulatory personnel and extensive scientific review of the data by regulatory personnel results in products derived from biotechnology that are safe and effective.

Animals↗
PubMed1994

Production performance of dairy cattle administered recombinantly derived bovine somatotropin (USAN, Somavubove) daily: a dose range study.

Herds (n = 9) were used on which cattle (n = 598) received 0, 4.3, 8.6, 12.9 or 17.2 mg of recombinant bovine somatotropin (rbST; USAN, Somavubove) daily from about 75 d postpartum until lactation end. Minimum effective dose to increase (3.5% fat corrected milk) FCM of cows (multiparous) compared with controls is 2.0 mg rbST/d and maximum is 16.6 mg/d. Minimum effective dose to increase FCM of heifers (primiparous) is 5.0 mg rbST/d while the maximum is 16.7 mg/d. Dosing of 4.3 to 13.2 mg rbST/d enhances efficiency of FCM production in cows. Milk fat, protein, calcium and phosphorus were not effected by rbST except for instances of transient changes. Lactose was greatest in heifers given 12.9 mg rbST/d. Days of lost milk, incidents of mastitis, and somatic cell counts were not affected by rbST. Cows given 12.9 or 17.2 mg of rbST had reduced pregnancy and conception rates, whereas heifers did not. Total services, first service conception rate, services per conception, days open and days to first AI (artificial insemination) were not affected by rbST. Days between AI were greater in cows given 17.2 mg rbST/d. Restoration of body weight and condition occurred at slower rates in rbST-dosed cows. Heifers given 8.6 or 12.9 mg rbST/d gained more weight than controls. Net energy and protein balance was reduced (less so in heifers) near start of rbST but recovered as intakes increased. Cattle given rbST produce more milk than controls and should be managed accordingly.

Animals↗
PubMed1992

Milk yield, health, and reproduction of dairy cows given somatotropin (Somavubove) beginning early postpartum.

Cows (n = 210) were assigned to the following treatments: uninjected controls through 130 d postpartum; zero to high, uninjected through 60 d then injected with 14 mg of bST/d from 61 through 130 d postpartum; low, 5 mg of bST/d from 14 through 130 d postpartum; low to high, 5 mg of bST/d from 14 through 60 d then 14 mg of BST/d from 61 through 130 d postpartum; and high, 14 mg of bST/d from 14 through 130 d postpartum. Cows given 5 mg of bST/d (low and low to high treatments) yielded 1.2 kg of FCM/d more and high group cows yielded 1.3 kg of FCM/d more than control cows between 14 and 60 d postpartum. Cows given bST yielded 2.7 to 4.1 kg of FCM/d more than control cows during 61 to 130 d postpartum. Overall, control cows yielded 35.1 kg of FCM/d, and bST-dosed cows yielded 2.2 to 3.2 kg/d more FCM. Low group cows had improved pregnancy rate (80.0%) and conception rate (82.2%) compared with high group cows (57.2 and 60.3%). Neither pregnancy (70.0%) nor conception rates (71.5%) of controls differed from other groups. However, low group cows had first service conception rate of 57.8% compared with 34.3% for high and 38.2% for low to high group cows. First postpartum estrus was observed in high group cows about 13 to 16 d later than in low and low to high group cows, whereas low group cows came into first estrus 9 d sooner than controls. Cows of high group had lower body condition than controls (2.5 vs. 2.9), but other groups did not differ (2.7 to 2.9) from controls. Health was not adversely affected. Early postpartum bST administration at 5 mg/d increases FCM and, perhaps, reproductive performance of dairy cattle compared with herdmates.

Animals↗
PubMed1991

Milk yield of dairy cows receiving somatotropin (somavubove) daily with periodic 14-day interruption.

Thirty multiparous (cows) and 15 primiparous (heifers) lactating Holstein cattle were used in a 112-d study to examine the effects of pattern of administration of recombinantly derived bST on 3.5% FCM yield. Ten cows and 5 heifers each received either no injection (controls), 14 mg of bST daily, or four repetitions of 14 mg of bST/d for 14 d followed by 14 d of no injection (intermittent bST). Because there was an interaction between treatment groups and parity, analyses were performed separately for cows and heifers. All cows and heifers produced more FCM when given bST than controls. Comparing FCM only during the last 7 d of each period of injection for the intermittent bST group with contemporary daily injected cattle indicated that cows produced equivalent amounts of milk at those times, whereas heifers given daily bST produced 3.4 kg/d more than intermittently injected animals. Furthermore, over each of the four repetitive periods, cows and heifers given daily or intermittent bST responded similarly, although heifers given continuous bST produced more FCM than the intermittent group during each of periods 2 through 4. We conclude that daily administration of bST lends itself to dosing termination during established lactation with concomitant decline of FCM; resumption of bST allows milk yields of cows to achieve levels comparable with those prior to short-term interruption.

Animals↗
PubMed1987

Response of postpartum beef cows to exogenous progestogens and gonadotropin releasing hormone.

Plasma progesterone (P4) profile and estrous detection were used during three experiments to evaluate the effects of exogenous progestogens on the life span of gonadotropin releasing hormone (GnRH)-induced corpora lutea (CL) in postpartum (pp) beef cows. Experiment 1 utilized primiparous fall-calving cows (n = 28, trial 1); and spring-calving cows (n = 29, trial 2). On d 18 to 27 pp (d 0) all cows received intravaginal devices containing either P4 or no P4 (NP) for 5 d. On d 5 the devices were removed and calves were either removed (CR) or were present (CP) with half of the cows within steroid group. At 50 h after device removal, 500 micrograms of GnRH was given (iv) to all cows, and weaned calves were reunited with their dams. The induced CL had a normal life span (greater than 16 d) in 17 and 86% (trial 1) and 8 and 79% (trial 2) of NP and P4 cows, respectively. Calf removal did not affect (P greater than .10) the life span of the CL. In Exp. 2, spring-calving multiparous cows (d 18 to 24 pp; d 0) received either no P4 (NP; n = 19), P4 for 6 d via intravaginal devices (P4H; n = 19) or a single im injection of 300 mg P4 (P4 IM; n = 18). At 48 h after device removal or at 8 d after the injection of P4, half of the cows within steroid group received either 500 micrograms GnRH or saline. Corpora lutea had a normal life span in 0, 11, and 80% of NP, P4 IM and P4H cows, respectively, that received GnRH and in 22% of P4-saline cows. In Exp. 3, fall-calving multiparous and primiparous cows (d 25 to 31 pp) received either no progestogen (NP; n = 20), P4 via intravaginal devices for 5 d (P4H; n = 21) or melengestrol acetate (MGA; .5 mg.head-1.d-1 for 5 d orally, n = 15). At 48 d after device removal or at 72 h after the last MGA feeding, all cows received 500 micrograms GnRH. Progesterone post-GnRH injection was increased (greater than 1 ng/ml) at d 7 in 64, 100 and 100%, and remained elevated at d 14 in 11, 46 and 100% of NP, MGA and P4H cows, respectively. For all experiments plasma P4 was increased (range 2 to 5 ng/ml) when the devices containing P4 were in place, then decreased (less than 1 ng/ml) by 48 to 50 h after device removal.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1986

A review of patterns of change in luteal function.

Puberty: For the gilt and filly, the first corpus luteum (CL) appears to have a normal lifespan. For both species, first CL usually is associated with estrus but can form in the absence of estrus. For the ewe and cow, a transient (1 to 4 d, ewe; 3 to 10 d, cow) rise and fall of ovarian derived progesterone (P4) is detected in peripheral blood (80% of ewes; 50% of heifers) prior to first "normal" CL. The first CL of apparent normal lifespan is not accompanied by estrus in the ewe. The first CL in the cow may or may not be accompanied by estrus; first estrus in the cow can be anovulatory. Data are required to describe definitively variation in lifespan of first CL in these species. Persistent CL: Data that the CL can be prolonged in the absence of uterine abnormality are strongest in the mare, suggestive for the ewe under conditions of "more constant light," equivocal in the cow, and not reported in the pig. First CL after the anovulatory season: As reported for the pubertal ewe, the anestrous ewe can have a progesterone rise over a 2- to 4-d interval at about 25 d before estrus. The ewe has a P4 pattern similar to that of a normal estrous cycle in the absence of estrus immediately prior to the first estrus and CL. CL lifespan was reported for the first estrous cycle to be both normal and on the order of 4 to 10 d in up to 50% of the ewes, following introduction of rams. For the mare, first CL usually is associated with estrus and has a normal lifespan. Data suggest no P4 rise prior to first CL. The occurrence of estrus without formation of a CL is usual during the anovulatory season and during the transition from anovulatory to ovulatory seasons. Postpartum: The CL of pregnancy regressed at parturition and was not functional postpartum in the sow and cow, regressed at about d 180 of gestation in the mare (both primary CL and secondary CL), and regressed after d 140 of gestation and before d 2 postpartum in the ewe. Postpartum estrus occurring within d 1 to 3 postpartum was anovulatory for both the sow and ewe; postpartum estrus within d 5 to 12 was ovulatory for the mare.(ABSTRACT TRUNCATED AT 400 WORDS)

Aging↗
PubMed1978

Pharmacologic and toxicologic study of prostaglandin F2alpha in cattle.

Prostaglandin F 1alpha (tham salt formulation) was injected IM into mature beef heifers at the rate of 0, 25, 75, 125, or 250 mg (4 heifers/dose group) on days 2 and 10, or 0 and 25 mg (4 heifers/dose group) on days 1 through 10. Drug effects were evaluated by means of 19 clinical observations, measurements of body weight and 10 organ weights, 15 clinical chemistry measurements, 9 hematologic measurements, 7 urinalysis measurements, and gross and microscopic observations of 27 tissues. Prostaglandin F2alpha administered on days 1 and 10 or daily for 10 days produced little evidence of pharmacologic effects and no evidence of toxicologic effects. Pharmacologic effects included a slight transitory increase in heart rate in all treated groups and slight hyperthermia in the 250-mg group. Failure to produce important toxicologic effects at 250 mg/day and with luteolytic doses occurring around 15 to 25 mg/day demonstrated that the safety factor was in excess of 10 X.

Alkaline Phosphatase↗
PubMed1976

Comparison of luteolytic effectiveness of several prostaglandin analogs in heifers and relative binding affinity for bovine luteal prostaglandin binding sites.

The relative binding affinities for both the prostaglandin (PG)E1 and PGF2alpha specific bovine luteal binding sites were determined for five PGE and fourteen PGF derivatives and analogs. Relative binding affinity was determined in vitro using membranes prepared from bovine corpora luteal (CL) obtained from the slaughterhouse. The parent structure of the analog was a dominant feature in determining the affinity for the respective PG binding site. Luteolysis was determined in cattle following intramuscular injection of various doses of prostaglandin once between days 6 and 14 after estrus and measuring CL regression by ovarian palpation per rectum, interval between injection and return to estrus and duration of the subsequent estrous cycle. A dose which was luteolytic was established for each of eight PGF-type compounds, and a dose which was not luteolytic was also established. There appeared to be limited association between the relative affinity for the PGF2alpha specific site in vitro and the estimated luteolytic dose range of these PGF analogs when tested in cattle. Differences in in vivo luteolytic potency for the compounds tested could not be explained by differences in binding affinity. Differences in metabolism and absorption may also be important in the determination of in vivo potency.

Animals↗
PubMed1975

Prostaglandin E1 and F2alpha specific binding in bovine corpora lutea: comparison with luteolytic effects.

Preliminary characterization indicated the presence of separate prostaglandin (PG)E1 and (PG)F2alpha binding sites in membrane fractions prepared from bovine corpora lutea. These differ in the rate and temperature dependence of the specific binding. Equilibrium binding data indicate the apparent dissociation constants as 1.32 x 10(-9)M and 1.1 x 10(-8)M for PGE1 and PGF2alpha, respectively. Competition of several natural prostaglandins for the PGE1 and PGF2alpha bovine luteal specific binding sites indicates specificity for the 9-keto or 9alpha-hydroxyl moiety, respectively. Differences in relative ability to inhibit 3H-PG binding were found due to sensitivity to the absence or presence of the 5, 6-cis-double bond as well. Bovine luteal function was affected following treatment of heifers with 25 mg PGF2alpha as measured by reduced estrous cycle length, decreased corpus luteum size and significantly decreased plasma progesterone levels. In contract, treatment with 25 mg PGE1 resulted in cycle lengths comparable to those of non-treated herdmates with no apparent modification in corpus luteum size. However, plasma progesterone levels were increased significantly following PGE1 treatment compared to pretreatment values. In so far as data obtained in vitro on PGF2alpha relative binding affinity to the bovine CL can be compared to data obtained independently in vitro on PGF2alpha induced luteolysis in the bovine, PGF2alpha relative binding to the CL and luteolysis appeared to be associated. By similar reasoning, there was no apparent relationship between PGE1 relative binding affinity in the luteal fractions and luteolysis in estrous cyclic cattle.

Animals↗
PubMed1975

Biological activities of 17-phenyl-18,19,20-trinorprostaglandins.

In a number of assay systems, some 17-phenyl-trinor-prostaglandins were similar in activity and potency to the corresponding parent prostaglandin. In others, the 17-phenyl analogs appeared several times more potent. In the hamster antifertility assay, which is considered to measure luteolytic activity, 17-phenyl-18,19,20-trinor prostaglandin F2alpha was about 90-times PGF2alpha in potency. Rat blood pressure responses to 17-phenyl analogs were significant. The 17-phenyl-trinor PGF2alpha pressor potency was 5 times that of PGF2alpha. The 17-phenyl-trinor PGE2 blood pressure response was atypical since a pressor rebound phenomenon followed the expected depressor response. Lastly, 17-phenyl-trinor PGF2alpha was more potent than PGF2alpha in synchronizing the estrous cycle in beef cows.

Animals↗