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101.
K L Moore J D Armstrong R W Harvey R M Campbell E P Heimer 《Domestic animal endocrinology》1992,9(2):125-139
Two experiments were conducted to determine the effects of immunoneutralization of growth hormone-releasing factor [GRF(1-29)-NH2] on concentrations of somatotropin (ST) and insulin-like growth factor I (IGF-I) in lactating beef cows. In Experiment 1, multiparous Hereford cows were immunized against 2 mg GRF(1-29)-(Gly)4-Cys-NH2 conjugated to human serum albumin (GRFi, n = 3) or 2 mg human serum albumin (HSAi, n = 3) at 52 +/- 1 d prior to parturition. Boosters (1 mg) were administered on days 12, 40 and 114 postpartum (pp). Serum samples were collected at 15-min intervals for 5 hr on days 18, 46 and 120 pp, followed by administration (IV) of an opioid agonist (FK33-824; 10 micrograms/kg) and an antagonist (naloxone; .5 mg/kg) at hours 5 and 7, respectively. A GRF-analog ([desamino-Tyr1, D-Ala2, Ala15] GRF (1-29)-NH2; 3.5 micrograms/kg) and arginine (.5 g/kg) were administered at hour 10 on days 47 and 121, respectively. Percentage binding of [125I]GRF (1:100 dilution of serum) 28 d after primary immunization was greater in GRFi (14.3 +/- 4.9) than in HSAi (.7 +/- .3) cows. Binding increased to 29.3 +/- 6.5% after first booster in GRFi cows. Episodic release of ST was abolished by immunization against GRF; concentration and frequency of release of ST were lower (P less than .05) in GRFi than in HSAi cows on all days pp. Concentrations of IGF-I were lower in GRFi than in HSAi cows throughout lactation. Serum ST failed to increase following FK33-824 or arginine in GRFi; however, ST increased after both compounds in HSAi cows. Concentrations of ST following GRF-analog were greater (P less than .05) in HSAi than in GRFi cows. Experiment 2 was conducted to determine if a lower dose of antigen and a single booster would be sufficient to lower ST and IGF-I in lactating cows. Multiparous Hereford and Angus cows were assigned to GRFi (n = 6) or HSAi (n = 6). Primary (1.2 mg) and booster (.5 mg) immunizations were administered -14 and 8 d from calving, respectively. Cows were restricted to 60% of recommended intake of energy during lactation in order to elevate concentrations of ST. Serum samples were collected at 15-min intervals for 6 hr on days 26, 50, 73, 90 and 109 pp. Two of six GRFi cows had binding less than 10% (1:1,000 dilution of serum) and were omitted from further analyses.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
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103.
The role of calcium in the secretion of growth hormone (GH) has been examined in vivo in immature domestic fowl. Chicks reared on a low calcium (0.16% calcium in the feed) diet showed a reduced growth rate, compared with those on a normal (0.86%) calcium diet and had lower basal levels of plasma GH 1, 5, 10 and 15 d after calcium deprivation, but not after 20, 25, 30 or 35 d of calcium deficiency. No consistent changes in the concentration of immunoreactive somatomedin C were observed during calcium restriction. In both the control and low calcium fed birds the plasma concentrations of GH were elevated by the intravenous administration of human pancreatic GH releasing factor (hpGRF) and by thyrotropin releasing hormone (TRH). The GH responses to these provocative stimuli were not reduced in magnitude by calcium deficiency. It is suggested, therefore, that the effect of calcium deprivation on the secretion of GH is mediated via the reduced release of stimulatory hypophysiotrophic factors from the hypothalamus.
Pharmacological alterations in calcium status also suggest that calcium deprivation inhibits GH secretion. Plasma concentrations of GH were acutely depressed in young chicks following the administration of a calcium chelator (ethylene diaminotetraacetic acid) a calcium channel blocker (verapamil) and after calmodulin inhibition (by chlordiazapine and trifluorpenazine administration). These data therefore demonstrate the importance of calcium in the stimulation of GH secretion in the domestic fowl. 相似文献
104.
Salinomycin and lasalocid effects on growth rate, mineral metabolism and ruminal fermentation in steers 总被引:1,自引:0,他引:1
Two experiments were conducted to determine the effects of salinomycin and lasalocid on metabolism and growth of growing steers. In Exp. 1, 80 Angus steers (228 kg) were assigned to the following treatments: 1) control, 2) 50 mg salinomycin.hd-1.d-1, 3) 100 mg salinomycin.hd-1.d-1 and 4) 250 mg lasalocid.hd-1.d-1. Steers were fed corn silage once daily with allotments based on the amount of silage that each pen of five steers would consume in a 24-h period. In addition, .81 kg/hd of a corn-soybean meal supplement was fed daily during the 112-d study. Daily gains were similar across treatments, but feed intake was lower (P less than .05) for steers fed ionophores. Molar proportions of ruminal acetate were lower (P less than .05) in steers fed ionophores at 28 and 90 d. Ruminal propionate was lower (P less than .05) in control steers at 28 d, but values were similar across treatments on d 90. Plasma copper (Cu) was lower (P less than .05) in control steers on both sampling days. In Exp. 2, 16 Hereford steers were allotted to two blocks of eight animals each and assigned to one of three treatments: 1) control (n = 6), 2) 11 mg salinomycin/kg diet (n = 6) and 3) 33 mg lasalocid/kg diet (n = 4). Following a 28-d adjustment period, apparent absorption and retention of macrominerals and nitrogen (N) were determined during a 5-d collection period. Apparent absorption and retention of N did not differ among treatments when data were analyzed using N intake as a covariate.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
105.
106.
Harvey S. James Jr. 《Agriculture and Human Values》2012,29(3):285-286
107.
108.
Carney HC Little S Brownlee-Tomasso D Harvey AM Mattox E Robertson S Rucinsky R Manley DS 《Journal of Feline Medicine and Surgery》2012,14(5):337-349
NURSING CARE: The term nursing care means different things to different people. The authors of these AAFP and ISFM Feline-Friendly Nursing Care Guidelines define nursing care as any interaction between the cat and the veterinary team (veterinarian, technician or nurse, receptionist or other support staff) in the clinic, or between the cat and its owner at home, that promotes wellness or recovery from illness or injury and addresses the patient's physical and emotional wellbeing. Nursing care also helps the sick or convalescing cat engage in activities that it would be unable to perform without help. GUIDELINES RATIONALE: The purpose of the Guidelines is to help all members of the veterinary team understand the basic concepts of nursing care, both in the clinic and at home. This includes methods for keeping the patient warm, comfortable, well nourished, clean and groomed. The Guidelines provide numerous practical tips gleaned from the authors' many years of clinical experience and encourage veterinary team members to look at feline nursing care in ways they previously may not have considered. OVERARCHING GOAL: The primary goal of feline-friendly nursing care is to make the cat feel safe and secure throughout its medical experience. 相似文献
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110.