The influence of dietary monensin and salinomycin on growth and endocrine status of gilts

1992 ◽  
Vol 72 (2) ◽  
pp. 427-429 ◽  
Author(s):  
T. A. Van Lunen ◽  
R. N. Kirkwood ◽  
P. A. Thacker

Seventy-two gilts were fed a 16% crude protein diet supplemented with monensin, salinomycin or not supplemented. There was no effect of treatment on gilt growth between 30 and 100 kg body weight. Monensin-fed gilts tended to have increased, while salinomycin-fed gilts had decreased (P < 0.01), serum growth hormone concentrations. Salinomycin-fed gilts were older and heavier at puberty (P < 0.05). Key words: Monensin, salinomycin, gilts, growth, reproduction

1998 ◽  
Vol 66 (3) ◽  
pp. 551-556 ◽  
Author(s):  
G. W. Kazmer ◽  
S. A. Zinn

AbstractDose-response experiments were designed to determine the dosage of somatostatin (SRIF) necessary to alter serum growth hormone (GH) response to administration of GH-releasing factor (1·44; GRF) in cattle. The objective of this experimentation was to develop a GRF/SRIF challenge model that might be useful in early identification of animals which are genetically superior for milk production traits. In experiment 1, calves received either 0, 5 or 10 /JLg GRF per 100 kg body weight (BW) or GRF 1·29 at 1 ug per 100 kg BW. Both the 5 and 10 ug GRF per 100 kg BW dosages increased GH concentrations (P < 0·05). In experiment 2, animals received 3 ug GRF per 100 kg BW concurrent with administration of 0, 0·5, 1 or 2 ug SRIF per 100 kg BW at 0 min, with second dosage of GRF at +120 min. Administration of SRIF in those dosages did not alter GH response to GRF. In experiment 3, animals received 5 ug SRIF per 100 kg BW at -2, -1, 0 or +1 min relative to 3 ug GRF per 100 kg BW, with a second GRF injection at +120 min. No differences (P < 0·05) were found in response due to timing of SRIF administration. In experiment 4, animals were administered 0, 5, 10 or 20 Xg SRIF per 100 kg BW concurrent with 3 ug GRF per 100 kg BW. SRIF delayed (P < 0·05) the occurrence of maximum GH concentrations but did not affect the maximum concentration nor the area under the GH response curve (AUC) following either the first or second GRF injection. Utilizing data from experiment 4, individual animal response to GRF was reasonably consistent, as repeatabilities of AUCs for 1 h following first and second GRF injections were 0·80 and 0·65, respectively. Furthermore, sufficient among-animal variation existed so that animals could be distinguished from each other. Thus we conclude the method described herein might be useful in identifying superior dairy calves but accuracy would potentially be enhanced by collecting blood samples more frequently during the 20 min immediately after GRF injection.


1980 ◽  
Vol 94 (3) ◽  
pp. 321-326 ◽  
Author(s):  
Kazue Takano ◽  
Naomi Hizuka ◽  
Kazuo Shizume ◽  
Yoko Hasumi ◽  
Toshio Tsushima

Abstract. Serum somatomedin A was significantly reduced after 3 days of fasting in rats with a mean decrease of 23.6 ± 2.4% (N = 18) of initial values. Re-feeding for one day produced a definite increase in somatomedin A, with a rise in body weight. When re-fed isocalorically for 21 days with diets of different quality, a low protein diet led to smaller increases in both seum somatomedin A and body weight in comparison to those of control-, high-protein- and high fat-diets (P < 0.001). There is a positive correlation between the increase in body weight and serum somatomedin A levels (N = 70, r = 0.71, P< 0.001). The effect of growth hormone on somatomedin generation was abolished in hypophysectomized rats fed with low-protein diet. Our study suggests that protein in the diet is important for the generation of somatomedin A, which is necessary for normal growth.


1990 ◽  
Vol 70 (3) ◽  
pp. 991-995 ◽  
Author(s):  
R. N. KIRKWOOD ◽  
P. A. THACKER ◽  
B. LAARVELD

Twelve castrated male pigs of Yorkshire and Landrace breeding were selected at 95.9 ± 1.6 kg body weight (BW) and allocated equally to receive daily injections of either porcine growth hormone (pGH) at 90 μg kg−1 BW or vehicle buffer for four consecutive days. Following the last pGH injection, the pigs were infused via indwelling vena caval cannulae with thyrotropin-releasing hormone (TRH) at 0.5 μg kg−1 BW. Blood samples were obtained at 10 and 0 min before TRH and thereafter at 10-min intervals for 90 min. Serum concentrations of thyroxine and thyrotropin were lower (P < 0.06 and P < 0.1, respectively) but those of triiodothyronine higher (P < 0.01) in pGH-treated pigs throughout the sampling period. There were no significant treatment-by-time interactions indicating that the thyroid response to TRH was not influenced by pGH treatment. Key words: Swine, thyroid, growth hormone, somatotropin


1995 ◽  
Vol 75 (3) ◽  
pp. 489-491
Author(s):  
Niu Zhi-Yuan ◽  
G. L. Campbell ◽  
R. S. Bhatty ◽  
B. G. Rossnagel

Five Condor and five CDC Richard hulless barley samples, representing a range in crude protein (12.4–15.3%), were fed to broiler chicks in β-glucanase-supplemented diets formulated to be moderately limiting in crude protein (18% CP). The barley varieties had comparable mean CP (Condor, 13.8%; CDC Richard, 14.1%) and starch (Condor, 56.4%; CDC Richard, 57.5%), although Condor was somewhat higher in β-glucan content (3.5 vs. 2.8%; P < 0.10). There were no differences (P > 0.05) in body weight or feed conversion among chicks fed the two barleys, indicating that protein utilization was similar in broiler chicks fed Condor and those fed CDC Richard hulless barleys. Key words: Hulless barley, chicks, protein, β-glucanase


1992 ◽  
Vol 72 (4) ◽  
pp. 959-963 ◽  
Author(s):  
G. W. Kazmer ◽  
S. A. Zinn ◽  
H. Rycroft ◽  
R. M. Campbell

A growth hormone-releasing factor (GRF) analog was administered at 11, 22 and 33 μg 100 kg−1 to proven dairy sires of varying genetic merit for production traits. Administration of GRF increased mean GH concentrations, but the area under the response curve was not different among the three dosages, nor were there differences between genetic groups overall. However, the maximum GH concentration following the administration of 11 μg 100 kg−1 was greater among superior sires. None of semen motility, sperm concentration or total sperm were affected through an entire spermatogonic cycle. Key words: GRF, growth hormone, semen, dairy bulls


1988 ◽  
Vol 68 (1) ◽  
pp. 311-313 ◽  
Author(s):  
DANY CINQ-MARS ◽  
G. GOULET ◽  
G. J. BRISSON

A 4-wk feeding trial was conducted with castrated piglets weaned between 18 and 21 d of age, and fed either 22, 29 or 17% crude protein isocaloric diets, adjusted to the same calculated content for total lysine, methionine, threonine and tryptophan. Piglets fed the 22 or 19% protein diets had the same feed intake, practically the same growth rate, and the same gain/feed ratio. Those fed the 17% protein diet had the same feed intake, but gained less than those fed the 19% protein diet. Therefore, it seems possible to lower the protein content of a weanling diet from 22 to 19%, provided that lysine, methionine, threonine, and tryptophan are adjusted to the same calculated content. Key words: Piglets, lysine, methionine, threonine, tryptophan


1990 ◽  
Vol 70 (1) ◽  
pp. 309-312 ◽  
Author(s):  
R. N. KIRKWOOD ◽  
P. A. THACKER ◽  
R. S. KORCHINSKI ◽  
B. LAARVELD

Twenty-three prepubertal Yorkshire × Landrace gilts were allocated to receive daily injections of either porcine growth hormone (pGH) or vehicle for 6 consecutive days. At the time of first pGH or buffer injection, all gilts received an injection of 500 IU PMSG. Blood samples were taken by jugular vein puncture at 0, 24 and 48 h then every 12 h until 96 h then every 8 h until 144 h. Samples were assayed for triiodothyronine (T3), insulin, glucose and LH. Treatment with pGH elevated (P < 0.01) serum concentrations of T3, insulin and glucose, and was associated with a reduced (P < 0.05) LH surge height. Fewer pGH-treated than vehicle-treated gilts ovulated (4/12 vs. 7/11), but the difference was not significant. Key words: Gilts, growth hormone, gonadotrophins, ovulation


1991 ◽  
Vol 71 (1) ◽  
pp. 249-251 ◽  
Author(s):  
R. N. Kirkwood ◽  
P. A. Thacker

At weaning (day 0), 120 mixed parity Yorkshire × Landrace sows were allocated in a 2 × 2 factorial arrangement to be fed a 16% crude protein diet at either 1.8 or 3.6 kg d−1 until breeding and to receive either no insulin or insulin (0.75 IU kg−1) on days 1–4, inclusively. There were no significant effects of dietary or insulin treatments on days to rebreeding, farrowing rate or subsequent litter size. Key words: Sow, nutrition, insulin, reproduction


1979 ◽  
Vol 59 (2) ◽  
pp. 367-373 ◽  
Author(s):  
D. G. KELLER ◽  
G. H. COULTER ◽  
V. G. SMITH ◽  
G. J. KING

Serum growth hormone (GH) concentrations were determined in 172 Hereford and 172 Angus bull and heifer calves before weaning and while restricted to the feedlot for 5.5 mo and fed either an 80% concentrate plus 20% roughage or roughage only diet. Blood samples were taken 1 mo before weaning (27 Sept.; T1), 2 mo into the feedlot period (5 Jan.; T2), and 5 mo into the feedlot period (5 Apr.; T3). GH concentrations and ratios of GH to body weight were greater in Angus than in Hereford at all sampling times. GH levels were higher in bulls than heifers 1 mo before weaning and at 5 mo into the feedlot period. However, the ratio of GH to body weight was higher in bulls than heifers only at 1 mo before weaning. The heritability estimates (h2) for GH and GH/100 kg body weight were generally low. The h2 of GH concentration 1 mo before weaning was 0.16 ± 0.13. Calves at 5 mo of age (T1) tended to have higher serum GH concentrations than at 8 (T2) or 11 (T3) mo of age. Age of dam and plane of nutrition had little effect on GH concentrations or its ratio with body weight in the calves, but had various degrees of influence on the performance traits. Correlations among GH and GH/100 kg body weight estimates with performance traits were also generally low. GH levels at the three sampling times that corresponded to 5, 8, and 11 mo of age in young beef bulls and heifers in this study will, apparently, not be a reliable indicator or predictor of the performance of a particular animal in a beef cattle selection program.


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