Reproductive and lactational responses and serum growth hormone and insulin in fine-wool ewes treated with ovine growth hormone

1988 ◽  
Vol 46 (2) ◽  
pp. 195-202 ◽  
Author(s):  
D. W. Holcombe ◽  
D. M. Hallford ◽  
W. C. Hoefler

AbstractEighteen mature (3 to 6 years) Debouillet × Rambouillet ewes (mean weight 79·2 (s.e. 21) kg) producing and nursing single offspring were randomly allotted to one of three groups to examine the influence of ovine growth hormone (oGH) on reproductive, hormonal and lactational responses of springlambing ewes. Each ewe received a daily subcutaneous injection of either 0, 5 or 10 mg oGH from day 11 through to day 20 post partum (day 0 = parturition). Treatment groups were subdivided into two pens (three ewes per pen) and food intake was monitored from day 1 through to day 20 post partum. On days 11 and 20 post partum, jugular blood samples were collected before and hourly for 8 h after treatment. Blood samples were also collected daily from day 10 through to day 21 post partum and on alternate days through to day 40 post partum. Milk production (oxytocin-induced hand milking) and fat and protein concentrations were determined 21 days post partum. Food intake did not differ before or during the treatment period (P > 0·05). Likewise, ewe and lamb weights were similar among treatment groups through to day 60 post partum (P > 0·05). Serum insulin did not differ before or after treatment on day 11 (P > 0·05); however, on day 20 before treatment, serum insulin was significantly higher in ewes receiving 5 (2·3 (s.e. 0·3) μg/I) and 10 (2·4 (s.e. 0·3) μg/1) mg oGH than in controls (1·2 (s.e. 0·3) μg/1) (P < 0·05). After treatment, no differences were detected in serum insulin among treatments on day 20 post partum (P > 0·05). Serum growth hormone (GH) was similar among groups before treatment on day 11 post partum; but by 8 h after treatment, serum GH was significantly elevated in ewes receiving 10 mg oGH (32·4 (s.e. 1·9) μg/1) compared with ewes receiving 5 (13·9 (s.e. 1·9) μg/1) or 0 (4·5 (s.e. 1·9) μg/1) mg oGH (P < 0·01). By 20 days after lambing, serum GH differed significantly among groups both before and after administration of exogenous oGH (P < 0·01). Ewes receiving 5 or 10 mg oGH produced 2·3 (s.e. 0·2) kg milk per day compared with 1·9 (s.e. 0·2) kg/day for controls (P < 0·10). Milk fat and protein concentrations did not differ significantly among treatments (P > 0·05), but total fat yield was higher in ewes receiving either dose of oGH (206 (s.e. 20) g/day) compared with control ewes (141 (s.e. 20) g/day) (P < 005). Serum progesterone remained less than 0·5 μg/1 in ewes through to day 40 post partum. A linear decrease was observed in interval from parturition to first observed oestrus as dosage of oGH increased (116, 108 and 102 (s.e. 6) days for ewes receiving 0, 5 and 10 mg oGH, respectively; P = 0·10). Administration of exogenous oGH to lactating. anoestrous ewes between days 11 and 20 post partum enhances milk production and may influence the interval to oestrus.

1996 ◽  
Vol 63 (2) ◽  
pp. 297-306 ◽  
Author(s):  
C. M. Carroll ◽  
P. B. Lynch ◽  
M. P. Boland ◽  
L. J. Spicer ◽  
F. H. Austin ◽  
...  

AbstractThe objective of this study was to investigate the effect of low food intake on post-weaning fertility and hormone concentrations in primiparous sows. One hundred and forty primiparous sows (Landrace × Large White) were randomly assigned to one of four treatment groups: (A) restricted to 3 kg food per day during lactation and 2 kg food per day post weaning (no. = 36); (B) restricted to 3 kg food per day during lactation and ad libitum feeding post weaning (no. = 33); (C) ad libitum feeding throughout with a mean voluntary food intake of 3·7 kg/day during lactation (no. = 36); and (D) ad libitum feeding throughout with a mean voluntary food intake of 4·9 kg/ day during lactation (no. = 35). Litters were standardized at eight to 10 pigs at 2 days post partum and were weaned at 27·2 (s.e. 0·5) days post partum. After weaning, sows were observed twice daily for signs of oestrus and were mated on the day(s) of standing oestrus. Six sows from each group were fitted with indwelling jugular cannulae 2 days before weaning. Blood samples were collected 1 day before weaning (W−l), 1 day after weaning (W+l) and 4 days after weaning (W+4), and these sows were slaughtered on W+4. Ovaries were recovered, follicles and corpora lutea were counted, and folUcular fluid collected. Sows given food at a restricted level (groups A and B) lost more backfat during lactation than sows given food ad libitum (groups C and D) (P < 0·01). Piglet weaning weights, weaning to conception intervals and the proportion of sows ovulating by W+4 were not significantly different among groups. In sows that did not ovulate, numbers of large follicles were not significantly different among groups but the low food intake (groups A, B and C) sows had more medium-sized follicles than high food intake (group D) sows (P < 0·01). FolUcular fluid concentrations of oestradiol, progesterone and insulin-like growth factor-1 (IGF-1) did not differ among groups (P > 0·05). Plasma non-esterified fatty acids concentrations were greater in groups C and D than in groups A and B on W−l, W+l and W+4. Serum insulin and plasma glucose concentrations were lower in groups C and D than in groups A and B on W−l and W+l, but were similar among groups on W+4. Serum growth hormone concentrations were lower in group D than group A and B on W−l and W+l but not W+4. Concentrations of IGF-1 in serum were greater in groups C and D than groups A and B on W−l and W+l but not W+4. It is concluded that low food intakes during lactation and post weaning affected body condition, serum hormones and metabolites and ovarian function of primiparous sows without dramatically affecting ovarian hormones or reproductive performance.


1977 ◽  
Vol 233 (5) ◽  
pp. E430
Author(s):  
R A Steiner ◽  
P Illner ◽  
P Marques ◽  
D Williams ◽  
L Shen ◽  
...  

The effects of thyrotropin-releasing hormone (TRH) and dopamine (DA) on serum growth hormone (GH) levels were examined in the adolescent male baboon. Intravenously administered DA (40 microgram/kg-min-1 for 20 min) raised serum GH and glucose and lowered serum insulin concentrations but caused no increase in blood pressure. Concomitant intravenous infusion of TRH at 2 doses (96 ng/kg-min-1 and 40 microgram/kg-min-1 for 20 min) blocked the DA-induced increase in serum GH. The relatively low effective doses of TRH used to suppress the DA-induced GH increase suggest an interaction with catecholamines at the hypothalamic and/or pituitary to influence GH release.


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.


2011 ◽  
Vol 78 (3) ◽  
pp. 308-317 ◽  
Author(s):  
Ian Hutchinson ◽  
Michael J de Veth ◽  
Catherine Stanton ◽  
Richard J Dewhurst ◽  
Pat Lonergan ◽  
...  

Conjugated linoleic acid (CLA) reduces mammary milk fat synthesis in a dose-dependent manner. Our objective was to determine the effects of lipid-encapsulated CLA (LE-CLA) supplementation on milk production, reproductive performance and metabolic responses in lactating dairy cows fed a grass silage-based diet. Seventy-two Holstein-Friesian cows (32 primiparous and 40 multiparous) were used in a completely randomized block design. Cows received either 80 g of LE-CLA daily or 60 g of calcium salts of palm fatty acids daily (control) from parturition until 60 days in milk. LE-CLA contained a 50:50 mix of cis-9,trans-11 CLA and trans-10,cis-12 CLA, resulting in a daily intake of 6 g of each isomer. Milk production and dry matter intake were recorded daily, and blood samples were collected 3-times a week. Blood samples were analysed for circulating concentrations of glucose, non-esterified fatty acids (NEFA), β-hydroxybutyrate (BHBA), insulin and insulin-like growth factor-I (IGF-I). Progesterone was measured in blood samples collected after the first post-partum insemination. Ovarian ultrasound examinations commenced at 8–10 d post partum and were carried out 3-times a week until first ovulation. LE-CLA treatment resulted in decreased milk fat concentration, with consequent improvements in energy balance and body condition score (BCS). The peak concentration of NEFA in blood was reduced by LE-CLA, but circulating concentrations of insulin, glucose, IGF-I, BHBA and progesterone were not affected. There was no effect of LE-CLA supplementation on the post-partum interval to first ovulation. Services per conception tended to be reduced. The reduction in milk energy output and improvement in energy status and BCS in LE-CLA-supplemented cows provides a strong rationale for further studies with greater cow numbers to test effects on reproductive performance.


1978 ◽  
Vol 234 (6) ◽  
pp. E611 ◽  
Author(s):  
K T Borer ◽  
R P Kelch

In freely feeding adult hamsters, voluntary exercise induces accelerated somatic growth and increased food consumption that last through several days of retirement. We examined the effects of exercise on serum concentrations of growth hormone (GH) and insulin during ad libitum or restricted intake of food. Serum insulin and GH concentrations were measured by radioimmunoassays in exercising, retired, or sedentary hamsters during ad libitum or restricted intake of food. Linear growth was delayed in food-restricted, exercising hamsters until they were retired and unlimited food consumption was allowed. Serum GH concentrations were increased during exercise and after retirement; serum insulin concentrations were increased only after retirement during both dietary regimes. In food-restricted hamsters, endocrine changes were noted after 4 h of feeding but not after a 14-h fast. We conclude that 1) in adult hamsters voluntary exercise leads to increased secretion of GH even when ingested nutrients are insufficient to support increased growth, and 2) increased secretion of insulin is not related directly to exercise.


2000 ◽  
Vol 51 (4) ◽  
pp. 515 ◽  
Author(s):  
M. R. Shariflou ◽  
C. Moran ◽  
F. W. Nicholas

The occurrence of the Leu127/Val127 variants of the bovine growth hormone (bGH) gene and their effect on milk production traits was investigated in Australian Holstein-Friesian cattle. Animals were genotyped for the Leu127/Val127 variants, with RFLP methodology, using PCR and AluI digestion of PCR products (AluI-RFLP). Alleles Leu127 and Val127 occurred with frequencies of 82% and 18%, respectively. The quantitative effect of this polymorphic site on milk-production traits was estimated from lactation data and test-day data. Results from the 2 data sets consistently showed that the Leu127 allele is associated with higher production of milk, fat, and protein and is dominant to Val127. The average effects of the gene substitution are 95 L for milk yield, 7 kg for fat yield, and 3 kg for protein yield per lactation. This locus may be directly responsible for quantitative variation or it may be a marker for a closely linked quantitative trait locus (QTL) for milk-production traits in Australian dairy cattle. In either case, it will be useful as an aid to selection for improvement of milk production traits. As the Leu127 allele is dominant, selection of AI sires homozygous for the Leu127 allele (Leu127/Leu127) will result in maximum benefit without the need for genotyping cows.


1983 ◽  
Vol 37 (3) ◽  
pp. 345-351 ◽  
Author(s):  
Janet M. Beeby ◽  
H. Swan

ABSTRACTSixteen British Friesian-cross steers of early- or late-maturity types were reared on either a 16- or a 24-month system of production. The steers on the 24-month system were subjected to a reduced nutrient intake during two phases of growth: 1) during early growth when the steers were approximately 9 months old and 2) during a store period when the steers were 13 to 19 months old. Animals on the 16-month system were fed to appetite throughout. Blood sampling was carried out at various periods during growth and serum samples were analysed for growth hormone, insulin, prolactin, glucose and blood urea nitrogen. Serum growth hormone concentrations were elevated during reduced nutrient intake, whilst serum insulin concentrations fell. Serum prolactin followed a seasonal pattern, but was lower in the underfed steers. Serum glucose concentrations also tended to fall during underfeeding, but blood urea nitrogen results were inconclusive. Hormone concentrations were not influenced by the maturity type of the steer, suggesting that the hormones measured are not primarily involved in determining the differential growth patterns in steers of different maturity types.


1985 ◽  
Vol 105 (2) ◽  
pp. 189-196 ◽  
Author(s):  
I. C. Hart ◽  
P. M. E. Chadwick ◽  
S. James ◽  
A. D. Simmonds

ABSTRACT Although it is well known that exogenous bovine GH (bGH) increases milk yield in ruminants it has not been possible to determine whether an increase in endogenous GH secretion has the same effect. The recent isolation of human pancreatic GH-releasing factor (hpGRF-44) has enabled this comparison of the effects of bGH and hpGRF-44 on milk production in sheep. Three pairs of Dorset ewes underwent three 4-day treatments according to a Latin square design. Treatment 1 involved: 2-hourly i.v. injections (∼ 3·0 ml) of bGH (15 μg/kg; 1·8 units/mg); treatment 2: 2-hourly i.v. injections (∼3·0 ml) of hpGRF-44 (0·6 μg/kg); treatment 3: 2-hourly i.v. injections (3·0 ml) of the vehicle. Treatment periods were separated by 10 days. Sheep were milked twice daily and the milk was analysed for fat, protein and lactose. Blood samples (5·0 ml) were taken before and at 15, 45, 75 and 100 min after every third injection throughout the 4 days. Plasma was analysed for insulin, glucose, urea and non-esterified fatty acids (NEFA). The changes in plasma GH stimulated by hpGRF-44 were consistent and repeatable throughout the 4 days of treatment. In comparison to the controls, treatment with hpGRF-44 and bGH significantly increased average plasma GH (μg/l) for the 4 days (control, 5·7±0·2 (s.e.m.); hpGRF-44, 12·3±0·4, P<0·001; bGH, 14·5±0·5, P<0·001), and this was accompanied by similar increases in milk yield (hpGRF-44, 26·7±2·6%, P<0·001; bGH, 30·7±2·9%, P<0·001) and the concentration of milk fat (g/kg) (control, 28·6±0·5; hpGRF-44, 33·2±0·5; bGH 34·8±1·5, P<0·01 for both treatments). The post-treatment decline in milk yield was much slower after hpGRF-44 than after bGH injections. Both treatments stimulated significant increases in the average concentrations of plasma insulin, glucose and NEFA, and plasma urea was significantly reduced by treatment with bGH only. It is concluded that raising endogenous GH secretion is equally as effective as exogenous bGH in stimulating milk production in sheep. J. Endocr. (1985) 105, 189–196


1993 ◽  
Vol 129 (5) ◽  
pp. 409-413 ◽  
Author(s):  
Katharina M Main ◽  
Jörgen Lindholm ◽  
Mark Vandeweghe ◽  
Niels E Skakkebaek

The biochemical assessment of disease activity in acromegaly still presents a problem, especially in treated patients with mild clinical symptoms. We therefore examined the diagnostic value of the measurement of urinary growth hormone (GH) excretion in seventy unselected patients with acromegaly of different activity by comparing it to serum GH, serum insulin-like growth factor I (IGF-I) and clinical activity. There were highly significant, positive correlations between urinary GH and serum GH, serum IGF-I as well as clinical activity score (p<0.00005), although some overlap between the groups was observed. In seven patients with low serum GH values (<2.0 μg/l) discordant results were found. Two of the seven patients were clinically mildly active, but only IGF-I was either elevated or within the upper normal range; in three other patients who appeared clinically cured either IGF-I (N = 1) or urinary GH (n = 2) alone were increased. In the remaining two patients elevated serum IGF-I and urinary GH as well as activity score suggested disease activity. Thus, in the majority of cases, urinary GH was significantly correlated to the other three parameters, but added little information to that obtained by serum IGF-I. In conclusion, urinary GH measurements in difficult cases may provide a more direct information on the GH status than IGF-I.


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