Type

Journal Article

Authors

D.A Kenny
Patrick Lonergan
M.A Crowe
H Sauerwein
C Urh
A.M English
Seán Fair
C.J Byrne

Subjects

Veterinary

Topics
follicle stimulating hormone growth and development igf 1 calf hood nutrition puberty hypothalamus insulin endocrinology

Effect of breed, plane of nutrition and age on growth, scrotal development, metabolite concentrations and on systemic gonadotropin and testosterone concentrations following a GnRH challenge in young dairy bulls (2017)

Abstract The full text of this article will not be available on ULIR until the embargo expires on the 3/4/2018 The onset of puberty in the bull is regulated by the timing of early GnRH pulsatility release from the hypothalamus, which has been demonstrated to be affected by plane of nutrition during calf-hood. The aim of this study was to determine the effect of plane of nutrition on growth rate, scrotal development, metabolite concentrations and exogenous gonadotrophin (GnRH) induced release of luteinizing hormone (LH), follicle stimulating hormone (FSH) and testosterone (TT) in pre-pubertal bulls of two contrasting dairy breeds. Holstein-Friesian and Jersey bull calves were assigned to either a high or low plane of nutrition from 3 to 49 weeks of age. Intensive blood sampling was conducted at 16, 24 and 32 weeks of age, every 15 min from 30 min prior to intravenous administration of exogenous GnRH to 135 min after. Monthly blood samples were also collected and analyzed for insulin like growth factor 1 (IGF-1), insulin, leptin, adiponectin and metabolite concentration. Insulin and IGF-1 were higher in bulls on a high plane of nutrition (P < 0.001) but were not affected by breed (P > 0.05). Leptin was not affected by plane of nutrition or breed (P > 0.05). Adiponectin tended to be higher in bulls on a high plane of nutrition (P = 0.05), but was not affected by breed (P > 0.05). Bulls on a high plane of nutrition had a greater concentration of LH in response to GnRH (P < 0.05) but there was no effect of breed (P > 0.05). FSH concentration was not influenced by breed or plane of nutrition but FSH concentrations did decrease with age (P < 0.01), while, LH was not affected by age (P > 0.05). Jersey bulls, particularly those on a high plane of nutrition, had higher TT production in the pre-pubertal period (P < 0.001). Using 28 cm as a proxy for age at puberty, bulls on a high plane of nutrition were predicted to reach puberty earlier than bulls on a low plane. In conclusion, the data clearly demonstrate that a high plane of nutrition positively affects several key nutritional and reproductive hormones which are critical to the endocrinological functionality of the hypothalamic-pituitary-testicular axis in dairy-bred bull calves.
Collections Ireland -> University of Limerick -> Biological Sciences
Ireland -> University of Limerick -> Faculty of Science and Engineering
Ireland -> University of Limerick -> Departments Science and Engineering

Full list of authors on original publication

D.A Kenny, Patrick Lonergan, M.A Crowe, H Sauerwein, C Urh, A.M English, Seán Fair, C.J Byrne

Experts in our system

1
D.A. Kenny
Teagasc
Total Publications: 138
 
2
P. Lonergan
University College Dublin
Total Publications: 190
 
3
M A Crowe
University College Dublin
Total Publications: 101
 
4
A M English
Teagasc
Total Publications: 11
 
5
Seán Fair
University of Limerick
Total Publications: 54
 
6
C J Byrne
Teagasc
Total Publications: 11