Fecha/hora: 30/05/2024 07:49:14

Biblioteca(s): 	INIA La Estanzuela.	
Fecha corriente: 	02/10/2017	
Fecha de la última actualización: 	05/11/2019	
Autoria: 	DAMIAN, J.P.; HÖTZEL, M.J.; BANCHERO, G.; UNGELFERD, R.	
Afiliación: 	JUAN PABLO  DAMIAN, UdelaR (Universidad de la República), FVET ( Facultad de Veterinaria), Montevideo, Uruguay.; MARIA JOSÉ HÖTZEL, Laborat#1;orio de Etologia Aplicada e Bem-Estar Animal, Departamento de Zootecnia e Desenvolvimento Rural, Universidade Federal de Santa Catarina, Florian#1;opolis, Brazil.; GEORGGET ELIZABETH BANCHERO HUNZIKER, INIA (Instituto Nacional de Investigación Agropecuaria), Uruguay; RODOLFO  UNGELFERD, RODOLFO UNGERFELD, UdelaR (Universidad de la República), FVET ( Facultad de Veterinaria), Montevideo, Uruguay.	
Título: 	Competition for oestrous ewes between rams reared by their mothers or artificially reared: Effects on sexual behaviour and testosterone and cortisol serum concentrations.	
Año de publicación: 	2017	
Fuente/Imprenta: 	Theriogenology, v.100, p. 134-138, 2017.	
DOI: 	doi.org/10.1016/j.theriogenology.2017.06.009	
Idioma: 	Inglés	
Notas: 	Article history: Received 4 November 2016//Received in revised form 5 June 2017//Accepted 6 June 2017//Available online 8 June 2017.	
Contenido: 	A b s t r a c t:
The objective of this study was to determine how the social competition for an oestrous ewe affects the
sexual behaviour and the endocrine response in two groups of rams, one reared by their mothers and
another artificially reared. Thus, we compared the sexual behaviour and testosterone and cortisol
changes in each group of rams in competitive and non-competitive tests, both during the first and second
breeding seasons. Two groups of rams were: 1) artificially reared lambs, separated from their dams 24
e36 h after birth (Week 0) and artificially fed with sheep milk until 10 weeks of age (group AR, n ¼ 14);
and 2) lambs reared by their dams until 10 weeks of age (group DR, n ¼ 13). Rams were subjected to noncompetitive
and competitive tests for an oestrous ewe during their first and second breeding seasons,
when they were 8 and 20 months old, respectively. Sexual behaviours toward an oestrous ewe were
recorded during 20 min and the testosterone and cortisol concentrations were determined in serum
samples collected immediately before the test, and 20, 40 and 60 min after it. During the first breeding
season, the number of flehmen decreased in DR rams, and the number of flehmen and ano-genital
sniffings also decreased in DR rams, but the frequency of some copulatory behaviours increased (matings
and ejaculation/total mounts in DR rams, and total mounts in AR rams) in competitive tests. During
the second breeding season, competition caused a decrease in the number of all the recorded behaviours
(courtship and copulation) with the exception of flehmen in AR rams; however, in DR rams only the
number of the copulatory behaviours decreased under competition. Competition did not affect the
endocrine response during the first breeding season. During the second breeding season, while testosterone
concentrations were greater in non-competitive than in competitive tests at 60 min (P ¼ 0.0008)
in AR rams, in DR rams it tended to be greater (P ¼ 0.09). Competition did not affect cortisol concentrations
in any group or season, but in all tests the concentrations increased at the end of the test
(P < 0.05). In conclusion, the lack of the mother during rearing negatively affected the sexual motivation
and the testosterone response of rams to oestrous ewes in competitive tests, effects that were more
evident when adults. Neither the absence of the mother during rearing nor competition for oestrous
ewes affected the stress response (evidenced by increase in cortisol concentration) in rams during both
seasons.	
Palabras-Clave: 	CORTISOL; MOTHER-OFFSPRING; SHEEP; STRESS; TESTOSTERONE.	
Thesagro: 	OVEJA.	
Categoría del tema: 	--	
Registro original: 	INIA La Estanzuela (LE)	
Ejemplares: 	LE - (102221-1) - PXI - AP - DD -  -  -  - DIS