Small Ruminant Research 57 (2005) 277–280 Technical note Preantral follicular development in Massese lambs born during two seasons of the year D. Rondina a,∗ , V.J.F. Freitas a , C.A. Amorim a , A. Mafucci b , S. Conti b , R. Cecchi b , N.R.O. Paula a , A. Martini c a Faculdade de Veterin´ aria, Universidade Estadual do Cear´ a, Av. Paranjana, 1700 C.d. Itaperi, Fortaleza, CEP 60740-000, Brazil b Facolt` a di Scienze Matematiche Fisiche e Naturali, Universit` a di Firenze, Via Romana 7, Firenze 50125, Italy c Dipartimento di Scienze Zootecniche, Universit` a di Firenze, Via delle Cascine 5, Firenze 50144, Italy Received 7 March 2003; received in revised form 8 July 2004; accepted 21 July 2004 Abstract The aim of this work was to evaluate the influence of season of birth on the development of the preantral follicular population in Massese lambs. The ovaries of 30 lambs (15–30 days old) were collected at a local slaughterhouse from May to June (M–J) (n = 15) and from October to November (O–N) (n = 15). The research was conducted in Tuscany (Italy), a region characterized by a Mediterranean climate, with a nutritional and photoperiodic peak in the spring (March–June) and a decrease during summer–autumn (August–November). The lamb ovaries were submitted to quantitative and qualitative hystological analyses. Results in the M–J group showed an increase of primary follicles (P < 0.05), and a lower number of primordial populations, compared to the O–N (P < 0.05) group. In the O–N group, qualitative analysis showed a significant (P < 0.05) reduction in follicle size, oocyte size and number of granulosa cells, in the primary and secondary follicle classes, when compared to the M–J group. It was concluded that the autumn season of birth negatively affected the preantral follicular population in Massese lambs. © 2004 Elsevier B.V. All rights reserved. Keywords: Preantral follicle; Massese; Lamb; Season 1. Introduction Environmental cues (i.e. feeding, photoperiod) are important for pregnancy success and the subsequent development of the offspring (Bassett, 1992; Robinson ∗ Corresponding author. Tel.: +55 85 2992761; fax: +55 85 2992740. E-mail address: davide@uece.br (D. Rondina). et al., 1999). At high latitudes (>40 ◦ ), sheep have de- veloped seasonal breeding patterns that maximize the chances for survival of both the mother and offspring (Lindsay, 1996). Maternal nutrition in sheep has been shown to play an important role during fetal oogen- esis (Borwick et al., 1997), while season also affects the placental and fetal mass (McCoard et al., 1997) — as well as plasma prolactin concentrations and the achievement of sexual maturity (Bassett, 1992). Both 0921-4488/$ – see front matter © 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.smallrumres.2004.07.011