03511naa a2200277 a 450000100080000000500110000800800410001902400250006010000170008524501260010226000090022850004600023752022620069765000180295965000110297765000110298865300210299965300220302070000200304270000120306270000160307470000150309070000160310570000170312177300950313810508062020-04-29       2012    bl uuuu     u00u1 u    #d7 a10.1071/AN113652DOI1 aVIÑOLES, C.  aLong-term effect of nutrition on the metabolic status and reproductive potential of Merino rams under grazing conditions.  c2012  aHistory article: Received 2 November 2011; accepted 17 March 2012; published online 16 July 2012.Corresponding author.  Acknowledgements: The authors wish to thank the staff of INIA’s Research Station and the studentsin thesis from the Faculty of Veterinary Medicine for their invaluable helpduring the experiment. We wish to thank Marcia del Campo for her input intothe analysis and interpretation of the behavioural data. Email: cvinoles@adinet.com.uy  aTo evaluate the impact of feeding rams for 14 weeks with legumes and supplement on their clinical, behavioural and endocrine responses, 32 Merino rams, 17 months old, were allocated to four groups (n = 8). The 2 · 2 factorial arrangement evaluated the pasture type (IP, improved pasture; NP, native pasture) and the effect of feeding (+S) or not (?S) feeding a supplement. Every 2 weeks liveweight, scrotal circumference and serving capacity were evaluated and blood samples taken to measure the concentrations of metabolites and metabolic hormones. Grazing behaviour was evaluated every 4 weeks. Rams grazing IP (61.8± 0.7 kg) were heavier than those grazing NP (59.6± 0.7 kg; P < 0.05), and +S rams (61.8 ± 0.7 kg) heavier than ?S rams (59.3 ± 0.6 kg; P < 0.05). Compared with rams from the IP+S, IP?S and NP+S, rams grazing NP?S lost weight (P < 0.001) during the experiment. The scrotal circumference was larger in IP+S (30 ± 0.4 cm), IP?S (30±0.4 cm) and NP+S (31±04 cm) than inNP?S (29±0.4 cm; P < 0.001). Only in rams from the group NP+S was a significant increase in scrotal circumference observed during the trial (P < 0.05). The supplement tended to maintain the mating potential elevated towards the end of the experiment (+S: 74.3 ± 5.4 and ?S: 61.7 ± 6.3 ewes/ram; P = 0.07). Supplemented rams were less frequently seen grazing (47 ± 3%) than non-supplemented rams (57 ± 4%; P = 0.09). Rams grazing IP ruminated more frequently (13 ± 2%) than those grazing NP (9 ± 2%; P < 0.001). Events such as lying down, playing, self-grooming and drinking water were more frequent in supplemented (36 ± 2%) than on-supplemented rams (30±2%; P= 0.09). The supplement increased the concentrations of insulin and glucose and decreased the concentrations of non-esterified fatty acids, albumin and urea (P<0.05). IP increased the concentrations of insulin-like growth factor-I, protein, albumin and urea and tended to increase the concentrations of insulin.Weconclude that feeding Merino rams a high plane of nutrition reduced the frequency of grazing events and stimulated a long-term improvement of the metabolic status, evidenced by an increase in liveweight and scrotal circumference, with relevant implications for their mating potential.  aALIMENTACIÓN  aMERINO  aOVINOS  aANIMAL NUTRITION  aANIMAL PRODUCTION1 aDE BARBIERI, I.1 aGIL, J.1 aOLIVERA, J.1 aFIERRO, S.1 aBIALADE, F.1 aMONTOSSI, F.  tAnimal Production Science, 2012gv. 52, no.10, p. 881-889. https://doi.org/10.1071/AN11365