title: Short-term supplementation with maize increases ovulation rate in goats when dietary metabolizable energy provides requirements for both maintenance and 1.5 times maintenance.
abstract: This study aimed to evaluate ovarian follicular dynamics in goats submitted to synchronization of estrus and supplemented with diets that differed in the metabolizable energy source and amount of energy. The experiment was carried out using 42 does allocated into three treatments, fed for 9 days with a ration providing 1.0 times maintenance containing maize (1 MM, n = 14) or without maize (1 M, n = 14) or a ration providing 1.5 times maintenance containing maize (1.5 MM, n = 14). Estrus was synchronized with two injections of cloprostenol given 7 days apart. Does were also treated with intravaginal progesterone inserts and eCG. The number of ovulations and size of the follicles were measured using ultrasonography on Days 10, 11, and 12 after the start of the dietary treatment. The interval to estrus and duration of estrus did not differ between treatments (P = 0.382). Does fed with 1 and 1.5 MM had a similar number of ovulations but a greater number of ovulations than goats fed with 1 M (P = 0.028). The mean number of small, medium, large, and total number of follicles on Days 10 to 12 of ultrasound evaluations did not differ (P = 0.204) between treatments, but mean numbers changed over time (P < 0.001). The mean frequency and amplitude of LH pulses and concentrations of glucose, insulin, leptin, and insulin growth factor-1 in plasma were not significantly affected (P > 0.258) by any of the treatments. In summary, the inclusion of maize in the ration can stimulate ovulation rate at maintenance level. Similar results between groups fed diets that included maize and provided metabolizable energy at 1.0 and 1.5 maintenance demonstrate that to increase the ovulation rate when synchronizing estrous cycles in does, dietary supplementation with maize can be restricted to provide a maintenance level of metabolizable energy only, which would reduce dietary costs.
authors.affiliation: Animal Production and Reproduction, Embrapa Semiárido, Petrolina, Brazil; College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, Australia. Electronic address: daniel.nogueira@embrapa.br.
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Nogueira
authors.affiliation: College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, Australia.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Eshtaeba
authors.affiliation: College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, Australia.
authors.forename: John
authors.initials: J
authors.lastname: Cavalieri
authors.affiliation: College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, Australia.
authors.forename: Lee A
authors.initials: LA
authors.lastname: Fitzpatrick
authors.affiliation: College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, Australia; Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa.
authors.forename: Bruce
authors.initials: B
authors.lastname: Gummow
authors.affiliation: School of Animal Biology/Institute of Agriculture, University of Western Australia, Crawley, Western Australia, Australia.
authors.forename: Dominique
authors.initials: D
authors.lastname: Blache
authors.affiliation: College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, Australia; Department of Animal Science, The Ohio State University, Wooster, Ohio, USA.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Parker
mesh_terms: D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D004032:Diet / Q000662:veterinary; D004973:Estrus Synchronization; D005260:Female; D006041:Goats / Q000502:physiology*; D006080:Ovarian Follicle / Q000502:physiology; D010060:Ovulation / Q000502:physiology*; D003313:Zea mays
keywords: Breeding season; Corn; Follicular dynamics; Reproduction