Ovulation and ovulation rate in ewes under grazing conditions: factors affecting the response to short-term supplementation

The relationships between ovulation rate and nutrition remain confused, probably because of uncontrolled variation in experimental conditions. To help resolve the problem, we analyzed data from 20 experiments conducted 2002 2016, Uruguay with grazing ewes. All were carried out by a single laboratory under comparable conditions design measured variables. studies used total 3 720 ewes, purebred Corriedale, Polwarth, or East Friesian x Polwarth genotypes. In all experiments, control group grazed native pastures extra was provided to treatment groups using either improved supplements. Ovulation counting corpora lutea laparoscopy rectal ultrasound foetuses at on day 45 gestation. For statistical analysis, grouped according nutritional (control supplemented) and, within these groups, type supplement provide energy protein (protected not rumen degradation). Across 92–99% ewes ovulated effects diet, length supplementation, initial live weight genotype are reported. Within diets, most affected overall intake during supplementation (P < 0.01). Ewes that supplemented supplements had higher rates 0.05) than only pastures. addition tannins supplement, protect it degradation rumen, did further increase rate. unsupplemented access legume pastures, when pasture rich although tanniniferous legumes marginally 0.05). When energy, their above those nonsupplemented Live start also We conclude intake, whereas factors short-tern highly digested dietary protected ruminal degradation.