Cruz LC, Fernández-Baca S, Alvarez LJA, Pérez RH

Language: English/Spanish
References: 26
Page: 23-27
PDF size: 561.93 Kb.

ABSTRACT

The study was conducted at the Center for Teaching, Research and Extension in Tropical Animal Production of the Faculty of Veterinary Medicine and Animañ Production of the National Autonomous University of Mexico, located in the State of Veracruz at 20°4´N and 97°3´W. Eighty Tabasco ewes were used in order to study the onset of oestrus. The animals were kept grazing 24 hours a day on Star-Grass (Cynodon nlemfuensis) paddocks, where they had free access to shade, water and a mineral mixture. No significant differences were observed in the presentation of oestrus throughout the year. Oestrus cycles had a duration of 16 to 18 days. Some ewes had longer oestrus cycles which lasted 20 to 24 days. Ovulation rates were significantly lower in the ewes served in April (P ‹ 0.05); the ova number per ewe was 1.25, 1.50, 2.0 and 2.0 in April, July, October and January, respectively. A higher number of non-fertilized ova was found after the April service (P ‹ 0.05). Embryo loss was not affected by the season.

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