Abstract 478

Peron,-N; Tarrero,-R; Morales,-JR

Centro de Investigacion para el Mejoramiento Animal, Cuba.

Memoria,-Asociacion-Latinoamericana-de-Produccion-Animal. 1981, 16, 126; Proceedings of the 8th Meeting of the Latin American Association of Animal Production, held in the Dominican Republic on 8 Oct. 1981.

Between the ages of 9 and 13 months, 40 Holstein-Friesian heifers were fed (1) forage supplemented with 1 kg concentrates per day or (2) molasses and urea ad lib., with restricted forage, plus 250 g fish meal per day. In the 2 groups, age at puberty averaged 496 and 508 days resp., and body weight at puberty averaged 257.3 and 257.5 kg, the differences between the groups being non-significant. Heifers fed molasses had a greater percentage of cycles shorter than 17 days than heifers in the other group. In the 2 groups, cycle length averaged 20.1ñ2.59 and 19.7ñ2.69 days resp., duration of oestrus 19.2ñ8.18 and 17.8 [sic] h, and conception rate was 61.5 and 75.0%. There were interactions (P less than 0.01) between season and diet for levels of blood cholesterol, potassium, magnesium and copper. It was concluded that reproductive performance is not affected by a molasses/urea diet.