Bibliographic citations
Sessarego, E., (2017). Edad al primer parto y productividad lechera de la raza Holstein en la costa central de Perú (2003-2012) [Tesis, Universidad Nacional Agraria La Molina]. https://hdl.handle.net/20.500.12996/2921
Sessarego, E., Edad al primer parto y productividad lechera de la raza Holstein en la costa central de Perú (2003-2012) [Tesis]. : Universidad Nacional Agraria La Molina; 2017. https://hdl.handle.net/20.500.12996/2921
@mastersthesis{renati/1114846,
title = "Edad al primer parto y productividad lechera de la raza Holstein en la costa central de Perú (2003-2012)",
author = "Sessarego Dávila, Emmanuel Alexander",
publisher = "Universidad Nacional Agraria La Molina",
year = "2017"
}
Records of 4,215 cows, from nine dairy herds at Lima region, registered in the Dairy Productivity Service conducted by the Animal Research and Social Improvement Program of the National Agrarian University La Molina (PMA-UNALM), collected between January 2003 and December 2012, were analyzed to determine the effect of age at first calving (AFC) on standardized milk production (SMP) and calving interval (CI) The information was analyzed using descriptive statistics and a mixed linear model, using the statistical package SAS 9.4 The mean AFC found was of 24.89 ± 2.34 months; and the mean SMP for the first lactation was 8,275.72 ± 1,471.10 kg, whereas for the second lactation it was 9,068.53 ± 1,746.98 kg. The mean CI, between the first and second and between the second and third calving were 437.22 ± 93.69 and 447.39 ± 94.40 days, respectively. AFC influenced the SMP (P = 0.0008), but not CI (P = 0.3969). Also, significant differences (P <0.01) were found between lactations, between seasons and between years, for the two traits under study. It was concludedthat higher SMP and lower CI were observed at intermediate ages, between 22 and 30 months, so that the optimal AFC would be around 22 months, which would maximize the productive, reproductive and economic yield of dairy cows.
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