Records of 234 lactations from F1 Holstein x Gyr daughters of proven bulls were used in this study for the evaluation of productive and reproductive characteristics of cows. Data were collected from a private farm located in the municipality of Santo Antônio do Monte, MG, Brazil. The objective of this study was to evaluate the effects of Holstein bull’s PTA milk (predicted transmitting ability) calving year, season, and parity on the productive and reproductive characteristics of F! cows. The productive characteristics analyzed were total milk production (TMP), average daily production (ADP), days in milk (DIM), and milk yield per day of calving interval (MYDCI). The studied reproductive characteristics were service interval (SI), calving interval (CI), and gestation length (GL). The results were subjected to statistical analysis and means for significant effects were compared using Duncan’s test at a significance level of 5%. F1 animals efficiently expressed their genetic potential for milk production with an average total milk production of 7842.61 kg and average daily production of 24.53 kg. Means for days in milk, milk yield per day of calving interval, service interval, calving interval, and gestation length were 322.52 days, 20.73 kg, 106.0 days, 383.23 days, and 276.18 days, respectively. Properly managed F1 Holstein x Gyr daughters of proven bulls fed a balanced diet efficiently expressed their genetic potential for milk production without adverse effects on reproduction. Moreover, Holstein x Gyr cows should be selected based on parents’ PTA for milk traits and other factors such as environmental conditions and management.

在这项研究中，使用了F1 Holstein x Gyr公认公牛的女儿的234次泌乳记录来评估奶牛的生产和生殖特性。数据是从位于巴西MG的SantoAntôniodo Monte市的一个私人农场收集的。这项研究的目的是评估荷斯坦公牛的PTA产犊（预测的传播能力）产犊年，季节和胎次对F！的生产和生殖特性的影响！牛。分析的生产特性是总产奶量（TMP），平均日产量（ADP），产奶天数（DIM）和每天产犊间隔的产奶量（MYDCI）。研究的生殖特性是服务间隔（SI），产犊间隔（CI）和妊娠期（GL）。对结果进行统计学分析，并使用邓肯检验以5％的显着性水平比较显着效果的平均值。F1动物有效地表达了其产奶的遗传潜力，平均总产奶量为7842.61公斤，平均日产量为24.53公斤。平均产奶天数，产犊间隔，服务间隔，产犊间隔和妊娠长度的每天产奶量分别为322.52天，20.73公斤，106.0天，383.23天和276.18天。正确管理的F1荷斯坦公牛和吉尔的成年公牛的女儿饲喂均衡饮食，可以有效地表达其产奶的遗传潜力，而不会对繁殖造成不利影响。此外，