DOI: 10.5593/sgem2017/61/S25.145


R.C. Manea, L. Manea
Tuesday 12 September 2017 by Libadmin2017

References: 17th International Multidisciplinary Scientific GeoConference SGEM 2017, www.sgem.org, SGEM2017 Conference Proceedings, ISBN 978-619-7408-12-6 / ISSN 1314-2704, 29 June - 5 July, 2017, Vol. 17, Issue 61, 1111-1116 pp, DOI: 10.5593/sgem2017/61/S25.145


The research conducted at farms in mountain areas have shown that the average age at first calving is 849.15 days (28 months and 5 days). The variability of this index is extremely large with the minimum of 570 days (19 months) and a maximum of 1350 days (45 months). It follows that the average age at first breeding would be 18 months and 10 days. At first glance this figure fits perfectly within the limits recommended by the literature, but the reality is different. Because of the desire to have the calving group against grazing, insemination the heifers are at the younger age of 18 months, few matings are made at 18 months.

The two peaks in the graphical presentation of the variability of age at first calving and calculating statistical parameters show correctness of the statement. The first peak is given by the inseminated calved at less than 18 months of age and the second of the ones inseminated too late. The distance between the two peaks is 390 days, corresponding to the delay of the insemination of the calves with one year. The standard deviation (s) is of 159.48 days, and the coefficient of variation (V%) is 18.78. The standard deviation from the mean (± SX) is 12.45 days. The high value of the coefficient of variability as well as the standard deviation is due to the presence of the two peaks of the variation string that was previously discussed. Premature insemination of heifers at an early age and its delay is damaging for cattle breeder generating significant economic losses.

Keywords: insemination, heifers, cattle breeder, variance, standard deviation.