For an effective, in determining the index „Calving Interval“ we take into consideration the two components of each interval: service period (SP) and duration of gestation (DG). In order to obtain the optimal interval between calving (365 days) the cow should become gestant at 81 days after calving, because along with 284-285 days, length of gestation, to provide 305 days for normal lactation and 60 days for the rest of the breast enough for the formation of the udder for the next lactation.
The frequency curve has a single peak, 43.5% placed around 361 days after which the frequencies fall along a period of time long enough. The probably average of „CI“ of 360 days, which corresponds to the class with highest frequency, shows that the fecundity is good and that it can provide a rest for brest for 55 days in the case of normal lactations of 305 days.
The 42 days difference between the arithmetic mean of the „CI“ (402 days ago) and the likely media (360 days) is caused by the presence of breeding disorders. The large values of the coefficient of variance is due to the very long ranges as well as very short intervals of calving interval.
The production of milk, the quantity of fat respectively constitute the main criterion of assessment of dairy cows in the mountain area and downhill. The average performance in the succession of eight lactations per total lactation is 3420.67 kg, and per normal lactation is 3209.20 kg milk. The limits vary between 1506 kg of milk and 8835 kg milk recorded for lactation and 1506 kg of milk and 7322 kg milk for normal lactation. The study of statistical parameters of index of the total duration of lactation allows us to affirm that the cows from the herd studied have the genetic potential to increase lactation beyond the limits of normal lactation of 305 per days. Milk production per day is higher with + 0.45 kg per total lactation than normal lactation. Extension of lactation and breast resting shortening represents loss of milk production in both current lactation and the next lactation. To estimate the effect of localities was used the analysis of variance within samples. Raw data tables have been processed to create tables of variances between herds of the 6 localities and within the herd in each locality. The influence of the locality on the milk production is null.
The output production of milk cows has as enablers: daily output and duration of lactation on her. The raise of the productive cows milk level in the mountain area and hence income breeders is achievable through the integration and expansion of biotechnology.