ContentsMultiple Trait Derivative Free Restricted Maximum Likelihood procedures were uscd to analyse the relationships between persistency and daily milk yield performance. Genetic and phenotypic (co)variances were generated from this analysis to construct full and reduced selection indices, selection subindices and reduced selection sub-indices. The structure of the data consisted of 281 half-sib families and the lactation records in each group ranged between 12-24 records. The expected genetic gain in daily milk yield by selection sub-indices was similar to the corresponding value calculated by selection index, so the breeder can use a selection sub-index in the breeding program to improve daily milk yield. The contribution of persistency to improvement in daily milk yield was higher by sub-index than selection index application. The highest improvement of persistency was associated with the maximum improvement in daily milk yield per lactation and per calving interval and was achieved by a selection index which involved all these traits.

The objective of the study was to examine the effects of mannanoligosaccharide (MOS) or inulin on fourtyfive HF calves' performance and certain physiological parameters. Next to the control group (15 calves, no treatment), 15-15 calves received 18.7 g/calf/day MOS or inulin supplementation with milk replacer from 1st day of age to weaning. Feed intake was measured daily. Body weight was monitored on days 1, 14, 21 and 60. Blood samples were taken on days 30 and 60 to determine clinicochemical parameters Total faecal counts of the main faecal bacteria contents were determined from faecal samples collected on days 15 and 30. Mean feed intake, body weight and daily weight gain were similar in the groups. Inulin caused lower total protein level of the blood. Faecal concentration of total anaerobic bacteria and Lactobacillus was significantly increased by inulin compared to MOS. Inulin caused higher total aerobic bacteria count in faeces compared to control. The germ count of Clostridium perfringens from calves fed inulin was higher than that of other treatments. It should be stated that higher (18.7 g/day/calf) dietary level of inulin or MOS had minor alterations in parameters and failed to significantly modulate performance and physiological parameters of calves.

The objective of this study was to compare the effects of calf starters of different starch and fibre content on the growth, blood and rumen parameters of Holstein female calves during the pre-weaning period. A total of 60 calves were divided into two groups. Group A/B was fed according to a two-phase calf nutrition system: the calves received calf starter “A” (28.5% starch content, 16% neutral detergent fibre (NDF), 9.2% acid detergent fibre (ADF)) in days 7–45 and then calf starter “B” (14.2% starch content, 32.4% NDF, 14.3% ADF) in days 46–70. Calves of group B received calf starter “B” throughout the experimental period. The calves were weaned between 52 and 61 days of life. The data on body weight, weight gain, starter feed intake, blood metabolites and rumen fermentation parameters were collected individually. In the first phase of experiment, the starter feed consumption of A/B group was higher than that of B group (P < 0.05), but it did not manifest in differences in body weight at weaning time. At some of the sampling times, the different composition of starter diets significantly (P < 0.05) influenced the plasma urea, albumin, glucose and triglyceride concentrations. The consumption of diet with different starch and NDF content had no significant effect either on the composition of the rumen microbiota or on the ruminal concentration of volatile fatty acids (VFA) and ammonia. In some cases significant correlations (–0.83 and –0.93; 0.82 and 0.90) were found between the composition of rumen microbiota and ruminal VFA concentration. Feeding a diet of higher starch content (28.5 vs 14.2%) in the first 45 days of life did not affect rumen fermentation, rumen microbiota and the most important blood metabolites, apart from a few exceptions. The production parameters of calves, including total feed intake and body weight gain, were similar in the experiment.

The aim of the reproductive management of dairy farms is to keep low the days in milk (DIM). Milk production can be profitable only in that case. Calvings make only low DIM. From the economic point of view, to evaluate the amount of the calving is not simple because in many cases the insemination and the calving are not in the same year. We wanted to find a reproduction parameter, which is easy to record, available real time, and corrrelate well with other parameters. We collected reproduction data from 21 farms from 2016. Average numbers of cows, number of the ai (artificial insemination) in cows, number of cows pregnancies, open days (OD), service period (SP), time of first ai (TFAI), conception rate of first ai (CRFAI), conception rate of all ai (CRSAI) were collected. The number of the pregnant cows were grouped, pregancies under 120 days after calving -U120- and pregnancies above 200 -A200- days after calving. The economical effect of open days are well-known. OD correlated with the rate of the pregnancies under 120 days after calving (r = -0.802; P ≤ 0.001). The open days correlated with the rate of the pregnancis above 200 days after calving (r = 0.889; P ≤ 0.001). If the rate of U120 is high, the rate of pregnant cows (ROPC) will be high too (r = 0.611; P = 0.003). A200 is in negative relation with ROPC (r = -0.525; P = 0.015). OD correlated with TFAI (r = 0.562; P = 0.008). ROPC correlated with TFAI (r = -0.457; P = 0.037). OD correlated with SP (r = 0.778; P ≤ 0.001). SP is in negative correlation with CRFAI and CRSAI (r = - 0.577, P = 0.006; r = - 0.773, P ≤ 0.001). SP correlated with U120 and A200 (r= - 0.572, P = 0.007; r = 0.788 P ≤ 0.001). Our study shows that the rate of the pregnant cows are stasistically correlated with many important reproduction parameters. The measurement of the number of pregnant cows is easy, available real time and it has important economical effect on milk production. In summary, the number of pregnant cows is a useful parameter to evaluate the reproductive performance and current status of the farms.

The aim of this study was to evaluate the effects of increasing amounts and quality of liquid feed of calves on starter feed intake in real farm situations. Three calf rearing system were compared. We offered different type and amount of solids content of liquid feed by using whole milk and two different milk replacer (MR). The dry matter intake in group A, B and C were accordingly 898; 1033; 1050 g/calf/day. In group A whole milk and MR1 were used, instead of group B and C where MR1 or MR2 were used exclusively. The MRs differed in CP level (21 % vs. 27 %), in proportion of palm/coconut oil (80/20; 60/40) and in technology of production (spray drying vs. spray cooling). The statistical analyses shown strong connection between the amount and quality of milk replacer intake and starter feed intake (P<0.001) before, under and after the weaning period. Between week 2 and 7 the calves in group C ate three times more starter than members of group A and B (129 g/day; 135 g/day; 464 g/day). This difference remained significant later on too. The data of group B differs significantly (P<0.05) only the 9 th week of life from group A. The feeding systems also effect changes in BW (P<0.01) and ADG (P<0.001).