ABSTRACT
Data utilised in this study were obtained from a herd on a large dairy farm (428 Black and White cows) collected by official AP control. Average milk yield of cows in 1997 was 6 382 kg of milk with 3.82 % of fat and 3.35 % of protein in standard lactation. Feeding strategy on the farm was similar to circumstances on many other farms in Slovenia: pasture, maize silage, hay, mineral-vitamin mixture and adequate feeding of concentrates in grazing period and grass silage, maize silage, hay and adequate feeding of mineral-vitamin mixture and concentrates in housing period (open free stall bedded with straw). There existed significant differences in milk yield of cows that calved in different seasons or months of the year. The average lactation curve course indicated a very small rise in milk yield in the first period of lactation and later on a satisfactory milk persistency. Between seasons existed differences in lactation curve course, where a decline in milk yield in the fourth month after calving in autumn calving cows was significant and clearly worsened milk persistency in all cows in summer months. Cows that calved in March and September attained the same milk yield in standard lactation (6 345 kg and 6 371 kg) with quite different lactation curve course. Out of the results it can be concluded that differences in milk yield due to seasonal impacts can be explained by differences in lactation curve course. It is likely that factors other than only temperature (nutrition) have to be involved in interpretations of estimated seasonal effects on milk production.

Key words: cattle / dairy cows / reproduction / season of calving / lactation curve

EFFECT OF PREVIOUS AND PRESENT CALVING INTERVAL ON MILK YIELD IN PRESENT STANDARD LACTATION

ABSTRACT
Some experiences and data on suckler cows and sheep wintering on abandoned agricultural land are presented. The aim of work is to develop management system for the cattle that could help to recultivate karst pasture during winter time, and for the sheep that could be used to stop the invasion of tall herbage (weeds) in an extensive orchard. During winter the standing litter of vegetation was very effectively broken down and mixed with the soil by the hooves of animals. Cattle were fed hay and silage to appetite, sheep had hay and daily supply of some barley. Round feeding cages were used to feed big bales. Periodically moved feeding and bedding location throughout wintering period encouraged animals to do the work over larger area and thus minimizing manure accumulation and preventing pollution through surface run-off water. At the end of wintering period on the bedded packs and on severely pugged sites white clover (Trifolium repens) was broadcasted on karst pasture. In the extensive orchard the fodder beet (Beta vulgaris) and grasses were planted (L. multiflorum, L. perenne, D. glomerata, F. pratensis, F. arundinacea) to investigate which species would be most suitable to renew the grass sward. Outdoor wintering management for cattle and sheep can be of great importance to develop low cost and low input livestock farming system too.

Key words: cattle / suckler cows / sheep / outdoor wintering / abandoned agricultural land / pasture / grassland / orchards / recultivation / Karst / Slovenia

ALTERNATIVE FEEDING PRACTICES FOR LIVESTOCK IN CONFINEMENT AND ON PASTURE

ABSTRACT
We discuss why herbivores eat a variety of foods and why diets that enable animals to select among alternative foods may enable individuals to better meet nutritional needs in confinement and on pastures. We suggest that: (1) animals can more efficiently meet their individual needs for macronutrients when offered a choice among dietary ingredients than when constrained to a single diet, even if it is nutritionally balanced; (2) transient food aversions compound the inefficiency of a single mixed diet by depressing intake even among animals suited to that nutritional profile; and (3) alternative feeding practices may allow producers to efficiently capitalize on the agency of animals, thus reducing illness and improving performance.

Key words: animal nutrition / feeding behaviour / diet selection / feed preference / macronutrients / toxins

EFFECT OF SEX AND SUCCESSIVE CALVING ON GROWTH RATE OF CHAROLAIS AND LIMOUSIN CALVES FROM BIRTH TO WEANING

ABSTRACT
Birth masses and daily gains until weaning at the end of pasture in Charolais (115) and Limousin (38) calves born from 1996 to 2000 at Educational and Research Centre Logatec were analysed. Year, breed (B), sex (S) and successive calving of suckler cows significantly influenced birth mass of calves. The difference in birth mass between sexes was higher in Limousin calves (4.3 kg) than in Charolais (1.3 kg). P-value for interaction S*B was 0.081. Daily gains in some periods of growth from birth to the end of pasture were influenced by year, breed and sex of calves as well as by age at the beginning of pasture, which was used to estimate the time of calving. The effect of successive calving on estimated daily gains in calves was less pronounced.

Key words: cattle / suckler cows / calves / breeds / Charolais / Limousin / successive calving / sex / birth mass / daily gain

ABSTRACT
Determing the content of the first colostrum of 25 Hungarian Large White × Dutch Landrace F₁ sows with respect to dry matter, total protein, whey protein, casein, non-protein nitrogen, ash and macro- and microelements (potassium, sodium, calcium, phosphorus, magnesium, zinc, iron, copper and manganese), it was established that most of the components examined were present in the highest concentrations when litter size was around 10 to 12, and that a decrease or an increase in litter size had accompanied by a decrease in the concentrations of the studied components. The changes, following a maximum curve dependent on litter size, observed in the concentration of these components were attributed partly to the effect of placental lactogen (in the section of the curve indicating increase), and partly to physiological overburden of mother (in that indicating decrease).

Key words: pigs / sows / reproduction / litter size / colostrum / composition

FUTURE ASPECTS OF PORCINE CARCASS AND MEAT QUALITY

ABSTRACT
In future production, swine carcasses should not only be lean but also homogeneous in weight and shape. Extreme conformation should be avoided. Classification systems will have to be non invasive, objective, evaluate proportions and also composition of whole sale cuts. Porcine meat quality is genetically determined by two major factors. Stress susceptibility (MHS) and the “Hampshire – factor” (RN) can nowadays easily be detected and eradicated in selection programs. MHS homozygous negative genotypes are essential for a high standard in meat quality. Even though intramuscular fat contents are negatively correlated with leanness the relation is not that close that both of them could not be combined at a reasonable level in one population in particularly if crossbreeding is applied. It is most likely that in near future the market and the consumer will require such actions. Transparency of the entire production line is one of the further essential demands in meat quality assurance.

Key words: pigs / meat / carcass / quality

MORE ON THE RELATION BETWEEN MEAT PERCENTAGE AND MEAT QUALITY TRAITS IN SWINE CARCASSES

ABSTRACT
This study involved 302 swine carcasses, dissected in the aim of their classification into (S)EUROP classes on the basis of relative share of muscle tissue. Following measures have been taken on the primarily processed swine carcasses: length, ham index, muscle and fat areas of m. longissimus dorsi, fat to meat ratio. The meat quality traits measured were: pH₁, pH₂, water holding capacity (w.h.c.) and colour. The differences in carcass quality indicators between pigs from different classes were statistically significant in the most of the cases (P < 0.05) and highly significant (P < 0.01). The analysis of meat quality traits showed that the meat had mostly normal characteristics, although it was also observed that swine carcasses from lower meat yield had more favourable quality traits than the carcasses with higher meat yield.

Key words: pigs / carcass / composition / muscles / fat / meat / quality

PERCENTAGE AND DISTRIBUTION OF TISSUES IN PIG CARCASSES IN RELATION TO (S)EUROP CLASSES

ABSTRACT
Four hundred of primarily processed carcasses of pigs with different genetic background and production conditions were included in this study. The average carcass mass was 80.43 kg (from 78.29 kg in class S to 88.34 kg in class O). The average lean meat percentage in carcasses was 54.31 %. According to classification (Pravilnik o utvrđivanju..., 1999) in S class were classified 10.25 %, 37.50 % in class E, 32.50 % in class U, 16.75 % in class R, 3.00 % in class O, while in class P there were no carcasses classified, which presents a satisfactory structure. By the dissection of the carcasses according to Weniger et al. (1963) into the main parts (ham, loin, belly-rib part, shoulder, neck) the shares of these parts became obvious. The differences in percentages of the main parts within classes were in favour of the higher classes, but statistically significant differences were established only in the case of ham (P < 0.01) belly-rib part (P < 0.01 and P < 0.05) and shoulder (P < 0.01 and P < 0.05). The percentages of lean meat in individual main parts, according to classification, were different in the most of the cases at the level of P < 0.01 and always in the favour of higher classes (S, E and U). Fat was almost always in negative proportion to the degree of meatiness. The percentages of bones showed relatively small differences between classes regarding the individual parts (P < 0.05) as well as the carcasses where differences were established at the levels of P < 0.01 and P < 0.05. In addition to presented results, the procedure for price determination according to lean meat percentage, i.e. classes were proposed.

Key words: pigs / carcass / composition / S(EUROP) classification system