Causes for cow culling in a tie stall system were investigated on a sample of 3060 cows culled in 2011, on seven large dairy farms in the Belgrade region. The total level of culling was 34.58% of the average number of cows. The number of cows culled decreased with lactation order (from 981 cows in the first to 294 cows in the sixth and later lactations). The most dominant cause for culling were diseases of the legs and hooves (28.4%), as was expected, having in mind the tie stall system. If selection (low production) is abstracted as the reason for culling, what stands out by importance are metabolic diseases (15.7%) and problems of reproduction (reproductive diseases-8.6%, and difficult calvings and abortions 5.7%). With the increase of duration of the lactation during which cows were culled, reproductive diseases gained importance as the reason for culling, while the importance of metabolic diseases and diseases of the legs and hooves in this context decreased. When culled, on the average, cows were 5.2 years old, having on the average spent 1112 days in production, of which 978 days in milking. Their average milk production per day of milking was 22.00 kg, per day of life 10.6 kg, and per day of production 19.8 kg.

It is general knowledge that management influences results in cattle production to the highest extent, and that the culling of cows is a very good indicator of the success of farm management. A comparison of results of culling for first calving cows on farms with various levels of production in 2011 established differences both for the number of culled animals and the reasons for culling. On farms with higher levels of production, the share of first calving cows in overall culling was 25.9% or 4.5% less than on farms with a lower level of production, i.e. 4.8% less died, and 0.7% first calving cows had to be slaughtered, while 5.6% more first calving cows were culled for economic reasons. At both levels of production, dominant reasons for culling were diseases of the legs and hoofs, which can be linked to the tie stall system (more pronounced on farms with higher production) and metabolic disorders (more dominant on farms with lower production). Reproduction was a more considerable problem on farms with higher milk production, while culling due to selection was more pronounced on farms with lower production. In early lactation of first calving cows, regardless of the level of production, dominant reasons for culling on farms are leg and hoof problems and metabolic disorders (total: 55% i.e. 55.9%). When reasons for culling of first calving cows after 100 days of lactation are investigated, on farms with high production the significance of diseases of legs and hoofs remains almost unchanged, but culling due to reproduction grows to 28%. On farms with lower production, culling due to leg and hoof diseases is considerably reduced after 100 days of lactation, however culling due to selection is tripled (62%).

This research was conducted with the aim оf estimating genetic trend for a functional length of productive life (FLPL) in the population of Black and White cattle in Serbia. Research and bulls genetic evaluation for functional longevity were performed on a set of data provided by Agricultural Corporation Belgrade AD (PKB) which contained data on longevity and origin of 22109 cows out of which 26% records were right-censored. Functional length of productive life (FPLP) represents a time period from the first calving to culling or censoring corrected for milk production. Breeding values were estimated using Weibull method of proportional risks within survival analysis a genetic trend for FLPL was calculated using of a regression analysis. The cows included in the analysis were on average first calved in the age of 809 days and had an average share of 81.9% genes of Holstein Friesian breed. An average length of productive life was 1267 days (41.6 months). Distribution of bull standardised breeding values did not statistically significantly differ from normal distribution. An average standardised breeding value was 99. A slightly positive genetic trend was determined, that is, the length of functional productive life was by selection increased by 0.021 day at an annual level while a reliability of estimated breeding values showed a negative trend.

The aim of this study was to investigate the effects of the use of soybean molasses in the nutrition of lactating cows on their performance and some blood and rumen content parameters. Treatments included isoenergetic and isoprotein rations: total mixed ration (TMR) which included 1 kg of soybean molasses and TMR without soybean molasses. The use of soybean molasses in TMR for lactating cows increased yield of 4 % FCM (5.03 %). There was no difference in milk fat content and yield between treatments. The use of soybean molasses increased the concentration (3.45 vs 3.32 %) and yield (from 0.81 to 0.88 kg/day) of milk protein. Improved utilization of consumed ration dry matter (DM), energy and crude protein by 4.60, 4.81 and 7.82 %, respectively, was confirmed. There was no significant effect of including soybean molasses in TMR on ruminal pH value, number and structure of protozoa population nor on their motility. Soybean molasses had a positive effect on decrease of the urea blood concentration (5.45 vs 6.30 mmol/L) while no significant effects were observed for the concentrations of glucose, Ca and P in blood. Results of this study indicate that soybean molasses, as a source of readily available energy, can be used successfully in rations for lactating cows.

SažetakIntenzivno mlečno govedarstvo, opravdano se karakteriše kao industrijska proizvodnja. Na Balkanu, u velikoj meri temelji se na brojnim saznanjima iz zemalja intenzivnog stočarstva, kako u oblasti selekcije tako i ishrane. Kao i u SAD najproduktivnija rasa je holštajn, a najznačajnija hraniva su kukuruzna silaža i seno, odnosno senaža, lucerke. Ipak, svedoci smo klimatskih promena koje ne pogoduju lucerki a još manje kukuruzu, naročito u uslovima suvog ratrenja. Sve je teže realizovati proizvodnju dovoljnih količina kvalitetne silaže kukuruza. Pored toga, energetska kriza koja će u decenijama pred nama biti još drastičnija, daje kukuruzu i dodatni značaj, kao dragocenoj sirovini za dobijanje etanola. To nameće potrebu iznalaženja drugih biljnih kultura pogodnih za proizvodnju kvalitetne silaže. Upravo zato, istraživanje mogućnosti upotrebe silaža strnih žita u ishrani preživara, sve više dobija na značaju, a cilj ovog rada je pregled značajnijih iskustava i rezultata istraživanja u toj oblasti. Rad je metodološki zasnovan na prikupljanju i analizi podataka iz literature.

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Organic farming, as an ecologically acceptable production method based on natural processes and the use of organic and natural materials, is becoming increasingly popular in Serbia. In addition to “organic”, this type of production is also commonly called “ecological” or “biological”. The objectives of organic agriculture are to maintain and increase fertility of the land, suppress land erosion, conserve biodiversity, protect natural resources from pollution and produce foods of high nutritional value. In organizing organic livestock production, priority is given to native (indigenous) breeds adapted to local growing conditions and resistant to diseases. Organic production, which is an integral part of the sustainable agriculture system, does not permit the use of protective and nutraceuticals of synthetic chemical origin and synthetic drugs, growth regulators, hormones and GMOs. Despite the common, classical means of goat farming, in recent years there has been increasing interest to change typical farming methods to introduce “Bio” systems, i.e. biologically clean farming methods. Such production methods result in products free of the chemicals that are common in numerous substances used in common production methods. Animal welfare is always a high priority in organic production. Primarily, animals should be provided with conditions for growth and development that are in compliance with their genetic potential. This implies respecting their physiological and ecological needs, and ensuring conditions to express their natural functions and behaviour. In order to start and later organize such production, certain conditions must be met. The appropriate, accredited institutions are responsible for ensuring that the required conditions are met and that production is in line with the principles of biological production. Holdings meeting the requirements of biological production receive the appropriate certificate. Today organic production in the EU is regulated by the EEC Directive 2092/91, and its amendments.

SažetakDomaći magarac (Equus asinus) potiče iz Afrike. Opšte je poznata velika radna izdržljivost magarca. Praktično ne postoje geografski predeli gde ova domaća životinja ne obavlja najrazličite oblike rada, pre svega transporta. U ovom istraživanju izvršeno je morfometrijsko ispitivanje 3 eksterijerna parametara kod 19 ženki magarca. Izvršena su merenja sledećih eksterijernih parametara: visina u grebenu, dužina glave i dužina karlice. Jedinke su merene u tri različite države: Rumunija (Sibiu, Turda), Makedonija (Ohrid, Prilep) i Turska (Eskišehir). Prikazane su srednje vrednosti merenih parametara i indeksa, a izračunata je i statistička značajnost razlike merenih parametra između jedinki podeljenih u tri grupe. Prosečna vrednost visine magarica bila je u Rumuniji 101,20 cm, u Makedoniji 99,70 cm, a u Turskoj 103,10 cm. Dužina glave magarica u Rumuniji prosečno je iznosila 49,10 cm u Makedoniji 50,40 cm, a u Turskoj 50,00 cm. Kada se posmatra dužina karlice najveća je bila kod magarica u Turskoj 35,80 cm, zatim u Rumuniji 35,60 cm, a najmanja u Makedoniji 34,60 cm. Između navedenih grupa nije utvrđena statistička značajanost razlika niti za jedan parametar.