S. Hristov

DAIRY COWS WELFARE QUALITY IN LOOSE VS TIE HOUSING SYSTEM

The subject of this research was to determine the effect of the housing system on quality of welfare of dairy cattle in Serbia. Study was realized on six farms, capacity of 30 to 900 cows, with loose and tie housing system. Assessment of the welfare quality parameters was done by using the Welfare Quality ® Assessment Protocol for Cattle, 2009. Results of the research show that the welfare quality of dairy animals is under the significant effect of housing system, and that loose system has the advantage when it comes to comfort around resting, easy of movements and health condition of cows. Share of not lame cows (81%) and cows with no lesion (86%) was significantly higher (p<0.01) in loose system. Indicator values: duration of lying down movements (6.53 sec), lying down movements with collisions (18.7%) and lying outside lying area (28.4%) in tie system were significantly higher (p<0.01) compared to loose system indicating the inadequacy of the housing and lack of comfort. Analysis of indicators associated with cow hygiene (dirty legs and udder) and diseases (dystocia) points to significant gaps in management in both housing systems which represent significant threat to cow welfare quality.

Effect of heat stress on milk production in dairy cows

Heat stress in dairy cows is caused by a combination of environmental factors (temperature, relative humidity, solar radiation and air movement). Continual genetic selectin for greater performance results to increased sensitivity to heat stress. It was one of the reasons why lactation curve during summer has decreasing trend compared to spring in which lactation curve maintained within high levels. The trial was conducted in spring (April-May) and summer period (June-July) on total of 40 dairy cows of Holstein-Friesian breed in early lactation period (first 60 days of lactation). Milking capacity in cows and milk chemical ingredients (milk fat and proteins) were statistically significantly higher in the spring period compared to summer, while higher values of lactose were not statistically significant. Total average milk production per cow was significantly higher in spring period (42.74±4.98l) than in summer (39.60±5.09l) at the level of P 0.05).

THE POSSIBILITY OF DAIRY FARMS ISOLATION ASSESSMENT - BIOSECURITY ASPECT

The effects of general and special biosecurity measures to prevent introduction of infectious agents in a dairy farm or its spreading from farm were analysed in details in this paper. Investigations were conducted on five different dairy farm production with different technology and capacity using a questionnaire method (Hristov and Stankovic, 2009), as well as scrutinizing their positions in relation to possible sources bio-risks from the near and far away environment. Test results showed that there are serious shortcomings on all observed farms, regarding the possibility of introduction of infectious agents in the production herd, and its possible spread to the environment. Although all fenced and a position of the most of the farms mostly favourable, there are some serious threats to the herd health and farm production, regarding open space and lack of green belt, the uncontrolled presence of wild birds and rodents in facilities and even in feed storage, as well as contact of the employees with other cows not belonging to the farm.

THE EFFECT OF CROSSING OF DOMESTIC SIMMENTAL BREED AND FRENCH FATTENING BREEDS ON CONFORMATION AND FAT COVER OF BEEF CARCASSES

Evaluation of conformation and fat cover of beef carcasses has great importance in modern systems of carcass quality evaluation. In this way, adequate price is achieved for every classified carcass side according to market demand. In this paper, the effect of experimental crossing of Domestic Simmental breed with Charolais and Limousine breed (N=96) on conformation and fat cover was investigated. Evaluation was carried out on the whole carcass and partially for certain parts of carcass according to special evaluation pattern/form (1-5). In regard to evaluation of carcass conformation, statistically significant differences (p<0,01) were established between crosses and Domestic Simmental breed. Crosses with Charolais achieved the highest score for conformation (3,94), the highest score for round conformation (3,77) and shoulder (4,06). Considerably more fat tissue on outside of the carcass was determined in Domestic Simmental breed (3,44) compared to crosses with Charolais (3,27). Presence of fat in pelvic cavity was more expressed in Charolais (3,34) and Limousine crosses (3,28), with better score for covering of kidneys (3,50 and 3,53) compared to Domestic breed (3,17).

Analysis of applied biosecurity measures in boars sperm production.

This paper gives a detailed analysis of the applied biosecurity measures in the production of boar sperm at a swine reproduction center. Biosecurity indicators (existence of a written biosecurity plan, isolation, introduction of newly acquired animals into the herd, herd health, assessment of the personnel attitude towards equipment, traffic control, attitude towards visitors, feeding and watering control, manure management, disposal of dead animal carcasses, attitude towards other animals, rodents and birds control, sanitation) were viewed and evaluated by rating scale: (5) - excellent, (4) - very good, (3) - good, (2) - sufficient, (1) - insufficient, there are resources for improvement (0) - insufficient, with no resources for improvement. Obtained data were analyzed in the SWOT process, taking into account all the strengths, weaknesses, threats and opportunities for improving the biosecurity level. The situation in the center is rated as very good, with an average rating of 4.15. However, one disadvantage is serious and related to the boar facilities isolation possibilities, taking into account their location and the presence of two types of male breeding animals (boars and bulls) in the same location. Newly acquired breeding animals are purchased from various sources, but with a rigorous regime of control and not at the same time.

Clinical and subclinical mastitis in cows

The most important aspects of diagnosis and occurrence of clinical and subclinical mastitis are presented in this paper. Mastitis is inflammation of udders parenchyma characterized by pathological changes, and physical chemical and bacteriological changes of milk. Subclinical mastitis could be diagnosed by direct or indirect somatic cell count (SCC) by California Mastitis test and N-acetyl-B-D-glucosamynidasys test, ELISA and Whiteside test, and also by chloride and bovine serum albumin level, as well as by electric conductivity of milk. Therapy of mastitis is more successful with appropriate information about pathogen, which demands special mediums laboratory conditions and stuff, in order to evaluate antibiotic sensitivity of specific pathogen. In the majority of countries, similar rate of morbidity (about 40%) and infection rate (25%) of dairy cows were reported, regardless of the cause. Prevalence investigations show similarity in the most of the countries. Predominant cause of mastitis is Staphylococcus aureus, followed by Streptococcus agalactiae. Available data show that incidence rate of mastitis caused by E. coli, Pseudomonas aeruginosa, Aerobacter aerogenes and Klebsiella spp. is increasing. Similar data on incidence of mastits and prevalence of specific pathogen were established in our country.

Sustainibility ahd Efficiency of Dairy Farms Biosecurity Plans

Basic principles of biosecurity plans creation and inplementation were given in this review paper. This include goals wanted to be acheived related to specificities of dairy farm technology, sellection of measures that have to be included, order and manner of measures description, inplementation, as well as failures in plan execution. Efficiacy and further sustainibility of biosecurity plans inplementation could be measured through differences between biosecurity level before and after plans application established by questionnaire about biosecurity indicators, such as: 1. isolation of the farm and its organization, 2. quarantine and newly purchased cows policy, 3. visitors policy, 4. attitude towards equipment use, 5. pest control, 6. sanitation efficasy and 7. farm impact on environment. The stakeholders have to define and develop plan to keep potential pathogens for dairy herd health and production in cooperation with the veterinarian and the other professionals advising on organisation and production technology. At least once a year, it is necessary to reconsider the plan and supplemented by new practical experience and scientific knowledge.