No abstract

Lactoferrin (LTF) is a glycoprotein, a member of transferrin gene family which plays an important role in immune mechanisms in the mammary glands of cows. The amount of lactoferrin increases during inflammatory processes and viral infections. The aim of this investigation was to monitor the distribution of lactoferrin gene genotypes and its connection to milk quality and the occurrence of mammary gland diseases in 46 Holstein-Freisian cows of different age(2-7 years) on a farm near Belgrade. DNA was isolated from blood samples, and the polymorphism of lactoferrin gene was deterimined by PCR-RFLP method using the restriction enzyme Eco RI. We found two alelic forms of this gene in cows included in these experiments (A and B) and two genotypes (AA and AB) in a ratio 71.7% to 28.3%. The genotype BB was not found in this sample. In order to determine the degree of differences between genotypes we used discriminant analysis which has shown that there is a statistically significant difference between genotypes AA and AB with respect to productive parameters. When analysed separately, the only parameter which differed significantly (p=0.021) between two genotypes was total milk production. Individuals with observed genotypes are most similar for the amount of milk fat (p=0.271). There is no statistically significant difference in the number of somatic cells in milk samples between the examined genotypes.

This study investigated the effects of dietary supplementation with chestnut tannins (CNT) on metabolic and antioxidant status of prepartum cows along with their colostrum quality. Pregnant multiparous Holstein cows were paired according to parity and body condition score, and assigned either to a diet supplemented with 20 g/d of commercially available product containing chestnut tannins (CNT, n=20) or to an unsupplemented control diet (CON, n=20) for the last 25±2 d of pregnancy. Serum metabolite, insulin and antioxidant capacity indices were measured in blood samples taken at d 25 and d 5 before expected parturition. Chemical composition and IgG concentration were determined in colostrum samples collected from the first milking postpartum. The addition of CNT led to lower BUN (P=0.02) and consequently higher serum glucose (P=0.02) and insulin (P<0.01) concentrations which were associated with lower circulating NEFA (P<0.01) and BHBA (P<0.01) in CNT group than those of CON. The serum paraoxonase 1 (PON 1) activity and total antioxidant capacity (TAOC) were higher at -5 d in CNT than in CON (P<0.01, P=0.03; respectively). Close-up CNT improved lactose percentage and IgG concentration (P=0.03, P=0.04; respectively) and tended to improve percentage of protein and SNF (Solid Not Fat) in primary colostrum (P=0.06, respectively), without affecting colostrum fat and total solid (P=0.98, P=0.43; respectively). Supplementation of CNT in the diet during close-up period did not have adverse effects on metabolic profiles prepartum. Instead, this feeding regimen was more beneficial to antioxidant capacity and colostrum quality than feeding the control diet.

Inflammation of the mammary gland, mastitis in cows, presents one of the most acute problems in intensive dairy production, inflicting huge economic losses. In the course of one year, 80 samples were taken at investigated farms from udder quarters of cows with clinical mastitis and 160 samples from udder quarters of cows with subclinical mastitis. The efficacy of three preparations, A, B, and C, was examined in the treatment of clinical and subclinical mastitis in cows. The investigations indicate that antibiotic preparation A (neomycin, polimixine B, oleandomycin and prednisolone) exhibited a greater efficacy in the treatment of clinical mastitis caused by Streptococcus agalactiae, Streptococcus dysgalactiae, Streptococcus uberis and Micrococcus sp., but a smaller efficacy in the treatment of subclinical mastitis caused by Staphylococcus aureus. Preparation B (amoxicillin, clavulanic acid and prednisolone) exhibited a higher efficacy in the treatment of clinical mastitis caused by Streptococcus agalactiae, Streptococcus dysgalactiae, Streptococcus uberis and Micrococcus, but a weaker effect in the treatment of subclinical mastitis caused by Staphylococcus aureus. Preparation C (procaine penicillin G, streptomycin, neomycin sulfate and prednisolone acetate) exihibited efficacy in the treatment of clinical and subclinical mastitis caused by Streptococcus agalactiae, Streptococcus dysgalactiae, Streptococcus uberis, Micrococcus, Staphylococcus aureus and Esherichie coli. [Projekat Ministarstva nauke Republike Srbije, br. III 46002: Molekularno-genetička i ekofiziološka istraživanja u zaštiti autohtonih animalnih genetičkih resursa, očuvanju dobrobiti, zdravlja i reprodukcije gajenih životinja i proizvodnji bezbedne hrane

Mycoplasma bovis infection in grazing dairy cows has not been reported in the Republic of Serbia to date. It is important to monitor its seroprevalence on the field. The presence of specific antibodies against M. bovis in the blood serum of grazing dairy cows is investigated in the present study. A total of 131 blood serum samples of clinically healthy dairy cows were examined. Sampling was performed during 2013 from five different areas in Serbia: Zasavica, Pozarevac, Gruza, Novi Sad and Banatski Karlovac. A commercial ELISA kit for diagnosis of M. bovis antibodies in blood serum samples, manufactured by Bio-X Diagnostics, Belgium, was used. Specific antibodies against M. bovis were identified in 13 out of 131 samples (9.92%) from 4 locations; the only negative location was the most southern Gruza. The revealed seroprevalence is evidence for the presence of M. bovis in grazing dairy cows in different locations of Serbia. Figure 1: Location of the 5 different areas of Serbia where grazing cows were sampled for Mycoplasma bovis serology: 1 -Zasavica, 2 -Pozarevac, 3 -Gruza, 4 -Novi Sad and 5 -Banatski Karlovac (MapCustomizer, https://www.mapcustomizer.com/). CONCLUSIONSSpecific antibodies against M. bovis were identified in 9.92% of the grazing cows from 4 areas; the only negative was the most southern region, Gruza. The revealed seroprevalence is the first evidence for the presence of M. bovis in grazing dairy cows in different locations of Serbia.

The estrus cycle of bitches is divided into four phases: proestrus, estrus, diestrus and anestrus, during which different morphological changes, and also cyclic changes of estrogen and progesterone receptors are present. Several pathological changes can be differentiated on the endometrium, but one of these is the most important - cystic endometrial hyperplasia, which frequently develops into pyometra. The aim of the present study was to describe morphological characteristics, and expression of estrogen and progesterone receptors on the endometrium of mixedbreed bitches during the different phases of the estrus cycle, cystic endometrial hyperplasia and pyometra. The uterus and ovaries of 36 mixed breed bitches in different phases of the estrus cycle and also with cystic endometrial hyperplasia (CEH) and chronic purulent endometritis - pyometra were examined macroscopically, histopathologically, and immunohistochemically for estrogen receptors (ΕR) and progesterone receptors (PR). During proestrus uterine cells showed a weak reaction for both estrogen and progesterone receptors, but during estrus a large number of uterine cells showed a strong reaction on estrogen receptors and moderate reaction on progesterone receptors. On the contrary, during diestrus the scores for the estrogen receptors decreased, while the progesterone receptors level increased - uterine cells expressed strong reaction for progesterone receptors, and moderate reaction for estrogen receptors. Uterine cells in cystic endometrial hyperplasia expressed a strong reaction for estrogen receptors, and moderate reaction for progesterone receptors, but on the other hand the uterine cells in the uterus with pyometra expressed a moderate to strong reaction for progesterone receptors, and a weak reaction for estrogen receptors. In further investigations it would be interesting to perform quantitative analysis for both estrogen and progesterone receptors during different phases of the estrus cycle and also in the uterus with cystic endometrial hyperplasia and pyometra.

Mastitis in cows represents one of the most actual problems in intensive dairy production. The longtime different approaches to the treatment of mastitis have not offered a suitable solution, and the problem of mastitis is still present and acute. Prevention of pathogen penetration into the mammary gland, its colonization and multiplication impose a constant need for regular inspections of milk, as well as preventive and therapeutic measures to reduce the incidence of mastitis. Studies in the field of vaccination of ruminants against mastitis pathogens suggest a limited success in obtaining significant results in immunoprophylaxis. Considering the results of other researchers and our own research, and bearing in mind the problems mastitis caused by Staphylococcus aureus and Streptococcus agalactiae represent, the aim of this study was the preparation and testing of an indigenous vaccine prepared with two stable strains, SAU 7 (S. aureus) and SAG 3 (Str.agalactiae). The dose was 5 mL/cow and consisted of inactivated bacterial S. aureus SAU 7 cells in a concentration of 1x10 10 cfu/mL and Str. agalactiae SAG 3 in a concentration of 4 x 10 9 cfu/mL. The number of somatic cells in the milk samples during the whole study period was higher in vaccinated cows in both groups compared with the control, but this difference was not statistically significant. The concentration of immunoglobulin IgG in the milk of vaccinated cows was significantly higher than the concentration of this class of proteins in the milk of unvaccinated cows.

Cows in the peripartal period undergo changes in thyroid hormones and are susceptible to lipomobilization and/or oxidative stress. The addition of chestnut tannins as polyphenolic compounds in the diet may improve feed efficiency and prevent oxidative stress-related health disorders in transition cows. However, the relationship between chestnut tannin supplementation and thyroid function, which plays an important role in metabolic regulation, has not been investigated in dairy cows. This study was conducted to investigate the effects of chestnut tannin supplementation during the close-up period on thyroid status and to evaluate the interaction between thyroid hormones and oxidative stress biomarkers in prepartum dairy cows. Forty multiparous Holstein cows were fed either a diet containing chestnut tannins (CNTs, n = 20, 1.96 g chestnut tannins/kg feed, dry matter) or a non-supplemented diet (CON, n = 20) during the last 25 ± 2 days of gestation. Blood samples were collected on the first day of study (before chestnut tannin supplementation) and d 5 before parturition to measure hormonal and oxidative stress indices. Serum concentrations of T3 (p = 0.04) and T4 (p = 0.05) were higher in CNT cows than in the CON group on day 5 before parturition. Thyroid status of CNT cows was associated with higher serum total antioxidant capacity (T-AOC, p < 0.01), activities of superoxide dismutase (SOD, p = 0.03) and glutathione peroxidase (GPx, p = 0.01), and reduced glutathione concentration (GSH, p = 0.05). Serum thiobarbituric acid reactive substances (TBARS) were lower (p = 0.04) which was associated with lower aspartate aminotransferase (AST, p = 0.02), and lactate dehydrogenase (LDH, p = 0.01) activities in the CNT than in the CON group. Estradiol and progesterone did not differ between CNT and CON cows. Chestnut tannin supplementation improves antioxidant protection, prevents oxidation-reduction processes, reduces the degree of liver cell membrane damage, and protects thyroid tissue from damage, allowing higher T3 and T4 synthesis. Considering the importance of the thyroid hormone status before parturition, mechanisms of thyroid hormone regulation in CNT-supplemented dairy cows require more detailed investigations.