The influence of high vitamine c doses on neutrophil granulocytes functions in cows with subclinical masitis

Napredak tehnologije i direktna primena najnovijih nauĉnih saznanja omogućili su, do sada, najvišu produkciju mleka po kravi u farmskim uslovima. Usled intenzivne i jednostrane selekcije na visoku mleĉnost, došlo se do granica biološkog potencijala ove ţivotinjske vrste. Imperativ povećanja proizvodnje (odnosno profita), gde se u velikom broju sluĉajeva, krave iscrpljuju do krajnjih fizioloških granica, nanosi štetu njihovom zdravstvenom stanju uz zanemarivanje osnovnih bioloških principa. Visoko-mleĉne krave se uvode u stanje kontinuiranog metaboliĉkog stresa, koji neminovno rezultira zdravstvenim i proizvodnim problemima. Indirektno se, kao posledica narušavanja imunološkog statusa jedinki, pojavljuje najvaţniji zdravstveni i ekonomski problem u mleĉnom govedarstvu, a to je upala mleĉne ţlezde - mastitis. Štete u vidu smanjene proizvodnje ĉine preko 70% svih gubitaka produkcije mleka, dok leĉenje mastitisa ĉini preko 50% svih intervencija na farmama mleĉnih krava. Posebno treba naglasiti ĉinjenicu da se najveći deo problema u realnim uslovima proizvodnje odnosi na supkliniĉke mastitise, koji nisu direktno vidljivi i oni dovode do najvećih finansijskih gubitaka. Zbog toga su farme bez adekvatnog programa mera kontrole i suzbijanja supkliniĉkog mastitisa, zapati sa ugroţenim opstankom. Smatra se da se fiziološke potrebe odraslih preţivara u vitaminu C obezbeĊuju aktivnošću bakterijske mikroflore buraga. Vitamin C nije esencijalan dijetalni dodatak u ishrani odraslih preţivara. MeĊutim, istovremeno je dokazano da se zdravstveno stanje organizma preţivara poboljšava kada se vitamin C dodaje u hranu u uslovima stresa ili bolesti. TakoĊe je poznato da oralna aplikacija nije toliko efikasna kao parenteralna. Rana laktacija predstavlja najkritiĉniji period reproduktivno-proizvodnog ciklusa, kada se mobilišu gotovo svi raspoloţivi fiziološki resursi i tada dolazi do pada koncentracije askorbinske kiseline u krvnoj plazmi mleĉnih krava. Istovremeno se od mleĉnih krava oĉekuje oporavak od teljenja, postizanje vrhunske mleĉnosti i novog graviditeta u što kraćem vremenskom periodu. Postoje podaci koji dokazuju da je i tokom supkliniĉkog, a pogotovo kliniĉkog mastitisa izraţen pad koncentracije vitamina C u krvnoj plazmi plotkinja. Shodno tome, osnova ovog istraţivanja je bila zasnovana na pretpostavci da se poboljšanje opšte otpornosti organizma stimulacijom funkcija neutrofilnih granulocita (stepena fagocitoze i respiratornnog praska) kao prve linije odbrane od infekcija, moţe postići produţenom aplikacijom visokih doza vitamina C, višestruko većim od farmakološki preporuĉenih. Kliniĉki su oĉekivani pozitivni efekti na smanjenje broja somatskih ćelija u mleku i poboljšanje ukupnog zdravstvenog i reproduktivnog statusa. Sa druge strane, ne postoje dostupni podaci o toksiĉnosti vitamina C kod preţivara prekomernim doziranjem. Ciljevi ovog istraţivanja su bili da se utvrdi uticaj visokih doza vitamina C na kvalitet mleka ocenjen CMT (California Mastitis Test), 10 do 30 dana posle teljenja, pre i nakon tretmana vitaminom C (tretirana grupa), odnosno, na poĉetku i na kraju ogleda u kontrolnoj grupi (bez tretmana). Osim toga ispitan je bakteriološki nalaz mleka iz CMT pozitivnih ĉetvrti na poĉetku i na kraju ogleda, u zavisnosti od tretmana vitaminom C. Kod svih jedinki, ukljuĉenih u ogled odreĊivane su kompletna krvna sliku i leukogram, pre i nakon tretmana vitaminom C. Na kraju je utvrĊivan stepen funkcionalne aktivnosti neutrofilnih granulocita (intenzitet fagocitoze i repiratornog praska) u punoj krvi i mleku krava u navedenom periodu. U ispitivanja je bilo ukljuĉeno 40 grla, odabranih prema sledećim kriterijumima: 1) da je od teljenja prošlo najmanje 10 a ne više od 30 dana; 2) da je na jutarnjoj muţi mleko krava ispoljavalo pozitivnu reakciju u CMT (sa ++ i +++ reakcijom) u jednoj ili više ĉetvrti, bez kliniĉki vidljivog mastitisa; 3) da je zapis toka teljenja bio normalan, bez dodatne asistencije akušera; 4) da su odabrane krave kliniĉki bile zdrave...Development of new technologies and direct application of the latest scientific findings enabled the highest milk production per cow ever in farm conditions. Due to the intense and narrow selection for high milk yield today, we approached the limits of the biological potential of this species. The imperative of increased production (or profit), where in a good number of cases cows are exhausted to the extreme physiological limits in order to achieve greater milk production, harming their health status and fully neglecting basic biological principles. In this way, we are introducing them into a state of continuous stress, which inevitably results in a wide range of health and/or production problems. Indirectly, as a result of disturbance of the immune status, the most important health and economic problem within dairy cattle production, appears inflammation of the mammary gland - mastitis. The damage in terms of reduced milk production account for over 70% of all milk production losses, while treating mastitis comprise over 50% of all interventions on dairy farms. We should emphasize the fact that the biggest part of the problem in real production conditions is related to subclinical mastitis, which is not directly visible. The real fact is that subclinical mastitis brings the largest financial losses. A farm without adequate program of measures to control and combat subclinical mastitis doesn’t have “bright” future. It is believed that sufficient physiological needs of adult ruminants in vitamin C are provided by activity of the rumen bacterial microflora. Also, it is believed that vitamin C is not essential dietary nutrient in the diet of adult ruminants, but their body condition are improved when they had vitamin C added to the diet in situation of stress or illness. Also, oral application is not as effective as the parenteral route. After calving, in its early phase of lactation there is a decrease in concentration of ascorbic acid (vitamin C) in the blood plasma of dairy cows. Early lactation represents the most critical period of reproductive-production cycle, when almost all available physiological resources are mobilized and pushed to the final limits. The dairy cows are expected to recover from calving, reaching soon the peak of lactation and a new pregnancy in the shortest possible time. The decrease in the concentration of vitamin C is expressed during subclinical, especially during clinical mastitis. Consequently, the platform of this research is based on the assumption that an improvement in the general resistance of the organism by stimulating the neutrophil granulocytes (phagocytosis and respiratory burst) as a first line of defence against infection can be achieved by prolonged application of high vitamin C doses, a multiple higher than the pharmacologically recommended. Clinically, the expected positive effects are the reduction of somatic cells in milk and improved overall health and reproductive status. On the other hand, there are no available data on the toxicity of vitamin C in ruminants excessive dosing. The main objectives of this study were: to determine the effect of high doses of vitamin C on the quality of milk, estimated with CMT test; 10 to 30 days after calving, before and after treatment with vitamin C (experimental group), respectively, at the beginning and end of the experiment in the control group (no treatment); to perform milk bacteriological examination of CMT positive udder quarters at the beginning and end of the trial, depending on the treatment of vitamin C; to determine complete blood count and leukogram in cows before and after the treatment with vitamin C; to determine degree of functional activity of neutrophil granulocytes (phagocytosis and respiratory burst) from whole blood and CMT positive milk samples (++, +++) in the related period (before and after the treatment). Fourty cows has been selected, according to the following selection criteria: 1) from the calving has passed at least 10 days and not more than 30 days; 2) at the morning milking cows milk produced positive reaction to the CMT (with ++ and +++ reaction) from one or more udder quarters, without clinically apparent mastitis; 3) the calving was normal, without additional assistance of veterinarian; 4) selected cows had to be clinically healthy..