Sadržaj lipida i glikogena u jetri kod visokoproduktivnih mlečnih krava u peripartalnom periodu

Od krava holštajn rase u visokom graviditetu i ranoj laktaciji biopsijom su uzimani uzorci tkiva jetre za patološko-histološka ispitivanja. Sadržaj masti u hepatocitima je određivan stereometrijskom metodom izračunavanjem volumenske gustine, a glikogena semikvantitativno mikroskopskim pregledom isečaka bojenih metodom po Bestu. Patološko-histološkim ispitivanjem uzoraka tkiva jetre kod zdravih, steonih i tek oteljenih krava nisu utvrđene masna infiltracija i degeneracija ćelija jetre a hepatociti su u potpunosti ili delimično ispunjeni glikogenom. Kod krava obolelih od ketoze patološko-histološkim ispitivanjem uzoraka tkiva jetre su utvrđena masna infiltracija i degeneracija hepatocita, različitog intenziteta. Samo kod jedne krave obolele od ketoze utvrđen je blagi stepen masne infiltracije, kod šest krava srednji stepen masne infiltracije i degeneracije, a kod tri krave težak oblik zamašćenja ćelija jetre. Količina glikogena u hepatocitima je u negativnoj korelaciji sa stepenom masne infiltracije i degeneracije. Pri teškom stanju zamašćenja u citoplazmi hepatocita u potpunosti nedostaje glikogen.Liver tissue samples were taken by biopsy from Holstein cows in advanced stages of gravidity and in early lactation for pathological-histological examinations. Lipid content in hepatocytes was determined using the stereometric method by calculating volume density, and of glycogen using semi-quantitative microscopic examination of sections stained according to the method of Best. Pathological-histological examinations of liver tissue samples in healthy animals, gravid or peripartal cows did not reveal lipid infiltration or cell degeneration, and hepatocytes were completely or partly filled with glycogen. In ketotic cows, pathological-histological examinations of liver tissue samples showed lipid infiltration and hepatocyte degeneration of different intensity. In only one ketotic cow, we determined a slight degree of lipid infiltration, there was a medium degree of lipid infiltration and degeneration in six cows, and three cows were found to have a grave form of fatty liver. The quantity of glycogen in hepatocytes is in negative correlation with the degree of lipid infiltration and degeneration. In severe cases of fatty liver, glycogen is completely absent from hepatocyte cytoplasm

The influence of heat stress on metabolic status of cows

It is considered that high air temperature and humidity during the summer are the main factors which adversely affect both the health and production-reproductive performance of high yielding dairy cows. The resulting heath stress leads to a series of changes in endocrine regulation of homeostasis. The changes in hormonal status reflect in some way to the indicators of metabolic status of the cows. The objective of this work was to investigate the influence of heat stress on metabolic status of cows. The experiment was carried out on 20 cows of Holstein-Friesian breed during the summer, in the period from 18th to 45th day of lactation. During the performance of the experiment, the value of heat index (THI) was determined hourly and then the value of average morning (from 10 pm the previous day to 9 am the current day), afternoon (from 10 am to 9 pm the current day) and all-day THI was calculated. Blood sampling was carried out on the 1st, 2nd, 8th, 11th, 14th, 18th, 25th, 29th and 37th day of the experiment, in the morning and the afternoon. On the basis of hourly THI values, whole experimental period was divided into three periods: period A during which the cows were exposed to a extreme high heat stress (THI≥78) at least 7 hours in 24 hours; period B during which the cows were exposed to a moderate heat stress (72≥THI≤78) at least 7 hours in 24 hours; period C during which the cows were not exposed to a heat stress (THI≤72) in 24 hours. The average daily THI in period A (73,25±0,89) was significantly higher (p<0,01, individually) in regard to period B (71,45±0,96) and period C (65,41±2,09). THI was significantly higher in the period B than in the period C (p<0,01). Significantly lower blood glucose value (p<0,05) during the afternoon period in the cows exposed to the extreme heat stress (3,02±0,31 mmol/L) in regard to the morning period (3,14±0,41 mmol/L) points to the fact that in such conditions, metabolism redirects to use of glucose as an energy source because in that way less thermal energy is produced than during decomposition of fatty acids. Concentration of most important metabolic profile parameters in blood (cholesterol, triglycerides, total proteins, albumin, urea, total bilirubin, calcium, inorganic phosphorus as well as AST and ALT activity) did not vary significantly under the influence of heat stress. The exception was ionic calcium concentration which, under the conditions of extreme heat stress, was on the lower limit of physiological values (1.17±0.16 mmol/L)

Effect of zeolite on health condition of canines

The paper shows the results of investigations of elementary hematological and biochemical blood parameters of German Shepherd dogs administered zeolite through feed daily for a period of 50 days. No undesired effects were established during the period of observation, and in fact there was a full normalization of the condition of the dogs that previously exhibited transitory symptoms of gastrointestinal tract disorders. No significant digressions were observed in the examined biochemical parameters of blood, either, that could indicate any harmful effects of zeolite, with the exception of the tendency toward a reduction in the concentrations of phosphorus and calcium, which was not manifest clinically as well during this period

Koncentracija teških metala u krmnim smešama i tkivima kod svinja u intenzivnom uzgoju

Heavy metals cause oxidative stress, including the creation of reactive oxygen species, inhibiting anti-oxidative defense of biological systems through the reduction of glutation, inhibiting sulfhydrillic dependent enzymes, interfere with some essential metals necessary for antioxidative enzyme activity and/or interreact with cellular membranes causing lipid peroxidation. Large numbers of endogenous or exogenous antioxidants have a protective effect against toxic effects of heavy metals. We followed the presence of heavy metals in samples of fodder, serum, parenchymatous organs (kidney, liver, spleen, heart, lungs) and semen of boars at a farm of Landrace pigs maintained in intensive breeding conditions, during the period from 2002 until 2003. We determined the presence of heavy metals (As, Cd, Pb Ni, Cr, Hg) in both fodder and in the other examined samples, in various concentrations. The target organs for the examined heavy metals were in most cases the kidneys and the liver. It was proven that there is a difference in the accumulation of heavy metals depending on the age of the animal, as well as a threat to the reproductive capability of the boars. In order to decrease the presence of heavy metals and reduce the risk of their effects, it is necessaty to subject the fodder mix before utilization to the presence of heavy metals and also other xenobiotics.Teški metali uzrokuju oksidativni stres uključujući stvaranje reaktivnih kiseoničnih vrsta inhibirajući antioksidativnu odbranu bioloških sistema preko smanjenja glutationa, inhibirajući sulfhidrilne zavisne enzime interferiraju sa nekim esencijalnim metalima neophodnim za antioksidativnu enzimsku aktivnost i /ili interaguju sa ćelijskim membranama, izazivajući lipidnu peroksidaciju. Veliki broj endogenih i egzogenih antioksidanata imaju zaštitno dejstvo od toksičnih efekata teških metala. Na farmi svinja u intenzivnom uzgoju, rase landras, u periodu od 2002. i 2003. godine praćeno je prisustvo teških metala u uzorcima hrane, seruma, parenhimatoznih organa (bubreg, jetra, slezina, srce i pluća) i semena nerastova. Ustanovljeno je prisustvo teških metala (As, Cd, Pb, Ni, Cr i Hg) u hrani i u ostalim ispitivanim uzorcima, u različitim koncentracijama. Target organi za ispitivane teške metale u većini slučajeva su bubrezi i jetra. Dokazano je da postoji razlika u akumulaciji teških metala u zavisnosti od starosti jedinke i opasnost na reproduktivnu sposobnost nerastova. Da bi se smanjilo prisustvo teških metala i smanjio rizik od njihovog dejstva potrebno je da se krmna smeša analizira pre upotrebe kako na prisustvo teških metala, tako i na prisustvo drugih ksenobiotika

Biološki aktivna jedinjenja u kolostrumu i njihov uticaj na porast prasadi u neonatalnom periodu

Colostrum in domestic animals contains numerous bioactive substances like insulin and insulin-like growth factors (IGF-I and IGF-II), epidermal growth factor (EGF), immunoglobulins (Ig), lactoferin (Lf), transferin (Tf) and others. Many of them have distinct functions and stimulate growth and glucose utilization, or have some other, still unknown regulatory function. Bioactive substances influence growth and development of the gastrointestinal tract (GT), and cause many metabolic and endocrine changes in the neonate. Resoption of the bioactive substances from the GT of the neonate could be a specific, receptor dependant, or nonspecific process, and in many cases the exact mechanism(s) have not been completely elucidated. On the other hand there are technological procedures and substances that could effectively increase concentration of some bioactive compounds in the systemic circulation of the neonate. Mineral adsorbent zeolite based on the clinoptilolite could effectively increase blood serum concentrations of some growth factors and hormones, as well as IgG molecules. We are still unaware of the full importance of these technological procedures and products, partly because of very complex additive and/or synergic effects of the different bioactive substances from colostrum on the new borne animals.Kolostrum svinja sadrži mnogobrojne biološki aktivne materije koje imaju utvrđenu ulogu i deluju kao faktori rasta, hormoni ili imaju druga regulatorna dejstva. Pod uticajem kolostruma u organizmu novorođ ene prasadi nastaje veliki broj metaboličkih i endokrinih promena, a rast i funkcionalno sazrevanje je najviše izraženo u sluzokoži digestivnog trakta. Razvoj ovog organskog sistema modifikovan je delovanjem većeg broja bioaktivnih jedinjanja koja potiču iz kolostruma, ali njihovi efekti za sada nisu sasvim ispitani, niti su dovoljno istraženi mehanizmi resorpcije pojedinih biološki aktivnih jedinjenja. Određenim tehnološkim postupcima i nekim materijama (zeolit, na primer), međutim, može da se pospeši transfer bioaktivnih materija iz kolostruma u cirkulaciju novorođene prasadi, i time izazove porast njihove koncentracije u krvi. Značaj ovih tehnoloških postupaka i supstancija još uvek nije potpuno istražen, kao i mogući sistemski efekti biološki aktivnih materija posle resorpcije iz kolostruma

Effect of glycerol based energy supplementation on body condition score of dairy cows

Циљ рада је био да се утврди утицај енергетског додатка на бази глицерола на тjелесну кондицију крава. Петнаест дана прије тељења одабрано је 80 крава подијељених у двије групе од по 40 крава: контролну и огледну. Кравама огледне групе је у посљедње двије недјеље засушења и до 60. дана лактације додаван у храну енергетски додатак на бази глицерола. Оцјена тјелесне кондиције (ОТК) одређена је 15 дана прије, као и 7, 30 и 60 дана послије тељења. Краве огледне групе су имале значајно вишу вриједност ОТК у односу на контролну групу само 7. дана лактације. Разлика у ОТК између периода засушења и пуерперијума је била у оквиру физиолошки дозвољеног опсега вриједности код огледне групе, док је код контролне групе била виша од дозвољеног, указујући да је код огледних крава постпартални негативан биланс енергије био слабије изражен.The objective of the investigation presented in this study was to establish the effects of a glycerol-based energy supplement in the diet of high-yield dairy cows on their body condition. Eighty cows were selected 2 weeks before calving, and they were divided into two groups with 40 cows: control and experimental. Cows of the experimental group orally received glycerol based energy supplement during the final two weeks of the dry period until the day 60 of lactation. Body condition scoring (BCS) was done 15 days before and 7, 30 and 60 days after calving. Experimental cows had significantly higher BCS only on day 7 after calving compared to control group. Difference in BCS between dry and puerperal period was within physiological value in experimental but higher than physiologically accepted in control group, indicating that negative energy balance in experimental cows was not so pronounced

Savremeni pristup u dijagnostici, profilaksi i terapiji zarazne šepavosti ovaca

Zarazna šepavost ovaca je hronično, infektivno oboljenje akropodijuma ovaca, ređe koza i divokoza, polifaktorijalne prirode, za koju se smatra i da je bolest lošeg menandžmenta u ovčarstvu. Poslednjih nekoliko godina se kao glavni uzročnik navodi Dichelobacter nodosus, raniji naziv Bacteroides nodosus. Sadejstvo sa nekoliko drugih saprofitnih i patogenih bakterija nije više toliko značajno u etiopatogenezi, već se smatra važnijim da se odredi virulentnost soja D. nodosus. Ukoliko je infekcija izazvana vrlo virulentnim sojem D. nodosus, oboljenje se naziva Contagiosus ovine digital dermatitis (CODD) i tok bolesti se često završava „izuvanjem papka” Brzom identifikacijom agensa može da se predvide klinički oblik oboljenja, tok i prognoza bolesti. Benigni soj agensa izaziva samo blagi do srednje virulentan laminitis, sa slabo izraženim interdigitalnim dermatitisom, kada je ispoljeno šepanje životinje, na jednu ili dve noge. Vrlo virulentni soj uzrokuje težak oblik infektivnog interdigitalnog dermatitisa, kao gnojno-nekrotičnog dermatitisa, sa značajnim oštećenjem rožine, uz izrazitio šepanje životinja. Zarazna šepavost ovaca je prisutna u skoro svim zemljama sveta, naročito u zemljama sa razvijenom ovčarskom proizvodnjom (Novi Zeland, Australija i UK), u kojima nanosi i značajne ekonomske štete. U našoj zemlji zarazna šepavost ovaca se uglavnom javlja u Raškoj oblasti, Istočnoj Srbiji i Vojvodini, ali u različitom procentu od stada do stada. Nastanku i rasprostranjenosti ovog oboljenja značajno doprinosi neredovna i nepravilna obrada papaka (važna zootehnička mera), kao i niz drugih predisponirajućih faktora kao što su meka i vlažna zemlja, loši klimatski uslovi (toplo i vlažno vreme). U preveniranju, odnosno profilaksi, kao i terapiji zarazne šepavosti ovaca koja je kompleksne prirode, bilo je pokušaja sa primenom različitih dezinficijenasa. Tako se u literaturi navodi a u praksi sprovodi, dezinfekcija sa 10 posto bakar sulfatom, 5-8 posto formalinom, kao i u poslednje vreme, cink sulfatom, kako u supstanciji u obliku praška, tako i u obliku rastvora (od 1o-2o% ZnS04), više puta, u različitim vremenskim intervalima. Za dezinfekciju papaka ima nekoliko preskripcija. Neka od ovih sredstava su se pokazala kao vrlo efikasna. Cink sulfat ima izvesne prednosti u dezinfekciji papaka: baktericidan je, dublje prodire u tkivo na mestu dejstva, štiti rožnati deo papka, manje je toksičan, ekološki je prihvatljiv (lakše rešiv za uklanjanje) i jeftiniji je od ostalih pomenutih dezinficijenasa. Upotreba antibiotika je opravdana samo kod pojedinačnih, izolovanih slučajeva i to u lečenju interdigitalnih dermatitisa, dijagnostikovanih na više nogu. Međutim, upotreba antibiotika širokog spektra u obliku spreja u interdigitalni prostor, pokazala se opravdanom i efikasnom. Imunoprofilaksa daje različite rezultate i uglavnom se primenjuje kod mladunčadi (šilježadi) i ovaca u ranom graviditetu. Samo redovna i stručna obrada papaka, upotreba dezinficijensa cink sulfata u obliku rastvora po utvrđenoj proceduri, primena antibiotika u retkim slučajevima, korišćenje pašnjaka na dobro dreniranim zemljištima i vakcinacija određenih kategorija životinja, mogu zajedno, da doprinesu efikasnoj eradikaciji ovog „upornog” oboljenja ovaca.Footrot in sheep is a chronic, infectious disease of the acropodium in sheep, less frequently in goats and mountain goats, of a multifactor nature, which is also considered to be a disease of poor management in sheep breeding. Over the recent years, Dichelobacter nodosus is given as the main cause, previously known as Bacteroides nodosus. Coaction with several other saprophytic and pathogenic bacteria is no longer so significant in etiopathogenesis, and it is considered more important to determine the virulence of the strain D. nodosus. The disease is called contagiousus ovine digital dermatitis (CODD) if the infection was caused by a very virulent strain of D. nodosus, and the disease often ends with the so-called removal of the foot. A speedy identification of the agent can provide insight into the clinical form of the disease, its course and predicted outcome. A benign strain of the agent causes only a mild to medium virulent laminitis, with poorly expressed interdigital dermatitis, when the animal openly limps on one or two legs. A very virulent strain leads to a grave form of infectious interdigital dermatitis, as a supurous-necrotic dermatitis, with significant damage to the bone and expressed limping of the animal. Footrot is present in sheep in almost all countries of the world, in particular in countries with a developed sheep production (New Zealand, Australia and the United Kingdom), where it causes significant economic damages. In our country, footrot in sheep occurs mainly in the Raska district, eastern Serbia and Vojvodina province, but the percentage varies from herd to herd. The irregular and incorrect processing of hoofs (an important zootechnical measure) significantly contributes to the occurrence and spreading of this disease, as well as a series of other contributing factors, such as soft and moist earch, bad climatic conditions (warm and humid weather). In activities on prevention and prophylaxis of this disease, as well as the treatment of footrot in sheep, which is complex in nature, there have been attempts to apply different disinfectants. For instance, disinfection with 10% copper sulphate, 5-8% formalin, as well as, more recently, zink sulphate, either in the form of a powder or as a solution (from 10-20% ZnSO4), several times during different time intervals, are recommended in litera ture and are being implemented in practice. There are a number of prescriptions for disinfection of hoofs and some of them have been shown to be very efficient. Zink sulphate has certain advantages in hoof disinfection: it is a bactericide, it penetrates deeper into the tissue in the crucial spot, it protects the horny part of the hoof, it is less toxic, ecologically acceptable (more readily disposable), and less expensive than other mentioned disinfectants. The use of antibiotics is justified only in individual isolated cases, in the treatment of interdigital dermatitis diagnozed on several legs. However, the application of widespecter antibiotics sprayed into the interdigital space has proven justified and efficient. Immunoprophylaxis yields different results and is mostly implemented in lambs and sheep in early stages of gravidity. Only regular and expert processing of hoofs, using a zink sulphate disinfectant in the form of a solution according to a prescribed procedure, the use of antibiotics in rare cases, putting animals to pasture in well-drained soil, and vaccination of certain categories of animals can all significantly contribute to the efficient eradication of this persistent disease in sheep

Effects of buffering mineral mixtures on milk yield, milk composition, rumen pH and some blood biochemical parameters in heat stressed dairy cows

The objective of the work was to investigate the influence of partial substitution of magnesium oxide with natural bentonite in feed mixtures used in feeding of cows during their exposure to heat stress. The investigation lasted 30 days and was carried out during last ten days of may and first twenty days of June when average air temperature in stables was 36.6±2.5oC. In the experiment there were included 30 cows of Holstein breed in first phase of lactation, which were divided into two groups of 15 cows: control (C) and experimental (E). Group C was fed with experimental mineral mixture that contained 60% of magnesium oxide during the whole investigation period. Group E was fed with experimental mineral mixture that contained 40% of magnesium oxide as well as 20% of natural bentonite. Remaining ingredients in both control and experimental mineral mixtures were the same and also contained 20% of sodium bicarbonate and 20% of zeolite in the same quantities. The control and experimental mineral mixtures were mixed into complete feed mixture (18% UP) in the amount of 1%. At tne end of the investigation period, on the 30th day, there were taken samples of rumens contents for determining pH, and after that blood samples, in which, after the separation of blood serum, were determined glucose concentration, total proteins, albumin, globulin, urea, HDL cholesterol, LDL cholesterol, total bilirubin, calcium and phosphorus, as well as the activity of ALT and AST. By computation there was calculated the ratio between albumin and globulin, ALT and AST, and the ratio between calcium and phosphorus. Daily allowance and milk chemical composition ( percentage of fat, proteins and dry substance) were determined at the end of the investigation period, that is on the 30th day of lactation, for each cow individually. Partial substitution of magnesium oxide with bentonite influenced milk production increase, but it was statistically insignificant. Besides that, in E group of cows, percentage of fat and dry substance in milk was significantly increased (p<0.05 and 0.01 respectively), while percentage of protein increase was insignificant. The substitution of magnesium oxide with bentonite had no impact on the values of examined parameters of metabolic profile, but it led to statistically significant increase of rumen contents pH values (p<0.05). From the obtained results it can be concluded that substitution of magnesium oxide with bentonite in feed mixtures that are used for feeding cows during summer period, can prevent rumen acidosis, which high yielding cows incline to under the conditions of elevated external temperatures. Besides that, this kind of substitution leads to improvement of milk composition, especially when percentage of fat and dry substance in milk is concerned. [Projekat Ministarstva nauke Republike Srbije, br. TR 31003 i br. TR 34013

Parazitske infekcije goveda Severnobačkog okruga

Because of indirect and direct damages, parasitic infections of cattle pose a threat to animals, so it is necessary to suppress them continuously. In order to carry out the action successfully, it is of crucial importance to deal with current data on their presence. The investigation was carried out in the region of North Bačka District during 2009. and 2010., in 224 heads of cattle grown at farms of various hygienic status and housing conditions. In this study, there are presented the results relating to helminthosis and mange prevalence in different age categories of cattle. Positive parasitological findings were determined in 43.30% of tested animals. There were diagnosed cestodes of Moniezia and Dicrocoelium dendriticum strain, gastro intestinal strongilides as well as mites of Psoroptes strain. During two years' investigation, there was found out the greatest prevalence of infections caused by gastro intestinal strongilides (19.78% and 29.32%). On the basis of the obtained results, it will be possible to use modern antihelmintics more effectively, as well as to implement measures in order to prevent both growth and survival of preparasitic stadiums in the environment and animal infection. The ultimate goal is to help providing more economical cattle production in the investigated region.Zbog indirektnih i direktnih šteta parazitske infekcije goveda predstavljaju opasnost za životinje i potrebno ih je kontinuirano suzbijati, a da bi se taj proces uspešno sproveo neophodno je imati na raspolaganju realne podatke o njihovoj zastupljenosti. Istraživanje je sprovedeno na području Severnobačkog okruga, tokom 2009. i 2010. godine, kod 224 govečeta, uzgajana na farmama različitog higijenskog statusa i u različitim uslovima držanja. U radu su prikazani rezultati koji se odnose na prevalenciju helmintoza i šuge kod različitih starosnih kategorija goveda. Pozitivan parazitološki nalaz je ustanovljen kod 43,30% pregledanih životinja. Dijagnostikovane su cestode iz roda Moniezia, Dicrocoelium dendriticum, želudačno-crevne strongilide i šugarci roda Psoroptes. Tokom obe godine istraživanja ustanovljena je najveća prevalencija infekcije želudačno-crevnim strongilidama (19,78% i 29,32%). Na osnovu dobijenih rezultata biće omogućena efikasnija primena modernih antihelmintika, sprovođenje mera u cilju sprečavanja razvoja i preživljavanja preparazitskih stadijuma u spoljašnjoj sredini i sprečavanje infekcije životinja, a sve sa ciljem da se obezbedi ekonomičnija govedarska proizvodnja u ispitivanom području

Postpartalni nastavak ciklične funkcije jajnika, prvi estrus i ponovno oplođenje i njihov odnos prema metabolizmu energije kod visoko-mlečnih krava

In the last few decades a continuous increase was observed in average milk production of dairy cows all over the world. Simultaneously, however, a dramatic decrease was seen in reproductive performance. This tendency is attributed to the increased incidence of bacterial complications in uterine involution, as well as to the high occurrence of ovarian malfunctions in the postpartum period. The aim of this paper is to review the physiology and pathology of the latter, really complex phenomenon. The nutritional basis of this process, that the requirements of high-producing dairy cows shift abruptly after parturition as the daily milk yield rapidly increases and the ensuing negative energy balance (NEB) will extend 10-12 weeks. In the context of the high genetic merit dairy cow, the pp NEB is the difference between the dietary intake of utilizable energy and the expenditure of energy for body mass maintenance and milk synthesis. In principle, it is a physiological phenomenon, which may, however, result in more or less severe disorders in both the metabolism and reproduction and so it may lead to great economic losses in modern dairy practice [112]. In the first 3-4 weeks after calving the NEB is highly correlated with both milk yield and the interval to first ovulation. Because the number of ovulatory estrous cycles preceding the insemination (AI) has been shown to influence the conception rate, the length of the pp interval to first ovulation provides an important parameter for assessing the effect of NEB on reproductive performance [19, 20].U proteklih nekoliko decenija uočeno je stalno povećanje prosečne proizvodnje mleka kod mlečnih krava širom sveta. U isto vreme, međutim, zapaženo je dramatično smanjenje reproduktivnih rezultata. Ova tendencija je pripisana povećanom pojavljivanju bakterijskih komplikacija tokom involucije uterusa, kao i velikom broju disfunkcija jajnika u postpartalnom periodu. Cilj ovoga rada je da se razmotri fiziologija i patologija ove druge pojave, tog zaista kompleksnog fenomena. Nutriciona osnova ovog procesa je da se potrebe visoko mlečnih krava naglo promene posle partusa kada se dnevni prinos mleka naglo povećava, a posledični negativni energetski bilans se produžava na 10 do 12 sedmica. U kontekstu visoke genetske vrednosti mlečnih krava, postpartalni negativni energetski bilans je razlika između dijetetskog unosa iskoristive energije i potrošnje energije za održavanje telesne mase i sinteze mleka. U principu, to je fiziološki fenomen koji, međutim, može da rezultira u manje ili više teškim poremećajima kako u metabolizmu, tako i u reprodukciji, i tako može da dovede i do velikih finansijskih gubitaka u savremenoj proizvodnji mleka [112]. U prvih tri do četiri sedmice posle teljenja, negativni energetski bilans je u visokoj korelaciji i sa prinosom mleka i intervalom do prve ovulacije. Zbog toga što je ukazano da broj ovulatornih estrusnih ciklusa, koji prethode inseminaciji, utiče na stepen koncepcije, dužina postpartalnog intervala do prve ovulacije obezbeđuje važan parametar za procenu efekta negativnog energetskog bilansa na reproduktivne rezultate [19, 20]