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

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

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

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]

Esubacute acidosis in rumen of high-yield dairy cows: Prevalence and prevention

The objective of the investigations presented in this paper was to establish the frequency of the incidence of subacute acidosis in the rumen of cows (SARA) in the first three months of lactation and the possibilities for its prevention using a mineral mix based on bentonite, zeolite, magnesium oxide, and sodium bicarbonate (Mix plus). The values obtained for the rumen pH content show that subacute rumen acidosis occurs in in 20 percent of the examined cows in the early stage of lactation. For these investigations, cows in early stages of lactation were chosen and divided into 2 groups. Cows of the experimental group were administered a fodder mix which contained the mineral mix for a buffer effect (Mix plus). The average values of the rumen pH content in the control and the experimental group of cows at the beginning and on the 30th day of the experiment were approximately the same and did not differ significantly (p>0.05). On the 60th day of the experiment, the values for the electrochemical reaction of the rumen content for the control group amounted to an average of 6.219±0.18, and for the experimental group of cows it was 6.772±0.23. The obtained difference was statistically very significant (p<0.001). At the end of the experiment, on the 90th day, the average pH value of the rumen content of cows of the control group was 6.308±0.16, while this value in the experimental group of cows was significantly higher and amounted to 6.676±0.29 (p<0.01)

Relationship between serum iron and insulin-like growth factor-I concentrations in 10-day-old calves

Newborn calves are often deficient in iron and progressive reduction in blood iron concentration occurs over the first weeks of life. Some reports indicate the importance of interactions among iron and components of the insulin-like growth factor system. The aim of the study was to determine if there is a relationship between serum iron and insulin-like growth factor-I concentrations in neonatal calves. Blood samples were collected from 16 female Holstein-Friesian calves on day 10 of age. Erythrogram determination and measurements of serum iron, total protein, albumin, total iron binding capacity and serum insulin-like growth factor-I concentrations were performed. Haematological values were measured using an automatic analyzer, biochemical properties were determined spectrophotometrically, insulin-like growth factor-I concentration was measured by radioimmunoassay. Calves were divided into 2 groups according to iron concentrations; the first group of iron-deficient calves (n = 8, Fe 18 mu mol/l). Blood indicators in all calves from the first group followed a pattern typically observed in anaemic calves. Insulin-like growth factor-I concentrations were significantly (P 0.05, respectively). Based on our results, iron seems to have an important relationship to secretion of insulin-like growth factor-I in 10-day-old calves. This is the first report about such relationship in this age group of animals

Thyroid Hormones Concentrations during the Mid-Dry Period: An Early Indicator of Fatty Liver in Holstein-Friesian Dairy Cows

Relationship between postpartal fatty liver and thyroid gland activity during the peripartal and mid dry periods was studied. Twenty one dry cows were chosen. Blood samples were obtained on days −30, −2, and +12 related to calving and analized for thyroxine (T4) and triiodothyronine (T3). A T3/T4 ratio was calculated. Liver tissue samples were taken 12 d after calving and tested for the lipid content. Cows were divided into three groups: mild (<20% fat), moderate (20 to 30%), or severe fatty liver (>30%). Cows, that were affected with severe fatty liver, were hypothyroid prior to development of the condition due to lower T4 concentrations, and had significantly lower concentration of T3 and higher T3/T4 ratios than cows with mild and moderate fatty liver. Thus, hypothyroid state during mid-dry period may be an early indicator of postpartal fatty liver and may provoke T3/T4 ratio increase in this group of cows

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

Zavisnost rasta novorođene prasadi od sastava kolostruma i mleka prednjih odnosno zadnjih mamarnih kompleksa krmača

Piglets that nurse anterior mammary glands grow faster than those suckling posterior mammary glands. The underlying mechanisms are not known. The purpose of this study was to investigate if there is a difference in composition in colostrum and milk secreted by anterior and posterior mammary glands. Seven healthy sows were used. The first three pairs of mammary glands were defined as anterior mammary glands (AMG) and the rest as posterior mammary glands (PMG). Additionally, the total of 87 born piglets from 7 litters derived from the sows involved in the experiment was analyzed. Piglets from each litter that nursed AMG were defined as AMG group while the rest of piglets from the litter were defined as PMG group. Colostrum and milk were collected at days 1, 2, 3 and 7 after parturition. Samples taken from anterior and posterior mammary glands were pooled, respectively. Results showed that total protein, IGF-I and insulin concentrations were significantly higher in the colostrum of anterior than posterior glands and IGF-I concentration remained significantly higher in milk of anterior compared to posterior glands. There were no significant differences in fat, dry matter and lactose among anterior and posterior glands during all examined periods. Additionally, blood samples from nursing sows were obtained at days 1 and 7 after parturition. Results showed that concentrations of Ca, glucose, total protein, albumin, globulin, total bilirubin and insulin significantly increased from day 1 to day 7 of parturition while concentrations of P, BUN, CK and IGF-I did not significantly change during this period. Initial body weight of pigs nursing the anterior gland was higher but not significantly that those suckling posterior glands. Pigs that nursed anterior glands gained weight faster then those which suckled posterior glands resulting with significantly higher body weigh of piglets nursing anterior compared to posterior glands at day 8 of neonatal life (p lt 0.05). Therefore, it may be concluded that the priority of anterior glands milk secretion in total protein and grow stimulating factors may have an impact on increased body weight gain of nursing pigs.Prasad koja sisaju prednje mamarne komplekse rastu brže nego ona koja sisaju zadnje. Mehanizmi koji objašnjavaju ovu pojavu nisu sasvim poznati. Cilj ovog rada bio je da se ispita da li postoji razlika u sastavu kolostruma i mleka stvorenim u prednjim odnosno zadnjim mamarnim kompleksima. Sedam zdravih krmača je bilo uključeno u ogled. Prva tri para mamarnih kompleksa su definisana kao prednji (PMK), a ostali kao zadnji mamarni kompleksi (ZMK). Dodatno, ispitano je 87 prasadi iz 7 legala poreklom od krmača uključenih u ogled. Prasad iz legla koja su sisala PMK su pripala PMK grupi dok su prasad koja su sisala preostale mamarne komplekse grupisana u ZMK grupu. Kolostrum i mleko su uzorkovani 1., 2., 3. i 7. dana nakon prašenja. Uzorci uzeti iz prednjih odnosno zadnjih mamarnih kompleksa su zatim spojeni. Rezultati su ukazali da su koncentracije ukupnih proteina, IGF-I i insulina bile značajno više u kolostrumu PMK u odnosu na ZMK a koncentracija IGF-I je ostala značajno viša u mleku PMK u odnosu na ZMK. Nije bilo značajne razlike u koncentraciji masti, suvoj materiji i laktozi između sekreta PMK i ZMK tokom celog ispitivanog perioda. Dodatno, uzimani su uzorci krvi od krmača 1. i 7. dana posle prašenja. Rezultati su ukazali da su koncentracije Ca, glukoze, ukupnih proteina, albumina, globulina, ukupnog bilirubina i insulina značajno porasle od 1. do 7. dana nakon prašenja dok se koncentracija P, uree, kreatin kinaze i IGF-I nije značajno menjala tokom ovog perioda. Početna telesna masa prasadi koja su sisala PMK je bila viša, ali ne značajno, u odnosu na onu koju je sisalo ZMK. Posle toga, prasad koja su sisala PMK su imala veći dnevni telesni prirast nego ona koja su sisala ZMK što je rezultiralo da su 8. dana neonatalnog života prasad koja su sisala PMK imala značajno veću telesnu masu u odnosu na onu koja su sisala ZMK. Na osnovu svega navedenog se može zaključiti da kvalitetniji sastav sekreta PMK u pogledu sadržaja proteina i faktora rasta može da ima uticaj na veći telesni prirast prasadi koja sisaju ove komplekse u odnosu na prasad koja sisaju ZMK