Endocrine and metabolic adaptations of calves to extra-uterine life

The transition from intra-to extra-uterine life is one of the greatest physiological challenges that occur in the life of animals. Immediately after birth, newborn calves have to adapt to new environmental and feeding conditions. Namely, at birth a break of the thermal balance occurs, since calves abruptly pass from a 38.8 degrees C temperature in utero to an environmental temperature that is generally lower than 20 degrees C. Additionally, at birth, the energy intake shifts from a continuous parenteral supply of nutrients (mainly glucose) to discontinuous colostrum and milk intake with lactose and fat as the main energy sources. Therefore, the most important issues related to metabolic changes during the transition from intra-to extra-uterine life are related to maintaining the homoeothermic conditions and control of energy metabolism. Those metabolic adaptations are under control of the endocrine system that is relatively mature at birth, but still requires morphological and functional changes after birth. Key hormones whose concentrations are significantly changed around birth and are involved in an adequate adaptation of calves to extra-uterine life are those related to stress at birth (cortisol and cathecholamines), glucoregulatory processes (insulin and glucagon), thermogenesis (thyroid hormones) and growth (IGF axis)

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

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)

Relationship between the indexes of insulin resistance and metabolic status in dairy cows during early lactation

Insulin resistance is a phenomenon which accompanies the ongoing metabolic adaptation in cows during early lactation. The aim of our study was to determine the linear correlations of HOMA (Homeostatic Model Assessment), QUICKI (Quantitative Insulin Sensitivity Check Index) and RQUICKI (Revised Quantitative Insulin Sensitivity Check Index) indexes of insulin resistance with the metabolic status of cows (concentration of hormones, metabolites and body condition score). The experiment included 40 Holstein-Frisian cows in the first week after calving. Indexes of insulin resistance valued: 18.68 +/- 5.43 (HOMA), 0.39 +/- 0.06 (QUICKI) and 0.45 +/- 0.06 (RQUICKI). Linear correlations were examined by testing the coefficient of correlation (r), determination (r(2),%) and regression parameter beta (b) in linear equation. A negative correlation was found between HOMA and IGF-I (insulin growth factor I) (r=-0.51, r(2)=25.0, b=-1.1257, p<0.01). HOMA showed a positive correlation with BHB (beta-hidroxybutyrate) (r=0.48, r(2)=23.2, b=0.0234, p<0.01). A positive correlation was found between QUICKI and IGF-I (r=0.30, r(2)=10.0 b=46.7900, p<0.05) and cholesterol (r=0.44, r(2)=18.3, b=1.9021, p<0.01). In contrast, QUICKI and BHB (r=0.51, r(2)=27.1, b=-1.7241, p<0.01), just like QUICKI and BCS (r=0.46, r(2)=20.9, b=-2.424, p<0.01), showed a negative correlation. RQUICKI showed positive correlations with IGF-I (r=0.48, r(2)=22.8, b=28.1230, p<0.01), T4 (r=0.47, r(2)=22.1, b=87.142, p<0.01) and triglycerides (r=0.36, r(2)=13, b=0.0407, p<0.05) but negative correlations with cortisol (r=-0.36, r(2)=13.0, b=-9.0332, p<0.05), STH (somatotropic hormone) (r=-0.42, r(2)=17.3, b=-5.4976, p<0.01), BHB (r=-0.62, r(2)=38.3, b=-1.1872, p<0.01), total bilirubin (r=0.58, r(2)=33.7, b=-7.131, p<0.01) and BCS (body condition score) (r=-0.6, r(2)=36.4, b=1.8347, p<0.01). In conclusion, indexes of insulin resistance may be used to evaluate the metabolic status of cows in early lactation. RQUICKI might be the most appropriate predictor of metabolic status due to its linear relationship with most of the parameters included in homeorhetic process

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

Milk yield and composition, body condition, rumen characteristics, and blood metabolites of dairy cows fed diet supplemented with palm oil

Background: An addition of rumen-protected fat to the diet of cows may limit negative energy balance and/or shorten its duration, leading to increased milk production with reduced risk of metabolic disorders in dairy cows. The aim of the study was to test the effect of rumen-inert fat supplement of palm oil on milk production, milk composition, rumen characteristics, and metabolic variables of early lactating dairy cows. For this purpose, 24 Holstein-Friesian cows were divided into two equal groups and fed a corn silage-based diet, without palm oil supplementation (control) or with 300 g palm oil (Palm Fat 99, Noack & Co. GmbH, Vienna, Austria) per cow for 8 weeks starting from day 30 after parturition. Milk, rumen, and blood samples were taken three times during experiment at days 30, 58, and 86 of lactation. Body condition scores of cows were determined in the same time periods. Milk yields were measured at the morning and evening milking (6(00) and 18(00)). Milk samples were analyzed for milk fat and milk protein content. Rumen content was tested for electrochemical reaction. A native slide was prepared for microscopical examination of the rumen protozoa motility that was numerically estimated. Protozoa were counted in whole rumen contents by light microscopy. Blood samples were tested for total protein, albumin, urea, tryglicerides, cholesterol, total bilirubin, beta-hydroxybutyrate, Ca, and P. Results: Compared with the control, palm oil supplementation resulted in an increase of the average milk yield and milk fat content. The loss in body condition was significantly lower in the group fed palm oil than in the control group. Rumen pH, total number, and motility of protozoa in the group fed palm oil were significantly higher than those in the control group. Palm oil supplementation did not influence blood metabolite concentrations except for urea and glucose which were significantly lower and Ca and cholesterol which were significantly higher in the palm oil-supplemented group. Conclusions: Our results indicate that supplementation with palm oil in weeks 4 to 12 postpartum spared postpartum body weight loss, increased milk yield and milk fat content, and had positive effects on rumen characteristics

Servis period i antitela protiv spermatozoida kod veštački osemenjavanih krava

The aim of this study was to determine titers of antisperm antibodies (ASA) of Ig G and Ig A class in sera and cervical mucus of artificially inseminated Holstein cows in order to correlate these results with the duration of the open days period. Investigations were conducted on a total of 181 cows originating from three different dairy farms. Blood and cervical mucus samples for laboratory analyses were collected on the day of the last artificial insemination. Presence of ASA was determined by indirect immunofluorescence method (IIF) using bulls' sperm cells prepared for artificial insemination by suspending in TRIS - egg yolk or "Biociphos + " extenders prior to deep freezing. Our results strongly confirm the hypothesis that immune mechanisms may be involved in reproductive disturbances due to high levels of ASA of lg A class. In the sera and cervical mucus of cows, high levels of ASA were found in animals with longer open days period. In this study we were not able to demonstrate differences in ASA titers when sperm cells were suspended in different extenders and used for the IIF test.U ovom radu su izneti rezultati ispitivanja titra antitela Ig G i Ig A klase poreklom iz krvnog seruma i cervikalne sluzi veštački osemenjavanih holštajn krava protiv antigena spermatozoida bika. Ispitivanja su izvedena na ukupnom broju od 181 plotkinje sa tri regionalne farme muznih krava. Uzorci krvi i cervikalne sluzi su prikupljeni na dan poslednjeg veštačkog osemenjavanja. Titar antitela protiv antigena spermatozoida (ASA) je određivan metodom indirektne imunofluorescence a za izvođenje testa su korišćeni spermatozoidi suspendovani u TRIS žumanjčanom ili "Biociphos +" razređivaču. Naši rezultati potvrđuju hipotezu da su imunski mehanizmi uključeni u nastanak nekih reproduktivnih poremećaja jer su plotkinje sa visokim titrom ASA u serumu i cervikalnoj sluzi imala duži servis period. Osim toga, u ovim ispitivanjima nismo utvrdili postojanje razlika u titru ASA u zavisnosti od vrste korišćenog razređivača

Influence of the season on the metabolic profile in chios sheep

Chios is a breed of sheep selected for milk production, with metabolic features typical for a dairy sheep breed. The energy requirements of pregnant sheep is increase in the last weeks of gestation. Metabolic imbalance in the late pregnancy in sheep, usually cause a metabolic disorder known as pregnancy toxemia. Additionally, a pregnant sheep exposed to low environmental temperatures has increased energy demands, due to its adaptation to undesirable environmental conditions. The aim of this study was to compare the metabolic profile of Chios sheep exposed to different environmental conditions. Two groups of ewes were instigated. First group included 8 pregnant ewes with clinical signs of pregnancy toxemia exposed to cold stress during the winter season. The second group included 8 non-pregnant, clinically healthy ewes, that were examined during the non-breeding period, in the spring season. Blood samples were taken and serum concentrations of glucose, beta-hydroxybutirate (BHBA), total protein, albumin, urea, creatinine, triglyceride and cholesterol, as well as activity of AST and ALP were determined. Pregnant ewes exposed to cold stress had significantly lower levels of glucose and total protein, and significantly higher levels of BHBA, albumin and AST in the serum compared to non-pregnant ewes that were in optimal environmental conditions. There was no significant difference between the serum levels of urea, creatinine, cholesterol, triglycerides and ALP among the groups. In conclusion, low environmental temperature and poor feeding during the winter season caused metabolic distress in pregnant ewes during the early winter season

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

The dynamics of biochemical parameters in blood of clinically healthy holstein cows from day 5 before to day 60 after calving

The peripartal period in Holstein dairy cows is critical, due to the transition from pregnancy to lactation. We have studied the dynamics of biochemical parameters from day 5 before to day 60 after calving. The study included 10 multiparous Holstein cows, examined at days -5, 5, 10, 30 and 60 relative to calving. Blood samples were taken from vena jugularis. Analyzed biochemical parameters were glucose, triglycerides, total cholesterol, total bilirubin, albumin, total protein, urea, NEFA and BHBA. Milk production and body condition score were also estimated. Obtained results showed that cows were exposed to mild to marked metabolic distress. Energy status was changed due to increased values of NEFA and BHBA and decreased value of glucose after calving. Protein concentrations were increased at day 10 after calving, despite the decrease of the level of albumin. Urea concentrations before and after calving were within physiological range indicating an optimal protein diet. Increased values of total bilirubin at day 5 after calving indicated liver increased activity. Lipid status presented by triglycerides and total cholesterol revealed no differences in blood concentrations. Milk production was highest at day 30 after calving. BCS were highest in dry cows, thereafter they declined and recovered at day 60 after calving. In conclusion, biochemical parameters can be used as relevant indicators of metabolic distress in cows around calving with milk and BCS recording as aside parameters. Changes in some biochemical parameters indicate liver increased activity and metabolic stress, that could lead to decreased milk production, impaired reproductive performance and, finally, to illness