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The postpartal period in high-yielding dairy cows can be characterized as a time when animal has to undergo several important changes affecting all the organism. After pregnancy and parturition, organism has to adapt itself to the lactation and this stressing experience contributes to the high incidence of health disorders. These include ketosis, fatty liver, milk fever, retained placenta, metritis, mastitis, laminitis, and other metabolic and reproductive disorders. They may become clinically manifested in later stages of the reproduction cycle but have their primary cause in early postpartal period. To overcome these problems, every farmer has to practice good herd health management, especially when considering the transition period. To discover the weak points of the herd management we can use some indices that can be determined from the blood samples of dairy cows after partuition. We collected blood samples from 170 dairy cows of Slovak spotted breed 1 to 8 weeks after parturition. None of them manifested clinical signs of any illness. We divided them into the 6 groups depending on the number of weeks post partum.We observed and evaluated the main blood-chemistry parameters of energy and liver metabolism (glukose, triglycerides, total lipids, total cholesterol, non-esterified fatty acids, beta-hydroxybutyrate, total bilirubin), protein metabolism (total immunoglobulins, total protein, albumine, Creatinin, urea) and levels of some serum enzymes (AST, GGT, ALP, CPK, LDH). Even though there were no alterations in the health status present in that time, we found out that some indices, mostly of energy and liver metabolism, such as serum levels of non-esterified fatty acids, triglycerids, etc. were altered. This fact can help us to trace the potentially threatened individuals and to iniciate the steps that would minimize further damage.
Blood samples were taken from 134 Holstein cows between day 20 to 100 postpartum to determine the concentration of urea, cholesterol, glucose and total lipids and to define their relation to the reproductive performance traits: interval (I), service period (SP) and insemination index (II). Investigations were carried out in monthly intervals from October 1996 to October 1997. Average values of plasma urea, total lipids, cholesterol and glucose for the entire period studied were 5.78 mmol.1⁻¹, 3.61 g.l⁻¹, 3.34 mmol. l⁻¹ and 3.61 mmol. l⁻¹, respectively. High concentration of blood urea was related negatively with the value of the insemination index (rp = -0.51). When the average concentrations of total lipids were low in plasma in the specified time (month) negative correlations were found between total lipids and the length of service period (rp = from -0.23 to -0.54) and value of the insemination index (rp = -0.42). The concentration of plasma total lipids increased in time from post partum. Traits of reproductive performance were affected by the internal environment. Especially negative influences were observed when the concentration of plasma urea as well as total lipids and cholesterol increased or decreased abnormally.
The current methods of preventing calcium deficiency during the periparturient period are based primarily on a diet low in calcium and acidifying the rumen content before parturition, as well as on oral administration of liquid preparations or boluses. The available literature does not provide information on whether these forms of prevention are effective only immediately after the parturition, or whether they also affect an organism throughout the initial lactation period. The aim of the study was to examine the effects of three methods for the prevention of postpartum hypocalcaemia on selected indicators of mineral and energy metabolism, as well as on functional parameters of the parenchymal organs during the two week period following parturition in dairy cows diagnosed with low calcium concentrations before parturition, induced by a lower dietary mineral content. The study was conducted in 60 HF cows, aged 3-6 years old, fed TMR. The animals were divided into three groups: the first group received only a mineral preparation contained in the feed, adjusted to the physiological stage and milk production level; the second group received three additional doses (directly before the parturition, then 24 hours and 48 hours after the delivery) of an oral fluid preparation containing 62.5 g of Ca; while the third group received an intraruminal bolus containing 43 g of pure calcium (immediately after parturition). This research showed that physiological hypocalcaemia occurred at the beginning of lactation in the groups which had received additional calcium preparations (groups II and III), whereas in group I blood collection one week and two weeks after the parturition demonstrated subclinical hypocalcaemia. A statistically significant increase in magnesium and a decrease in phosphorus concentrations were also observed in the latter group, as well as an excessive GGTP activity and high bilirubin concentrations. Using only one complex mineral supplement in high yielding milk cows after parturition does not ensure the expected prophylactic effects, especially in the long term.
The aim of this study was to evaluate the trend of adrenocorticotrophic hormone (ACTH) and cortisol levels in mares during peripartum period. Twelve pregnant mares (Group A) were weekly monitored from the last 6 weeks before foaling (6BF-1BF) until the first 3 weeks after foaling (1AF-3AF). Twelve non-pregnant non-lactating mares constituted the control (Group B). Jugular blood samples were analyzed for plasma ACTH and serum cortisol concentration. ACTH showed higher values (P<0.05) at 1BF compared to the postpartum data points (1AF, 2AF and 3AF) in Group A. Cortisol levels were higher (P<0.05) at 1BF and 2BF compared to the 3AF in Group A. A significant positive correlation between ACTH and cortisol values was found in mares from Group A throughout the peripartum period (Pearson’s r=0.40; P=0.0028). The Dunnet’s test showed lower ACTH values in Group A at postpartum data points than control, and higher cortisol levels in Group A throughout prepartum times and at 1AF than control (P<0.0001). The decrease of ACTH and cortisol levels found during the early postpartum period could indicate a reduced HPA response to physical and/or psychological stress during this physiological phase. This could help the mare to protect against stress-associated inhibition of lactation, relieve psychological stress, and enhance her immune function. Further studies involving the evaluation of prolactin and sex steroid hormones values are needed to fully understand the dynamic hormonal changes occurring in pregnant and lactating mares in order to permit clinicians to make appropriate interpretation of the results.
Malfunction of glutamatergic neurotransmission in postnatal period is considered to be a risk factor for development of schizophrenia. Thus, the present study investigates the impact of NMDA receptor blockade in the postnatal period on the density of tyrosine hydroxylase immunoreactive axonal arbors in the rat medial prefrontal cortex. Behavioral experiments revealed that adult rats (60 days old) treated in the postnatal period with a competitive antagonist of NMDA receptors, CGP 40116 (1.25 mg/kg on days 1, 3, 6, 9; 2.5 mg/kg on days 12, 15, 18; and finally 5 mg/kg on day 21, all injections s.c.), showed enhancement of the locomotor activity stimulated by quinpirole (0.3 mg/kg s.c.) and amphetamine (0.5 mg/kg s.c.), which suggests development of functional supersensitivity of dopaminergic systems. It has been found that CGP 40116, given in postnatal period decreased the density of tyrosine hydroxylase immunoreactive axonal arbors in the medial prefrontal cortex of adult animals. The decrease was observed in superficial (II/III) and deep (V/VI) layers of the medial prefrontal cortex, while the average length of tyrosine hydroxylase immunoreactive axonal arbors was increased in both superficial and deep cortical layers. Changes in the density of tyrosine hydroxylase immunoreactive axonal arbors have not been followed by a significant decrease in the content of tyrosine hydroxylase protein measured by Western blot. Thus, NMDA receptor blockade in the early period of life evokes changes in architecture of tyrosine hydroxylase immunoreactive axonal arbors and that malfunction of glutamatergic neurotransmission, in early period of life may produce anatomical changes which resemble those observed in the brains of schizophrenics.
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