The aim of the present study was to investigate nutritional and metabolic parameters during the dry and early postpartum periods of ovulatory and anovulatory cows, as well as their postpartum reproductive performance. Blood samples from 20 multiparous Holstein cows were collected once a week from the far-off dry period to 3 weeks postpartum. Early postpartum (0-3 weeks) ovulation was confirmed ...

Cows with ovarian follicular cysts were treated with progesterone to determine whether a reduction in LH concentrations and initiation of ovulatory follicular waves would occur. Cysts were diagnosed using transrectal ultrasonography when single follicular structures > 20 mm or multiple structures > 15 mm in diameter were present for 7 d in the presence of low progesterone concentrations. Three ...

Ninety-nine multiparous Brahman-influenced (1/4 to 3/8 Brahman) cows were managed to achieve low (BCS = 4.3 +/- 0.1; n = 50) or moderate (BCS = 6.1 +/- 0.1; n = 49) body condition (BC) to determine the influence of bovine somatotropin (bST) on estrous characteristics, reproductive performance, and concentrations of serum GH and plasma NEFA. Beginning 32 d postpartum, cows within each BC were as...

New tools are needed to detect chronic sub-clinical mastitis, especially in automatic milking systems. Haptoglobin and serum amyloid A (SAA) are the two most sensitive bovine acute phase proteins, and their concentrations increase in milk from cows with clinical mastitis and in milk from cows with experimentally induced chronic sub-clinical Staphylococcus aureus mastitis. The aim of this study ...

Increased milk somatic cell counts (SCC) are used as an indicator for bovine mastitis. During mastitis, polymorphonuclear leukocytes (PMN) become the predominant cell type. Shortly after parturition, the severity of mastitis is increased and several PMN functions are downregulated. Apoptotic and necrotic processes of PMN could influence SCC and PMN functions. In this study, the percentages of a...

Levels of luteinizing hormone (LH), follicle stimulating hormone (FSH), progesterone and estradiol-17 beta were measured in five Polled Hereford cows. Blood samples were collected once or twice daily for 5 d, then every 6 h from 1 d before weaning (d 28 to 38 postpartum) until 10 d after the second postweaning estrus. Blood samples were again collected at daily intervals until the third postwea...

The study included 4 herds of dairy cows (C, D, E, F) from CentralEastern Poland. The objective of the study was to evaluate and compare selected haematological and biochemical indicators in the blood of dry and lactating cows from the studied region. Blood was sampled twice from the external jugular vein at two dates: 10-14 days prior to calving and after the first month of lactation. Determin...

For dairy cattle on pasture in temperate regions, it is largely unknown to what degree hot summer conditions impact energy metabolism, milk yield and milk composition and how effective shade is in reducing these negative effects. During the summer of 2012, a herd of Holstein cows was kept on pasture without access to shade (treatment NS). During the summers of 2011 and 2013, the herd was divide...

This study was conducted to test the effects of feeding supplemental Bulgarian nutritive additive OVOCAP® administrated per os, on blood lipid profile in lactating cows. Twelve lactating American Brown cows (BW = 695 ± 28 kg; at the beginning of the lactation) were separated to two treatments for 1,5 year. Cows were fed typical diets during the winter (corn silage, meadow hay, straw, wheat bran...

Adrenocorticotropic hormone (ACTH) challenge test is recognized as a method for evaluating some forms of stress. Six lacting cows, well trained to blood sampling were used for this study. Cows were randomly assigned to receive saline or an intramuscular single dose (0.5 μg/kg) of ACTH (Synacthen Depot). Blood samples (10 mL) were collected from the coccygeal blood vessels of all cows at 0 h (im...