Serotonin is known to regulate energy and calcium homeostasis in several mammalian species. The objective of this study was to determine if pre-partum infusions of 5-hydroxytryptophan (5-HTP), the immediate precursor to serotonin synthesis, could modulate energy homeostasis at the level of the hepatocyte in post-partum Holstein and Jersey dairy cows. Twelve multiparous Holstein cows and twelve ...

The present study aims to examine the effect of tropical temperatures on autonomic nervous activity in Cambodian dairy cattle by analyzing heart rate variability (HRV). Holter-type electrocardiograms were recorded in adult crossbred cows (Cambodian native × Holstein) either in a sheltered area or under direct sunlight. Rectal temperatures and heart rates increased in animals under direct sunlig...

BACKGROUND Downer cow syndrome (DCS) is often diagnosed in dairy cattle during the early post-partum period. The etiology of this condition is not completely understood, as it can be related to the energetic or electrolyte metabolism, as well as to infectious diseases or to trauma. HYPOTHESIS/OBJECTIVES The aim of this study is to compare energy metabolism and insulin sensitivity indices and ...

The study was conducted on 20 Holstein X Sahiwal cross bred dairy cows, with an average milk production of 2,752±113.79 liters in 284±5.75 days during a single lactation, that were divided in to two groups of 10 animals. We investigated the oxidative stress and antioxidant status during the transition period in dairy cows. In this study, plasma level of MDA was considered as an indicator of lip...

The purpose of this study was to investigate the effect of maternal inbreeding on incidence of twinning,dystocia and stillbirth in Holstein cows of Iran. Calving records from March 2000 to April 2009 comprisingof 365,021 calvings on 153,802 cows from 86 dairy herds were used. The mean level of inbreeding was0.7%, less than 37% of all animals were inbred, and a small proportion (3.45%) of inbree...

Growth patterns from birth to maturity were compared for 92 straightbred Herefords (H) and 299 Hereford crossbred (XB) cows. Crossbred cows were out of Hereford dams and were sired by bulls of two British [Angus (A) and Shorthorn (Sh)], two Continental [Charolais (C) and Simmental (S)] and two American dairy breeds [Brown Swiss (B) and Holstein (F)]. British XB and H cows differed only slightly...

Objective-To assess the effect of lameness on culling of dairy cows in Tehran province. Design- Historical cohort study. Study population and procedures- 7067 first- and second-parity Holstein dairy cows that calved from March, 21 2007 to March, 20 2008 were until next calving or culling. Logistic regression was conducted data. Results-The overall lactational culling rate for eligible cows i...

Bovine leukocyte antigen DRB3 alleles from Holstein x Zebu crossbred dairy cows (n = 409) were analyzed using the PCR-RFLP technique. Exon II of DRB3 was amplified using locus-specific primers (HLO30/HLO32), followed by digestion with 3 restriction enzymes (RsaI, BstyI, and HaeIII). Forty alleles were found with frequency ranging from 0.005 to 0.139. The most frequently detected alleles of Hols...

Pedigree information of 3972 Holstein cows and bulls, from 1961 to 2008, was used to calculate inbreeding coefficients and their effects on production traits and subclinical mastitis of dairy farm cows inAzerbaijan province,Iran. Inbreeding was included in a linear mixed model as a class variable. Data were analyzed using the PROC MIXED of SAS by MIVQUE method. Results showed that average inbre...

BACKGROUND Whether the measurement of cortisol in dairy cows can be used as a biomarker of adverse environmental or pathophysiological conditions is still under of scientific debate. In these situations, several systems mainly the hypothalamic-pituitary-adrenal axis, the autonomic nervous system, and the immune system are recruited to reestablish homeostasis. A first aim of the present study wa...