peer reviewed | OBJECTIVE: To determine the effect of histamine on the contractile elements of the respiratory tract in neonatal calves and young adult cattle. SAMPLE POPULATION: Samples of trachealis muscle, bronchi, and intrapulmonary arteries and veins dissected from the respiratory tracts of healthy bovids (2 to 8 days and 16 to 20 months old). PROCEDURE: Histamine cumulative concentration-effect curves (10(-6) to 10(-3) M) were constructed in duplicate smooth muscle samples mounted in organ baths. Contractile responses to histamine were compared with reference contractions elicited by methacholine (10(-5) M) for airways or KCl (127 mM) for vessels. RESULTS: In young adult cattle, trachealis muscle had a substantial contractile response to histamine (84% of methacholine-induced contraction), whereas bronchi reacted slightly (15 and 20% for large and small bronchi, respectively). Although contractile responses to KCl were comparable in arteries and veins, histamine-induced contractions were greater for intrapulmonary veins than for arteries (202 vs 48% of KCl-induced contraction). In neonatal calves, histamine-induced contraction of veins also exceeded that of arteries (230 vs 54% of KCl-induced contraction); however, unlike in young adult cattle, histamine produced notable contraction of large and small bronchi (48 and 60% of methacholine-induced contraction, respectively). CONCLUSIONS AND CLINICAL RELEVANCE: Compared with intrapulmonary arteries, intrapulmonary veins have greater contractile responses to histamine in neonatal and young adult cattle. Data suggest loss of histamine responsiveness in bronchial smooth muscle as neonatal calves grow to young adults. Venodilation may be useful in treatment of lung edema in cattle.

In the context of health monitoring of a group of cattle and buffalo farms in marsh and swamp areas, these animals displayed evident clinical signs of nutritional deficiency in addition to symptoms that included high temperature (41 °C or higher), swollen lymph nodes, diarrhea, anemia, weakness, and decreased appetite. And, in some cases, cough. The presence of ticks in various areas of the body, especially the edges of the ear, the neck area and the area beneath the tail, indicated the possible presence of Theileriosis, a parasitic infection. Random blood samples were collected from sixteen individuals. Subsequently, DNA was extracted from these samples and Polymerase Chain Reaction (PCR) was utilized to amplify the small subunit of the 18S rRNA gene, which is highly specific for the detection of Babesia/Theileria species. The PCR procedure employed the GF (5'-G(C/T) (C/T) TTGT AAT TGG AAT GAT GG-3') and GR (5'-CCA AAG ACT TTG ATT TCT CTC-3') primers. The results were then compared to international isolates via an analysis of genetic nucleotide sequences using the Basic Local Alignment Search Tool (BLASTn) algorithm, available at the National Center for Biotechnology Information (NCBI). This analysis unveiled a significant genetic resemblance between the 18S rRNA gene sequences and T. annulata species, suggesting the presence of this parasite. As a consequential outcome of this study, it has been established that Bos taurus and Bubalus bubalis, can be a new host for T. annulata, particularly in the southern regions of Iraq.