Clarifications on breakpoints in HSAX and BTAX by comparative mapping of F9, HPRT, and XIST in cattle

The coagulation factor IX gene (179), the hypoxanthine phosphoribosyl transferase 1 gene (HPRT1), and the X-inactive specific transcript gene (XIST) were physically assigned in cattle to analyze chromosomal breakpoints on BTAX recently identified by radiation hybrid (RH) mapping experiments. Whereas the FISH assignment of XIST indicates a similar location on the q-arm of the human and cattle X chromosomes, the locus of HPRT1 supported the assumption of a chromosome rearrangement between the distal half of the q-arm of HSAX and the p-arm of BTAX identified by RH mapping. F9 previously located on the Cl-arm of BTAX was assigned to the p-arm of BTAX using RH mapping and FISH. The suggested new position of F9 close to HPRT I supports the homology between HSAXq and BTAXp. The F9 locus corresponds with the gene order found in the homologous human chromosome segment. XIST was assigned on BTAXq23, HPRT1 and F9 were mapped to BTAXp22, and the verification of the location of F9 in a 5000 rad cattle-hamster whole genome radiation hybrid panel linked the gene to markers URB10 and HPRT1. Copyright (C) 2003 S. Karger AG, Basel.

Pharmacokinetics of a new long acting endectocide formulation containing 2.25% ivermectin and 1.25% abamectin in cattle

The objective of this study was to determine the kinetic parameters of a new formulation that contained 2.25% ivermectin combined with 1.25% abamectin in bovine plasma. The results for 2.25% ivermectin: C-max (37.11 ng/mL +/- 7.42), T-max (16 days +/- 5.29), T-1/2 (44.62 days +/- 53.89), AUC (928.2 ng.day/mL +/- 153.83) and MRT (36.73 days +/- 33.64), and for 1.25% abamectin: C-max (28.70 ng/mL +/- 9.54), T-max (14 days +/- 4.04), T-1/2 (15.40 days +/- 11.43), AUC (618.05 ng.day/mL +/- 80.27) and MRT (20.79 days +/- 8.43) suggest that this combination of 2.25% ivermectin + 1.25% abamectin possesses properties that give this pharmaceutical formula a longer activity time than two of the commercial products tested (1% ivermectin and 1% abamectin), and showed similarity to 3.15% ivermectin.

Differential response of the luteal phase and fertility in cattle following ovulation of the first-wave follicle with human chorionic gonadotropin or an agonist of gonadotropin-releasing hormone

A series of experiments with Holstein heifers was conducted to develop the capability of inducing accessory corpus luteum (CL) with a GnRH agonist (Buserelin, 8 mu g; GnRHa) or hCG; (3,000 IU) to increase plasma progesterone concentrations (Exp. 1, 2, and 3) and to test whether induction of accessory CL with hCG will increase conception rates in heifers (Exp. 4) and lactating cows (Exp. 5). In Exp. 1, heifers were treated on d 5 after estrus with GnRHa (n = 8) or saline (n = 7); heifers in Exp. 2 received hCG (n = 5) or saline (n = 4) on d 5. Experiment 3 allowed a contemporary evaluation of heifers treated on d 5 with GnRHa (n = 6), hCG (n = 6), saline (n = 6), or GnRHa at d 5 and hCG at the time of the induced ovulation (n = 5). The GnRHa and hCG were equally effective in inducing an accessory CL (93% induction rate), but the subsequent increase in progesterone concentrations was greater in hCG-treated heifers. A greater half life of hCG may provide longer LH-like stimulation of the first-wave follicle and subsequent developing accessory CL or a greater luteotropic effect on the original CL. Induction of an accessory CL with hCG on d 5 or 6 after insemination did not increase pregnancy rates in fertile heifers (Exp. 4: hCG = 64.8% vs control = 62.9%; n = 243) or lactating dairy cows during summer heat stress (Exp. 5: hCG = 24.2% vs control = 23.5%; n = 201).

Productive and reproductive performance in cattle infected with bovine leukosis virus

Economic losses caused by enzootic bovine leukosis (EBL) have been of interest since World War II, when the neoplastic form of EEL increased dramatically in Europe. Olson (1974) and House et al. (1975) ed that animals with lymphosarcoma caused by the bovine leukosis virus (BLV) had reduced milk yields. a less efficient reproductive performance and high veterinary costs and mortality rates, while many carcasses were rejected at slaughter. However, the actual impact of BLV infection in cattle without lymphosarcoma is not; clear. The purpose of the study reported here was to compare some productive and reproductive responses of cattle that were antibody-positive (BLV+) or negative (BLV-) for BLV.Holstein dairy cows in commercial dairy farms were used in this study. Blood samples were collected and subjected to BLV serological examination by the agar gel immunodiffusion test of Miller & van der Maaten (1976). Animals were then grouped as BLV+ or BLV- according to their serological response to the BLV antigen. Productive and reproductive histories were obtained from individual animal records and the following factors were considered: milk production, calving interval and birth rate. For milk production, we had the daily milk yields of 547 animals, and for calving interval the time between two successive parturitions for 444 cows. These values were examined by ANOVA and when this was significant a Student's t test was carried out for each age group. Birth rates, the percentage of animals that calved in 1 gear, were available for 557 animals and were examined with the Z-two proportion test. For all analyses, P < 0.05 was considered significant.

Lead poisoning in cattle grazing pasture contaminated by industrial waste

Lead poisoning is described in a herd of 120 Nelore cows of which 35 were affected. All affected cows died after a clinical course of 2-7 d with clinical signs related to cortical neurological disturbances. The source of Pb was fumes from a car battery recycling plant which has had a failure in its filtering system. Lead concentrations in liver and kidneys of 2 cows, in soil;and in grass where the cows were held were respective 39 to 431 ppm, 147 to 431 ppm,and 245ppm. No significant gross changes were observed. Histopathology revealed of neuronal necrosis, vacuolation of the neuropil and hypertrophy of the vascular endothelium inthecerebral cortices, degeneration of the epithelial cellsofrenal proximal tubules, and hemosiderosis of kidney, spleen and liver.

Endectocide activity of a new long-action formulation containing 2.25% ivermectin+1.25% abamectin in cattle

The present work aimed to evaluate the endectocide activity of a new injectable long-action formulation, containing ivermectin (IVM) and abamectin (ABA). In each one of the four experiments performed, the following groups were formed: group I: 2.25% IVM (450 mu g/kg) + 1.25% ABA (250 mu g/kg), group II: 3.15% IVM (630 mu g/kg) and group III: control. Eighteen bovine naturally infected by gastrointestinal nematoda were selected for anthelmintic evaluation and necropsied on posttreatment day (PTD) 14 to estimate the total parasitic burden. For the Rhipicephalus (Boophilus) microplus field trial, 30 bovine were selected by means of counts of semi-engorged R. (B.) microplus and the therapeutic and residual efficacy evaluated by tick counts on PTDs 1, 3, 7, 14, 21, 28, 35, 42, 49, 56, 63, 70, 77, 84 and 91. In the stall test, 15 calves were artificially infested with 5000 R. (B.) microplus (Mozzo strain) larvae three times a week and daily collections of all the engorged female ticks detached from each calf were performed until the PTD 80. Forty bovine naturally infected with Dermatobia hominis larvae were selected and the number of larvae was counted by visual and tactile inspection on PTDs 3, 7, 14, 28, 35, 49, 63, 77, 91 and 105. In this trial, a formulation containing 1% doramectin (200 mu g/kg) was also used. IVM + ABA formulation and 3.15% IVM eliminated four of the eight species of nematode identified. The anthelmintic efficacy of the avermectins association against Haemonchus placei, Cooperia spatulata and C. punctata was 89.64%, 98.84% and 97.69%, while 3.15% IVM achieved 30.98%, 84.79% and 75.56%, respectively. The two formulations evaluated showed reduced acaricide action on the PTD I and 3, reaching high efficacy percentages from PTD 14 onward. The IVM + ABA showed efficacy above 95% in the period between PTDs 21 and 49. In the stall test, it observed no difference (P > 0.05) between the two formulations regarding the R. (B.) microplus counts during the entire evaluation period. IVM + ABA reduced the number of ticks from the PTD 1 to 77 (P < 0.05) and 3.15% IVM reduced (P < 0.05) the tick number from PTD 4 up to PTD 80. The three endectocides showed no difference (P > 0.05) regarding the number of D. hominis larvae and prevented this parasite reestablishment until PTD 105. These results indicate that the IVM + ABA association showed higher anthelmintic activity and similar efficacy against arthropods to the formulation containing 3.15% IVM. (C) 2008 Elsevier B.V. All rights reserved.

Expression and Function of Fibroblast Growth Factor 18 in the Ovarian Follicle in Cattle

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Cara inchada and cellular immunity in cattle

Attempts were made to study possible effects of the periodontal disease cara inchada (CI) on the cellular immunity of cattle, using adherence-, chemotaxis- and ph-agocytosis-determinations. Adherence of Bacteroides melaninogenicus to bovine granulocytes was significantly decreased in animals with CI. Phagacytosis of B. melaninogenicus by polymorphonuclear granulocytes (PMN) was also decreased in CI-diseased animals. Chemotaxis of the granulocytes appeared to be slightly increased in animals with CI and animals without CI coming from CI-affected herds.

An enzyme-linked immunosorbent assay (elisa) for the detection of antibodies against babesia boris in cattle

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Associated and independent comparisons between the two largest follicles preceding follicle deviation in cattle

Follicle diameters and concentrations of follicular fluid factors were studied in the two largest follicles (F1 and F2) using F1 diameters in increments of 0.2 mm (equivalent to 4 h intervals) and extending from 7.4 to 8.4 mm (12 heifers in each of 6 groups). Changes were compared between follicles using the F2 associated with each F1-diameter group. Diameter deviation began in the 8.2-mm group as indicated by a greater (P < 0.05) diameter difference between F1 and F2 in the 8.4-mm group than in the 8.2-mm group. In the 8.0-mm group, estradiol concentrations began to increase (P < 0.05) differentially in F1 versus F2, and free insulin-like growth factor-1 (IGF-1) began to decrease differentially in F2 (P < 0.06). Combined for F1 and the associated F2, activin-A concentrations increased (P < 0.05) between the 7.6- and 8.2-mm groups and then decreased (P < 0.05). Results supported the hypothesis that estradiol and free IGF-1 concentrations simultaneously become higher in F1 than in the associated F2 by the beginning of diameter deviation. Results did not support the hypothesis that a transient elevation in activin-A is present in F1 but not in the associated F2 at the beginning of the estradiol and IGF-1 changes; instead, a mean transient elevation in activin-A occurred at this time only when data for the two follicles were combined. Comparisons between F1 and F2 also were made by independently grouping F2 and using diameter groups at 0.2-mm increments for F2 as well as for F1. In the diameter groups common to F1 and F2 (7.4, 7.6, 7.8, and 8.0 mm) there was a group effect (P < 0.003) for estradiol involving an increase (P < 0.05) beginning at the 7.6-mm group averaged over F1 and F2. For free IGF-1 concentrations, a fluctuation (a significant increase followed by a significant decrease) occurred independently in F1 between the 7.4-to 7.8-mm groups and independently in F2 between the 7.0- to 7.4-mm groups.