Four virgin heifers were experimentally inoculated intravaginally with 7 X 10(6) Tritrichomonas foetus, and 2 heifers served as uninfected controls. The durations of infection were 13, 20, 21, and 28 weeks, respectively. An ELISA that used whole T foetus antigen was used to detect anti-T foetus immunoglobulins (IgA, IgG1, IgG2, and IgM) in vaginal, cervical, and uterine secretions, and sera during the course of infection. The vaginal and cervical antibody responses were characterized by significantly increased T foetus-specific IgA and IgG1 at 7 to 9 weeks of infection, whereas uterine IgA and IgG1 responses peaked at 10 to 12 weeks. The antibody response in serum was predominantly of the IgG1 and IgG2 subclasses. In all reproductive tract regions, IgA persisted at least until the time of T foetus clearance, and usually longer. The next most persistent isotype was IgG1, lasting longest in the vagina, then cervix, and for the shortest time in the uterus. In local secretions, IgG2 was seen only transiently, increasing at weeks 13 to 15 in the vagina, and at weeks 10 to 12 in the cervix. Little IgM, relative to that present before infection, was detected in any secretion or serum, although cervical secretions had the greatest amount. Eight to 12 weeks after clearance, the 4 experimental heifers were inoculated intravaginally with 1 x 10(5) T foetus, transient infections (2 to 3 weeks' duration) were established in only 2 of 4 heifers, as determined by culturing of reproductive tract secretions. The lag times of antibody responses during this reinfection were shorter than in the initial infection, and ELISA optical densities were at least as high as during the primary infection, suggesting an anamnestic response.

Heifers were inoculated IV with 1 of 4 modified-live bovine herpesvirus-1 vaccinal strains against infectious bovine rhinotracheitis (2 heifers/strain) on postbreeding day (PBD) 14. The effect of infection on fertility was monitored by plasma progesterone assay at 1- to 3-day intervals from the time of virus exposure until PBD 60. Infertility was detected in 4 of 8 inoculated heifers. In 2 heifers, progestrone concentrations decreased to values indicative of estrus within 10 days after inoculation (PBD 24). The 2 other heifers had evidence of embryonic death on PBD 40 and 42. Two control heifers inoculated with culture medium from noninfected cells maintained their pregnancies.

Heifers injected with 10(8) (n = 40), 10(9) (n = 39), or 10(10) (n =39) colony-forming units of Brucella abortus strain 19 were conjunctivally exposed to 10(7) colony-forming units of strain 2308 during gestation. At parturition, milk from each quarter of the udder, a piece of placenta, and 2 swab specimens of the uterus from the dam plus a swab specimen of the rectum from each calf were cultured for Brucella. If the calf was dead or died, additional specimens of lung, stomach contents, and a mediastinal lymph node also were cultured. Days in gestation was determined for each heifer, using data from rectal palpation after breeding and crown-rump length and weight of calf at parturition, with the median value used for data analysis. In each vaccine dosage group, the proportion (%) of heifers developing brucellosis increased as days in gestation at exposure increased. Strain 2308 was isolated from 3 (11%) of 26, 16 (25%) of 64, and 18 (64%) of 28 heifers that were grouped as less than 121, 121 to 150, and greater than 150 days in gestation at time of exposure, respectively. Thirty-two (86%) of the 37 infected heifers were less than 260 days in gestation at parturition, and calves were premature. Heifers with premature calves were more likely to be infected, and tissues were more likely to yield multiple isolations of strain 2308, regardless of days in gestation at exposure or of days after exposure to parturition. Days after exposure to premature parturition of infected heifers ranged from 35 to 110.

The objective of this study was to evaluate the effect of late-gestation vaccination of beef heifers with 2 doses of a killed-virus (KV) vaccine containing bovine herpesvirus 1 (BoHV-1), bovine viral diarrhea virus 1 (BVDV-1), and bovine viral diarrhea virus 2 (BVDV-2) on the serum concentrations of antibody against BoHV-1, BVDV-1, and BVDV-2 in heifers and their calves and on the IgG concentration in the calves. Of the 47 pregnant beef heifers selected, 26 received 2 doses of the vaccine at 6.5 to 8 mo of gestation (at pregnancy check), and 21 received 2 doses of saline. The mean log2 serum titers of neutralizing antibody against BoHV-1, BVDV-1, and BVDV-2 before vaccination did not differ significantly between the treatment groups; however, at calving all 3 mean titers were significantly greater (P < 0.05) in the vaccinated heifers than in the control heifers. At 24 h after birth the mean serum IgG levels in the calves did not differ significantly between the 2 groups, at 30.18 and 32.28 g/L, respectively (P < 0.05); however, the mean log2 serum titers of antibody to all 3 viruses were greater in the calves nursing colostrum from the vaccinated heifers than in the calves nursing colostrum from the nonvaccinated heifers and significantly so for BoHV-1 and BVDV-1 (P < 0.001 and P = 0.009, respectively). Thus, late-gestation vaccination of beef heifers could result in a greater and more consistent deposition of specific antibodies in colostrum, reducing the variability of initial titers in calves and increasing the duration of maternal immunity.

The present study was designed to assess the therapeutic efficacy of Randia dumetorum, Tinospora cordifolia and commercial herbal medicine (Prajana HS, Indian Herbs Overseas) for induction of cyclicity in anoestrus buffalo heifers.Fourty eight anoestrus buffalo heifers were examined and redistributed into six groups(G0, G1, G2, G3, G4 and G5) and each comprising of eight (n=8) animals. Untreated anoestrus animals (G0) andcyclic animals (G6) were kept as an anoestrus control and cyclic control, respectively. Group G1 wassupplemented with the mineral mixture, while G2, G3, G4, and G5 groups were treated with Prajana HS, Randiadumetorum,Tinospora cordifolia,and the combination of Randia dumetorum andTinospora cordifolia,respectively along with supplementation of mineral mixture. Overall estrus induction and conception rate were recorded as 50 % and 75 % in mineral mixture (G1),75 and 83.33 % in Prajana HS (G2), 87.50 % and 85.71 % in Randia dumetorum (G3), 62.5% and 80% inTinospora cordifolia (G4), and 87.5% and 85.71% in Randia dumetorum and Tinospora cordifolia combination(G5) whereas none of heifers were exhibited estrus symptom in untreated anoestrus control group.

Objective—To evaluate immunomodulatory properties of all-trans retinoic acid and a fully oxidized β-carotene dietary product in calves with Mannheimia haemolytica–induced pneumonia. Animals—Twenty-five 6- to 10-week-old male Holstein calves for experimental inoculations and three 8- to 30-week-old Angus heifers for blood donations. Procedures—In vitro, neutrophils and monocyte-derived macrophages isolated from blood of healthy Angus heifers were treated with all-trans retinoic acid (1μM) or fully oxidized β-carotene (8.3 μg/mL) for various times and assessed for markers of cellular death, antimicrobial function, and production of proinflammatory leukotriene B4. Following 28 days of dietary supplementation with fully oxidized β-carotene, Holstein calves were experimentally inoculated with M haemolytica. Bronchoalveolar lavage fluid was collected at 3 and 24 hours after challenge inoculation and analyzed for markers of apoptosis. Results—In vitro, all-trans retinoic acid and fully oxidized β-carotene induced cell-selective, caspase-3–dependent apoptosis in neutrophils, which subsequently enhanced efferocytosis in macrophages. Conversely, neither treatment altered phorbol 12-myristate 13-acetate–induced oxidative burst, phagocytosis of nonopsonized zymosan (complement or antibody independent), or M haemolytica–induced leukotriene B4 production in bovine neutrophils. In vivo, fully oxidized β-carotene enhanced leukocyte apoptosis in bronchoalveolar lavage fluid as well as subsequent efferocytosis by macrophages without altering numbers of circulating leukocytes. Conclusions and Clinical Relevance—Neutrophil apoptosis and subsequent efferocytosis by macrophages are key mechanisms in the resolution of inflammation. Findings for the present study indicated that all-trans retinoic acid and fully oxidized β-carotene could be novel nutraceutical strategies that may confer anti-inflammatory benefits for cattle with respiratory tract disease.

Changes in luteinizing hormone (LH) secretion after 17beta-estradiol (E2) injection were evaluated during sexual maturation in 10 prepubertal Nelore heifers. Heifers were divided into 2 groups: intact (I) and ovariectomized (OVX). 17beta-estradiol (2 micrograms/kg) was administered to both groups at 10, 13, and 17 mo of age. Only at 10 mo of age was there a greater mean LH concentration in OVX heifers (1.33 +/- 0.29 ng/mL) compared with the I group (0.57 +/- 0.15 ng/mL). At 13 and 17 mo of age there was no significant difference between the 2 groups in any of the evaluated variables (number of peaks, total peak area, greatest peak area, and time to greatest peak occurrence). This suggests a decrease in negative E2 feedback associated with an increase in positive feedback to LH secretion during sexual maturation, and these were likely the key factors that determined the time of first ovulation in Nelore heifers.