Changes in the testis seminiferous tubules and interstitium in prepubertal bull calves immunised against inhibin at the time of gonadotropin administration

The aim of the present study was to evaluate the effects of gonadotropin administration at initiation of inhibin passive immunisation in Jersey bull calves (age 27 � 5 days) on testicular morphology and development. Primary treatments consisted of control (keyhole limpet haemocyanin, KLH; n = 9) or immunisation against inhibin (INH; n = 9). Subsets of calves were randomly assigned within primary treatments (TRT) to receive saline ( n = 3 per TRT), follicle-stimulating hormone (FSH; n = 3 per TRT) or gonadotrophin-releasing hormone (GnRH, n = 3 per TRT). The right testis was removed (age 118 � 5 days) to determine volumes of testicular components and cell numbers per testis using stereology. Data were analysed using the MIXED procedure of the SAS program. Antibody titres against inhibin were increased in INH bulls compared with KLH bulls (P < 0.05). In addition, a significant immunisation � hormone treatment interaction was noted for the number of germ cells. Administration of FSH at the time of initial immunisation against inhibin significantly increased the number of germ cells (92.2 � 9 � 106 cells) compared with INH+saline bulls (54.9 � 10 � 106 cells), with INH+GnRH bulls having an intermediate number of cells (64.5 � 9 � 106 cells; P < 0.05). These results suggest that gonadotropin administration at the time of inhibin immunisation increases the number of germ cells in the testis.

Fertility aspects in yearling beef bulls grazing endophyte-infected tall fescue pastures

During a 2-year study, yearling beef bulls were used to determine the effects of grazing on endophyte-infected tall fescue on endocrine profiles, semen quality and fertilisation potential. Bulls were allotted to graze tall fescue pastures infected with Neotyphodium coenophialum (E+; n = 20 per year) or Jesup/MaxQ (Pennington Seed, Atlanta, GA, USA; NTE; n = 10 per year). Bulls were grouped by scrotal circumference (SC), bodyweight (BW), breed composites and age to graze tall fescue pastures from mid-November until the end of June (within each year). Blood samples, BW, SC and rectal temperatures (RT) were collected every 14 days. Semen was collected from bulls every 60 days by electroejaculation and evaluated for motility and morphology. The developmental competence of oocytes fertilised in vitro with semen from respective treatments was determined. Bulls grazing E+ pastures had decreased BW gain (P < 0.01), increased overall RT (P < 0.01) and decreased prolactin (P < 0.01) compared with animals grazing NTE pastures. Neither percentage of normal sperm morphology nor motility differed between bulls grazed on the two pasture types. Semen from E+ bulls demonstrated decreased cleavage rates (P = 0.02) compared with semen from NTE bulls. However, development of cleaved embryos to the eight-cell and blastocyst stages did not differ between the two groups. In conclusion, semen from bulls grazing E+ tall fescue resulted in decreased cleavage rates in vitro, which may lower reproductive performance owing to reduced fertilisation ability.

308 TESTICULAR DEVELOPMENT IN PREPUBERTAL JERSEY BULL CALVES IMMUNIZED AGAINST INHIBIN

Previous studies have shown that immunization against inhibin (INH) in bull calves increased subsequent sperm production (Martin et al. 1991 Biol. Reprod. 45, 73; Bame et al. 1996 Biol. Reprod. 54, 328). The objective of the current study was to evaluate the effectiveness of gonadotropin administration at initiation of inhibin immunization in bull calves on testicular morphology. The study was performed using the inhibin peptide (bovine inhibin α1–26) conjugated to keyhole limpet hemocyanin (KLH). Primary treatments administered to Jersey bull calves (initial immunization at 27 ± 5 days of age; Day 1 of the experimental period) consisted of control (KLH, 250 µg, n = 9) or immunization (INH; 500 μg INH: 250 µg KLH, n = 9) with each emulsified in 2 mL of Freund's complete adjuvant (FCA). Booster immunizations (identical preparation in FCA) occurred every 21 days with the last administration on Day 84 of the trial. Subsets of calves were randomly assigned within primary treatments (TRT) to receive saline (1 mL, n = 3/TRT), FSH (20 mg, n = 3/TRT), or GnRH (50 μg, n = 3/TRT) every 8 h (0600, 1400, and 2200 h) from Day 1 to Day 3 of the study. Blood samples were obtained daily from Days 0–14 and weekly until testes collection (Day 91) for FSH, LH, testosterone (T), and determination of antibody titers. Body weight and scrotal circumference (SC) were measured at each immunization and immediately before testes removal. The right testis was weighed and used for absolute volume calculation of cell components per testis. Tissue sections were examined using a light microscope (400×). For each cell type, absolute volume of Sertoli, Leydig, and germ cells were counted according to the point counting method. Data were analyzed using MIXED procedure of SAS (SaS Institute, Inc., Cary, NC, USA). Antibody titers were increased in INH bulls compared to KLH bulls (P < 0.05) during the experimental period. Body weight (89.8 ± 14.2 kg), SC (14.6 ± 1.3 cm), and single testicular weight (19.2 ± 6.2 g) recorded at the end of the experimental period did not differ between treatments. Neither serum concentrations of FSH, LH, and T nor population of Leydig and Sertoli cells differed between treatment groups. However, a significant immunization X hormone treatment interaction was noted for germ cell volume per testis (P < 0.008). Administration of FSH at the time of initial immunization against inhibin significantly increased germ cell population (1.22 ± 0.1 cm3) compared to INH-saline bulls (0.64 ± 0.1 cm3) with INH-GnRH bulls intermediate (0.84 ± 0.1 cm3; P < 0.05). In contrast, germ cell volume was not increased following hormone administration in KLH bulls. These results suggest that gonadotropin administration at the time of inhibin immunization increases germ cell volume in the testis without altering Sertoli and Leydig cell volume.

Cloning adult farm animals: a review of the possibilities and problems associated with somatic cell nuclear transfer

In 1997, Wilmut et al. announced the birth of Dolly, the first ever clone of an adult animal. To date, adult sheep, goats, cattle, mice, pigs, cats and rabbits have been cloned using somatic cell nuclear transfer. The ultimate challenge of cloning procedures is to reprogram the somatic cell nucleus for development of the early embryo. The cell type of choice for reprogramming the somatic nucleus is an enucleated oocyte. Given that somatic cells are easily obtained from adult animals, cultured in the laboratory and then genetically modified, cloning procedures are ideal for introducing specific genetic modifications in farm animals. Genetic modification of farm animals provides a means of studying genes involved in a variety of biological systems and disease processes. Moreover, genetically modified farm animals have created a new form of 'pharming' whereby farm animals serve as bioreactors for production of pharmaceuticals or organ donors. A major limitation of cloning procedures is the extreme inefficiency for producing live offspring. Dolly was the only live offspring produced after 277 attempts. Similar inefficiencies for cloning adult animals of other species have been described by others. Many factors related to cloning procedures and culture environment contribute to the death of clones, both in the embryonic and fetal periods as well as during neonatal life. Extreme inefficiencies of this magnitude, along with the fact that death of the surrogate may occur, continue to raise great concerns with cloning humans.

Breeding soundness evaluations of 3,648 yearling beef bulls using the 1993 Society for Theriogenology guidelines

Our objective was to perform a retrospective analysis of breeding soundness evaluations (BSEs) as classified by the 1993 Society for Theriogenology (SFT) guidelines [Chenoweth et al., Guidelines for using the bull breeding soundness evaluation form, in: Theriogenology Handbook, 1993, pp. B-10]. Data included BSE information obtained from five performance-testing stations in South Carolina (SC1, SC2, SC3) and Tennessee (TN1, TN2) from 1986 through 1999 on 3648 Angus, Brangus, Charolais, Chianina, Gelbvieh, Limousin, Polled Hereford, Santa Gertrudis, Simbrah, and Simmental bulls. Analyses were simplified by classifying all bulls as either satisfactory or unsatisfactory potential breeders. Of the 3648 bulls evaluated, 76.2% were classified as satisfactory potential breeders. Of all bulls evaluated, 4.0% were unsatisfactory due to inadequate spermatozoal motility, 7.0% due to inadequate spermatozoal morphology and 2.6% due to a combination of inadequate motility and morphology. Unsatisfactory classifications due to non-spermatozoal parameters out of all bulls were 10.2%, with 7.1% for inadequate scrotal circumference and 3.1% for physical abnormalities. For satisfactory and unsatisfactory bulls, respectively, means and standard deviations were 35.8 +/- 2.7 and 33.0 +/- 4.1 cm (P < 0.001) for scrotal circumference, 63 +/- 18 and 35 +/- 24% (P < 0.001) for percent motility, and 86 +/- 7 and 63 +/- 21% (P < 0.001) for percent normal morphology.

Outcomes of breeding soundness evaluation of 2898 yearling bulls subjected to different classification systems

This study is a retrospective analysis comparing data on yearling bull breeding soundness evaluation (BSE) subjected to 3 different classification systems: the Society for Theriogenology (SFT) 1983 and 1993 systems, and the Western Canadian Association of Bovine Practitioners (WC) 1993 system. Data were collected at 5 performance bull-test stations located in South Carolina and Tennessee from 1986 through 1996. Yearling bulls (n=2898) that were 10 to 20 mo of age were used in the analysis. To simplify analysis, bulls were determined to be either satisfactory or unsatisfactory potential breeders (including those classified as questionable, deferred or unsatisfactory). Data were analyzed 1) within location where a location was treated as an individual experiment, 2) with breeds and locations collapsed, and 3) within age-group where each age-group was treated as an individual experiment. An ANOVA was performed using GLM procedures of SAS, and this model was used to generate least square means for the proportion of bulls classified as satisfactory and the 5 possible unsatisfactory outcomes due to inadequacies in scrotal circumference, spermatozoal morphology, spermatozoal motility, a combination of inadequate spermatozoal morphology and motility, or physical abnormalities. Inadequate scrotal circumference or physical abnormality did not affect differences for BSE outcomes among systems. Using the SFT93 system, bulls failed at a higher rate due to inadequate spermatozoal morphology (P < 0.05) than when subjected to the SFT83 system. In the WC93 system, a higher percentage of bulls failed due to inadequate spermatozoal motility and to a combination of inadequate spermatozoal morphology and motility than in the other 2 systems (P < 0.05). The proportion of bulls in this data failing under the WC93 system appears to be the result of overestimation.

Endocrine profiles of dairy cows following experimentally induced clinical mastitis during early lactation

Concentrations of LH, cortisol, estradiol-17beta (E(2)), prolactin and 13,14-dihydro-15-keto-prostaglandin F(2alpha) (PGFM) were determined in cows with experimentally induced clinical mastitis during early lactation. Cows free of intramammary infection (IMI) and in the luteal phase of the estrous cycle were balanced by lactation number and days in milk and assigned to either control (n=5) or treatment (n=5) groups. Treated cows were infected experimentally (day 0), in two mammary quarters, with Streptococcus uberis and developed clinical mastitis within 60 h after inoculation as evidenced by increased mastitis scores, elevated rectal temperatures, mammary swelling and isolation of S. uberis pathogen. Four days following bacterial challenge, blood samples were collected every 20 min for 8 h for determination of PGFM and LH following administration of oxytocin and GnRH, respectively. Blood samples were also collected on days 0, 4 and 7 of the experiment to determine concentrations of E(2), prolactin and cortisol. Four days after bacterial challenge, concentrations of cortisol were higher (P=0.04) in experimentally infected cows than controls. Experimentally challenged cows had increased (P=0.02) concentrations of cortisol on days 4 and 7 compared with day 0. Control cows had no significant increase in blood cortisol during the experimental period. Baseline concentrations of PGFM did not differ between groups; however, peak concentrations of PGFM following oxytocin challenge were elevated (P=0.006) in cows with clinical mastitis compared with control animals. Prolactin, E(2) and LH did not differ between cows with clinical mastitis or controls. Experimentally induced mastitis during early lactation elevated concentrations of cortisol during the luteal phase of the estrous cycle. Furthermore, mastitic cows demonstrated an increased PGFM response following oxytocin administration. Altered reproductive efficiency in cows with clinical mastitis caused by Gram-positive pathogens may be the result of increased uterine sensitivity to prostaglandin F(2alpha) (PGF(2alpha)).

Effects of administration of oxytocin on embryonic survival in progestogen supplemented cattle

Embryonic survival after administration of oxytocin (OT) was examined in 42 beef cows. All cows were bred (Day 0) and randomly assigned to receive either 25 mL saline (CON; n = 10), 100 IU OT + 20 mL saline (OT; n = 12), 100 IU OT + 1 g flunixin meglumine (OT + FM; inhibitor of prostaglandin endoperoxide synthase; n = 10), or 100 IU OT + lutectomy (OT + LUT; n = 10) administered (i.m.) at 8-h intervals on Days 5-8 after mating. Lutectomies were performed by transrectal digital pressure prior to initiation of treatments (0600, Day 5). All cows were fed 4 mg/head/day of melengesterol acetate (an orally administered exogenous progestogen) through Days 3-30 and were bled by jugular venipuncture at 0600 and 0700 h on Day 5 for determination of 13,14-dihydro-15-keto-PGF2a (PGFM). Pregnancy rates, as determined by transrectal ultrasonography at Day 30, were reduced in OT (33.3%) and OT + LUT (30%) groups compared to CON and OT + FM (80%; p < or = 0.03). Number of short cycles were increased in OT (n = 6/12) group compared to CON (n = 0/10; p < or = 0.009) and OT + FM (n = 1/10; p < or = 0.045). Mean change in PGFM from the 0600 to 0700 h bleed was different (p < or = 0.01) between the OT + LUT (31.6 +/- 11.0 pg/mL) group versus CON (-11.2 +/- 10.6 pg/mL) and OT + FM (-13.8 +/- 10.6 pg/mL) groups. Administration of oxytocin appears to decrease embryonic survival by stimulating uterine PGF2a. Thus, previous reports indicating that removal of the corpus luteum during progestogen supplementation and prior to PGF2a administration increases embryonic survival can be explained through interruption of the luteal oxytocin-uterine PGF2a feedback loop.

Effects of elevated concentrations of prostaglandin F2 alpha on pregnancy rates in progestogen supplemented cattle

An experiment was performed to determine the effect of elevated prostaglandin F2 alpha (PGF2 alpha) on pregnancy rates of progestogen-treated bred cows in the presence or absence of luteal tissue. Ninety-one beef cows were bred (Day 0) and assigned randomly to receive either 3 mL saline (CON), 15 mg PGF2 alpha, or 15 mg PGF2 alpha + lutectomy (P + L) administered intramuscularly (i.m.) at 8 h intervals on either Days 5-8, 10-13, or 15-18 postbreeding. Lutectomies were performed by transrectal digital pressure before initiation of treatment on Day 5, 10, or 15 for the respective treatment groups. All cows were fed 4 mg/day of melengesterol acetate from two days prior to initiation of treatment until Day 30 postbreeding. Mean concentrations of 13,14-dihydro-15-keto-PGF2 alpha (PGFM) were increased in cows administered PGF2 alpha and P + L treatments (398 +/- 23 and 413 +/- 22 pg/ml, respectively; p < 0.01) compared to the CON group (80 +/- 29 pg/ml) regardless of treatment group. Mean concentrations of oxytocin (OT) were increased in cows given PGF2 alpha on Day 10 and 15 (p < or = 0.0001) and tended to be increased on d 5 when compared to CON and P + L treatment groups on Day 5. Pregnancy rates were reduced (p < or = 0.03) in the PGF2 alpha treatment group (23%) and by Day 5-8 compared to CON (72%). Lutectomy tended to improve pregnancy rate in P + L (5-8; 55%) compared to PGF2 alpha (5-8; p = 0.1). Pregnancy rates tended (p < or = 0.07) to increase in the PGF2 alpha treatment groups on Days 5-8 treatment (23%, 50%, and 60% for Days 5-8, 10-13, and 15-18, respectively). The later the treatments were initiated pregnancy rates did not differ between treatments given on Days 10-13 and 15-18. In conclusion, the most susceptible period of embryonic growth to the negative effects of PGF2 alpha was during morula to blastocyst development. Removal of luteal tissue diminishes the negative effects of PGF2 alpha through interruption of the luteal oxytocin-uterine PGF2 alpha feedback loop.

Breeding soundness evaluation of yearling bulls

Breeding Soundness Evaluations (BSEs) are a useful tool to improve reproductive performance and profitability in beef herds. Veterinarians providing this service must be thorough in their evaluation, especially in yearling bulls. The 1993 Society for Theriogenology guidelines for BSE provide appropriate standards for classifying yearling bulls; veterinarians are advised to adhere to these standards as minimums for classification of the satisfactory potential breeder.

The new Society for Theriogenology breeding soundness evaluation system

In 1993, The Society for Theriogenology published revised standards for breeding soundness evaluation of bulls. These revised standards replaced the old semen score format with minimum acceptable scores for scrotal circumference (varies with age), motility (30% or fair), and morphology (70%).

Successful treatment of retained placenta with umbilical cord injections of collagenase in cows

Fetal membranes usually are released from the uterus between 2 and 6 postpartum hours. However, in a substantial percentage of cows (11%), fetal membranes are retained for several days. In part, failure of collagen breakdown seems to be related to retention of fetal membranes. Injections of 200,000 U of bacterial collagenase in 1,000 ml of physiologic saline solution via umbilical arteries (1 or 2) between 24 and 72 hours of retention caused release of retained fetal membranes in 23 of 27 cows (85%) with noninduced retained fetal membranes and in 10 of 14 cows (71%) with experimentally induced retained fetal membranes, within 36 hours after injection. Controls (n = 36) did not release retained fetal membranes within this time. Injections of collagenase via a jugular vein (2.2 x 10(6) U in 1,000 ml of physiologic saline solution), administered over a 30-minute period, caused release of retained fetal membranes within 36 hours in 3 of 6 cows with experimentally induced retained fetal membranes. Clinical complications did not follow treatments with collagenase. Umbilical injections of bacterial collagenase were highly effective in the treatment of retained fetal membranes in cows. The procedure is simple, safe, affordable, and can be completed in 25 minutes.

Expression and cellular localization of retinol-binding protein messenger ribonucleic acid in bovine blastocysts and extraembryonic membranes

A cDNA clone encoding retinol-binding protein (RBP) was isolated from a bovine conceptus cDNA library by use of an antiserum specific for bovine conceptus RBP (bcRBP). The RBP cDNA clone, designated bcRBP-700, is 732 bp in length and codes for a protein whose predicted amino acid sequence is identical to that of bovine plasma RBP. The size of the RBP mRNA transcript in bovine chorioallantois was approximately 1.4 kb as determined by Northern blot analysis. Expression of the protein and its mRNA in expanding bovine conceptuses (Day 13) and extraembryonic membranes (Day 45) was determined by immunocytochemistry with anti-bcRBP serum and in situ hybridization with 35S-labeled bcRBP-700 cDNA. Strong immunostaining for RBP and hybridization signals for RBP mRNA were observed in trophectoderm of tubular but not spherical Day 13 blastocysts. RBP mRNA was localized in epithelial cells lining the chorion, allantois, and amnion at Day 45 of pregnancy. In addition, RBP mRNA was detected in cotyledons, the sites of chorionic attachment to the uterine endometrium and physiological exchange between the embryo and its mother. Expression of RBP in expanding conceptuses, developing extraembryonic membranes, and sites of fetal-maternal attachment suggests that the extraembryonic membranes regulate retinol transport and availability within the conceptus.

Bovine retained placenta: effects of collagenase and hyaluronidase on detachment of placenta

A significant percentage of cows (11%) fail to release the placenta within 12 h postpartum. Failure of collagen breakdown seems to be related to the retention of placentas. Sections of placentomes incubated with bacterial collagenase caused an increase in placentome proteolysis (6.6-fold) and placentome collagenolysis (94-fold) within 4 h in a dose-related fashion (r = 0.94). Injections of collagenase (825 U/cc) into the placentomes, via umbilical vessels, decreased the cotyledon-caruncle binding force (determined by manometry) to 30 +/- 5 mm Hg from 97 +/- 2 mm Hg, and increased proteolysis by 42% within 8 h (r = -0.95). Hyaluronidase at various concentrations (400-8 250 U/cc) and at various incubation times (up to 8 h) was not effective. Hyaluronidase (825 U/cc) and collagenase (825 U/cc) were not synergistic in loosening cotyledon-caruncle attachment. A single 15-min collagenase pulse, given prior to perfusion with collagenase-free blood, was as effective in loosening cotyledon attachment as was a sustained 2-h perfusion of blood with collagenase added. It was concluded that collagenase caused collagenolysis and loosening of cotyledon from caruncle, but collagenolysis and cotyledon-caruncle separation were not facilitated by the presence of hyaluronidase.

Total mesh wrapping for parenchymal liver injuries--a combined experimental and clinical study

This study examined a mesh wrap technique that provides effective hepatic tamponade and clinical experience with the technique in 6 patients is reported. Technical feasibility and effectiveness were investigated in 8 miniature swine. The animals were divided into two groups: group A (n = 4), control animals; stellate liver lacerations without mesh wrap or other measures for hemostasis, and group B (n = 4); stellate liver laceration with synthetic absorbable mesh wrap applied for hepatic hemostasis. Except for mesh application, all variables were held constant for both groups. All animals in the control group died within 20 to 120 minutes (mean: 65 minutes). All animals in group B survived (p = 0.029). The livers were harvested for gross and microscopic examinations. No abscess, bile leak, or hematoma was noted. Clinically, total mesh wrapping was attempted in 6 patients with blunt exsanguinating liver injuries. The technique failed intraoperatively in two patients with juxtacaval lacerations and hepatic vein avulsion injuries. One patient with a bilobar gunshot wound died later of sepsis. In three patients with bursting injuries, the technique successfully controlled bleeding and resulted in long-term survival. In conclusion, the total hepatic mesh wrap (1) is geometrically, technically, and mechanically feasible, (2) was not associated with complications in this series, and (3) can effectively secure hemostasis following parenchymal liver injury.

Clearance of exogenous carnitine in bovine semen: Potential diagnosis of epididymal function and patency of the ductus deferens

Carnitine content in the ejaculate depends mainly on the capability of the epididymis wall to transfer carnitine from the blood and on the patency of ejaculatory ductus systems. An elevation of carnitine in semen subsequent to an intravenous injection of carnitine is expected. Intravenous injections of carnitine (L-isomer and DL-isomers) caused a significant (P <0.05) elevation (more than 10-fold) in blood carnitine. However, carnitine injection failed to increase net secretion of carnitine into the ejaculate and blood elimination half-life was 2.3 hours. Mean concentrations of carnitine in the electroejaculate (3.0 nmoles/ml) were significantly lower than in the ejaculate following natural mating (180 nmoles/ml). Vasectomy decreased net carnitine per ejaculate to about 1/5 the prevasectomy value, when ejaculate was collected following natural mating. However, vasectomy did not affect carnitine concentrations in semen collected by electroejaculation. Twenty-one percent of the carnitine in semen originated in the accessory glands and 79% in the epididymides. Carnitine in the electroejaculate was originated almost exclusively in the accessory glands. It was concluded that the diagnostic value of carnitine in semen is limited. Some considerations are: secretion of carnitine is not organ specific, there are large individual variations, there is a negative effect of electroejaculation, and a carnitine loading dose technique is not feasible. However, there is a diagnostic potential in using carnitine assay to detect epididymides occlusion, but only when ejaculate is collected by an artificial vagina.

Changes in the proportion of type I and type III collagen in the developing and retained bovine placentome

The proportions of Type I and Type III collagen were evaluated from gestational, postpartum-retained, and released bovine placental membranes. Placentomes were excised at 90, 150, 210, and 270 days of gestation (n = 32) and from postpartum-retained (2 and 12 h, n = 8) and released (2 h, n = 4) membranes. Placentome components were processed for collagen, hydroxyproline, protein, and dry weight determination. Collagen extracts were separated by SDS-PAGE. Densitometry was used to establish the proportions of collagen alpha chains (Type I = 2 alpha 1 + 1 alpha 2; Type III = 3 alpha 1). No difference in the proportion of maternal caruncular Type I and Type III collagen was found. The proportion of Type I fetal cotyledonary collagen was lowest (p less than 0.05) at Day 90 of gestation but did not differ between Days 150, 210, 270, or between retained and released fetal membranes. The proportion of Type III fetal cotyledonary collagen was greatest (p less than 0.05) at Day 90. Retained fetal cotyledons had a greater (p less than 0.05) proportion of Type III collagen than did released fetal cotyledons. Therefore, although hydroxyproline content was not different between retained and released fetal membranes, the retained bovine fetal cotyledon was characterized by disproportionate amounts of Type III collagen as compared to the fetal cotyledon that was not retained.

Uterokinetic activity of fenprostalene (a prostaglandin F2α analog) in vivo and in vitro in the bovine

The luteolytic potency of fenprostalene (a PGF2alpha analog) is about 20-times that of naturally produced PGF2alpha. The objective of this research was to investigate the uterokinetic effects of fenprostalene at a luteolytic dosage (1.0 mg) in the cyclic and early postpartum cow, and in the isolated uterine horn. Uterine motility measurements were conducted on two consecutive days in each cow. Experimental protocol on Day 1 was: spontaneous motility was recorded for 1 h; fenprostalene was injected (1.0 mg i.m.), after which motility was recorded for 2 h; fenprostalene was injected (1.0 mg i.v.) and motility was recorded for 30 min; and oxytocin was injected (40 U i.v.), followed by a 30-min recording period. On Day 2, the treatment sequence was reversed: spontaneous motility was recorded for 1 h; oxytocin was injected (100 U i.m.), after which motility was recorded for 2 h; fenprostalene was injected (1.0 mg i.v.) and motility recorded for 30 min; and oxytocin was injected (40 U i.v.), followed by a 30-min recording period. In the in vitro experiment, different dosages of fenprostalene (5.9, 11.8, 17.6, and 29.4 ng/ml bath solutions) and oxytocin (0.06, 0.12, 0.18, and 0.60 mU/ml bath solutions) were tested in pairs for 1 h. The treatment was then repeated. In a different group, fenprostalene (5.9 ng/ml bath solution) and oxytocin (0.06 mU/ml bath solution) treatments were alternated. Fenprostalene (at luteolytic dosage) was not uterokinetic in either the cyclic or postpartum cow. However, fenprostalene and oxytocin had a significant uterokinetic effect (five- to six-fold pretreatment value) on the isolated uterine horn preparation at all dosages studied. Peak motility occurred between 10 to 15 min, followed by a gradual decrease to 40% at 60 min. When the treatments were repeated at 60 min, oxytocin but not fenprostalene caused a minute, transient contraction. However, fenprostalene-desensitized (by exposure to fenprostalene) uteri reacted significantly to oxytocin, and vice versa.

Induction of pulmonary antibodies to Pasteurella haemolytica following intraduodenal stimulation of the gut-associated lymphatic tissue in cattle

The induction of pulmonary antibodies to a bacterial antigen following intraduodenal (D) stimulation of the gut-associated lymphatic tissue (GALT) was investigated. Six calves were divided into two groups of three calves each. The GALT-primed calves received an ID dose of live Pasteurella haemolytica A1 followed by a subcutaneous (SC) dose of killed P. haemolytica. The sham-primed calves received an ID dose of phosphate-buffered saline solution (PBSS) followed by a SC dose of killed bacteria. Serum and pulmonary lavage fluids were collected weekly from each calf and assayed for titers of leukotoxin neutralizing antibodies (LNA), as well as IgG and IgA (lavage fluids only) to P. haemolytica. The GALT-primed calves responded to the ID stimulation by bacteria with increased serum IgG. The sham-primed calves had no change in antibody titers following ID stimulation. The GALT-primed calves had increased serum IgG, lavage IgG and IgA and increased LNA titers in both lavage fluids and serum following the SC dose of killed bacteria. The sham-primed calves demonstrated only an increase in serum IgG following the SC inoculation. A challenge study to evaluate if antibodies induced by GALT stimulation could reduce pulmonary lesions was performed using six calves divided into two groups. One group received an ID dose of P. haemolytica followed two weeks later by a SC dose of killed P. haemolytica. The sham vaccinated calves received an ID dose of PBSS followed in two weeks by a SC dose of killed bacterin. Calves were challenged by an intrapulmonary dose of live P. haemolytica A1 eleven days after the SC inoculation.(ABSTRACT TRUNCATED AT 250 WORDS)

Morphometric analysis of collagen in gestational and retained bovine placentomes

Bovine placentome collagen was quantified (P<0.01) at four gestational stages (90, 150, 210 and 270 d, n = 8 d ), at 2 h post partum without (n = 4) and at 2 and 12 h post partum with (n = 8) experimentally-induced placental retention. Placentome sections were fixed and stained for collagen. Fetal cotyledonary (FC) collagen volume fraction (V(V)) increased over days of gestation studied (V(V)=0.03+/-0.01, 0.06+/-0.01, 0.13+/-0.01 and 0.19+/-0.01). Fetal cotyledonary hydroxyproline (3.15+/-0.41, 4.55+/-0.41 and 7.04+/-0.41 mg/g) and FC protein (432.0+/-17.1, 479.9+/-17.1, 585.4+/-17.1 mg/g) increased over Days 90, 150 and 210 and were similar on Days 210 and 270. Fetal cotyledonary collagen V(V) and hydroxyproline did not differ between Day 270, retained and nonretained cotyledons. Protein concentration was higher in 2 h (578.1+/-18.5 mg/g) and 12 h (526.0+/-18.5 mg/g) retained versus nonretained (400.4+/-36.2 mg/g) cotyledons. Maternal caruncular (MC) collagen V(V) and protein concentration were higher on Days 90 and 150 than on Days 210 and 270. Maternal caruncular hydroxyproline was similar from Day 90 to 210 and increased from Day 210 to 270. Maternal caruncular collagen V(V), hydroxyproline and protein concentrations were similar on Day 270 and in 2 h and 12 h retained membrane caruncles. Gestational increases in placentome collagen occurred from FC sources. No difference in FC or MC collagen V(V) existed between Day 270, retained and nonretained placentomes.

Breeding soundness examination of yearling beef bulls

Yearling beef bulls were subjected to a breeding soundness examination (BSE) at completion of performance testing programs at 4 locations over 5 years. Of 862 bulls, 80.1% were classified as satisfactory potential breeders, 7.3% as questionable potential breeders, and 12.7% as unsatisfactory potential breeders. Year (P less than 0.01), location (P less than 0.01), and breed (P less than 0.01) affected the percentage of bulls classified as satisfactory; age of the bulls did not affect this percentage. Adjusted mean scrotal circumference (SC) measurements were 31, 33.2, and 34.8 cm for bulls classified as unsatisfactory, questionable, and satisfactory (P less than 0.01), respectively. Of 109 bulls classified as unsatisfactory, 2.8% were so classified because of poor semen quality alone; 41.3% had no ejaculate in 4 separate electroejaculation attempts. Other abnormalities in these 109 bulls included reproductive tract infections (22%), persistent penile frenulum (16.5%), testicular abnormalities (8.3%), fibropapilloma (1.8%), hernia (1.8%), aplastic epididymis (1.8%), penile abnormalities (1.8%), pendulous sheath (0.9%), and eye abnormalities (0.9%). Age had a significant effect on SC in bulls at 3 locations and on percentage of normal cells, primary abnormalities, and secondary abnormalities as well as BSE score at 1 location. Percentage of primary and secondary abnormalities as well as SC were different across years at 2 locations, and percentage of normal and motile cells as well as BSE score were different across years at 1 location. Breed effects were significant for SC, percentage of primary abnormalities, and BSE score at 3 locations and for percentage of normal and motile cells at 1 location.

Pulmonary lesions induced by Pasteurella haemolytica in neutrophil sufficient and neutrophil deficient calves

The role of neutrophils in the development of peracute lung lesions of bovine pneumonic pasteurellosis was investigated. Eight calves were divided into two groups of four calves each. Group I was treated with intravenous phosphate-buffered saline and served as the neutrophil sufficient calves. Group II was treated with intravenous hydroxyurea which produced a state of neutropenia. When peripheral blood neutrophil numbers dropped below 300 cells/microL in group II, all calves were challenged with an intrabronchial bolus of Pasteurella haemolytica in the log phase of growth. An acute inflammatory process occurred in both groups of calves indicated by a rise in body temperature. While pulmonary lesions occurred in both groups by six hours postinoculation, they varied in pathological characteristics. Pulmonary lesions in the neutrophil sufficient calves consisted of fibrinopurulent alveolitis-bronchiolitis with associated alveolar septal necrosis, interlobular edema, and intravascular thrombi. The neutrophil deficient calves had extensive intra-alveolar edema, interlobular edema, intraalveolar hemorrhage, atelectasis, and focal areas of alveolar septal necrosis. These results show that P. haemolytica can induce severe pulmonary tissue damage through both neutrophil dependent and neutrophil independent mechanisms.

Absence of uterokinetic effects of prostaglandin F2α on oxytocin-reactive uterus in the mare

In most cyclic females, prostaglandin F(2 alpha) (PGF(2 alpha)) triggers a uterine motility response resembling that of oxytocin (OT). To determine if PGF(2 alpha) is a uterokinetic substance in the cycling mare, uterine motility was measured by intrauterine balloon technique in 12 conscious, normally cyclic mares. After 60 min of saline infusion, continuous intravenous (i.v.) infusion with OT (1 i.u./min) was followed by PGF(2 alpha) (200 microg/min) for 60 min each. The experiment was repeated 3 wk later except with PGF(2 alpha) preceding OT. A second group of mares was administered OT (60 i.u.) either i.v., intramuscularly (i.m.), or intrauterinely (i.u.). Plasma samples were studied for progesterone concentration. Control uterine motility for the first group of mares was (mean +/- SEM) 545.83 +/- 45.10 mm(2). Significant (P<0.05) elevation in uterine motility was recorded for OT (1118.60 +/- 70.56 mm(2)) regardless if PGF(2 alpha) preceded OT infusion or vice-versa. No significant difference (P>0.05) was seen in motility after PGF(2 alpha) (423.33 +/- 31.12 mm(2)) infusion. The uterokinetic effect of OT was greatest when OT was administered i.v. (1696.50 +/- 195.46 mm(2)) followed by i.m. (819.82 +/- 39.96 mm(2)), and it was least effective when administered i.u. (607.83 +/- 21.56 mm(2)) as compared to control uterine motility (279.78 +/- 22.33 mm(2)). Skin electrical resistance values rose from 0 to 2000 ohms with PGF(2 alpha) infusion (but not with OT), indicating that PGF(2 alpha) was bioactive. It was concluded that PGF(2 alpha) was not a uterokinetic substance in the cyclic mare.

Changes in leukocyte populations in pulmonary lavage fluids of calves after inhalation of Pasteurella haemolytica

The distribution of leukocytes in bovine bronchoalveolar lavage fluids was determined in 15 calves at various times after aerosol exposure to Pasteurella haemolytica. For comparison, 10 calves were exposed to aerosols of phosphate-buffered saline solution; 15 calves, to Staphylococcus epidermidis; and 10 calves, to Salmonella typhimurium endotoxin. At 10 minutes after inhalation exposure for each group, the predominant cell type was the macrophage. Macrophages remained the predominant cell type throughout each lavage interval for calves exposed to phosphate-buffered saline solution and Staph epidermidis. For calves exposed to P haemolytica, there was a decrease in the percentage of macrophages detectable by 30 minutes after exposure, with a corresponding increase in the percentage of neutrophils. Sixty minutes after the inhalation exposure to P haemolytica, the percentages of macrophages and neutrophils in the lavage fluid were equal. By 240 minutes after exposure to P haemolytica, greater than 90% of the cells in the lavage fluids was neutrophils. The increase in the percentage of neutrophils in lavage fluids from calves exposed to S typhimurium endotoxin was similar to that seen for the calves exposed to P haemolytica.

Antileukotoxin antibody produced in the bovine lung after aerosol exposure to viable Pasteurella haemolytica

Experiments were performed to determine the in vivo immunogenicity of Pasteurella haemolytica leukotoxin. Calves were exposed twice to aerosol mists of viable P haemolytica, using a treatment regimen previously shown to induce a resistant state. Pulmonary lavage fluids and serum samples from these calves were assayed for leukotoxin-neutralizing antibodies. Before aerosol exposure, neutralizing antibody titers were routinely found in serum samples, but were not detectable in pulmonary lavage concentrates before exposure. After aerosol exposure, titers of toxin-neutralizing immunoglobulin (Ig)A and IgG antibodies were found in pulmonary lavage concentrates and were accompanied by increased serum toxin neutralization titers.

Comparison of the pneumopathogenicity of two strains of bovine viral diarrhea virus

The pneumopathogenicity in calves of 2 strains of bovine viral diarrhea (BVD) virus, isolate 2724 (a noncytopathogenic virus) and isolate 72 (a cytopathogenic virus), was compared. All calves were inoculated endobronchially, using fiberoptic bronchoscopy. Two calves were given Pasteurella haemolytica, 2 calves were given the noncytopathogenic BVD virus, and 2 calves were given cytopathogenic BVD virus. Five calves were inoculated sequentially with BVD virus and, 5 days later, with P haemolytica. Two of these calves were inoculated with the noncytopathogenic BVD virus and the other 3 with the cytopathogenic strain. Both BVD virus strains caused marked respiratory tract disease in the calves sequentially inoculated with P haemolytica and also impaired pulmonary clearance of P haemolytica. However, the effect of the cytopathogenic strain was more severe than the noncytopathogenic strain, indicating that strains of BVD virus may vary in their pneumopathogenicity for calves.

Failure of passive transfer in calves: comparison of field diagnosis methods

Calves with serum immunoglobulin levels less than 800 mg/dl have a failure of passive transfer of maternal antibodies, those with 800-1600 mg/dl have a partial failure of passive transfer, and those with greater than 1600 mg/dl have adequate immunoglobulin levels. Tests for immunoglobulin level evaluation are most accurate when serum from healthy animals 1-8 days old is used. Of the sodium sulfite precipitation, zinc sulfate turbidity and glutaraldehyde coagulation tests, the first is the most useful field test for evaluation of serum immunoglobulin levels in calves. It is inexpensive, easy to perform and relatively accurate.

Experimental production of bovine respiratory tract disease with bovine viral diarrhea virus

Five 6-month-old calves were inoculated with bovine viral diarrhea (BVD) virus (n = 3) or Pasteurella haemolytica (n = 2) endobronchially with a fiberoptic bronchoscope. Five additional calves were inoculated sequentially with BVD virus followed by P haemolytica at a 5-day interval. Blood samples were collected daily from the calves for bacterial isolation. Clinical signs of respiratory tract disease in calves were recorded daily. If the calves survived, they were killed for necropsy 3 or 4 days after inoculation with P haemolytica (or 8 days after inoculation with BVD virus). The extent and nature of pulmonary lesions in the calves were determined, and the lower portion of the respiratory tract (lungs and trachea) was examined for both these organisms. The 3 calves, inoculated with BVD virus only, developed mild clinical signs mainly manifested as fever, nasal discharge, and occasional cough. Approximately 2% to 7% of the total lung capacity of these calves was pneumonic. Mild clinical signs and localized lesions involving about 15% of the lung volume developed in the 2 calves exposed to P haemolytica only. However, severe fibrinopurulent bronchopneumonia and pleuritis involving 40% to 75% of lung volume developed in the 5 calves inoculated sequentially with BVD virus and P haemolytica. The possible role BVD virus may have in bovine respiratory tract disease is discussed.

Growth phase-dependent phagocytosis of Pasteurella haemolytica by bovine pulmonary macrophages

The ability of the bovine pulmonary macrophage (PM) to phagocytize Pasteurella haemolytica in its logarithmic and declining phases of growth was characterized. Pulmonary macrophages were harvested from bovine lungs before and after their in vivo exposure to P haemolytica. The PM from each lavage period phagocytized P haemolytica in the declining phase of growth. However, P haemolytica in the log phase of growth was not phagocytized by PM from any of the lavage periods. Instead, PM exposed to P haemolytica in the log phase of growth had altered cellular morphologic features and were cytolytic. Pasteurella haemolytica in the log phase also inhibited phagocytosis of Saccharomyces cerevisiae by PM. This inhibition of phagocytosis, as well as morphologic alterations, was evident in PM cultures exposed to P haemolytica for less than 1 minute.

Use of fiberoptic bronchoscopy in experimental production of bovine respiratory tract disease

Fourteen 6-month-old calves were infected with Pasteurella haemolytica or infectious bovine rhinotracheitis (IBR) virus. Four calves were inoculated sequentially with IBR virus followed by P haemolytica at a 5-day interval. Calves were inoculated by allowing them to inhale an aerosol of the organism or by placing an inoculum in the right lung, using fiberoptic bronchoscopy. Clinical signs of infection were recorded, and the calves, if they survived, were killed and necropsied 3 days after inoculation with P haemolytica (or 8 days after inoculation with IBR virus). The extent of pulmonary lesions was determined, and the lower respiratory tract (lungs and lower trachea) was examined for both organisms. Inoculation of the calves by aerosolization with IBR virus alone resulted in mild respiratory tract disease. Mild-to-moderately severe respiratory tract disease developed as a result of sequential inoculations by aerosolization with IBR virus and P haemolytica. However, respiratory tract disease did not develop in calves exposed by aerosol to P haemolytica alone. Large numbers of these organisms were recovered from the lower respiratory tract of the dually inoculated calves, only indicating delayed pulmonary clearance. Mild clinical signs of disease but substantial, though localized, pneumonic lesions developed in calves inoculated with P haemolytica by fiberoptic bronchoscopy. Calves inoculated with IBR virus by the latter procedure developed moderately severe respiratory tract disease involving 25% to 30% of the total lung volume. Lesions occurred mainly in the right lung, but the left lung also had marked lesions in these calves.(ABSTRACT TRUNCATED AT 250 WORDS)

Uterotonic effect of prostaglandin F2 alpha and oxytocin on the postpartum cow

Uterine motility was measured in 6 mixed-breed beef cows 48 to 72 hours after parturition, using an intrauterine balloon technique. Baseline uterine motility was measured for 30 minutes after a stabilization period. After 25 mg of prostaglandin F2 alpha (PGF2 alpha) was given IM, motility was recorded for 2 to 4 hours. After PGF2 alpha injection, 200 IU of oxytocin was given IM and motility was recorded for 2 to 4 hours. Twenty-four hours later, oxytocin treatment was administered, and 2 to 4 hours later, PGF2 alpha was given. The tension-time index was calculated. When PGF2 alpha was given initially, it did not affect (P greater than 0.05) uterine motility. However, oxytocin after PGF2 alpha increased uterine motility an average of about 225% of that of base line 20 minutes after injection. When oxytocin was given before PGF2 alpha treatment, the average increment of uterine motility was 875% above base line 20 minutes after oxytocin injection. The injection of PGF2 alpha did not affect uterine motility significantly (P greater than 0.05), whether given before or after oxytocin treatment. There was a linear decrease in the uterotonic effect of oxytocin between 10 minutes and 2 hours. When oxytocin was injected first, the correlation coefficient for the time-response relationship was -0.98. When oxytocin was injected after PGF2 alpha, the correlation coefficient was -0.84. Seemingly, PGF2 alpha should not be used as a uterotonic agent in the postpartum cow; however, oxytocin was an effective uterotonic agent.

Effect of bovine viral diarrhea virus infection on the distribution of infectious bovine rhinotracheitis virus in calves

Four calves (control animals) were inoculated (by aerosol) with Cooper's strain of infectious bovine rhinotracheitis (IBR) virus given with an ultrasonic nebulizer. Seven other calves (principals) were inoculated (by aerosol) with a noncytopathic strain of bovine viral diarrhea (BVD) virus and 7 days later, with IBR virus. The calves were killed 3 to 8 days after the latter virus was inoculated. Various tissues were collected from the calves during necropsy and assayed for IBR virus. In the control calves, the IBR virus was recovered only from the cranial part of the respiratory tract and, in much lower concentrations, from the caudal part of the respiratory tract. In contrast, the same virus was widely disseminated in most tissues, usually in high concentrations, of the calves first inoculated with BVD virus (principals). These observations indicate that initial BVD virus infection may impair the ability of calves to clear IBR virus from the lungs and to contain the latter virus at the local infection site. The pathogenesis of various forms of IBR virus-induced diseases in calves is discussed.