Comparison of media to isolate Staphylococcus aureus from teat skin and milking unit liners.

Four procedures were compared for isolation of Staphylococcus aureus from swabbing solutions of teat skin and milking unit liners from commercial dairies. In 2 procedures, 0.1 ml of swabbing solutions were added to either 5 ml Vogel-Johnson or Baird Parker broth media and enriched at 37 degrees C, 4 h. Following enrichment, 0.1 ml culture was transferred to modified Baird-Parker agar and incubated at 37 degrees C, 48 h. In the other 2 procedures, 0.1 ml of swabbing solution was directly placed on either blood or modified Baird-Parker agar plates and incubated at 37 degrees C 48 h. Combining results from all methods, Staphylococcus aureus were isolated from 72 of 913 (7.9%) skin samples, and 34 of 268 liners (12.6%). On average, 43.1% (31/72) of the S. aureus isolates were found by the enrichment in liquid Vogel-Johnson procedure. The average isolation percentage for other methods ranged from 19.4% to 25.0%. Isolation of S. aureus from milking unit liner or teat skin swabbing solutions was approximately twice as likely after enrichment in Vogel-Johnson liquid media as opposed to other methods of isolation. This indicates that enrichment in Vogel-Johnson liquid media improved recovery of S. aureus from swabbing solutions.     

Escherichia coli challenge and one type of smectite alter intestinal barrier of pigs

An experiment was conducted to determine how an E. coil challenge and dietary clays affect the intestinal barrier of pigs. Two groups of 32 pigs （initial BW： 6.9 ± 1.0 kg） were distributed in a 2 x 4 factorial arrangement of a randomized complete block design （2 challenge treatments： sham or E. coil, and 4 dietary treatments： control, 0.3% smectite A, 0.3% smectite B and 0.3% zeolite）, with 8 replicates total. Diarrhea score, growth performance, goblet cell size and number, bacterial translocation from intestinal lumen to lymph nodes, intestinal morphology, and relative amounts of sulfo and sialo mucins were measured. The E. coli challenge reduced performance, increased goblet cell size and number in the ileum, increased bacterial translocation from the intestinal lumen to the lymph nodes, and increased ileal crypt depth. One of the clays （smectite A） tended to increase goblet cell size in ileum, which may indicate enhanced protection. In conclusion, E. coli infection degrades intestinal barrier integrity but smectite A may enhance it.     

A direct method for fatty acid methyl ester synthesis: application to wet meat tissues, oils, and feedstuffs

A simplified protocol to obtain fatty acid methyl esters (FAME) directly from fresh tissue, oils, or feedstuffs, without prior organic solvent extraction, is presented. With this protocol, FAME synthesis is conducted in the presence of up to 33% water. Wet tissues, or other samples, are permeabilized and hydrolyzed for 1.5 h at 55 degrees C in 1 N KOH in MeOH containing C13:0 as the internal standard. The KOH is neutralized, and the FFA are methylated by H(2)SO(4) catalysis for 1.5 h at 55 degrees C. Hexane is then added to the reaction tube, which is vortex-mixed and centrifuged. The hexane is pipetted into a gas chromatography vial for subsequent gas chromatography. All reactions are conducted in a single screw-cap Pyrex tube for convenience. The method meets many criteria for fatty acid analysis, including not isomerizing CLA or introducing fatty acid artifacts. It is applicable to fresh, frozen, or lyophilized tissue samples, in addition to oils, waxes, and feedstuffs. The method saves time and effort and is economical when compared with other methods. Its unique performance, including easy sample preparation, is achieved because water is included rather than eliminated in the FAME reaction mixtures.     

Inbreeding and immunoglobulin G1 concentrations in cattle

Immunoglobulin G1 concentration (IgG1) was measured in presuckle colostrum and calf serum obtained at 36 h and at weaning from inbred and straightbred Angus, Brangus, Hereford, Red Angus and Simmental cattle. Sources of variation considered as dam traits examined for IgG1 in colostrum and 36-h calf serum included line of sire, sire within line, age, and linear regression of IgG1 on inbreeding of dam. Only line of sire and inbreeding of dam were significant in the analysis of 36-h calf serum. Sources of variation considered as calf traits examined for IgG1 in calf serum at 36 h and at weaning included line of sire, sire within line, sex of calf, age of dam, and regressions of calf serum IgG1 on inbreeding of the calf and on dam's colostral IgG1. Only sire within line and the regression on dam's colostral IgG1 were significant for calf serum IgG1 at 36 h. Large differences existed in 36-h calf serum IgG1 between sires both within lines and when lines were ignored. Calves with 36-h serum IgG1 of less than 10 mg/ml were two to four times more likely to die before weaning than calves with higher IgG1 levels. The heritability estimates of IgG1 by paternal half-sib analysis were .41 +/- .30 for colostrum measured as a trait of the dam and .56 +/- .25 for 36-h. calf serum and .05 +/- .17 for calf serum at weaning considered as a trait of the calf. These estimates indicate that IgG1 in colostrum and 36-h calf serum could be increased by selection.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluating longevity of composite beef females using survival analysis techniques

Objectives were to 1) identify risk factors affecting the longevity of beef females, 2) evaluate the utility of measures collected early in life in predicting longevity, and 3) estimate the heritability of longevity when females were culled primarily for not being pregnant following a 45-d breeding season. Data were from 1,379 Composite Gene Combination (CGC; 1/2 Red Angus, 1/4 Charolais, 1/4 Tarentaise) cows born from 1982 through 1999 at the USDA-ARS, Fort Keogh Livestock and Range Research Laboratory, Miles City, MT, and first calving at approximately 2 yr of age. The length of productive life was modeled using Cox regression to identify factors affecting the longevity of beef females. Age at first calving and calf birth weight did not influence longevity. Cows that experienced dystocia were at greater risk of being culled than those that calved without assistance (P < 0.01). On average, as breeding value for cow weight increased, the risk of being culled decreased (P < 0.01), whereas the risk of being culled increased with increasing maternal breeding values for preweaning gain (P < 0.05). Traits measured before 1 yr of age were not useful in predicting the subsequent longevity of cows. The heritability of functional longevity was estimated to be 0.14. Relatively low heritability and the lack of indicators of longevity expressed early in life suggest that genetic improvement of longevity will be difficult. Matching the genetic potential of cows for size and milk production to the production environment such that rebreeding performance is not compromised by concurrent lactation seems to be a consideration in retaining beef females when open cows are culled.     

Feedlot performance of hysterectomized and ovariectomized heifers

Seventy-five crossbred heifers (mean weight 304 kg) were stratified by weight and source and placed in eight pens. Four duplicate treatments were randomly assigned to pens as follows: (1) intact-control (n = 19), (2) intact + melengestrol acetate (MGA, n = 20), (3) hysterectomy (n = 17) and (4) ovariectomy (OVX, n = 19). All heifers were preconditioned for 2 mo before beginning the finishing study. Surgery was performed through a high lumbar incision approximately 3 wk before the finishing study began. Group 2 heifers were fed .4 mg X head-1 X d-1 MGA. Blood samples were collected at 28-d intervals throughout the 112-d finishing phase. Ovaries were collected at slaughter and carcass data were obtained 24 h after slaughter. On d 112, progesterone was higher (P less than .05) in hysterectomized heifers than in other treatment groups. Serum progesterone concentration was nondetectable (less than .35 ng/ml) in OVX and MGA heifers. There were no differences (P greater than .05) in feed efficiency or carcass characteristics among the four treatments. Hysterectomized and MGA heifers had similar (P greater than .05) average daily gains, which were higher (P less than .15) than control and OVX heifers. These data suggest that the elevated levels of progesterone from the maintained corpora lutea and the subsequent absence of estrous activity in the hysterectomized heifers are advantageous for promoting growth in feedlot heifers.     

Genetic and environmental factors affecting immunoglobulin G1 concentrations in ewe colostrum and lamb serum

Presuckle colostral samples and lamb serum samples taken 36 h postpartum were assayed for immunoglobulin G1 (IgG1) concentration (mg/ml) using single radial immunodiffusion. Breeds sampled included Polypay (P), Rambouillet (R), Targhee (T), Columbia (C), Finnish Landrace (F) and Finn crosses (Fx). Sources of variation examined in IgG1 concentration in colostrum (dam trait) included dam's sire breed, dam's sire, age of ewe and number of lambs born. All sources of variation were statistically significant. Least-squares means of IgG1 levels for sire breed were 80, 64, 67, 64, 72 and 69 mg/ml for P, R, T, C, F and Fx breed groups, respectively. A fetal stimulus may exist to increase the mass of IgG1 in colostrum available for multiple births (61, 69 and 77 mg/ml for single, twin and triplet, respectively). Ewe age was a significant source of variation because of a high mean concentration of IgG1 in the yearling's colostrum (100 mg/ml), whereas only slight differences occurred between the other age groups (65 to 67 mg/ml), except for the 7-yr older group (53 mg/ml). Sources of variation examined in IgG1 concentration of lamb serum at 36 h postpartum (lamb trait) included lamb's sire breed, lamb's sire, age of dam, birth type and sex, with dam's colostral IgG1 concentration and day born as covariates. Sire within breed, birth type and the two covariates were significant. Least squares means for sire breed were 36, 32, 33, 32, 31 and 32 mg/ml of serum for P, R, T, C, F and Fx groups, respectively. Lamb serum IgG1 decreased as birth type increased. The heritability of IgG1, estimated by paternal half-sib analyses, was .19 +/- .12 for colostrum and .18 +/- .06 for lamb serum.     

Long term use of hydraulic artificial urethral sphincters in nine dogs from New Zealand with urethral sphincter mechanism incompetence

AIMS: To report on the long-term outcomes of hydraulic artificial urethral sphincter (HAUS) placement for the correction of urethral sphincter mechanism incompetence (USMI) in New Zealand dogs.

METHODS: Retrospective data were obtained from cases of dogs which had a HAUS placed after failed medical and/or surgical management of USMI between August 2012 and November 2016. Owner assessment of urinary incontinence was evaluated by an online survey in May 2017 using a visual analogue scale (0 being normal, 100 being severely affected) for the frequency, volume and severity of any straining to urinate, immediately prior to the placement of the HAUS and at the time of the survey. The number of days between surgery and the completion of survey were recorded.

RESULTS: Seven females and two male dogs, which were all desexed except for one female, were eligible for inclusion in the study. The period of follow-up following HAUS placement ranged from 206–1,685 days. Following HAUS placement, frequency and volume of urinary incontinence decreased for six dogs and were practically unchanged for three dogs. The median frequency score decreased from 70 to 13 and the volume score decreased from 73 to 12. There was no consistent change in the perceived degree of straining to urinate. Complications occurred in three dogs; one required repositioning of a dislodged injection port, one required management for haematuria and a hypoplastic bladder, and one required surgical removal of fibrous tissue around the HAUS cuff.

CONCLUSIONS AND CLINICAL RELEVENCE: HAUS placement was an effective method for the treatment of persistent USMI in most dogs and provided good clinical results based on owner assessment. The technique was associated with few complications and allowed successful long-term control of urinary incontinence without the need for medical management.     

Reproductive characteristics of grass-fed, luteinizing hormone-releasing hormone-immunocastrated Bos indicus bulls

Two field trials were conducted in Brazil to evaluate LHRH immunocastration of Bos indicus bulls (d 0 = 2 yr of age). In Study I, 72 bulls were assigned randomly to one of three treatment groups: LHRH0-immunized, castrated, and intact. Immunized animals (n = 25) received a primary and two booster injections of ovalbumin-LHRH-7 and thioredoxin-LHRH-7 fusion proteins on d 0, 141, and 287. Twenty-three bulls were surgically castrated on d 141, and 24 served as intact controls. All animals were slaughtered on d 385, at approximately 3 yr of age. In Study II, 216 bulls were assigned randomly to the same three treatments as in Study I; however, because of a drought in the area, bulls were kept on pasture an additional year, and a fourth treatment was added, in which one-half the LHRH-immunized bulls received an additional booster on d 639 (fourth immunization). All animals in Study II were slaughtered on d 741 (4 yr of age). Luteinizing hormone-releasing hormone antibodies increased following each immunization for immunized bulls, but they were not detectable in castrate or intact animals in either study. Consequently, scrotal circumference was suppressed in immunized bulls compared with intact controls in both studies. By d 287, serum concentrations of testosterone in LHRH-immunized bulls were decreased compared with intact controls (P < 0.01). In both studies, testes and epididymal weights at slaughter were greater (P < 0.01) for intact (500 +/- 17 and 60 +/- 2 g, respectively) than for immunized bulls (173 +/- 22 and 26 +/- 2 g, respectively) and fourth immunization bulls (78 +/- 23 and 20 +/- 2 g, respectively; Study II). At the end of each study, BW was greater (P < 0.01) for intact bulls than for castrated and LHRH-immunized animals. In these two studies, the efficacy of the LHRH fusion proteins to induce an effect similar to that of surgical castration was considered 92 and 93%, respectively. These data support the concept that immunocastration of bulls at 2 yr of age was successful and that it has practical application as a tool for producing grass-fattened bulls in Brazil.     

Luteinizing hormone-releasing hormone fusion protein vaccines block estrous cycle activity in beef heifers

Two LHRH fusion proteins, thioredoxin and ovalbumin, each containing seven LHRH inserts were tested for their ability to inhibit estrous cycle activity. The objective was to evaluate immune and biological responses from alternating the two fusion proteins in an immunization schedule. One hundred ten heifers were divided equally into 11 groups. Two control groups consisted of either spayed or intact, untreated heifers. Heifers in the other nine groups were immunized on wk 0, 4, and 9. Treatments were immunizations of the same protein throughout or alternating the proteins in different booster sequences. Blood was collected weekly for 22 wk, and serum was assayed for concentrations of progesterone and titers of anti-LHRH. At slaughter, reproductive tracts were removed from each heifer and weighed. Heifers with >or=1 ng/mL of progesterone were considered to have a functional corpus luteum and thus to have estrous cycle activity. All LHRH-immunized groups of heifers had a smaller (P < 0.05) proportion of heifers showing estrous cycle activity after 6 wk than the intact, untreated control group. There was no difference in number of heifers cycling between the immunized groups and the spayed heifers during wk 9 to 22. Anti-LHRH did not differ among immunized groups during wk 1 to 9. Starting at wk 10 and continuing through the conclusion of the study, there was an overall difference among treatment groups for anti-LHRH (P < 0.05). Uterine weights differed among treatments (P < 0.05), with intact control animals having heavier uteri than all other groups (P < 0.05). Uterine weights were negatively correlated with maximum LHRH antibody binding (r = -0.44). In summary, the LHRH fusion proteins were as effective as surgical spaying in suppression of estrous cycle activity, but alternating the two proteins in an immunization schedule did not enhance the immunological or biological effectiveness of the vaccine.