Ultrasonic, needle, and carcass measurements for predicting chemical composition of lamb carcasses

Three groups (n = 147) of New Zealand mixed breed lambs averaging 170 d of age and 31.7 kg in weight were killed after a diet of pasture to determine whether the total depth of soft tissues over the 12th rib 11 cm from the dorsal midline (GR) could be measured in live lambs with sufficient accuracy to warrant its use as a selection tool for breeding flock replacements. Relationships among live and carcass measurements and carcass chemical composition also were determined. An ultrasonic measurement of GR in the live lambs was a more accurate predictor of carcass GR (r = .87) and percentage carcass fat (r = .80) than was a measurement of GR made with a needle (r = .80 and .67, respectively). Both measurements were sufficiently accurate to permit culling of over-fat lambs from breeding flock replacement prospects. The best single indicator of percentage carcass fat (r = .87) was a shoulder fat measurement, followed closely by carcass GR (r = .85). Both were superior to USDA yield grade for estimating carcass chemical composition in these young, lightweight lambs. These two measurements also were most highly related to percentage carcass protein (r = -.78 and r = -.77, respectively). These results indicate possibilities for improving the method of evaluating the composition of U. S. lamb carcasses.     

Intriguing interplay between viral proteins during herpesvirus assembly or: the herpesvirus assembly puzzle

Herpes virions are complex particles that consist of more than 30 different virally encoded proteins. The molecular basis of how this complicated structure is assembled is only recently beginning to emerge. After replication in the host cell nucleus viral DNA is incorporated into preformed capsids which leave the nucleus by budding at the inner nuclear membrane resulting in the formation of primary enveloped virions in the perinuclear space. The primary envelope then fuses with the outer leaflet of the nuclear membrane, thereby releasing nucleocapsids into the cytoplasm. Final envelopment including the acquisition of more than 15 tegument and more than 10 envelope (glyco)proteins occurs by budding into Golgi-derived vesicles. Mature virions are released after fusion of the vesicle membrane with the plasma membrane of the cell. Thus, herpesvirus morphogenesis requires a sequence of envelopment--de-envelopment--re-envelopment processes which are distinct not only in the subcellular compartments in which they occur but also in the viral proteins involved. This review summarizes recent advances in our understanding of the complex protein-protein interactions involved in herpesvirus assembly and egress.     

Evaluation of platelet aggregation using a point-of-care instrument in retired racing Greyhounds

Veterinarians involved in Greyhound rescue have anecdotally observed that 10-15% of Greyhounds bleed profusely after simple surgical procedures. In most patients, platelet counts and hemostasis profiles are normal; therefore, it is possible that these dogs have platelet dysfunction. The PFA-100 is a novel point-of-care platelet function analyzer that has recently been evaluated as a rapid method to assess platelet function in dogs. The objectives of this study were to characterize platelet function in a group of healthy Greyhounds by means of the PFA-100. Blood samples were collected from the jugular vein from 30 healthy Greyhounds. CBC, biochemical profile, PFA-100 assay with collagen/epinephrine (COL-EPI) and collagen/ adenosindiphosphate (COL-ADP), plasma von Willebrand factor antigen concentration (vWF:Ag), and vWF collagen-binding assay (vWF:CBA) were performed. PFA-100 closure times (CTs) with COL/ADP ranged from 63 to 92 seconds (mean +/- SD, 74.7 +/- 7.9 seconds) and with COL/EPI from 87 to 238 seconds (138 +/- 41 seconds); vWF: Ag ranged from 22 to 120% (87.52 +/- 25.5%) and vWF: CBA ranged from 36 to 102% (77.4 +/- 17.3%); and platelet counts ranged from 147 to 265 x 10(9)/L (194.6 +/- 31.64 x 10(9)/L). Greyhound CTs were significantly shorter than CTs in a mixed population of 50 healthy non-Greyhound dogs, in which the COL/ADP CTs ranged from 61 to 172 seconds (mean +/- SD, 87 +/- 21.6 seconds), and the COL/ EPI CTs ranged from 81 to 300 seconds (mean +/- SD, 183 +/- 67.6 seconds; P = 0.005 for COL/ADP CT; P = 0.001 for COL/ EPI CT). Also, platelet counts were significantly lower (P = 0.001) and packed cell volume was significantly higher (P = 0.001) in the Greyhound than in the non-Greyhound group. The PFA-100 is a reproducible method that can be used in the clinical setting to assess platelet function in Greyhounds; however, normal CTs in healthy Greyhounds are shorter than in other breeds. The results obtained in this study will be used to screen for abnormal platelet function in Greyhounds with postoperative bleeding.     

Interindividual variability in plasma concentrations after systemic exposure of swine to dietary doxycycline supplied with and without paracetamol: a population pharmacokinetic approach

Anorexigenic substances released during infection may hinder the therapeutic efficacy of in-feed antibiotics. Paracetamol (acetaminophen; PARA) inhibits the anorexia of infection and seems to improve the clinical efficacy of doxycycline (DOX) against bacterial respiratory disease in swine herds. In order to verify whether PARA selectively stimulates intake of DOX-medicated feed in diseased pigs, we documented the pharmacokinetics (PK) of DOX when coadministered with PARA and examined the effect of in-feed PARA on the interindividual variability in plasma concentrations after systemic exposure to in-feed DOX in swine herds with respiratory disease. Systemic exposure to DOX was measured with the area under the curve (AUC) of its plasma concentrations over time. First, a rich-sampling PK study of in-feed and i.v. DOX (10 mg/kg of BW) and PARA (30 and 10 mg/kg of BW, respectively) was performed on 5 pigs. The PK profiles of in-feed DOX were used in mathematical simulations to determine 5 optimal sampling times for the farm-based population PK study. A randomized, blind, parallel PK study was performed in 2 herds with bacterial respiratory disease, where liquid feed was fortified with DOX alone (5 mg x kg of BW(-1) x meal(-1)) or combined with PARA (15 mg x kg of BW(-1) x meal(-1)). Medicated meals were given twice, 12 h apart, to group-housed growing pigs (n > 50 pigs x treatment(-1) x herd(-1), totaling 215 pigs). Plasma concentrations of DOX and PARA were measured with HPLC. At variance with our expectations, PARA decreased (P = 0.069) mean AUC of in-feed DOX and did not decrease its variability (P > 0.34). Mean AUC of DOX increased with feed intake and with initial exposure to DOX, and was greater in sick animals. Therefore, symptomatic PARA-induced improvement in bacterial respiratory disease control with DOX is more likely caused by its analgesic/antipyretic effects than by its orexigenic effect. Interindividual variation in the AUC of DOX was large in pigs given group medication, even when sufficient feeding space was allowed and the amount of feed offered was greater than their requirements. Therefore, future studies to improve the efficacy of group antibiotic therapy should focus on feeding behavior characteristics as well as biopharmaceutical properties of medicated feeds.     

Effects of alfalfa extract, anise, capsicum, and a mixture of cinnamaldehyde and eugenol on ruminal fermentation and protein degradation in beef heifers fed a high-concentrate diet

Four Holstein heifers (360 +/- 22 and 450 +/- 28 kg of BW in Exp. 1 and 2, respectively) fitted with ruminal trocars were used in 4 x 4 Latin square designs to evaluate the effects on ruminal microbial fermentation of the following: Exp. 1, no additive, alfalfa extract (30 g/d, AEX), a mixture of cinnamaldehyde (0.18 g/d) and eugenol (0.09 g/d; CIE1), and AEX and CIE1 in combination; and Exp. 2, no additive, anise oil (2 g/d), capsicum oil (1 g/d), and a mixture of cinnamaldehyde (0.6 g/d) and eugenol (0.3 g/d). Heifers were fed a 90:10 concentrate:barley straw diet (16% CP; 25% NDF) for ad libitum intake. Each period consisted of 15 d for adaptation and 6 d for sampling. On d 16 to 18, DM and water intakes were measured. On d 19 to 21 ruminal contents were sampled at 0, 3, 6, 9, and 12 h after feeding to determine ruminal pH and the concentrations of VFA, L-lactate, large peptides, small peptides plus AA (SPep+AA), and ammonia N. On d 20 and 21, samples of ruminal fluid were collected at 0 and 3 h after feeding to determine protozoal counts. In Exp. 1, CIE1 and AEX decreased (P < 0.05) total DMI, concentrate DMI, and water intake. The increase (P < 0.05) in SPep+AA and the decrease (P < 0.05) in ammonia N when supplementing CIE1 suggest that deamination was inhibited. Treatment AEX increased (P < 0.05) the acetate to propionate ratio, which is less efficient for beef production. Treatment CIE1 increased (P < 0.05) counts of holotrichs. Effects of AEX and CIE1 were not additive for many of the measured metabolites. In Exp. 2, treatments had no effect on ruminal pH, total VFA concentration, and butyrate proportion. The capsicum oil treatment increased (P < 0.05) DMI, water intake, and SPep+AA N concentration and decreased (P < 0.05) acetate proportion, branched-chain VFA concentration, and large peptide N concentration. The cinnamaldehyde (0.6 g/d) and eugenol (0.3 g/d) treatment decreased (P < 0.05) water intake, acetate proportion, branched-chain VFA, L-lactate, and ammonia N concentrations and increased (P < 0.05) propionate proportion and SPep+AA N concentration. The anise oil treatment decreased (P < 0.05) acetate to propionate ratio, branched-chain VFA and ammonia N concentrations, and protozoal counts. The results indicate that at the doses used a mixture of cinnamaldehyde and eugenol, anise oil, and capsicum oil may be useful as modifiers of rumen fermentation in beef production systems.     

Compensation for changes in hoof conformation between shoeing sessions through the adaptation of angular kinematics of the distal segments of the limbs of horses

OBJECTIVE: To determine the mechanism that enables horses to partially counteract the shift of the center of pressure under the hoof induced by changes in hoof morphology attributable to growth and wear during a shoeing interval. ANIMALS: 18 clinically sound Warmblood horses. PROCEDURES: Horses were evaluated 2 days and 8 weeks after shoeing during trotting on a track containing pressure-force measuring plates and by use of a synchronous infrared gait analysis system set at a frequency of 240 Hz. All feet were trimmed toward straight alignment of the proximal, middle, and distal phalanges and shod with standard flat shoes. Results-Temporal characteristics such as stance time and the time between heel lift and toe off (ie, breakover duration) did not change significantly as a result of shoeing interval. Protraction and retraction angles of the limbs did not change. Compensation was achieved through an increase in the dorsal angle of the metacarpohalangeal or metarsophalangeal (fetlock) joint and a concomitant decrease of the dorsal angle of the hoof wall and fetlock. There was an additional compensatory mechanism in the hind limbs during the landing phase. CONCLUSIONS AND CLINICAL RELEVANCE: Horses compensate for changes in hoof morphology that develop during an 8-week shoeing interval such that they are able to maintain their neuromuscular pattern of movement. The compensation consists of slight alterations in the angles between the distal segments of the limb. Insight into natural compensation mechanisms for hoof imbalance will aid in the understanding and treatment of pathologic conditions in horses.     

Use of 25-hydroxyvitamin D3 and dietary calcium to improve tenderness of beef from the round of beef cows

The objective of this trial was to determine how 25-hydroxyvitamin D(3) (25-OH D(3)) supplementation, altering supplemental dietary calcium, or their combination influence postmortem biochemical and tenderness changes in muscles from the round of mature cows. Twenty-seven Angus cows (3 to 7 yr old) were allotted randomly to 9 pens with 3 cows per pen. Treatments were arranged in a 3 x 3 factorial design with 3 dosages of 25-OH D(3) (0, 250, or 500 mg of 25-OH D(3) administered as a 1-time oral bolus 7 d before slaughter) and 3 percentages of supplemental limestone (0.5, 0.75, and 1.0%) replenished in the diet for 3 d before slaughter and after a 2-wk limestone withdrawal. Plasma samples were obtained during the feeding period. Upon slaughter, adductor, gracilus, pectineus, sartorius, semimembranosus, vastus intermedius, and vastus lateralis muscles were obtained and aged for 1, 3, or 7 d. Calcium concentrations were increased in plasma when 250 or 500 mg of 25-OH D(3) were administered (P 相似文献   

Neuroanatomy of the equine dorsal cricoarytenoid muscle: surgical implications

Reason for performing study: Studies are required to define more accurately and completely the neuroanatomy of the equine dorsal cricoarytenoid muscle as a prerequisite for developing a neuroprosthesis for recurrent laryngeal neuropathy. Objective: To describe the anatomy, innervation, fibre types and function of the equine dorsal cricoarytenoid muscle. Methods: Thirty‐one larynges were collected at necropsy from horses with no history of upper airway disease and 25 subjected to gross dissection. Thereafter, the following preparations were made on a subset of larynges: histochemical staining (n = 5), Sihler's and acetylcholinesterase staining for motor endplates (n = 2). An additional 6 larynges were collected and used for a muscle stimulation study. Results: Two neuromuscular compartments (NMC), each innervated by a primary nerve branch of the recurrent laryngeal nerve, were identified in all larynges. Stimulation of the lateral NMC produced more lateral displacement of the arytenoid cartilage than the medial NMC (P<0.05). The medial NMC tended to rotate the arytenoid cartilage dorsally. Motor endplates were identified at the junction of the middle and caudal thirds of each NMC. If fibre type grouping was present it was always present in both NMCs. Conclusions: The equine dorsal cricoarytenoid muscle has 2 distinct muscle NMCs with discrete innervation and lines of action. The lateral NMC appears to have a larger role in increasing cross‐sectional area of the rima glottidis. Potential relevance: This information should assist in planning surgical reinnervation procedures and development of a neuroprosthesis for recurrent laryngeal neuropathy.