Evaluation in beef cattle of six deoxyribonucleic acid markers developed for dairy traits reveals an osteopontin polymorphism associated with postweaning growth

The objectives of this study were to 1) estimate the allelic frequencies in US beef cattle of 6 DNA markers reported to be associated with variation in dairy production traits; and 2) evaluate the association of these markers with beef production traits. Several genetic markers have been associated with milk yield or composition, including polymorphisms in secreted phosphoprotein 1 (SPP1; also called osteopontin), growth hormone receptor (GHR), casein S1 (CSN1S1), diacylglycerol O-acyltransferase 1 (DGAT1), peroxisome proliferator-activated receptor gamma co-activator-1alpha (PPARGC1A), and ATP-binding cassette subfamily G (white) member 2 (ABCG2). Allelic frequencies for these 6 markers, and their association with 21 phenotypes, were evaluated in 2 crossbred beef cattle populations that sample influential industry sires. Five of 6 markers were segregating in beef cattle populations; the exception was ABCG2. The SPP1 marker was associated with yearling weight (P = 0.025), live weight at slaughter (P = 0.016), postweaning ADG (P = 0.007), and HCW (P = 0.007) in a large, multisire population representing the 7 most populous beef breeds in the United States. Postweaning growth trait associations were confirmed in an independent population of similar construction, including sires from tropically adapted breeds. The SPP1 marker was associated with yearling weight (P = 0.034), live weight at slaughter (P = 0.011), and postweaning ADG (P = 0.015) and showed a trend toward association with HCW (P = 0.083) in this population. Whereas DGAT1, GHR, and CSN1S1 polymorphisms showed association with some traits in individual populations, the lack of consistent predictive merit between populations indicates they may not be suited for beef cattle selection. No significant associations were observed for the PPARGC1A marker and any of 21 recorded traits, indicating this marker had no apparent value in selection for the beef cattle traits tested in these populations. The SPP1 marker had consistent associations and effect sizes (10.5 to 11.5 kg of live weight at slaughter) in both populations, providing strong evidence for utility of the SPP1 marker for postweaning growth in beef cattle.     

Comparison of anthelmintic activity of pyrantel, praziquantel, and nitazoxanide against Anoplocephala perfoliata in Horses

Three anthelmintics were compared for efficacy in reducing the egg production of Anoplocephala perfoliata in a herd of central Texas horses. Two trials were run, 1 in mares and the other in weanlings that were diagnosed as being infected with Anoplocephala by recovery of eggs in 5 g of feces with sugar centrifugation. Each animal was evaluated twice before treatment and again twice following treatment (at weeks 2 and 4 after treatment). The criteria for infection were the recovery of eggs on at least 1 occasion before treatment and the finding of eggs on 1 day following treatment. The mares were treated 1 time with either pyrantel pamoate at 13.2 mg/kg, nitazoxanide at 100 mg/kg, praziquantel at 1.23 mg/kg or remained as untreated controls. The weanlings were treated with pyrantel at 13.7 mg/kg nitazoxanide at 100 mg/kg or remained as untreated controls. The percentage reduction of patient infection in mares after treatment with pyrantel was 83%, with nitazoxanide was 78%, and with praziquantel was 83% and in controls was 17%. There was a 75% reduction of patient weanlings treated with pyrantel or nitazoxanide and a 17% reduction in untreated controls. The reduction of infection in all horses treated with any drug was significantly different from controls. All of the drugs were somewhat effective in the control of Anoplocephala, and there were no differences among the drugs in their effectiveness.

Introduction

Anoplocephala perfoliata, the lappeted tapeworm, is an inhabitant of the intestine of equids. Adult tapeworms attach to the intestinal mucosa at the ileocaecal valve and, when present in large numbers, cause edema and hypertrophy of the ileum. The disease manifest by this infection may be inapparent or may give rise to colic (abdominal pain) in the horse apparently from mechanical obstruction or intussusception of the small intestine into the caecocolon.^{1, 2, 3, 4, 5, 6, 7 and 8} The prevalence of infection is geographically variable^{9, 10, 11, 12 and 13} but appears to be increasing,¹⁴ with a much higher rate of infection found with necropsy as opposed to fecal observations. Horses become infected by the ingestion of infected orbatid mites in pastures. Orbatid mites, the intermediate hosts, are predatory and are found in decaying organic material, such as leaf litter. Horses of all ages are infected, but there are lower numbers of clinical cases in horses older than 4 years of age.⁴ The intensity of infection is highest in the late summer and autumn.^{8 and 12} Anthelmintics with reported efficacy against A perfoliata include pyrantel pamoate at 13.2 mg/kg,¹⁰ pyrantel tartrate at 2.6 mg/kg for 30 days,¹⁵ pyrantel embonate at 38 mg/kg,¹⁶ and praziquantel at 1 to 2 mg/kg.^{17 and 18} Nitazoxanide has not been evaluated for Anoplocephala but was included in the trial because of its effects against nematodes and tapeworms in humans.¹⁹ Because Anoplocephala infections may cause disease and there is a perception that current anthelmintics may not be as effective as in the past, a study was done to compare anthelmintics to lower the intensity of fecal egg counts in a herd of horses in central Texas.

Materials and methods

Quarter horse mares and weanlings from a single herd were evaluated with 5 g of feces with a sucrose double centrifugation test to determine whether eggs of Anoplocephala were present.²⁰ Feces from each individual horse were evaluated twice, once approximately 2 weeks before treatment and again on the day of treatment. If Anoplocephala eggs were found on either date, the horse was considered to have positive results. Within each group (mares or weanlings), the treatment selection was randomly allocated as the horses were restrained for treatment. Fecal samples were again evaluated at 14 and 28 days after treatment for the presence or absence of eggs on either day.The dose for each individual horse was determined by chest girth weight tape at the time of treatment. The treatments were as follows: pyrantel pamoate (Strongid-T, Pfizer Animal Health, Exton, Pa) at 13.7 mg/kg via nasogastric intubation (12 mares, 8 weanlings), nitazoxanide oral paste (Nitazoxanide, Idexx Laboratories, Westbrook, Me) at 100 mg/kg (9 mares, 8 weanlings), praziquantel (Droncet injectable, Bayer Corp, Shawnee Mission, Kan) at 1.23 mg/kg via nasogastric intubation (6 mares), and untreated controls (6 mares, 6 weanlings). A 1-tailed Fisher exact test was used to compare rates of infection before and after treatment. If a mare or foal did not have positive results before treatment, it was not evaluated in this study.

Results and discussion

No abnormal clinical signs were seen after treatment with any of the products. Treatment was administered to several additional animals with each product, but they were not included in the analysis if they did not have positive results on 1 of the 2 evaluations before treatment, hence, the different numbers of horses in treatment groups.None of the horses in the trial exhibited clinical signs associated with the infection of A perfoliata. However, before the trial, a mare from the infected herd exhibited signs of colic and Anoplocephala eggs were detected in the feces. Examination of the remainder of the herd gave impetus to the study.Mean egg counts before and after treatment are given in the Table.The presence of strongylate and Parascaris eggs in weanlings served as a control of the methodology of evaluation. The difficulty of finding Anoplocephala eggs has been recognized by several authors,^{5, 8, 13, 14 and 21} but the authors also recognize that when there were greater numbers of parasites there was increased egg production. Therefore, finding of eggs with fecal flotation indicated that there were 20 worms or more. However, there appears to be no correlation between the number of worms and egg counts once the detection threshold is reached,²² so the criterion for evaluation was the presence of eggs in the feces before treatment compared with after treatment. Although mean egg counts were not compared, the number of eggs in each infected horse was less after treatment in all groups compared with untreated controls (Table). The method of evaluation used in this study cannot be equated to those of critical^{10 and 16} or control¹⁴ studies in which horses are killed so that all worms are detected. However, the use of clinical studies to compare compounds is useful in detecting which anthelmintics are likely to be of value against geographically distinct populations of worms. Admittedly, more sampling may have increased the number of horses with positive results, both before and after treatment.     

The effects of GnRH and adrenergic agents on PRL and beta-endorphin secretion by porcine pituitary cells in vitro

The direct effects of alpha- and beta-adrenergic agents on PRL and beta-endorphin (beta-END) secretion in vitro by porcine pituitary cells have been investigated. Pituitary glands were obtained from mature gilts, which were ovariectomised (OVX) one month before slaughter. Ovariectomised gilts, assigned to four groups, were primed with: (1) vehicle (OVX); (2) and (3) oestradiol benzoate (EB; 2.5 mg/100 kg b.w.) at 30-36 h (OVX+EB I) and 60-66 h (OVX+EB II) before slaughter, respectively; and (4) progesterone (P4; 120 mg/100 kg b.w.) for 5 consecutive days before slaughter (OVX+P4). Isolated anterior pituitary cells were submitted to 3.5 h incubation in the presence of GnRH, alpha- and beta-adrenergic agonists [phenylephrine (PHEN) and isoproterenol (ISOP), respectively], or alpha- and beta-adrenergic blockers [phentolamine (PHENT) and propranolol (PROP), respectively]. The culture media were assayed for PRL (exp. I) and beta-endorphin-like immunoreactivity (beta-END-LI) (experiment II). In experiment I, GnRH did not influence PRL release by pituitary cells in all experimental groups. Some of tested doses of adrenergic agonists, PHEN and ISOP, increased PRL release from pituitary cells of OVX gilts, but not from those of OVX+EB I animals. In the OVX+EB II group, PHEN alone, but ISOP with PROP, potentiated PRL secretion by the cells. In OVX+P4 animals, PHEN alone or in combination with PHENT and also ISOP alone or with PROP enhanced PRL output from the cells. In experiment II, addition of GnRH increased beta-END-LI release from pituitary cells only in the OVX+EB II group. PHEN and PHENT potentiated beta-END-LI secretion by pituitary cells in OVX+EB II and OVX+P4 groups, while ISOP and PROP increased beta-END-LI secretion by the cells of OVX and OVX+EB II animals. In turn, in the OVX+EB I group, effect of PHENT and PROP on PRL secretion by pituitary cells was inhibitory. In conclusion, our results suggest that adrenergic agents can modulate PRL and beta-END secretion by porcine pituitary cells in a manner dependent on the hormonal status of gilts.     

Risk factors of contamination of pig farms in the Netherlands with pig diseases and agents thereof: a review of the literature

Part of the project 'Clean pigs' an extensive study of literature was made of the risk factors related to the introduction of pathogenic micro-organisms in pigfarms in the Netherlands. On the basis of this study of literature and in close cooperation with the experts of the steering group of the project 'Clean pigs' a number of risk factors relevant for the Dutch pig farming were estimated. The impact of these risk factors on the introduction of the most important pig diseases/-agents in Dutch pig farming was quantified for three different levels of preventive measures. It is shown that many risks can be reduced or even be neglected by the biosecurity measures already applied on pig farms. For most diseases, including list A and B diseases of the OIE list, introduction of new animals is regarded as the main risk factor, but this risk can be reduced in several ways. Besides this, aerogenic transmission and introduction by rodents and pet animals need the most attention. Through specific actions and measures several important risk factors can be diminished or even eliminated.     

Disease-induced alterations in plasma drug-binding proteins and their influence on drug binding percentages in dogs

Disease-induced variations of plasma albumin (ALB) and alpha 1-acid glycoprotein (AAG) levels were investigated in dogs. Lower ALB (sometimes > 50% reduction) and higher AAG (sometimes > 10-fold increase) levels were observed in dogs with various diseases. Drug binding was determined at therapeutic concentrations using normal, low-ALB and high-AAG dog plasma. The binding percentages of the ALB-binding drugs decreased in low-ALB plasma, resulting in a large increase in unbound drug, particularly for naproxen (a 13-fold increase). The binding percentages of all AAG-binding drugs investigated in this study increased in high-AAG plasma, resulting in a large decrease in unbound drug, particularly for quinidine (99% decrease). The fluctuation in the unbound fraction of drugs could affect their efficacy or could cause side-effects. Veterinary clinicians should monitor the ALB and AAG levels in the plasma of patients and correct dosage regimens according to these levels, where field conditions permit this, in order to ensure the proper usage of drugs with high affinity for ALB or AAG.     

Canine serum protein patterns using high-resolution electrophoresis (HRE)

Serum protein values were determined in 26 healthy dogs using agarose gel electrophoresis (SPE), splitting the electrophoretic separation into six regions: albumin, alpha(1), alpha(2), beta(1), beta(2)and gamma globulins. High-resolution electrophoresis (HRE) was used to separate single proteins. Serum proteins from dogs (26 healthy and 20 affected by various diseases) were then characterized by electrophoretic immunofixation (IFE) and Sudan black staining on HRE film. Haemoglobin and normal canine plasma and serum were used to identify haptoglobin and fibrinogen, respectively.In the standard pattern, determined by HRE, the following proteins were identified: albumin, alpha(1)-lipoprotein (alpha(1)-region), haptoglobin and alpha(2)-macroglobulin (alpha(2)-region), beta -lipoprotein and C3 (beta(1)-region), transferrin and IgM (beta(2)-region), IgG (mostly in gamma -region and partly in beta(2)-region). The HRE pattern shown by healthy dogs could be compared with those of dogs affected by various diseases to obtain clinical information.     

Parenterally administered gastrointestinal nematode infective larvae viable after more than 15 years in liquid nitrogen

After cryopreservation for 13.3-15.8 years, the viability of the infective larvae (L3) of Trichostrongylus axei, T. colubriformis, Oesophagostomum columbianum, Haemonchus contortus, Ostertagia circumcincta, T. falculatus, Nematodirus spathiger, Chabertia ovina and Dictyocaulus filaria was assessed in sheep, by being deposited at their predilection sites. D. filaria was, however, an exception, in that the L3 were injected into the jugular vein. The mean development of all the species was 22.8%, but if three species (O. columbianum, C. ovina and D. filaria), that developed poorly are disregarded, then the mean development was 33.4%, similar to previous tests after shorter periods of cryopreservation. The L3 of some of the species appeared sluggish when examined 10-15 min after being thawed, and in the case of H. contortus practically all the larvae of the original batch tested in the previous trials of the series appeared dead when thawed for use in the present trial, and were replaced by another batch of L3 of the same species. When re-examined after about 8 h, however, a high percentage of the L3 of the original batch appeared to have become revitalised, and their viability was tested in a trial reported elsewhere. The intestinal cells of the majority of the L3 of N. spathiger, O. circumcincta and C. ovina were vesiculated when they were thawed. Nevertheless, the degree of development of the former two species was of the highest in the trial, and it can be concluded that this phenomenon does not necessarily impede the viability of larvae.     

Short-term effects of ecadotril in dogs with induced congestive heart failure

OBJECTIVE: To evaluate short-term hemodynamic effects of ecadotril in a model of congestive heart failure in dogs. ANIMALS: 6 conscious adult male dogs. PROCEDURES: Instruments were placed in dogs to measure left ventricular, aortic, and atrial blood pressures. Heart failure was induced by repeated coronary embolization with latex microspheres. Four times, and in random order, dogs were given vehicle or active drug (3, 10, or 30 mg/kg of body weight) orally. Hemodynamic variables, urine flow, and urinary electrolyte excretion were measured before and 30, 90, and 150 minutes, and 10 and 21 hours after drug administration. RESULTS: Changes in urine flow, heart rate, mean arterial pressure, or peak positive and negative rate of change in ventricular pressure were not apparent. Urinary sodium excretion significantly increased in response to the low and high doses of ecadotril but not in response to the 10 mg/kg dose. Left ventricular end diastolic pressure (LVEDP) consistently decreased in dose- and time-dependent manner. Maximal group-averaged reductions in LVEDP were 5.2, 8.1, and 10 mm Hg for the low, middle, and high doses, respectively. The magnitude of the decrease in LVEDP was not related to cumulative change in urine flow. CONCLUSIONS AND CLINICAL RELEVANCE: Orally administered ecadotril reduced left ventricular filling pressures in these dogs by a mechanism that does not require a substantial diuretic effect. Ecadotril may be effective for alleviating clinical signs in dogs with left-sided heart failure and may be particularly beneficial for use in dogs that are refractory to traditional diuretic therapy.