Reproductive behavior in hair sheep rams under tropical conditions

The reproductive efficiency of sheep herds depends to a great extent on the ram. Male reproductive evaluation allows to select for the best and eliminate those with reproductive problems. The objective was to evaluate the effect of breed and age group on the reproductive behavior of hair sheep rams in the tropics of Mexico. Pelibuey (n?=?42), Blackbelly (n?=?30), Dorper (n?=?44), and Katahdin (n?=?30) rams of two age groups: young (n?=?74, 1–1.5 years old) and adult (n?=?72, 2–4 years old) were evaluated. Serving capacity (10-min duration) and breeding soundness evaluation (BSE) tests were carried out in each ram. In the first test, rams were classified as suitable and unsuitable, and in the BSE test, they were classified as satisfactory, questionable, or unsatisfactory. The response variables were analyzed using chi-square test or analyses of variance (ANOVA). ANOVA included the fixed effects of breed, age group, and their interaction. In the serving capacity test, 79.5% of the rams were considered suitable, with no breed differences (P?>?0.05). Adult rams (90.3%) had the highest proportion of suitable rams (P?<?0.05). In the BSE test, 80.2% of the rams were satisfactory; only breed being significant (P?<?0.05). Pelibuey breed had the highest proportion of satisfactory rams (91.4%). Breed × age interaction was no significant for any trait. After serving capacity and BSE tests, a high proportion of rams was found not suitable for reproduction (36.3%), which is expected to cause low fertility in the flock.

     

Ruminal and morphometric parameters of the rumen and intestines of sheep fed with increasing levels of spineless cactus (Nopalea cochenillifera Salm-Dyck)

Tropical Animal Health and Production - The objective of this study was to evaluate the ruminal parameters (pH, N-NH3, and microbial protein) and morphometry of the rumen and intestine of sheep fed...     

Carcass characteristics and meat quality of sheep fed alfalfa hay to replace Bermuda grass hay

Tropical Animal Health and Production - The objective of this study was to evaluate carcass characteristics, meat quality, and organ and viscera weight of forty male sheep, not castrated, initially...     

Characterization of fluoroquinolone resistance in Escherichia coli strains from ruminants.

Thirty-seven fluoroquinolone-resistant Escherichia coli strains from ruminants (according to Clinical and Laboratory Standards Institute guidelines) were screened by molecular methods for mutations in the quinolone resistance-determining region (QRDR) of the gyrA and parC genes and for the presence of the qnrA gene. One of the strains studied was an enterohemorrhagic E. coli (EHEC) strain potentially pathogenic for humans. Three E. coli strains resistant to enrofloxacin (minimal inhibitory concentration [MIC] = 2 microg/ml) but not to ciprofloxacin (MIC = 1 microg/ml) presented single mutations in the gyrA and parC genes, while 34 strains resistant to both fluoroquinolones presented double and single mutations in gyrA and parC, respectively (31 strains), or double mutations in gyrA and parC (3 strains). The EHEC strain presented a double amino acid substitution in the GyrA protein (Ser-83-->Leu and Asp-87-->Gly) and a double amino acid substitution in the ParC protein (Gly-78-->Cys and Ser-80-->Arg), one of which has not been previously described. The present study shows that most of the mutations in the QRDR of the gyrA and parC genes of fluoroquinolone-resistant E. coli strains from ruminants are the same as those seen in E. coli strains from other animal species and humans and that there are no differences in mutation patterns in the QRDR of E. coli strains from healthy ruminants and those with diarrhea. No strains carried qnrA, which indicates that this gene does not play an important role in the selection of fluoroquinolone-resistant E. coli strains from ruminants.     

Contrasting Effects of Long-Term Fire on Sagebrush Steppe Shrubs Mediated by Topography and Plant Community

The role of fire in restoration of sagebrush plant communities remains controversial mainly because of paucity of information from long-term studies. Here, we examine 15-year post-fire responses of big sagebrush (Artemisia tridentata ssp wyomingensis) and broom snakeweed (Gutierrezia sarothrae), the two most abundant native shrubs at the John Day Fossil Beds National Monument, a protected area in north-central Oregon, USA. Fire effects were studied along gradients of topography and community type through time post-burn. Community types were distinguished as brush, plots dominated by big sagebrush and woodland, plots with a significant presence of Western juniper (Juniperus occidentalis) trees. Fire reduced big sagebrush cover in brush plots up to 100% and in woodland plots up to 86%. Broom snakeweed cover declined by 92% and 73% in brush plots and woodland plots, respectively. Big sagebrush did not show signs of recovery 15 years after burning regardless of topography and community type while broom snakeweed populations were clearly rebounding and prospering beyond pre-burn levels. Our results showed that an area initially dominated by big sagebrush (cover of big sagebrush 10-20%, cover of broom snakeweed 2-4%) dramatically shifted to an area dominated by broom snakeweed (cover of big sagebrush < 1%, cover of broom snakeweed 5%) in brush-dominated plots. Our results indicated that brush-dominated plots at lower elevation and southern exposures are the least post-fire resilient. We also observed a declining population of big sagebrush on unburned areas, suggesting the lack of post-fire recovery on burned areas was perhaps a result of low seeding potential by extant populations. Although more years of observation are required, these data indicate that recovery time, the encroachment of opportunistic competing shrubs, and the initial condition of vegetation are essential considerations by land managers when prescribing fire in big sagebrush communities.     

Vegetation Response to Juniper Reduction and Grazing Exclusion in Sagebrush-Steppe Habitat in Eastern Oregon

Western juniper expansion is one of the largest threats to conserving sagebrush steppe ecosystems in the northwestern United States. Juniper expansion has degraded the sagebrush steppe by altering fire regimes and outcompeting shrubs and herbaceous vegetation for limited resources. We characterized the effect of juniper removal in a severely degraded sagebrush steppe habitat for 3 yr following juniper cutting. In addition, we measured the effect of low-intensity seasonal grazing on plant community recovery through cattle exclusion treatments. We monitored plant community composition (exotic annual grasses, preferred grasses, preferred forbs, and shrubs); fuel loads; and juniper recruitment in a factorial design of juniper removal and grazing exclusion. We found that although there were significant differences between cut and uncut juniper treatments, there were no consistent trends across all 3 yr. Our results suggest that other factors, such as timing of precipitation, may also have strong short-term effects on plant community composition. We detected no significant grazing effects during the study period, suggesting the current grazing regime is appropriate for the area. The cutting of juniper increased total fuel loads and herbaceous fuel loads. Compared with open interspace, a twofold increase in juniper seedlings and saplings was detected beneath juniper piles, which will act as sources for future juniper encroachment.     

Cataracts in Labrador Retriever and Jack Russell Terrier From the United Kingdom: A Two-Year Retrospective Study

Cataracts are among the most common ocular diseases, and are a leading cause of vision loss in humans and dogs. Jack Russell Terriers (JRT) and Labrador Retrievers (LR) are among the most popular canine breeds in the United Kingdom, and also among the most affected by cataracts.This study aimed to analyze the clinical features and the surgical outcome of cataracts in JRT and LR in an ophthalmologic reference Veterinary Hospital in the United Kingdom. For that purpose, medical records from JRT and LR diagnosed with cataracts between January 2015 and December 2016 were retrospectively evaluated. Data related to identification, clinical history, preoperative features, and surgical outcomes were analyzed.Forty-four dogs (81 eyes), including 26 JRT and 18 LR, were enrolled in the study. Mean ages were 10.2 ± 3.2 years in JRT and 8.5 ± 3.7 years in LR. Twenty-eight (63.6%) were females and 16 (36.4%) were males. Most dogs (84.1%) presented with bilateral cataracts. Nuclear and cortical cataracts were the most prevalent type in both breeds (JRT: n?=?30, 61.2%; LR: n?=?16, 50.0%), although subcapsular cataracts were also frequent in LR (n?=?10, 31.3%). Significant differences in cataract location within the lens were detected between the two breeds (P?=?.002).Senile in JRT (n?=?7) and genetic in LR (n?=?7) were the most common etiologies. Concomitant ocular lesions were more frequent in dogs presented with cataracts in advanced stages, and included lens (n?=?18; JRT: n?=?15; LR: n?=?3) and retinal alterations (n?=?8; JRT: n?=?2; LR: n?=?6), and glaucoma (n?=?6; JRT: n?=?5; LR: n?=?1). Thirty-three animals (75.0%, 51 eyes) were submitted to phacoemulsification with intraocular lens placement. Of these, 28 eyes (54.9%; JRT: n?=?21; LR: n?=?7) were visual, 19 eyes (37.3%; JRT: n?=?11; LR: n?=?8) presented impaired vision and four eyes (7.8%; JRT: n?=?0; LR: n?=?4) were blind at last clinical record. Postoperative complications were detected in 11 eyes (21.6%), and were more frequent in dogs presented with cataracts in advanced stages.These results and the multifactorial nature of cataracts call for further studies to identify and characterize the variables in a broader assessment, including other breeds and influencing factors.     

Use of an insect cell culture growth medium to isolate bacteria from horses with effusive, fibrinous pericarditis: a preliminary study

Effusive, fibrinous pericarditis is an uncommon disease entity in horses. In 2001, pericarditis occurred in conjunction with an epizootic in central Kentucky that was associated with exposure to eastern tent caterpillars (ETCs). Bacterial isolation from equine pericardial fluid samples was attempted using an insect cell culture growth medium (ICCGM). Using previously cultured, stored frozen samples from four horses with fibrinous pericarditis, inoculation of 10% blood agar plates yielded no growth, whereas simultaneous inoculation of ICCGM resulted in the isolation of Proprionibacterium acnes, Staphylococcus equorum, a Streptococcus sp. and Pseudomonas rhodesiae from pericardial fluid samples. A similar or novel caterpillar-associated bacteria was not identified; however, use of an ICCGM might enhance isolation of bacteria from equine pericardial fluid.     

Purification and characterization of a 45-kDa concealed antigen from the midgut membranes of Ornithodoros erraticus that induces lethal anti-tick immune responses in pigs

Ornithodoros erraticus is an argasid tick that can transmit severe diseases such as human relapsing fever and African swine fever. In the search for a vaccine against this parasite, a crude extract of tick midgut membranes (GME) was obtained that in pigs and mice induced a protective response able to kill up to 80% of the nymphs in the first 72 h post-feeding and to reduce the fecundity of females by more than 50%. To identify the protective antigens, the GME was subjected to successive biochemical fractionations and the resulting simpler protein fractions were inoculated in pigs. A 45-kDa antigen, the so-called Oe45, was detected, purified and demonstrated to be responsible for the protection induced by the GME. Oe45 seems to be a membrane protein that is presumably expressed on the luminal membrane of midgut epithelial cells. Oe45 consists of at least two differently charged bands (cationic and neutral), which show antigenic cross-reactivity. The possibility that these bands might be different isoforms of the same protein is discussed. Although Oe45 is constitutively expressed at low levels throughout the trophogonic cycle, its expression is up-regulated by the ingestion of blood, as suggested by the higher levels observed between 6 and 72 h post-feeding.