日粮中蛋白质和纤维水平对仔猪生产性能和健康状况的影响

为了研究日粮的蛋白质和纤维水平对仔猪生产性能和健康状况的互作,特选择96头35日龄的仔猪（体重为9.11±0.60kg）,分32个栏饲养,每栏3头,分成4个日粮处理组,饲喂期21d。在设定的2×2因子处理中,4种日粮以大米、奶制品和大豆粕为基础配制,日粮蛋白质设两个水平（15.4%与19.4%,风干基）,纤维也设两个水平[低水平纤维（LF）为含5.3%中性洗涤纤维,高水平纤维（HF）为含7.15%中性洗涤纤维,风干基]。高水平纤维日粮组在基础日粮中添加了40g/kg的小麦麸和20g/kg的甜菜浆。每周测定动物生产性能,试验第1天和最后一天收集粪样进行微生物学分析,并且按1（液态）到4（硬实）的评分体系对粪便进行评分。在试验最后1d,每栏选1头猪采集血液,分析急性期反应蛋白（acute-phase protein）和主要急性期反应蛋白（major acute-phase prot）（即Pig-MAP）的含量,随后进行屠宰,对消化道（包括内容物）进行称重,并进行结肠组织学分析。饲喂高水平纤维日粮的仔猪具有较大的平均日增重（390g与457g,P≤0.001）和大肠重量（以占体重比例衡量为4.4%与5.4%,P≤0.05）。这与较高的短链脂肪酸浓度（尤其是乙酸和丁酸）、较少的大肠杆菌数量（每克粪便含7.77与6.86logcfu,P≤0.05）和较高乳酸杆菌与肠道细菌比（0.76与1.37,P≤0.05）是相符的。虽然日粮蛋白质水平没有改变猪的生产性能,但是20%的蛋白质水平提高（P≤0.05）了小肠（6.5与7.7）和大肠（3.8与4.3）的相对重量（占体重的百分比）。在大肠内,含20%蛋白质的日粮使仔猪杯状细胞数量增加（4.6/100与5.4/100μm;P≤0.05）,并使肠上皮内淋巴细胞数量减少（1.8/100与1.3/100μm;P≤0.05）。在健康状况方面,提高日粮纤维水平所产生的效果与日粮中的蛋白质含量有关。在含16%蛋白质的日粮中增加纤维水平可降低粪便评分值、增加抗生素治疗次数,然而在?     

Stress response of extensively reared young bulls being transported to growing-finishing farms under Spanish summer commercial conditions

To evaluate the effect of Spanish summer commercial journeys on the stress response of young bulls born and reared under extensive conditions, 2 replicates of a transport from an assembly centre to a growing-finishing farm were studied. Journeys lasted 27 h, involving a total of 62 young bulls. Variables under study included haematocrit, red blood cell count (RBC), total white blood cell count (WBC), differential WBC counts, serum haptoglobin (Hp), cortisol, glucose, creatine phosphokinase (CPK), lactate dehydrogenase (LDH), total protein, and albumin at loading, at the end of an intermediate market stop, and at the unloading. Before the beginning of the journey elevated WBC and neutrophil counts, and high Hp values were detected, reflecting high stress levels probably as a consequence of previous procedures associated with the grouping at the assembly centre. Some stress was also detected at the end of the market stop, with cortisol increasing from 6.5 to 12.6 ± 2.0 ng/mL (P < 0.001), although a change in Hp concentration was not observed. Neither CPK and LDH activities, related to muscular tissue damage, nor haematocrit and RBC count, related to dehydration revealed a significant effect of this first stage of the journey on the physical stress of the young bulls. Subsequent 13 h transport to the growing-finishing farm induced an increase in Hp levels from 0.48 to 0.78 ± 0.16 mg/mL (P < 0.001), reflecting an onset of the acute stress response, although cortisol levels immediately after the unloading were similar to those found before loading at the market, suggesting that calves got accustomed to transport. At the end of the journey some dehydration and physical stress were also detected. Overall, our study provides new information to the discussion of the effect of temperatures during cattle transport. Although an improvement in pre-transport conditions is essential if the welfare of assembled and transported cattle is to be improved, the stress-related alteration of cattle physiology under Spanish summer commercial transport conditions is similar to that observed under colder conditions.     

Pathological studies of cheek teeth apical infections in the horse: 4. Aetiopathological findings in 41 apically infected mandibular cheek teeth

Examination of 41 extracted, apically infected mandibular cheek teeth (CT) without obvious causes of infection included radiography, computerised axial tomography and decalcified and undecalcified histology. In CT with recent infections, some pulps remained viable, with proliferative soft and calcified tissue changes confined to the apex. With more advanced CT infections, occlusal pulpar exposure was sometimes present (in 34% of the 41 CT), some infected pulp chambers were filled with necrotic pulp or food, and extensive destructive or proliferative changes were present in the calcified apical tissues.No physical route of infection to the apex was found in 24 CT (59%) that consequently were believed to have anachoretic infections. Fractures involving pulps, including fissure fractures between the clinical crown and infected pulps, were found in eight (20%) CT. Some CT had vertical, full length periodontal destruction between the infected apex and the gingival margin that were believed to be the route of infection in four (19%) CT and dysplastic changes were believed to have caused one (2%) infections.     

Infection with Menangle virus in flying foxes (Pteropus spp.) in Australia

Objective To examine flying foxes (Pteropus spp.) for evidence of infection with Menangle virus. Design Clustered non‐random sampling for serology, virus isolation and electron microscopy (EM). Procedure Serum samples were collected from 306 Pteropus spp. in northern and eastern Australia and tested for antibodies against Menangle virus (MenV) using a virus neutralisation test (VNT). Virus isolation was attempted from tissues and faeces collected from 215 Pteropus spp. in New South Wales. Faecal samples from 68 individual Pteropus spp. and four pools of faeces were examined by transmission EM following routine negative staining and immunogold labelling. Results Neutralising antibodies (VNT titres ≥ 8) against MenV were detected in 46% of black flying foxes (P. alecto), 41% of grey‐headed flying foxes (P. poliocephalus), 25% of spectacled flying foxes (P. conspicillatus) and 1% of little red flying foxes (P. scapulatus) in Australia. Positive sera included samples collected from P. poliocephalus in a colony adjacent to a piggery that had experienced reproductive disease caused by MenV. Virus‐like particles were observed by EM in faeces from Pteropus spp. and reactivity was detected in pooled faeces and urine by immunogold EM using sera from sows that had been exposed to MenV. Attempts to isolate the virus from the faeces and tissues from Pteropus spp. were unsuccessful. Conclusion Serological evidence of infection with MenV was detected in Pteropus spp. in Australia. Although virus‐like particles were detected in faeces, no viruses were isolated from faeces, urine or tissues of Pteropus spp.     

Glucagon stimulation test for estimating endogenous insulin secretion in dogs

Fifty-one dogs (27 diabetic dogs, four that had recovered from diabetes and 20 healthy control dogs) were given 0.5 or 1.0 mg glucagon intravenously. Blood samples were taken before the injection and 10 and 20 minutes after it. Samples were analysed to determine C-peptide, insulin and glucose concentrations, and one sample from each dog was analysed for fructosamine. The median (interquartile range) concentrations of C-peptide in the samples taken at 10 minutes were 0.5 (0.3 to 0.8) nmol/l in the control dogs, 0.1 (0 to 0.2) nmol/l in the diabetic dogs, and 0.3 (0.2 to 0.4) nmol/l in the dogs that had recovered from diabetes. Seven of the 51 dogs showed mild adverse reactions after the injection of glucagon.     

Use of topical selamectin for the treatment of Trichosomoides crassicauda infection in laboratory rats

The present study investigated the efficacy of topical selamectin for elimination of naturally acquired Trichosomoides crassicauda infection in rats. Twelve T. crassicauda-positive rats were assigned to the treatment group and six rats were assigned to the control group. Selamectin (6 mg/kg) was applied topically to the skin in a single spot at the base of the neck in front of the scapulae in the treatment group. To assess the efficacy of the treatment, animal faeces were investigated with the use of the flotation technique on days 0, 4, 14 and 24 after selamectin application. The rats of the treatment and control groups were necropsied on the day 24. In the treatment group, 7 of 12 infected rats were cured completely. Topical selamectin was found to be effective in eliminating T. crassicauda infection in rats.     

Promoter region of the bovine growth hormone receptor gene: single nucleotide polymorphism discovery in cattle and association with performance in Brangus bulls

Expression of the GH receptor (GHR) gene and its binding with GH is essential for growth and fat metabolism. A GT microsatellite exists in the promoter of bovine GHR segregating short (11 bp) and long (16 to 20 bp) allele sequences. To detect SNP and complete an association study of genotype to phenotype, we resequenced a 1,195-bp fragment of DNA including the GT microsatellite and exon 1A. Resequencing was completed in 48 familialy unrelated Holstein, Jersey, Brown Swiss, Simmental, Angus, Brahman, and Brangus cattle. Nine SNP were identified. Phylogeny analyses revealed minor distance (i.e., <5%) in DNA sequence among the 5 Bos taurus breeds; however, sequence from Brahman cattle averaged 27.4 +/- 0.07% divergence from the Bos taurus breeds, whereas divergence of Brangus was intermediate. An association study of genotype to phenotype was completed with data from growing Brangus bulls (n = 553 from 96 sires) and data from 4 of the SNP flanking the GT microsatellite. These SNP were found to be in Hardy-Weinberg equilibrium and in phase based on linkage disequilibrium analyses (r(2) = 0.84 and D'= 0.92). An A/G tag SNP was identified (ss86273136) and was located in exon 1A, which began 88 bp downstream from the GT microsatellite. Minor allele frequency of the tag SNP was greater than 10%, and Mendelian segregation was verified in 3 generation pedigrees. The A allele was derived from Brahman, and the G allele was derived from Angus. This tag SNP genotype was a significant effect in analyses of rib fat data collected with ultrasound when bulls were ~365 d of age. Specifically, bulls of the GG genotype had 6.1% more (P = 0.0204) rib fat than bulls of the AA and AG genotypes, respectively. Tag SNP (ss86273136), located in the promoter of GHR, appears to be associated with a measure of corporal fat in Bos taurus x Bos indicus composite cattle.     

Effects of ammonia load on glucose metabolism by isolated ovine duodenal mucosa

To determine the effects of ammonia load on glucose metabolism in ruminant small intestinal tissues, duodenal mucosal cells (DMC) were isolated from growing female sheep (n = 10; 46. 0 +/- 0. 8 kg of BW) fed diets differing in CP content: high (19. 4%) vs. low (13. 1%). Ammonia concentration in the duodenal digesta fluid was greater for sheep fed a high CP diet compared with those fed a low CP diet (16. 4 +/- 1. 0 vs. 9. 1 +/- 1. 8 mM). The isolated primary mucosal cells were incubated for 90 min with [2-(13)C] glucose (3 mM) and ammonium chloride (0, 0. 1, 1, 5, 10, 20, or 50 mM) in Krebs-Ringer HEPES buffer. It was hypothesized that DMC would increase glucose carbon utilization for the synthesis of nonessential AA when the ammonia concentration in the incubation media increased. However, utilization of glucose carbon for alanine synthesis decreased linearly (P = 0. 03) as the ammonia concentration in the incubation media increased. Furthermore, glucose disappearance and utilization of glucose carbon for aspartate synthesis were not affected (P > 0. 47) by the ammonia concentration. Contrarily, in vitro glucose disappearance was greater (P = 0. 03) for DMC isolated from sheep fed a low CP diet vs. a high CP diet [14. 6 +/- 1. 6 vs. 8. 6 +/- 1. 3 nmol.(10(6) cells)(-1).(90 min) (-1)], and hexokinase activity was greater (P = 0. 01) in the mucosa of sheep fed a low CP diet compared with a high CP diet (1. 22 +/- 0. 05 vs. 1. 04 +/- 0. 02 mUnit/mg of protein). These observations indicate that ammonia load does not affect the extent of glucose utilization by DMC, and that glucose carbon may not play a significant role for the synthesis of alanine, aspartate, or glutamate when DMC are exposed to increased concentrations of ammonia.     

Interpopulation and intrapopulation maternal lineage genetics of the Lanyu pig (Sus scrofa) by analysis of mitochondrial cytochrome b and control region sequences

The Lanyu pig is an indigenous breed from the Lanyu Islet, which is southeast of Taiwan. Two herds of Lanyu pigs were introduced from the Lanyu Islet into Taiwan in 1975 and 1980. The current population of conserved Lanyu pigs consists of only 44 animals with unknown genetic lineage. The Lanyu pig possesses a distinct maternal genetic lineage remote from Asian and European pigs. The present study aimed to understand the phylogenetic relationship among conserved Lanyu, Asian, and European type pigs based on the cytochrome b coding gene, to ascertain the maternal lineage and genetic diversity within the conserved Lanyu pigs, and to address whether genetic introgression from exotic or Formosan wild pigs had occurred in the conserved Lanyu pigs. Entire mitochondrial genomes of both types of Lanyu pig comprised 2 ribosomal RNA, 22 transfer RNA, and 13 protein-coding genes. Only 2 haplotypes of the mitochondrial DNA (mtDNA) control region and cytochrome b were identified in the conserved Lanyu pig herds. When maximum likelihood trees were constructed, the Type I Lanyu mitochondrial genes formed a unique clade with a large pairwise distance of both cytochrome b and the control region from Asian and European type breeds, Formosan wild pigs, and exotic breeds. Significant loss of genetic diversity of mtDNA within the conserved Lanyu pigs was demonstrated by low haplotype and nucleotide diversities, supported by Fu and Li's D* neutrality test (1.44055; P < 0.05). The mtDNA control region sequences of extant pigs in the Lanyu Islet, however, showed high haplotype and nucleotide diversity, and clustered with exotic pigs. These results indicate no maternal lineage mtD-NA gene introgression from Formosan wild pigs and introduced exotic pigs to conserved Type I Lanyu pigs, and a severe loss of heterozygosity of mtDNA in conserved Lanyu pigs. The remaining extant pigs on the Lanyu Islet have been introgressed with exotic breeds. Strategies for future conservation of native Lanyu pigs are now even more urgent and important.     

Reducing phosphorus inputs for grazing Holstein steers

A 2-yr study was conducted to confirm that managed pastures can provide Holstein steers adequate P to meet their daily requirement. Treatments offered were trace mineralized salt with or without additional P. In the first year, 80 Holstein steers (248 kg of BW) were assigned to 4 grazing groups. Treatments were trace mineralized salt only or a 67:33 mixture of trace mineralized salt and dicalcium phosphate. Steers rotationally grazed a cool-season grass/legume mixture for 137 d. Fecal bags were placed on 3 steers from each grazing group (n = 12) over a 4-d period for estimation of forage DMI and forage contribution to daily P intake twice during the grazing season. Analyzed pasture samples contained 3.28 mg of P/g of DM. During the second year, 72 Holstein steers (297 kg of BW) were blocked into 2 BW groups and subsequently assigned to 1 of 4 pasture groups. Steers rotationally grazed the same forage base as the first year for 126 d. Pasture samples contained 3.27 mg of P/g of DM. No significant differences (P > 0.10) were detected for BW, ADG, or free-choice supplemental mineral intake. Forage provided 126% of the recommended NRC P requirement. Thus, supplemental phosphorous was not required for Holstein steers grazing mixed, cool-season, grass/legume pastures.