Genotyping Brahman cattle for generalised glycogenosis

OBJECTIVE: To develop procedures for genotyping Brahman cattle for loss-of-function alleles within the acidic alpha-glucosidase gene and to assess the risk of generalised glycogenosis in Australian Brahman cattle. DESIGN: PCR assays for three loss-of-function alleles were designed to exploit internal restriction sites within acidic alpha-glucosidase amplicons that are independent of allelic variants at the mutant sites. RESULTS: Genotyping 8529 clinically normal Brahmans between August 1996 and August 2001 revealed 16.4% were heterozygous for the more common of the two mutations (1057deltaTA, often referred to as the 'E7' mutation) that cause generalised glycogenosis in this breed. The less common 1783T mutation (often referred to as the 'E13' mutation) was restricted to descendants of one imported bull, and was not detected in 600 randomly selected Brahmans. Prior to definition of these two disease-causing mutations, 640 (18%), and 14 (0.4%), of 3559 clinically normal Brahmans analysed between January 1994 and December 1996, were heterozygous, and homozygous, respectively, for a silent polymorphism (2223G-->A) that is associated with generalised glycogenosis. In addition to the 1057deltaTA and 1783T mutations, approximately 15% of Brahmans were found to be heterozygous for a single base substitution in exon 9 (1351T, commonly referred to as the 'E9' mutation) that significantly reduces acidic alpha-glucosidase activity, but has not been associated with clinical disease. These three loss-of-function alleles were found in Brahmans imported, or selected for import, from the USA. CONCLUSION: The PCR procedures reported here represent a significant improvement in reliability and accuracy over previous published methods. Utilisation of these PCR/restriction enzyme based assays will facilitate precise selection against the 1057deltaTA and 1783T alleles, and consequently reduce the incidence of generalised glycogenosis in registered and commercial Brahman herds.     

Genotyping Shorthorn cattle for generalised glycogenosis

OBJECTIVE: To develop a procedure for routine genotyping of Shorthorn cattle for the generalised glycogenosis allele in exon 18 of the acidic alpha-glucosidase gene. PROCEDURE: Allele-specific amplification and double mismatch amplification procedures for the discrimination of the exon 18 alleles were evaluated using leucocytes and hair roots as sources of target DNA. RESULTS: Allele-specific amplification was effective for genotyping Shorthorn cattle at the 2454 site when purified DNA was used as target for the polymerase chain reaction. However, when the target DNA was derived from hair roots, differences in the relative yield of wild-type and mutant amplicons were observed. The double mismatch amplification procedure was effective in genotyping all subjects, independent of the source of DNA. The unique cleavage sites for Drd I and PshA I within exon 18 are present and absent respectively in the wildtype amplicon, and are lost and acquired, respectively, in the mutant amplicon. In addition, the Drd I and PshA I mismatching cleavage sites incorporated into the primers serve as internal controls for Drd I and PshA I cleavage. CONCLUSION: The double Drd I/PshA I mismatch amplification procedure using hair root samples as the source of DNA is a robust method for genotyping Shorthorns for generalised glycogenosis.     

Evidence of molecular heterogeneity for generalised glycogenosis between and within breeds of cattle

SUMMARY Northern analyses revealed normal levels of acidic α-glucosidase mRNA in cultured fibroblasts from a Shorthorn calf affected with glycogenosis but a gross deficiency in an affected Brahman calf. Analyses of acidic α-glucosidase activity, relative to that of other lysosomal enzymes, in blood mononuclear cells revealed greater variation within and between Brahman herds than Shorthorn herds. A Msp1 restriction fragment length polymorphism associated with glycogenosis in Brahmans was not found in Shorthorns. These results are considered in relation to molecular heterogeneity for AAG deficiency in cattle and its implications for disease control programs.     

(Co)variance components, genetic parameters and annual trends for calf weights in a pedigree Brahman herd under selection for three decades

A 300 cow Brahman herd kept on improved pasture was subjected to a selection and management programme based on a limited breeding season. Artificial insemination using mainly progeny tested bulls was used in part of the herd and the rest were bred in single sire herds. Of the 200 sires used during the 30 year period, 82% were homebred and selected principally for high estimated breeding value of 18-month weight. Variance components of birth (BW), weaning (205 W) and 18-month (548 W) weights of 6130 calves born 1968 through to 1997 were estimated by the Restricted Maximum Likelihood method (REML) using uni- and bivariate animal models. For each weight the animal's direct and maternal genetic and the dam's permanent environmental effects were considered random and those of sex, year and month of birth and age of cow were considered fixed, but the models differed as far as the number of significant interactions included. Adjusted least squares means for BW, 205 W and 548 W were 28, 158 and 292 kg. Phenotypic and direct and maternal genetic trends from univariate analysis were for BW: 0.156, 0.061 and −0.001 kg; for 205 W: 0.471, 0.126 and 0.044 kg; for 548 W: 1.973, 0.486 and 0.251 kg per year. Direct and maternal heritabilities from univariate analyses were for BW, 205 W and 548 W, 0.33 and 0.08; 0.07 and 0.14; 0.13 and 0.08, respectively. Genetic direct-maternal correlations for the three weights were −0.37, −0.13 and 0.49 and permanent environmental variance of the dam as proportion of phenotypic variance (c²) had values of 0.03, 0.16 and 0.01, respectively. Direct and maternal genetic correlations were for BW: 205 W, 0.64 and 0.74; for BW: 548 W, 0.35 and 0.74; and for 205 W: 548 W, 0.64 and 0.96. Future genetic work in the herd should put more emphasis on the improvement of cow efficiency for sustainable beef production on native and improved pasture.     

Control of bovine leukosis virus in a dairy herd by a change in dehorning.

Following the demonstration that bovine leukosis virus was transmitted in calves by gouge dehorning, electrical dehorning at a younger age was implemented in a commercial Holstein herd. Subsequently, annual testing of the herd revealed a decline in the prevalence of bovine leukosis virus antibodies as older cattle dehorned by the former method were replaced by younger cattle dehorned by the latter method.     

Control charts applied to simulated sow herd datasets

Statistical control charts were used to detect process change in pig production. Two charts were tested to detect small deviations in production processes: the cumulative sum (CUSUM) control chart and the exponentially weighted moving average (EWMA) control chart. A Monte-Carlo simulation was used for developing an optimal design of the EWMA and the CUSUM charts. The traits piglets born in total and the return to oestrus rate were considered. Over a given time period, small shifts were purposely implemented to test the performance of the charts. The average time to signal (ATS) and false positive rate (FPR) were taken as classification parameters to evaluate the performance of the charts. All shifts in the number of piglets born in total were detected with CUSUM and EWMA control charts. The trait piglets born in total showed an ATS ranging from 1.3 (FPR = 33.5%) to 6.8 weeks (FPR = 1.2%) using the CUSUM chart. The EWMA chart presented an ATS which ranged between 2.0 (FPR = 14.9%) and 6.3 (FPR = 1.9%) weeks. The application of the CUSUM to the return to oestrus rate resulted in an ATS of 2.6 (FPR =  38.3%) to 15.6 weeks (FPR = 3.0%) and the EWMA chart produced a signal between 4.1 (FPR = 14.5%) and 16.4 weeks (FPR = 1.4%). Both charts appear to be useful tools for tracking commercial swine farm processes and detecting emerging change in process performance.     

Cerebrospinal nematodiasis in a goat herd

During the fall of 1985, 4 Angora goats, from a herd of 40, were examined on a farm in central Michigan. Affected goats were alert but had neurologic deficits consistent with upper and lower moto neuron involvement. Eosinophilic pleocytosis in a cerebrospinal fluid sample from one goat was consistent with cerebrospinal nematodiasis. Parelaphostrongylosis was confirmed in 3 goats by identification of Parelaphostrongylosis tenuis larvae in spinal cord sections. Ivermectin may have influenced the herd's susceptibility to new parasitic infections. Control of parelaphostrongylosis probably is best achieved by removal of susceptible animals from treed swamps coinhabited by white-tailed deer from late summer until after the first killing frost.     

Terbufos poisoning in a dairy herd

This report describes the accidental poisoning of over 200 head of Holstein cattle by the organophosphate, terbufos. The ingestion of an acutely toxic dose (approximately 7.5 mg/kg) of terbufos by 84 heifers resulted in severe respiratory distress as the primary clinical sign and death within 12 hours. There was no response to treatment with atropine sulfate. One hundred and twenty milking cows received a portion of the contaminated feed diluted approximately ten times. These cattle had typical signs of organophosphate poisoning and responded to atropine sulfate. Severely affected cows received pralidoxime chloride and activated carbon 48 h after terbufos ingestion but did not respond to the drugs. Diagnosis of organophosphate poisoning was confirmed by tissue and feed analysis for terbufos and measurement of whole blood cholinesterase activity.     

Sheath area in Brahman and grade Brahman calves and its association with preweaning growth traits

Data from 439 Brahman (B) and grade Brahman (GB; 7/8 Brahman or more) calves born from 1970 through 1975 at the USDA Subtropical Agricultural Research Station were used to estimate least-squares means, heritabilities and genetic correlations for sheath area and preweaning growth traits. Grade Brahman calves weighed more (P less than .01) at birth and gained more (P less than .01) preweaning than B calves, although sheath areas were not different. Males exceeded (P less than .01) heifers in all preweaning growth traits and had larger (P less than .01) sheath areas. Heritabilities were: sheath area, .45 +/- .13; birth weight, .25 +/- .13; average daily gain, .38 +/- .15 and weaning weight, .35 +/- .15. Genetic correlations between sheath area and birth weight, average daily gain and weaning weight were .23 +/- .35, .58 +/- .25 and .52 +/- .27. These results suggest selection could be effective in reducing sheath area in B and B-derivative breeds, but would be antagonistic to preweaning growth traits. Because of relatively low phenotypic correlations between sheath area and preweaning growth rate (.27) and weaning weight (.29), continued emphasis on increasing growth rate or weaning weight could generally be maintained with careful attention to avoiding large sheath areas through independent culling level or index selection procedures.     

婆罗门牛及其改良云南黄牛的效果研究

通过婆罗门牛(种牛或冻精)与云南黄牛杂交改良比较,其F1代的初生重、6月龄断奶重、12月龄和18月龄体重分别比云南黄牛高64.53%、13.37%、24.87%、37.91%。24月龄F1代牛市场价每头比云南黄牛高出1500元。     

Neospora abortion epidemic in a dairy herd

Neospora caninrm is a protozoan closely related to Toxoplasma gonclii. It was discovered only a few years ago, but it is now recognised as one of the most common and important causes of abortion in cattle. Brain lesions characteristic of Neospora infection have been found in about 25% of aborted foetuses submitted to diagnostic laboratories in New Zealand and overseas⁽¹⁾⁽²⁾. Average abortion rates due to Neospora on New Zealand farms have been estimated at 7% of pregnancies compared with 4% due to other causes⁽¹⁾. The upper range of abortion rates for Neospora was 17–30% compared to only 7–10% for other causes, showing that the economic effects of Neospora abortions on the more severely affected farms can be devastating.     

Cutaneous ergotism in a herd of dairy calves

Weather conditions in northern Illinois favored infection of pasture grasses with Claviceps purpurea. A herd of 52 Holstein heifers selectively grazed the seedheads of an orchard grassbromegrass pasture infected with C purpurea and were poisoned. Peptide alkaloids were found in the sclerotia. Clinical signs of intoxication included lameness, edema of the hind limbs, epilation, areas of skin necrosis, and diarrhea. Pathologic findings included myopachynsis of arterioles in the deep dermal areas, lungs, kidney, spleen, submucosa of small intestines and cerebral cortex, focal cracks on the hoofs, and multifocal areas of detachment of the hoof wall. Of the 52 heifers, 3 died on the farm, 1 was euthanatized, and 3 were sold. The remaining heifers conceived without difficulty, and subsequent calvings were uncomplicated.     

Gossypol toxicosis in a herd of beef calves

A 6-month-old crossbred calf was examined as representative of a herd of calves experiencing dyspnea and death, with few other clinical signs of illness. Physical examination of the calf identified pleural and peritoneal effusion and poor body condition. The calf did not respond to supportive treatment, and necropsy of it and another calf from the herd identified congestive heart failure as the cause of death. Gossypol toxicosis was the cause of congestive heart failure in this herd; the source of the toxin was a cottonseed meal and cottonseed hull ration fed by the owner.     

Ophthalmological findings in a closed herd of Lipizzaners

Reasons for performing the study: There are no studies on the ophthalmic health status in the Lipizzaner breed. Objective: To perform an ophthalmological survey in a closed herd in 3 housing systems. Materials: All horses at the Federal Stud Piber, Heldenberg and the Spanish Riding School Vienna were subjected to ophthalmological examination. Findings were documented and correlated with factors such as age, gender, location and housing situation. The interrelation of abnormalities of different regions was determined by calculating accuracy. Pedigree analysis of horses affected by cataract was performed. Results: A total of 267 horses met the inclusion criteria of this study. Of these, 172 horses were stabled in Piber, 72 in Vienna and 23 in Heldenberg. Ophthalmological examination revealed 203 cases with ocular findings, predominantly involving the conjunctiva (44.6%), cornea (21.7%) and fundus (37.5%). In 24 (8.9%) horses a diagnosis of cataract was made. There was no interrelation between different eye diseases. Horses stabled at Piber were significantly more affected by conjunctival and fundic abnormalities. Fewer abnormalities were found in horses stabled in open boxes. Access to free stalls resulted in more cases of conjunctivitis. Pedigree analysis showed no evidence of inbreeding as a cause of cataract formation. Conclusion and potential relevance: Acquired corneal abnormalities were over‐represented in this study. This survey may serve as a basis for further research on the pathogenesis of ophthalmic diseases in Lipizzaners.     

Clinical acidosis in a Gippsland dairy herd

OBJECTIVE: To report on spontaneous clinical and subclinical acidosis in a large dairy herd, to evaluate the diets and feeding strategies involved, and to report on measures of rumen function in the cows affected. DESIGN: A Gippsland dairy herd was sampled as part of a wider randomised cross-sectional study that examined the prevalence, risk factors for, and effects of, acidosis on rumen function of dairy cattle. Three herds on the farm were involved in the study: the transition herd (cows 3 weeks prior to calving), the very fresh lactating herd (1 < days in milk < 10, herd 1) and the fresh lactating herd (10 < days in milk < 120, herd 2) including a small lame herd fed separately. The transition cows were fed 2 kg dry matter triticale per cow per day and hay with an estimated total dry matter intake of 4.8 kg per cow per day. The lactating cow diet included 6.75 kg dry matter triticale per cow per day with total concentrate fed being 8.1 kg dry matter per cow per day in the milking parlour. Silage, lucerne cubes, hay and pasture (herd 2 only) was also fed to the lactating cows with the estimated total dry matter intake for cows in herds 1 and 2 being 13.7 kg and 20.8 kg per cow per day respectively. Three primiparous and five multiparous cows in early lactation (< 100 days in milk) were randomly selected from each of two lactating herds: herds 1 and 2. Rumen fluid was sampled from each cow by both rumenocentesis and stomach tube. The rumenocentesis samples were tested for pH at the time of sampling. Stomach tube samples were frozen and subsequently tested for volatile fatty acid, ammonia, and D- and L-lactate concentration. RESULTS: In the very fresh herd, there was a high prevalence of severe lameness and scouring, coupled with a mean rumen pH 5.67, low mean total volatile fatty acid concentration 71.0 mM and high mean concentrations of L- and D-lactate, (7.71 mM and 7.31 mM), respectively. Cows in the fresh herd had moderate signs of scouring and lameness. A lame herd comprising approximately 50 cows separated from the fresh herd was also present on the farm. The mean rumen pH of the fresh herd was 5.74 and mean rumen concentrations of volatile fatty acids, ammonia, L- and D-lactate were within ranges considered normal. CONCLUSIONS: The transition diet failed to supply sufficient energy and protein for maintenance of cows of this live weight in late gestation. The diet fed to the very fresh herd was low in effective fibre and contained an excessive content of non-structural carbohydrate in the form of processed, rapidly fermentable grain. The sudden change from the transition diet to the diet fed to the very fresh herd probably also precipitated the outbreak of acidosis. This case report provides unique detail, including information on diets and rumen parameters, of an outbreak of acidosis in a pasture-fed herd.