Serum chlortetracycline concentrations in parrots fed medicated seed diets     

KL WARD 《Australian veterinary journal》1997,75(8):558-560

Various seed diets containing chlortetracycline were fed to large and small parrots to evaluate serum chlortetracycline concentrations. The substitution of dehulled sunflower seed for whole sunflower in the seed mix may have resulted in higher chlortetracycline concentrations in cockatoos and parrots. The serum chlortetracycline concentration achieved for all diets was less than the goal of 1 μg/mL, but the concentrations attained may be useful for therapy.  相似文献   

Evaluation of Certain Veterinary Drug Residues in Food     

KL Hughes 《Australian veterinary journal》1994,71(8):271-271

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Calving patterns in seasonal dairy herds     

K.L. Macmillan  R.I. Henry  V.K. Taufa  P. Phillips 《New Zealand veterinary journal》2013,61(4):151-155

Two field studies examined the calving patterns of cows in seasonal dairy herds in the Waikato (Field Study 1) and South Taranaki regions (Field Study 2). The first study examined patterns for cows commencing their second or subsequent lactation in herds which had used an inseminating service during the previous season. The second study included first lactation heifers only in 15 herds where animals had been naturally mated, and in 15 herds in which they had been synchronised and then artifically inseminated at the synchronised oestrus.

The parameters describing calving patterns were based on the date for each herd's planned start of calving (PSC), which was 282 days from the date on which breeding commenced in the preceding season. The average interval from PSC to mean calving date for the 35 herds in Field Study 1 was 22 days, with individual herds anging from 15 to 30 days. In herds with heifers which had been naturally mated (Field Study 2), it was 17.6 days compared to 11.0 days for previously synchronised animals. Calculating the intervals from PSC to median calving date and separately for the last two quartiles more effectively described a herd's calving pattern. The duration for the last quartile of the calving pattern was influenced by the extent and timing of induced calving. In Field Study 1, 88.6% of the 35 herd owners induced premature parturition in at least one cow. In these herds, 11.3% of cows were treated and calved prematurely.

Only 61.7% of heifers which had previously been naturally mated calved by 3 weeks after PSC. Their calving dates were not evenly distributed over this 3-week period, with 9.8% in the first week and 25.6% in the third week. The calving pattern for heifers which had been previously synchronised showed several distinct peaks. Calvings to the synchronised mating were completed 15 days after PSC, by which time 64.7% of animals had calved. By 3 weeks after PSC, 72.9% of these heifers had calved.

The results showed that there was considerable variation in calving patterns in seasonal dairy herds. This variation would have been due to differences in conception pattern, and the way induced calving had been applied. The calving pattern in heifers which had been naturally mated was less concentrated than had been expected. Synchronisation can significantly concentrate the calving pattern of these first lactation animals.

The parameters used to describe calving patterns may be less applicable in herds in which a high proportion of animals is induced to calve prematurely, or where a whole herd is synchronised. Nonetheless, they do serve as an illustrative example of the variation in calving patterns among herds.  相似文献   

Prostaglandin responses in dairy herd breeding programmes     

K. L. Macmillan 《New Zealand veterinary journal》2013,61(7):110-113

Abstract

A re-evaluation of results from ten trials conducted in commercial dairy herds between 1974 and 1981 in which lactating dairy cows were injected once or twice with either of two forms of prostaglandin F_2∞ (PGF) showed that:

• Key points

• ? the variation in the post-injection interval to oestrus was influenced by the stage of the oestrous cycle at which treatment was administered;

• ? this variation was suffkient to reduce pregnancy rates to set-time inseminations;

• ? an accurate aid for oestrus detection, such as tail painting, should be used routinely with PGF;

• ? if PGF-treated cows were detected in oestrus before being inseminated, the pregnancy rates to first insemination were usually 10% higher than in untreated herd mates.

The results show that PGF systems in dairy herds should not be used as au alternative to accurate oestrus detection. These systems can be used to condense the breeding programme and increase pregnancy rates to first insemination. The exnloitation of this fertility effect justifies the reassessment of PGF usage in New Zealand dairy herds.  相似文献   

Aspects of Reproduction in New Zealand Dairy Herds     

K.L. Macmillan  K. Moller 《New Zealand veterinary journal》2013,61(8):220-224

Summary

Records for over 28 000 cows in 316 herds serviced by the Bay of Plenty Livestock Improvement Association showed the average calving interval (CI) was 364 days (S.D. = ±31 days). Between-herd variation accounted for less than 1% of the total variation. The CI for cows conceiving to first insemination was 358 days compared to 367 days for conceptions to second inseminations, but the CI for this latter group of cows was significantly influenced by the interval between inseminations. When the between-service interval was 17 days or less the ensuing CI was 352 days, compared to 374 days for a between-service interval of 18 to 24 days. The results indicate that while the high incidence of short-return intervals to first insemination in New Zealand dairy cattle will reduce non-return rates, the factors producing these short-return intervals are not increasing CI's. The estimated intervals from calving to first service varied from 57 to 76 days.

Although the A.B. service was used for an average of only 36 days, the total breeding period averaged 102 days after which time 5.4% of the cows in the herd remained empty. The regression coefficient between total breeding period and percentage of empty cows was only ?0.28% fewer empty cows per extra week. While this relationship was statistically significant there was a wide variation in the percentage of empty cows among herds with the same breeding period.  相似文献   

Variation in selected blood plasma constituents during the post-partum and breeding periods in dairy cows     

E.S. Kolver  K.L. Macmillan 《New Zealand veterinary journal》2013,61(5):161-166

Concentrations of insulin-like growth factor-I, albumin, beta hydroxybutyrate, glucose and urea were measured in 12 plasma samples collected over 9 weeks from mid-August from each of 40 cows in four seasonal herds which calved from mid-July. These herds comprised Jersey or Holstein-Friesian animals, with each breed grazed at two stocking rates. Daily dry matter intakes (kg dry matter/cow/day), which were estimated from pasture assessments before and after grazing, ranged from 4% (low stocked Jersey herd) to 38% (high stocked Friesian herd) below recommended intakes for each breed of cow in peak lactatipn. Stocking rate was associated with a 4% reduction in liveweight for cows in the high stocked herds and a 20% reduction in daily milk production (as a proportion of the low stocked herds' liveweight and milk production).

Eight cows produced at least one blood sample with a beta hydroxybutyrate concentration of more than 1.0 mmol/l. There were 42% of samples with glucose concentrations greater than 4.1 mmol/l. These two concentrations were the maximum values classified as normal for these two metabolites by the Ruakura Animal Health Laboratory. No concentrations of the other metabolites were outside their respective normal ranges. Breed, age and individual animals usually had greater effects on the average metabolite concentrations than did stocking rate.

The greatest effect was associated with sample day, especially for insulin-like growth factor-I and urea. A significant breed x stocking rate x sample day interaction in urea concentrations indicated that changes in the feeding value of the grazed pastures available to each herd were sufficient to produce separate fluctuating patterns in the daily average concentrations.

These results showed that frequent sampling on a herd basis would be necessary to identify the significance of factors which may be contributing to sample day variation in the concentration of metabolites in the plasma of pasture-fed cows.  相似文献   

Demographics,farm and reproductive management strategies used in Australian automatic milking systems compared with regionally proximal conventional milking systems          下载免费PDF全文

DM Keeper  KL Kerrisk  JK House  SC Garcia  P Thomson 《Australian veterinary journal》2017,95(9):325-332

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Cat scratch disease     

KL Hughes  JT Faragher 《Australian veterinary journal》1994,71(8):266-266

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The effects of induced parturition in dairy cows on the incidence of mortality in calves from commercial herds in south-western Victoria     

JM MORTON  KL BUTLER† 《Australian veterinary journal》1995,72(1):5-7

SUMMARY The effects of induced parturition on calf mortality rates were studied in 24 winter-calving, pasture-fed, dairy herds in south-western Victoria. Parturition was induced when most cows were between 27 and 35 weeks of pregnancy. Control groups were selected from cows in the same herds in which calving was not induced. The incidence of mortality within 7 days of birth was much higher among calves from cows in induced groups relative to those in control groups (estimated median herd mortality incidence 72% and 7%, respectively). The incidence of calf mortality was high among groups induced at all stages of pregnancy that were investigated. However, differences in calf mortality incidence, relative to controls, were increased among groups induced at earlier stages of pregnancy.  相似文献   

The efficacy of a combination anthelmintic against oxibendazole resistant small strongyles, large strongyles and ascarids in horses     

PF ROLFE  KL DAWSON 《Australian veterinary journal》1994,71(9):304-306

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