Identifying factors which maximise the lambing performance of hoggets: a cross sectional study     

PR Kenyon  GL Pinchbeck  NR Perkins  ST Morris  DM West 《New Zealand veterinary journal》2013,61(6):371-377

AIM: To identity perceptions of farmers with respect to advantages of hogget lambing and to identify optimal management strategies for hogget lambing used in New Zealand.

METHODS: A questionnaire was sent to 1,038 sheep farmers in New Zealand who had indicated their hoggets would be lambing in 2002. Information was gathered on the practice of hogget lambing in New Zealand, in particular on the numbers and breeds of hoggets and rams used, selection criteria used for hoggets, use of teasers (vasectomised rams), length of mating period, use of mating crayons, vaccinations, medications and mineral supplements given, level of feed offered, use of pregnancy scanning, management during pregnancy and lambing, number of lambs present at docking, and shearing policies for hoggets. Farmers were also asked to indicate the relative importance of five stated reasons for choosing to have their hoggets mated in 2002.

RESULTS: A total of 629 (60.6%) responses were incorporated in the analysis, and the average percentage of hogget lambing was 60%. Use of vaccinations, length of the mating period, number of rams used, breed of hogget, weight at mating, management during lactation, and shearing policy were associated (p<0.05) with the lambing performance of hoggets, in the multivariate analysis.

CONCLUSIONS: This study indicated that to ensure high lambing percentages (LP) in hoggets in New Zealand, sheep farmers should: vaccinate hoggets against toxoplasmosis and campylobacteriosis; utilise a 40-day mating period; use 2.6–3.5% of rams during mating; incorporate Finn or East Friesian genetics; ensure liveweights at mating are as high as possible; manage single- and multiple-bearing/-rearing hoggets separately during the lambing and lactation periods; and shear hoggets pre-mating.  相似文献   

Comparison in Effect of Heatsynch with Heat Detection Aids and CIDR‐Heatsynch in Dairy Heifers     

M Yusuf  T Nakao  C Yoshida  ST Long  S Fujita  Y Inayoshi  T Furuya 《Reproduction in domestic animals》2010,45(3):500-504

The objective of the present study was to determine whether oestrous detection with the help of oestrous detection aids during the Heatsynch without timed AI protocol is equally effective with the progesterone‐combined protocol in dairy heifers. A total of 148 heifers were randomly assigned to one of the two groups. A group of heifers treated with Heatsynch with heat detection aids (n = 72) received GnRH on day 0, prostaglandin F_2α (PGF_2α) on day 7 and oestradiol benzoate (EB) on day 8, while in controlled internal drug release (CIDR)‐Heatsynch group (n = 76), CIDR was included during a period from GnRH to PGF_2α. Heifers were checked for oestrus twice daily, i.e. from 09:00 to 10:00 hours and from 15:00 to 16:00 hours starting on day 2 for Heatsynch group and on day 8 in CIDR‐Heatsynch group, and continued up to day 12. KAMAR^®heat mount detector (KAMAR^® Inc., Steamboat Springs, CO, USA) and ALL‐WEATHER^® PAINTSTIK^® (LA‐CO Industries Inc., Elk Grove Village, IL, USA) were used as heat detection aids. AI was conducted within 1 h after confirming oestrus in 72 heifers, while 19 animals were transferred with embryo 7 days after oestrus according to the request of the owners. Premature oestrus before PGF_2α injection occurred in 18% of Heatsynch group. Of 13 heifers which showed premature oestrus, six were inseminated and two of them conceived. Oestrus detection rate within 12 days after initiation of the protocols did not differ between the two groups (94% vs 95%). There was no difference in the conception rate after first AI (including heifers that were inseminated before PGF_2α injection) and embryo transfer between Heatsynch with heat detection aids and CIDR‐Heatsynch groups (36% vs 44% and 70% vs 56%). It is concluded that the use of heat detection aids to monitor the occurrence of premature oestrus prior to PGF_2α injection in Heatsynch protocol in dairy heifers was equally effective to the inclusion of CIDR.  相似文献   

Improved Prediction of Ovulation Time may Increase Pregnancy Rates to Artificial Insemination in Lactating Dairy Cattle     

CD Hockey  JM Morton  ST Norman  MR McGowan 《Reproduction in domestic animals》2010,45(6):e239-e248

A prospective observational study was conducted in two Australian dairy herds to assess the potential for improving pregnancy rates (proportions of inseminations that result in pregnancy) to artificial insemination (AI) if the time of ovulation could be predicted with more certainty. Herd 1 calved year‐round and inseminations were performed during two periods each day. Herd 2 calved during autumn–winter and inseminations were performed only after the morning milking each day. In both herds, the AI to ovulation interval of enrolled cows was determined by trans‐rectal ovarian ultrasonography approximately 0, 12, 24 and 36 h after AI, and pregnancy was assessed by palpation per rectum 35–56 days after AI. Also, in Herd 1 vaginal electrical resistance (VER) measurements were taken at approximately 0, 12, 24 and 36 h after AI, and in Herd 2 cows were fitted with neck mounted activity meters that monitored cow activity count in 2‐h periods. There was substantial variation in the intervals from AI to ovulation within and between herds (mean ± SD 21.2 ± 10.7, n = 102; 14.7 ± 10.4, n = 100 in herds 1 and 2, respectively). Pregnancy rates were higher for inseminations close to, but preceding, ovulation. Using combined herd data (n = 202), the highest pregnancy rate (50.8%) was observed for inseminations between 0 and 16 h before ovulation, a period in which only a modest proportion of inseminations (31.2%) occurred. In contrast, pregnancy rate was significantly lower (28.7%; risk ratio 0.6; 95% CI 0.4–1.0; p = 0.039) for inseminations between 16 and 32 h before ovulation, a period where the highest proportion of inseminations (53.2%) occurred. Thus pregnancy rates could potentially be improved if a greater proportion of inseminations were conducted shortly before ovulation. In Herd 1, mean VER during the peri‐ovulatory period varied with time from ovulation. Lowest values (mean ± SEM, VER = 64.8 ± 1.2, n = 55) occurred approximately 18 h before ovulation and were significantly lower than measurements approximately 6 h before ovulation (67.4 ± 1.0; n = 73; p = 0.003). Further work is required to determine if VER can be used to identify ovulation time and hence the optimal time to inseminate in individual animals. In Herd 2 a modest proportion of inseminations (26.9%) occurred between 24 and 40 h after the onset of increased cow activity where the highest pregnancy rate (67.9%) was observed, whereas a significantly lower pregnancy rate (42.4%; risk ratio 0.6; 95% CI 0.4–0.9; p = 0.036) was observed for inseminations between 8 and 24 h after the onset of increased cow activity where the highest proportion of inseminations (56.7%) occurred. Thus cow activity monitoring may be useful to identify the optimal time to inseminate cows. Results from this study indicate that improved methods of ovulation prediction may allow better insemination timing relative to ovulation and consequently increased pregnancy rates.  相似文献   

Letters to the Editor     

J. M. EVANS  M. ST. G. N. DREWITT  DAVID BENNETT 《The Journal of small animal practice》1973,14(9):573-575

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The cheek teeth of cattle     

JONES ND  ST. CLAIR LE 《American journal of veterinary research》1957,18(68):536-542

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Novel in vivo use of a polyvalent Streptomyces phage to disinfest Streptomyces scabies-infected seed potatoes   总被引：2，自引：0，他引：2  

F. McKenna †  K. A. El-Tarabily ‡  G. E. ST. J. Hardy  B. Dell 《Plant pathology》2001,50(6):666-675

A highly virulent and polyvalent Streptomyces phage was isolated from a potato field near Albany, Western Australia. The efficacy of the isolated phage to disinfest seed potato tubers artificially inoculated with a common scab-causing streptomycete was evaluated. The phage suspension was prepared in a mini-bioreactor. Diseased potatoes were bathed in a phage suspension (1 × 10⁹ plaque-forming units per mL) for 24 h. The suspension was constantly circulated within a novel 25 L phage bath by means of an air-sparging pipe driven from an air compressor. Phage-treated scab-affected seed potatoes planted into free-draining polystyrene boxes containing steam-pasteurized field soil produced tuber progeny with significantly ( P  < 0·05) reduced levels of surface lesions of scab (1·2%) compared with tubers harvested from nonphage-treated tubers (23%). The number of scab lesions was also significantly reduced ( P  < 0·05) by phage treatment of mother tubers. No significant differences were recorded in weight, size or number of harvested tubers from phage-treated or nontreated mother tubers. This is the first in vivo study that has used Streptomyces phage to significantly disinfest seed potatoes of Streptomyces scabies and thereby reduce contamination of soil from seed-tuber-borne inoculum and reduce infection of daughter tubers.  相似文献   

A REPORT ON THE PROGRESS OF THE 1972/73 EPIZOOTIC OF EPHEMERAL FEVER—1 DECEMBER 1972 TO 30 APRIL 1973     

T. D. ST. GEORGE M.V.Sc.  H. A. STANDFAST B.Sc.  J. M. ARMSTRONG B.V.Sc.    D. G. CHRISTIE B.V.Sc.  H.D.A.    M. R. IRVING B.V.Sc.    S. G. KNOTT B.V.Sc.  &#; B. L. RIDEOUT B.V.Sc.  ¶ 《Australian veterinary journal》1973,49(9):441-442

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The clinical susceptibility of sheep to four Australian serotypes of bluetongue virus     

M. F. UREN  T. D. ST GEORGE 《Australian veterinary journal》1985,62(5):175-176

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The light reaction in the bleaching of rhodopsin     

WALD G  DURELL J  ST GEORGE CC 《Science (New York, N.Y.)》1950,111(2877):179-181

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Metabolic studies with chloropropylate acaricide in the dairy cow     

L E ST John  D J Lisk 《Journal of agricultural and food chemistry》1973,21(4):644-646

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