Search Results

You are looking at 1 - 8 of 8 items for

  • Author or Editor: J. K. Shearer x
  • Refine by Access: All Content x
Clear All Modify Search

Abstract

OBJECTIVE To determine the optimal anatomic site and directional aim of a penetrating captive bolt (PCB) for euthanasia of goats.

SAMPLE 8 skulls from horned and polled goat cadavers and 10 anesthetized horned and polled goats scheduled to be euthanized at the end of a teaching laboratory.

PROCEDURES Sagittal sections of cadaver skulls from 8 horned and polled goats were used to determine the ideal anatomic site and aiming of a PCB to maximize damage to the midbrain region of the brainstem for euthanasia. Anatomic sites for ideal placement and directional aiming were confirmed by use of 10 anesthetized horned and polled goats.

RESULTS Clinical observation and postmortem examination of the sagittal sections of skulls from the 10 anesthetized goats that were euthanized confirmed that perpendicular placement and firing of a PCB at the intersection of 2 lines, each drawn from the lateral canthus of 1 eye to the middle of the base of the opposite ear, resulted in consistent disruption of the midbrain and thalamus in all goats. Immediate cessation of breathing, followed by a loss of heartbeat in all 10 of the anesthetized goats, confirmed that use of this site consistently resulted in effective euthanasia.

CONCLUSIONS AND CLINICAL RELEVANCE Damage to the brainstem and key adjacent structures may be accomplished by firing a PCB perpendicular to the skull over the anatomic site identified at the intersection of 2 lines, each drawn from the lateral canthus of 1 eye to the middle of the base of the opposite ear.

Full access
in American Journal of Veterinary Research

Summary

In October 1985, mycoplasmas were isolated from bulk tank milk samples in a large Florida dairy (>1,400 lactating cows). At that time, measures to isolate and control the spread of infection were instituted. In an initial screening test, Mycoplasma bovis was isolated from 21 of 153 milking string samples (milk from all quarters of 10 cows/string). Composite quarter milk samples from all quarters of every individual lactating cow in the herd were obtained for culture in November 1985 and December 1985. In October, 88 of 1,535 (5.7%) cows were identified as Mycoplasma-positive. An additional 31 Mycoplasma-infected cows were identified in December. The dairy elected to maintain the infected cows in a separate Mycoplasma-positive subherd, which would be milked at the end of each milking session. Seven additional Mycoplasma-positive cows were identified at initiation of lactation. All newly identified infected cows were transferred to the Mycoplasma-positive subherd. After segregation of Mycoplasma-positive cows, bulk tank milk samples obtained routinely from the main herd remained culture negative throughout the study. From February 1986 to October 1986, quarter milk samples were obtained monthly from cows in the Mycoplasma-positive subherd. Any cow that developed clinical mastitis or substantial decrease in milk production was, at the discretion of the herdsman, culled. Of the 126 cows in the subherd, 22 (17.5%) were culled for mastitis, 35 (27.8%) were culled for low production, and 9 (7.1%) were culled for other reasons. Of the remaining 60 cows, 16 (12.7% of the 126 cows) were Mycoplasma-positive on the basis of results from one or more samples obtained after February 1986. Significant differences were not observed in milk production between Mycoplasma-positive cows remaining in the subherd and uninfected control cows in the main herd. Cows culled for low milk production had significantly (P < 0.001) lower milk production than did cows of other groups. Cows culled for mastitis were more frequently in second lactation (P = 0.04).

Free access
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE

To assess the extent of damage to the skull and brain of cadaveric dairy goat kids caused by a .22-caliber, 16-g pellet fired from a multipump air pistol at various power levels.

SAMPLE

Cadavers of 8 male and 7 female dairy goat kids ≤ 5 days old.

PROCEDURES

Each cadaver was positioned in sternal recumbency with the head and neck extended on a straw bale. A multipump air pistol was held with the barrel perpendicular to and 2.5 cm from the head at the intersection of 2 imaginary lines that extended from the lateral canthus of each eye to the middle of the contralateral ear base and fired at half (5 pumps; n = 2), intermediate (7 pumps; 2), or full (10 pumps; 11) power. The head and neck were removed from the carcass for CT imaging and gross sectioning to determine the location of the pellet and extent of damage caused to the skull and brain.

RESULTS

The pellet successfully penetrated the skull of all 13 heads shot at full or intermediate power and 1 of the 2 heads shot at half power. The pellet did not fragment after entering the skull of any cadaver and penetrated the brainstem (necessary for instantaneous death) in only 7 cadavers.

CONCLUSIONS AND CLINICAL RELEVANCE

The described technique was insufficient for use as a stand-alone method for euthanizing young dairy goat kids. Modification of the technique warrants further research to determine whether air pistols can be used to effectively euthanize young goat kids.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To validate the effectiveness of a penetrating captive bolt device with a built-in low-pressure air channel pithing mechanism (PCBD) as a 1-step method for euthanasia of cattle.

DESIGN Clinical trial.

ANIMALS 66 feedlot steers and heifers (weight, 227 to 500 kg [500 to 1,100 lb]) that were not expected to survive or finish the feeding period with their cohorts.

PROCEDURES Cattle were transported to a university facility and euthanized with the PCBD. For each calf, clinical variables were monitored and recorded immediately before and for at least 10 minutes after application of the PCBD. Following euthanasia, the head of each calf was removed and trauma to the brain and skull was assessed and scored.

RESULTS Death was successfully achieved with the PCBD without application of an ancillary technique in all 66 cattle; however, 4 (6%) cattle required a second or third shot from the PCBD because of technical errors in its placement. All shots from the PCBD that entered the cranial vault successfully rendered cattle unconscious without a return to sensibility.

CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that the PCBD was an effective 1-step method of euthanasia for use in mass depopulation of feedlot cattle.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To compare calving-to-conception intervals among cows classified as nonlame, moderately lame, or lame during the prebreeding postpartum period and to examine the relationship between severity of lameness and time to conception in cows that were classified as lame.

Design—Longitudinal study.

Animals—499 Holstein cows.

Procedure—Cows in the prebreeding postpartum period were classified as nonlame, moderately lame, or lame by use of a 6-point locomotion scoring system. Time to conception (days) was compared among cows. A low, medium, or high cumulative locomotion score was assigned to lame cows, and time to conception among those cows was compared. Cows classified as lame were examined on a tilt table for diagnosis and treatment of lameness.

Results—154 (31%), 214 (43%), and 131 (26%) cows were classified as nonlame, moderately lame, and lame, respectively. Most cows classified as lame had laminitis (54%) or disorders of the claw (33%). Median time to conception was 36 to 50 days longer in lame cows than in nonlame cows. Among lame cows, the median time to conception was 66 days longer in cows with high cumulative locomotion scores than in cows with low scores.

Conclusion and Clinical Relevance—Nonlame cows became pregnant more quickly than lame cows. Lame cows with low cumulative locomotion scores during the prebreeding postpartum period became pregnant sooner than lame cows with high scores. Early diagnosis and intervention may mitigate the effects of lameness and improve reproductive performance in lame dairy cows. (J Am Vet Med Assoc 2005;227:1284–1291)

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To compare milk yield among cows classified as nonlame, moderately lame, and lame and to examine the relationship between severity of lameness and milk yield in cows classified as lame during the first 100 days after parturition.

Design—Longitudinal study.

Animals—465 Holstein cows.

Procedure—Cows were examined weekly during the first 100 days after parturition and assigned a lameness score by use of a 6-point locomotion scoring system (ie, 0 to 5). Milk yield was compared among cows classified as nonlame, moderately lame, and lame. Among cows classified as lame (locomotion score ≥ 4), milk yield was compared for cows with low, medium, and high cumulative locomotion scores. Cows classified as lame were further examined on a tilt table for diagnosis and treatment of lameness.

Results—84 (18%), 212 (46%), and 169 (36%) cows were classified as nonlame, moderately lame, and lame, respectively. Among cows in their second or later lactations, milk yield in lame cows was significantly lower than that in moderately lame and nonlame cows. In addition, among cows classified as lame, milk yield was significantly lower in cows with high locomotion scores during the first 100 days after parturition, compared with cows with low scores. Most (58%) cows classified as lame had laminitis.

Conclusions and Clinical Relevance—Results indicate a linear relationship between increasing degree of lameness and decreasing milk yield among cows in their second or later lactations. The locomotion scoring system used in this study may be a useful management tool that veterinarians and dairy farmers could adopt for early detection of lameness in dairy cows. (J Am Vet Med Assoc 2005;227:1292–1296)

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To assess the efficacy of prophylactic hoof health examination and trimming during midlactation at reducing the incidence of lameness during late lactation in dairy cows.

Design—Randomized field trial.

Animals—333 Holstein cows.

Procedures—Cows without apparent lameness were randomly allocated into 1 of 2 groups approximately 204 days after calving. Cows allocated to the treatment group (n = 161) were examined on a tilt table for diagnosis and underwent hoof-trimming procedures, if needed, for treatment of hoof disorders or lesions. Cows in the control group (n = 172) were not examined. Cows were assigned a locomotion score weekly for 28 weeks after allocation to a group. The number of cows classified as lame during late lactation (approx 205 to 400 days after calving) was compared between groups to assess the efficacy of prophylactic examination and trimming.

Results—Incidence of lameness during late lactation was 24% in cows in the control group and 18% in cows in the treatment group.

Conclusions and Clinical Relevance—The 25% decrease in number of new cases of lameness in cows undergoing prophylactic hoof health examination and trimming during midlactation may be relevant for the well-being of dairy cows and should not represent a major economic burden to producers.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To provide an updated evaluation of the efficacy and safety of sometribove zinc suspension (rbST-Zn), a form of recombinant bovine somatotropin, in lactating dairy cows.

Design—Meta-analysis.

Sample—26 studies published in peer-reviewed journals or reviewed by a regulatory agency.

Procedures—To be included, a study had to involve the use of the rbST-Zn formulation available to US producers in accordance with the label instructions for treatment initiation (57 to 70 days postpartum), dose (500 mg, q 14 d), and route (SC).

Results—For cows treated with rbST-Zn, mean milk, 3.5% fat-corrected milk, fat, and protein yields were increased by 4.00, 4.04, 0.144, and 0.137 kg/d (8.8, 8.89, 0.32, and 0.30 lb/d), respectively; however, the concentration of milk components did not change. Pregnancy proportion for the first 2 breeding cycles was increased by 5.4%, and pregnancy proportion for the duration of the trial was reduced by 5.5% for rbST-Zn–treated cows, compared with proportions for untreated cows. Mean body condition score (1 to 5 scale) was reduced by 0.06 points during the period of rbST-Zn use for treated cows. Administration of rbST-Zn had no effect on milk somatic cell count, the number of days to pregnancy, or inseminations per pregnancy; rates of fetal loss, twins, cystic ovaries, clinical lameness, lameness lesions, or traumatic lesions of the integumentary system; and odds of clinical mastitis or culling.

Conclusions and Clinical Relevance—Results indicated that rbST-Zn administration to dairy cows effectively increases milk production with no adverse effects on cow health and well-being.

Full access
in Journal of the American Veterinary Medical Association