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.
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)
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.
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.
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)
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.
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.