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Benchmarking reproductive efficiency in CA-dairies
A. H. Souza*, N. Silva-Del-Rio, E. O. S. Batista, P. S. Baruselli, P. J. Ross
*University of California Coop. Extension
California-dairies
USDA Ag-census 2012
Rationale Lack of information available on the topic in CA Reproductive performance in commercial herds by:
– Season, breed (Holstein vs Jerseys), herd size
Objectives To estimate conception (CR) and estrus detection (SR)
rates for HO and JE commercial herds Particular interest: effects of heat stress on fertility
Materials and Methods Only HO-JE herds reporting at least 200 AIs Conception results within 15% to 75% 1,377,729 AIs (1,262,926-HO; 114,803-JE) CR: pregnant/AI SR: average AI interval/21 (Woods index) Only AI intervals within 3 to 90 days Died/sold before preg outcome: disregarded Statistical analysis: Proc HPMIXED of SAS (9.3)
General herd-level data: milk production
Milk production (305ME)
<2000020000-25000
25000-30000>30000
% o
f her
ds
0
10
20
30
40
50
60
70
80
6
68
220
16
21
29
9
0
Holstein (n=310), average 305ME = 26,408 Jersey (n=59), average 305ME = 21,115
P < 0.01
*
*
*
Outline of results
Impact of heat stress on fertility
Breed effects (Holstein – Jersey)
Efficiency by herd size
Impact of heat stress on fertility
Year 2011 2011 2011 2011 2011 2011 2011 2011
Month May Jun Jul Aug Sep Oct Nov Dec
SR-JE 65.2% 66.4% 65.0% 65.0% 63.7% 64.1% 67.2% 62.8%
SR-HO 59.3% 59.2% 56.9% 56.7% 58.7% 59.6% 59.9% 57.5%
Year 2011 2011 2011 2011 2011 2011 2011 2011
Month May Jun Jul Aug Sep Oct Nov Dec
CR-JE 45.3% 42.3% 34.5%* 34.0%* 31.2%* 35.6%* 41.0% 43.2%
CR-HO 37.5% 33.2%* 28.2%* 27.6%* 25.9%* 28.7%* 35.0% 38.5%
Conception rate (%)
Service rate (%)
Impact of heat stress on fertility
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
% H
erds
with
CR
< 2
0%
0.00
0.05
0.10
0.15
0.20
Outline of results
Impact of heat stress on fertility
Breed effects (Holstein – Jersey)
Efficiency by herd size
Conception rate (%)
<25 25-30 31-35 36-40 >40
% o
f her
ds
0
10
20
30
40
50
155
67
43
86
99
9
27Holstein (n=310), average CR = 34.2% Jersey (n=59), average CR = 41.1%
P < 0.01
3
1210
Breed effects (Holstein – Jersey)
* *
*
Bottom 25% herds Top 25% herds
Ser
vice
rat
e (%
)
0
10
20
30
40
50
60
70
80
Breed effects (Holstein – Jersey)
Bottom 25% herds Top 25% herds
Con
cept
ion
rate
(%)
0
10
20
30
40
50
60
60%
35%
P > 0.10
P = 0.04
P > 0.10
P > 0.10
Outline of results
Impact of heat stress on fertility
Breed effects (Holstein – Jersey)
Efficiency by herd size
Efficiency by herd size
Herd size
<500 500-1000 1000-2000 >2000
%
0
10
20
30
40
50
60
70Service rate
Conception rate (P > 0.10)
(P = 0.07)
a ab ab b
Summary Heat stress lowers CR in both HO and JE herds at same extent
About 1 in 5 herds in CA have very poor (<20%) CR in summer
Although JE herds have better in SR/CR, well managed HO
herds can achieve outstanding reproductive results
Larger herds greater SR, but similar CR to smaller herds
Ongoing data collection: understand management strategies
in herds able to maintain good repro during summer months
Thanks! Questions?
