Ohio State University Extension Bulletin

Research and Reviews: Dairy 2001

Special Circular 182-01


Characteristics and Management Practices of Herds Enrolled on Official Dairy Herd Improvement Association (DHIA) Testing Programs in Nine Ohio Counties

General Management

Herd characteristics/management practices and their relationship to milk production

Sixty-four variables out of 136 survived the initial screening procedure at P < 0.25. Number of cows in milk was the variable most associated with Milk Production (F=341.88, P=0.0001) at the initial screening. Final model of variables most significantly associated with milk production in our study is shown (Table 2). For each one cow increase in herd size, there was a corresponding 200 lb (91 kg) increase in RHA milk production. For each one percent increase in detected estrus, there was a corresponding 54 lb (24 kg) increase in RHA milk production. For each one percent increase in death of heifer calves, there was a corre stalls. Forty-six percent of the producers had maternity/ calving or springer pens where cows routinely calved. Only 10% of the producers grouped first lactation cows separately from older lactating cattle. Dry cows were grouped , based on time to calving by 67% of the producers. Most producers (67%) cleaned the parlor holding pen at least once a day.

Table 2. Summary of final model for estimating milk production among dairy herds, using ANOVA.

Variables in final model dfa F Betab Standard Error of Beta
All cows in milk 1 164.55c 200.03 15.59
% detected heat 1 25.44c 53.72 10.65
Approximate % death loss
per year (heifer calves born alive
but dying before eight weeks of age)
1 11.56c -111.45 32.77
% days in milk 1 11.27c 156.82 46.72
adf = degrees of freedom
bRegression coefficients for continuous variables.
cP < 0.01.


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