Submitted to: Journal of Dairy Science
Publication Type: Abstract Only
Publication Acceptance Date: 7/21/2002
Publication Date: N/A
Technical Abstract: During dairy farm expansion, cows frequently spend more time standing in the holding pen before milking and are away longer from food, water and stalls. Thus, the objective of this study was to investigate the effect of time spent in the holding pen on milk production and blood parameters in Holsteins. Thirty-five cows were randomly assigned to two groups. During period 1 (wk 1 and 2), cows in group A (n=17) were kept in a holding pen for 40 minutes before milking and cows in group B (n=18) were kept in the same holding pen for 120 minutes before milking. Both groups of cows were off the study for 12 days between period 1 and 2 to reduce carryover effects. During period 2 (wk 3 and 4), cows in group A were kept in the holding pen for 120 min and group B 40 40 min. During this time, milk weights were measured daily and milk composition (protein, fat, lactose, and somatic cell scores, SCS) and post-milking blood samples were taken from each cow 4 times during each period. Fibrinogen, white blood cells, peripheral blood mononuclear cells, granulocytes (GRAN%), and hematocrit (HCT%), were examined as indicators of stress or dehydration from blood samples. Weekly means of weights, SCS, and blood components were obtained, as were differences between means for the 2 wks in each period. Statistical models used to analyze production and blood records included the effects of treatment, period and cow. Cow had a highly significant (P<.01) effect on all traits except for GRAN and HcT%, but not on differences from wk 1 to 2 within time period. The effect of period was highly significant (P<.01) for differences in milk component weights from wk 1 to 2 in each period and significant for milk (P<.01), lactose (P<.05), HCT% (P<.05) and difference in GRAN% from wk 1 to 2 (P<.05), but not fat (P<.10). Length of time in the holding pen affected only protein yield (P<.10), with cows held longer producing 0.03 kg more protein per day. Results indicate that exposure of cows for short times to increased stays in a holding pen does not significantly affect production or stress indicators.