Cows sold for dairy purposes bring a higher price per cow than cows 

 sold for other reasons as sterile cows and cows with udder trouble, for 

 example, usually are sold for beef. In Table 9, the reasons for removal are 

 also ranked for both raised and purchased cows, with cows sold for dairy 

 purposes excluded. On this basis, all other reasons for removal accounted 

 for similar proportions of removals, except removal of cows for low pro- 

 duction. Low production accounted for 42 percent of the removal of raised 

 cows, while it was the reason for only 35 percent of the removals of pur- 

 chased cows. A higher proportion of purchased cows, however, were re- 

 moved for miscellaneous reasons. 



An analysis of the differences in relative importance of the various 

 reasons for removal of raised and purchased cows indicates that age and 

 selection were responsible for much of the variation.-*^ Purchased cows were 

 considerably older than raised cows when removed from the herds. Old 

 cows are more likely to be sterile. More old cows were removed because of 

 general physical breakdown, a reason associated with old age (and in- 

 cluded under the heading of "Other" reasons in Table 9). Purchased cows 

 also were selected on the basis of their ability to produce milk when they 

 were orginally offered for sale. The farm survey of 38 dairy farms with 

 some purchased cows indicated that of the 528 purchased animals on these 

 farms, 447 were bought as mature cows. Thus, 85 percent of the purchased 

 cows were selected with some tangible evidence of their milk-producing 

 ability. Hence, it might be expected that the proportion of purchased cows 

 removed for low production would be lower than with raised cows. 



The fact that a higher percentage of purchased cows were removed 

 because of disease — udder trouble, brucellosis, and sterility — does not 

 indicate that purchased cows were not as healthy as raised cows of the 

 same age. This is important because whether purchased cows introduce dis- 

 ease into a herd and cause a higher rate of culling is the most controversial 

 question associated with buying replacements. 



To help answer this question. Dairy Herd Improvement Association 

 records of cow removals for a year from 62 herds with no purchased cows 

 and from 58 herds with both raised and purchased cows were tabulated. 

 Only the records for animals removed for reasons other than sale for dairy 

 purposes were used. Herds containing all raised cows averaged 34.9 cows. 

 The total removals from raised herds for reasons other than dairy purposes 

 was 487 cows, or 7.9 cows per herd. Of the total, 200 cows, or 41 percent, 

 were removed because of udder trouble, brucellosis, and sterility. Thus, 

 removal for disease from herds with all raised animals was at the annual 

 rate of 92 cows per 1,000. The raised-and-purchased herds averaged 34.2 

 cows. Total removals for reasons other than dairy purposes was 524 cows, 

 or 9.0 cows per herd. Of the total, 194, or 37 percent, were removed be- 

 cause of udder trouble, brucellosis, and sterility. Thus, removal for disease 

 from herds with both raised and purchased animals was at the annual rate 

 of 98 cows per 1,000. For this sample of cows, it was concluded that the 

 incidence of disease, as indicated by rate of removal, was no greater for 

 herds with some purchased cows than for herds with raised cows only. 



20 Appendix Tables 2 and 3 show the number and proportion of raised and pur- 

 chased cows removed by age and by reason for removal. Appendix Tables 4 and 5 

 show the number and proportion of raised and purchased cows removed by length of 

 herd life and reason for removal. 



24 



