Management Strategies: Replacement Heifers

The acquisition of replacement heifers is a significant cost to milk producers and has a significant effect on profit ability. About 20% of total variable expenses to produce milk, go to raising replacement heifers. A milk producer must first strategize if it is better to sell all calves and purchase needed replacements or raise re placements. The advantages and disadvantages of purchas ing needed replacements must be evaluated along with a careful analysis of the cost to raise replacements before a qual ity decision based on the evidence can be made. When a milk producer decides to maintain ownership of replacement heifers, a decision must still be made regard ing who will raise them. Custom rearing is still an option. This decision is very similar to the "sell/not sell" decision in the process of analyzing the advantages, disadvantages and cur rent situation but is vastly different in how it is implemented and managed. Whoever takes the responsibility to raise the replace ment heifers must consider many different strategies: to achieve a labor efficiency of 14-15 daily labor hours per preweaned calf and 80-90 daily labor hours per postweaned calf, to maintain reproductive efficiency at levels equivalent to lactating cows, to maintain a growth strategy but monitor ing and implementing a sound nutritional program. The AA. report the results of an investigation performed during a 30 year period on 1085 necropsied calves. The aim of the research was to estimate the frequency of con genital malformations in this species. 99 congenital anomalies were found and their frequency was 6.54% of the examined animals. The organ systems more com monly affected were the urogenital system (34 malfor mations) and digestive system (30 malformations). The most common defect found was intestinal atresia (7 cases). The results of the investigation showed that congenital defects consistently increased during the period consid ered. These findings highlight the necessity to charac terize the defects and to apply basic epidemiological methods in order to control congenital anomalies in feed lot, to ascertain the etiology and to prevent the economic losses and the spreading of heredity diseases.


Introduction
Replacement heifer rearing accounts for about twenty percent of the variable expenses on a dairy. 1 The replacement rearing program has a significant effect on profitability. If heifer rearing expenses were to be reduced by ten percent, a two percent change in total expenses for the dairy would result. If variable expense to raise a heifer to calve at 24 months are 780 dollars, that would be 1.07 dollars per day. A ten percent reduction in these expenses would be 11 cents per day per calf. A ten percent reduction in cost to raise a replacement is within the grasp of the majority of milk producers.
It has been estimated that the cost of raising replacement heifers ranges from less than 77 cents per hundred-weight-of-milk-sold to more than two dollars per hundred-weight-of-milk-sold, depending on cull rate, age at first calving, and pounds of milk sold per cow per year. 2 See Table 2. A ten percent decrease in the cost to raise replacement heifers could translate into a savings 88 of between 8 cents and 20 cents per hundred weight of milk sold.
Many different strategies can be implemented to economically acquire or raise replacement heifers. The first decision or strategy implemented must be to determine if it is better to sell all calves and buy only those needed as replacements or raise replacement heifers. If the decision is to raise replacement heifers then who, when, where and how is it to be done must be decided. If the milk producer decides to raise the replacements then many more alternative strategies oflabor efficiency, growth or nutrition, reproduction, and health must be decided upon and implemented. Each of these will be briefly discussed below.

To Sell or Not To Sell
The advantages of selling all calves when they are born are many. Those advantages would include the following: increase in the time and energy spent on managing the milking herd, resources previously used by the replacement herd could now be used for the milking herd, resources such as labor, buildings (increasing herd size) and feed. These changes could increase the efficiency and profitability of producing milk. Especially if better replacements could be purchased than were raised and the purchase price was lower than the true cost of raising replacements. Another advantage is that the producer can purchase only what is needed.
The disadvantages would include possible cash flow problems when purchasing needed replacement heifers. Potentially introducing disease into the milking herd from purchased heifers. Lost of control of how heifers are raised. Possible increased cost of replacements. Potentially purchasing heifers of lower quality than could be raised. Possibly giving up an outlet for lower quality feeds and otherwise unused facilities.
The decision "to sell or not to sell" may be easy for some milk producers. For others a careful analysis of the cost ofraising replacement animals and advantages and disadvantages of selling all calves must be done before any action is taken. An example of a Per Heifer Enterprise Budget Summary is given in Table 1.

Who, When, and Where
If the decision is not to sell all calves when they are born, then it must be decided who will raise the calves, at what ages and where will the calves be raised and how it is to be done. Many milk producers have made the decision that they will raise the calves all the way to calving. For these producers the strategies of how to do it are most important. But many are looking for alternatives and are trying to decide what combination of alternatives best fits a given set ofresources and management abilities.
The advantages and disadvantages of custom rearing replacement heifers are the same as selling or not selling calves except that the milk producer has greater control of management, growth, and breeding of calves because ofretained ownership. There is also greater potential for owner/custom grower conflicts to develop.
To determine who should raise the calves, a careful analysis of the cost to raise a calf on a per pen basis should be done. The summary in Table 1 should be completed on every pen from birth to calving. This will identify those pens (who) that are potential candidates for custom growing because of present inefficiencies. A careful assessment of current resources (building, labor equipment, feed, etc.) used in the heifer rearing enterprise and their alternative uses must also be completed.
To complete the analysis described above may require a lot of time and effort. The quality of the decision made will be determined by the quality of the data used to make the decision. If the cost data can not be obtained JANUARY, 1995 then survey values can be obtained and used as long as it is recognized that survey or published values may not reflect what is really happening on the farm.
Where the replacement heifers are raised will be dictated by who it is that will be raising them.

How
There are many strategies that can be implemented to achieve profitable introduction of a productive quality heifer into the milking herd. Table 3 shows the estimated variable cost to raise a heifer to 24 months in Michigan. 3 The major expense areas are feed and labor. These would be the major areas to develop key strategies for profitable rearing of dairy replacement heifers. Another area that doesn't appear as a cost item in Table  3 but is a major determinant of heifer rearing profitability, is reproductive efficiency. It's cost is hidden in all of the variable costs and therefore is often forgotten about or the focus is on nutrition and growth. Simple biology states that if she doesn't get bred she won't calve no matter how well she is cared for and grown.
The cost to maintain a replacement heifer per day over 24 months was reported to be $1.17. Another way of interpreting this is the cost per day open beyond 15 months for virgin heifers. Table 4 compares the results and distribution of ages-at-first-caving of 2 different heat detection rates assuming no variation and "ideal" growth rates (1250 pounds at 24 months of age), breeding begins at 13 months of age and 830 pounds of body weight, and a 65 percent conception rate. The difference between a 30% heat detection rate and a 50% heat detection rate, with all else being equal, was 1.3 months average age-at-firstcalving, 35 pounds of average body weight at calving, and $2527 .20 per 100 heifers raised.
For a variety of reasons, many milk producers like their heifers to be older and bigger when they breed them. Table 5 compares 2 different breeding policies and different heat detection rates assuming the same "ideal" growth rates and a 65 percent conception rate. The two breeding policies and heat detection rates are: 1) Beginbreeding at 13 months of age and 830 pounds of body weight with a 50 percent heat detection rate, 2) Begin breeding at 15 months of age and 930 pounds of body weight with a 30 percent heat detection rate. Assuming the same cost per day open beyond 15 months of $1.17, the difference between the two scenarios was $7757.10 per 100 heifers raised. This could also be interpreted as the potential savings of going from a breeding policy of 15 months at 930 pounds with a 30% heat detection rate to 13 months at 830 pounds with a 50% heat detection rate. To estimate actual savings would have to include the cost of improving the heat detection rate and any other changes that would need to be implemented. There is a lot of money to be saved by improving reproductive efficiency in virgin heifers. Labor expense is very variable between farms. This variability due to the value of labor (wage per hour), the facility, and management practices on a particular farm. Table 6 is a list of estimated labor requirements for a herd of 100 calves whose age-at-first-calving is 24 months. This table would indicate that 81 % of all labor in raising heifers is utilized in daily chores of feeding and heat detection. Because of the variation in value of labor the best measure of management practices in regards to labor is the Number of Calves per Daily Labor Hour (NC/DLH). Glton et. al. 4 proposed using this measure to evaluate labor efficiency of replacement heifer rearing on farms. Regular daily chores of feeding and heat detection along with cleaning, bedding, breeding and other regular chores should be included in the calculation. They propose goals of 14-15 NC/DLH for pre weaned calves and 80-90 NC/DLH for post weaned 90 calves. These are ambitious goals but not unattainable. For efficient and profitable rearing of replacement heifers these rates will have to be approached. This   means that daily chore routines need to be evaluated and critiqued to find a more efficient way of accomplishing the same task. The challenge is that chore routines are often dictated by the facilities and equipment utilized. Large gains in labor efficiency may not be achievable without major expenditure in capital investments.
The only exception to this would be to decrease age-atfirst-calving or shorten the distribution (variation) of ages-at-first-calving. This would decrease the number of times that daily chores need to be done for a particular calf to reach calving. The greatest variable expense in raising replacement heifers is feed expense. Feed expenses will vary a lot between farms primarily due to the value placed on feed stuffs and age-at-first-calving.
The value and quality of feed stuffs will vary from region to region and farm to farm. Balancing of rations to meet the requirements of different groups of heifers will certainly improve profitability and improve the efficiency of feed utilization. It will decrease the cost per pound of gain and the cost to grow heifers.
This idea implies that a strategy to manage growth is in place. Rations should be bala~ced for a certain rate of gain and maintenance. There also needs to be in place a monitoring system to evaluate how well the nutrition program is following the growth strategy. There is much debate about what this monitoring system should look like. AB age-at-first-calving decreases and growth rates increase, the level of monitoring must increase as well as the level of management. Cost per pound of gain will decrease, daily feed cost will increase, total feed cost will decrease and the economic window for conception will decrease as age-at-first-calving decreases and growth rates increase. Table 7 contains several possible growth strategies that might be implemented. Recognize the limitations stated above and that an excessively fat heifer is a problem no matter how you look at it.

Conclusion
There are many strategies that can be implemented to acquire replacement heifers profitably. The first and major decision is the source of heifers and who will raise them. In raising heifers alternative strategies Table 7. Monthly frame size body weights and aver-  The results of the investigation showed that congenital defects consistently increased during the period considered. These findings highlight the necessity to characterize the defects and to apply basic epidemiological methods in order to control congenital anomalies in feedlot, to ascertain the etiology and to prevent the economic losses and the spreading of heredity diseases.
Comparison of ultrasonographic and radiographic findings in cows with traumatic reticuloperitonitis The radiographic and ultrasonographic findings in 26 cows with traumatic reticuloperitonitis were compared. The cows were divided into three groups based on the radiographic findings; the first group consisted of 12 cows in which the principal radiographic finding was a foreign body penetrating the reticulum; the second group contained four cows in which the principal radiographic finding was gas shadows or a gas-fluid interface, the third group consisted of 10 cows that had no reliable radiographic evidence of traumatic reticuloperitonitis, such as an abnormal contour, posi-92 tion or shape of the reticulum. In no case could the foreign bodies be visualized by ultrasonography. In all the cows except one with radiographic evidence of abnormal gas inclusions and gas-fluid interfaces, ultrasonography revealed echogenic, partitioned and capsulated structures with central hypoechogenic cavities. In addition, in some of the cows with no radiographic evidence of the condition, severe changes indicative of inflammatory processes were visible by ultrasonography.