Heat Detection in Dairy Cattle - Part II

Recently, I received a phone call from a farm advisor who had concerns regarding the milk fat content in the herd of one of his clients. Cows were producing quite well, averaging 80 lb/day of milk, but the milk fat was hovering near 3.0%. Milk protein appeared relatively normal, at 3.9%. Herd health was normal, indicating that the low milk fat had not been associated with acidosis (at least to this point). The producer did not want to implement changes in the feeding program because he feared that if milk fat was brought within the normal range (3.5 to 3.7% for Holstein), milk production would drop and his milk paycheck would be severely reduced. What this producer needed to understand is that due to the last Federal Milk Marketing Order reform, milk in Federal Order 33 is now priced based on components: fat, protein, and other solids. A few other factors affect the monthly milk check (e.g. somatic cell counts), but these are relatively small and are not relevant to the analysis we are about to proceed with. Also, this producer needed to understand that nutrients are needed to produce the "other solids" fraction of milk.

Nutritional requirements change with the composition of the milk produced. The analysis must factor in the amount of milk components produced, their respective prices, the amounts of each nutrient required, and their respective prices. We used nutritional requirements calculated using the 2001 edition of the National Research Council publication, "Nutritional Requirements of Dairy Cattle". Costs of nutrients were those calculated for Ohio for July 2004 using the software SESAME. Price of milk components were those for Federal Order 33 in June 2004. Calculations were made for the current situation: 80 lb/day of milk with a 3.0% fat content. Calculations were also made for an alternate scenario where milk production was dropped 6 lb/day to 74 lb/cow/day, while raising the milk fat to 3.6% and maintaining other milk components at the same levels.

Results of our calculations are presented in Table 1. Under the new scenario, cows would produce an additional 0.26 lb/day of fat, but production of protein and other solids would drop by 0.17 and 0.35 lbs/day, respectively. The gross milk income would remain virtually unchanged to approximately $13.05/cow/day.

Because of the different nutrient requirements, the cost of providing the necessary nutrients to support milk production would actually be reduced under the new scenario by a calculated $0.08/cow per day. The income-over-nutrient cost favors marginally the new scenario by $0.06/cow/day. The point is that this producer could afford losing 6 lb/cow/day in milk production to correct the milk fat content problem without any negative financial impact. It is very likely that correcting the milk fat problem would not result in a loss of 6 lb/cow/day. Depending on the exact cause of the milk fat depression, one could actually see an increase in the volume produced. The lessons to be learned for this exercise are:

1. You are now mostly paid for the pounds of components shipped. The volume of milk is somewhat irrelevant.
2. There is no free lunch. It costs something to produce milk components. For the other-solids fraction (lactose, minerals, and other small components), it costs you more to provide the nutrients required to their production than what you are getting paid for them ($0.134/lb in June).

For those who want to explore other scenarios, we prepared an Excel spreadsheet (click here).

Table 1. Analysis of income-over-nutrient costs under two different scenarios.

Item
Current
Alternate
Milk production (lb/cow/day)
80
74
Fat (%)
3.0
3.6
Protein (%)
2.9
2.9
Other solids (%)
5.9
5.9
Production (lb/cow/day)
 
 
Fat
2.40
2.66
Protein
2.32
2.15
Other solids

4.72

4.37
Nutritional requirements
 
 
Net energy lactation (Mcal/day)
33.83
33.96
Rumen degradable protein (lb/day)
5.24
5.29
Rumen undegradable protein (lb/day)
2.71
2.39
Non-effective NDF (lb/day)
4.57
4.63
Effective NDF (lb/day)
10.67
10.80
Gross income from milk ($/cow/day)
 
 
Fat
5.22
5.80
Protein
7.21
6.67
Other solids
0.63
5.90
Total gross income
13.07
13.05
Nutrient costs ($/cow/day)
 
 
Net energy lactation
2.94
2.96
Rumen degradable protein
0.12
0.12
Rumen undegradable protein
0.78
0.68
Non-effective NDF
(0.27)
(0.27)
Effective NDF
0.57
0.58
Minerals and vitamins
0.20
0.20
Total nutrient costs
4.35
4.27
Income-over-nutrient costs
8.72
8.78