ANSC 3261 / SAAS 261
Oct 28, 2015NAME:______
SECTION A. Briefly define the following within the context of the dairy industry, noting that just “translating” abbreviations is only half the job! (2 pts @):
2. Milk-Feed Price Ratio
SECTION B. Associate the following minerals from the list on the left with the appropriate item from the list on the right by writing the letter designating the association in the blank beside the mineral. Use each letter only once. Admittedly, some of the compounds may be associated with more than one effect or condition, but only one assortment of the letters will result in ten correct answers. (2 pt @)
IodineA)Deficiency reduces iron absorption
CopperD)Important dietary ingredient if NPN is fed
ZincE)Necessary for normal muscle function
MagnesiumF)Low concentrations in forages in Northeast
PhosphorusG)Vitamin B12 co-factor
SeleniumJ)A major constituent of bone
SECTION C.Essay time! Answer these questions on the lined paper provided and please write neatly. Thanks. Note that the questions 1, and 2 are worth 5 points each 3, 4 and 5 are worth 10 points each. Provide detail accordingly.
1.Name three different measures of fiber content of dairy rations. What does each measure? Which is the most accurate predictor of intake? Why?
2. Diagram the relationship (draw a graph!) between milk production, dry matter intake and body weight that occurs during the lactation cycle and explain how these factors interact. Also, indicate on diagram energy balance status on diagram.
3. Compare TDN and Calorie systems for measuring the energy content of feed. What methods are used to measure feed energy for each system? Which one provides a more accurate estimate of energy content to support milk production? Why?
4.Dairy cattle differ from non-ruminants regarding the compounds that represent dietary energy in the ration. What are these three compounds? Distinguish between them (structure). What are they called as a group? Explain their presence in the rumen. Trace their path to their eventual physiological use, mentioning any other use beyond providing energy.
5.Managing dairy cattle to avoid problems during the transition period is crucial to the success of a dairy operation. From a nutritional point of view, what consideration should be addressed to provide cows with the greatest chance to survive unscathed? Your response should focus on nutritional management during the dry period, including a definition of DCAD and why it is important. What is an appropriate DCAD value for a prepartum ration? What about postpartum? Explain why in each case.
SECTION D. OK...here's the ration balancing problem, as advertised. Balance a ration for a fourth lactation 1400 pound cow producing 130 pounds of 3.5% fat milk. See nutrient content data listed below for values you'll need to perform these calculations. Interpolate any values not expressly provided. Estimate roughage DMI at 1.75% of BW. Use corn silage as roughage source and add concentrates and minerals as necessary. Finally, do you think this cow will consume the ration? Explain. If not, what happens? NOTE: Answer this section on lined paper provided. Nothing written on this sheet will receive any credit!!! Don’t goof up here...this thing is worth 20 points!
Maintenance of Mature Lactating Cows
BW CP ENECaPVit A
(lbs)(lbs) (Therms)(lbs)(lbs) (1000 units)
700 0.71 6.020.0280.02324
800 0.77 6.650.0320.02628
900 0.83 7.270.0350.02831
1000 0.89 7.860.0380.03035
1100 0.95 8.450.0400.03238
1200 1.01 9.020.0430.03441
1300 1.06 9.570.0460.03745
1400 1.12 10.120.0480.03948
1500 1.17 10.660.0510.04152
1600 1.22 11.190.0530.04355
1700 1.27 11.710.0560.04559
1800 1.32 12.220.0590.04762
Milk Production - Nutrients/lb of Milk of Different Fat Percentages
Fat %CP ENE Ca PVit A
(lbs) (Therms) (lbs) (lbs) (1000 units)
Nutrient Composition of Feeds
Feed Dry MatterCP ENECaPVit A
%% (Therms/lb)%% (1000 units)