Dl4-lancaster Farming Saturday, April 6,1991 'JIjM Beef Briefs JThfl THE ECONOMICS OF COW SIZE AND MILK PRODUCTION Beef breeders have several tools available to them to rapidly change the individual cow size and pro ductivity of the herd. The use of expected prodigy dif ferences (EPDs) is a widely accepted and accurate means of improving growth performance and milking ability. However, these changes do not come without some cost to the enterprise. The nutritional requirements of a beef cow are based on: • The weight of the cow as a means of determining the mainte nance or the amount of feed needed to keep the animal alive and functioning. • The stage of production such as gestation, lactation, or growth. • The environment, particularly for outside temperature. • The rate at which animals are expected to grow. The first two are of greatest Nutritional Requirements of Cows of Differing Weight and Similar Milk Production (1) Cow Weight 1000 pounds 1300 pounds Stage (2) Nutrient (3) Total protein TON Net energy (1) NRC, Nutritional Requirements of Beef Cattle. (2) l=Mid pregnancy; 2= Last 1/3 of gestation; 3=First 3-4 months of lactation. (3) Total protcin=pounds per day; TDN=Total digestible nutrients in pounds per day; Net energy= Meal per day. To describe the difference in these requirements on a corn-equivalent basis valued at $2.75 per bushel, the following calculations can be made; Maintenance: 9.33 Meal NEm/day-7.52 Meal NEm/day=l.Bl Mcal/day; 1.81 Mcal/.92 Meal per pound of c0m=1.96 pounds of com per day; 1.96 pounds com X 365 days= 718 pounds com per year, 718 pounds/56 pounds bushel= 12.8 bu. com per year, 12.8 bu. X $2.75 per bu.= $35.26. Production: For 6 months 105% of maintenance= .376 Mcal/day: .376/.92 Meal per pound of com= .4 pounds of com per day; .4 pounds X 180 days = 72 pounds of com; 72 pounds of com @ $2.75/bu.= $3.54. For last 3 months of gestation: 10.93 pounds TDN-9.36 pounds TDN= 1.57 pounds TDN; 1.57 pounds TDN/81% TDN in com= 1.94 pounds com per day; 1.94 pounds X 90 days= 174.6 pounds com; 174.6 pounds com @ $2.75/bu.= 58.57. For first 3 months of lactation: 12.39 pounds TDN-10.75 pounds TDN=I.64 pounds TDN/day; 147.6 pounds TDN/81% TDN in com= 182.2 pounds com; 182.2 pounds com $2.75/bu.= $8.95. Total additional annual cost of 1300-pound cow : $56.32. It follows that the heavier cow must indeed be more productive (pro duce more annual value in weaning weight) in order to recover this additional cost to the enterprise. The addition of maternal milk production EPDs has given breeders the ability to change milk production potential in the cow herd through direct selection for the trait. Again, more milk production does not come without a cost, since more feed is needed to produce that milk. Similar to cow size, a scenario can be developed to describe the actual cost of this additional production. by John Comerford Penn State Beef Specialist importance to the cow-calf opera tor, since we do not expect the environment to drastically and consistently change feed needs in Pennsylvania. We will dedicate the remainer of the information to mature beef cows. Mature cow size will change when there is selection for larger frame size and greater yearling weight in replacement heifers because there is a positive genetic correlation between these traits and mature size. That is, as selec tion for larger frame size and year ling weight continues, the mature size of the cow herd will also increase. Since maintenance feed require ments are based on cow weight, it follows there will be a greater feed requirements as the cattle get bigger. In Table 1, the actual differ ences in feed needs are detailed for cows with similar potential for milk production, but varying in mature weight by 300 pounds. Table 1 12 3 12 3 88 1.06 1.90 1.06 1.24 2.19 7.74 9.36 10.75 9.35 10.93 12.39 7.52 7.52 7.52 9.33 9.33 Milk production Cow size Table 2 Feed Requirements of Cows of Differing Milk Production at 1200 Lbs. Body Weight Average Milk Superior Milk production Nutrient (2) Total protein TON Difference (1) NRC, Nutrient Requirements fra - Beef Cattle. (2) Total protein= pounds per day; TON= Total digestible nutrients in pounds per day. Using the same procedure as described for the calculations for cow size, this results in an addi tional 330 pounds of com for the 90-day lactation period for the hea vier milking cow. Again valued at $2.75 per bushel, this is an addi tional cost of $16.20. However, since milk production also entails a greater protein requirement compared to size, additional protein' supplementa tion is also needed. The values in Table 2 indicate there is an addi tional 46 pounds of protein required for the 90-day period for the heavier milking cow in addi tion to what the com would supply. On a soybean meal equivalent basis valued at $3OO per ton, this means the additional protein cost is $15.65. The total cost for the addi tional milk production is $31.85 for the 90-day period for cows of the same body weight. In the case of both larger size and greater milk production poten tial, there is an additive effect on feed requirements. Determination of the additional cost of both cow size and milk production would include adding the additional cost of maintenance and gestation for PLAN NOW FOR BEST PRICES ON YOUR GRAIN SET-UP EARL GSf hr #r* a FEED BINS j From 2'A I 3T£ CAN BE PICKED I P KNOCKED DOWN, PICKED CP PIT TOGETHER, OR DELIVERED INSTALLED ★ FULL LINE PARTS DEPARTMENT ★ WE SELL. SERVICE & INSTALL ★ : E/MHBRR equipment, INC. 730 AM- 14 Hem/ille Rd., Willow Street, PA 17584 800 PM Rhone 717-464-3321 or Toll Free: 800-732-0053 4-e 2.11 11.91 .84 the larger cow as previously shown ($35.26+53.54+58.57+58.95) with an additional cost for the milk production in a 90-day period. For 1000-pound average milk ing cows vs. 1300-pound superior milking cows, the additional feed WEST CHESTER (Chester Co.) The Chester Co. Coopera tive Extension is offering a tractor and farm machinery education course during April. Designed for young people aged 14-16, the course will be held Wednesday evenings, April 10,17 and 24,6:30 p.m.-9 p.m. at the Vo- Ag Department, Octorara High School, Route 41 and Highland Road, Alglen. A written and driving exam will be held Saturday, April 27, 8 a.m.-noon. The cost is $3 for the study manual. Contact the Exten sion office at (215) 696-3500 to register. Flex-Auger Systems, PVC Tubing, 2”, 3”, 3 Vi ”& 5” Dla. Systems Im loot Curved Au|er Tube 2.95 14.88 2.97 Chester Co. Offers Tractor Ed Course ' Suspemton Weed AuierTub# V Meterinf Hook» / Drop I Drop A A " energy requirement is 416 pounds of TDN. On a com equivalent basis, this would be $25.20 worth of additional com. The protein requirement for the 90 days not supplied by the com is 57.3 pounds of actual protein. On a soybean meal equivalent basis at $3OO per ton, this cost is $19.53 for protein supplementation. There fore, the total additional cost to cow size and milk production is $101.05. It is easy to see there must be substantial additional production from cows that are selected for both larger mature size and milk production. Beef breeders must balance this selection with their feed resources to effectively increase profit potential to the enteiprise. The course will give particip ants 14 hours of classroom and hands-on training in the safe use and operation of farm tractors and farm machinery. A certificate will be awarded to all who successfully complete the course. This certificate permits 14-16 year olds to operate certain machinery where they ale employ ed. Teens working for their parents do not require the permit, but are encouraged to attend to help pre vent serious accidents on their farm. For further information, contact the Chester County Cooperative Extension, 23S W. Market Street, West Chester, PA 19382. • Welght-Tronlx Feed c Mill r» * Transport Augers • Bucket Elevators • Stirring Systems • Grain Bins • Feed Bins • Wet Tanks • Utility Augers • Grain Dryers • Air Drying Systems Also Available For Air Drying Computerized Aeration Monitor
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