1. Energy balance changes in cows and matching calving seasons with forage availability TIES Seminar Kotaro Baba

2. 1. Tedeschi, L. O., D. G. Fox, M. J. Baker.2004 Unveiling the production efficiency of the beef cow: A systematic approach using nutrition models modification of paper presented at the NY beef cattle winter management meeting. Jan.2004 2.Reynoso-Campos, O., D. G. Fox, R. W. Blake,M. C. Barry, L. O. Tedeschi. C. F. Nicholson, H. M. Kaiser, P. A. Oltenacu.2004. Predicting nutritional requirements and lactation performance of dual-purpose cows using a dynamic model. Agricultural Systems. 80:67-83

3. PAPER # 1 Tedeschi., L. O., D. G. Fox, M. J. Baker.2004 Unveiling the production efficiency of the beef cow: A systematic approach using nutrition models modification of paper Increase beef production -Enhance reproduction indexes -Enhance nutrition concepts -Enhance genetic selection - Enhance ranch management

4. This paper introduces a model (CVDS) which Tedeschi is developing. The objectives of the model Computing the energy requirements of individual beef cows each day of the year and simulating the growth of the nursing calf given the information available Computing energy balances for the herd each day of the year to evaluate the balance between herd numbers and requirements with the forage available Identifying differences in efficiency among individual beef cows in a herd

5. The brief description of the model This model is based on those developed at Cornell as described by Reynoso-Campos et al.(2004) Fox et al. (1988)

6. An evaluation of the model, as the peak milk yield increases, the weaning weight increases. Paste figure 3

7. An evaluation of the model, energy efficiency of the cows Paste figure 3 B

8. Tedeschi implies Forage availability, milk yield, calf growth, and calving interval - The milk level should be based on forage available.

9. A practical application of the model

11. Hints from the Tedeschi’s paper for our Yucatan case 1. The milk level should be based on forage available. 2. Matching breeding and calving seasons with availability of forage.

12. Reynoso-Campos et al Reynoso-Campos, O., D. G. Fox, R. W. Blake,M. C. Barry,L. O. Tedeschi. C. F. Nicholson, H. M. Kaiser, P. A. Oltenacu.2004. Predicting nutritional requirements and lactation performance of dual- purpose cows using a dynamic model. Agricultural Systems. 80:67-83

13. Animal nutrition Cornell Net Carbohydrate and Protein System(CNCPS) -Milk production -ME balance -MP balance -BW change -Changes in Body reserve through the reproductive cycle.

14. Look at table 1. Page 70-71. Table 1 is nicely summarized nutritional constraints and strategies for intensifying dual-purpose cattle systems in the tropics. This table is related to our Yucatan beef project very much.

15. Objectives of this study 1 1. Describe a dynamic application of the CNCPS model that was developed to account for the cyclical changes in energy and protein balances that occur during the reproductive cycle of dual-purpose cows in the tropics.

16. Objectives of this study 2 2. Demonstrate the use of this dynamic application of the CNCPS model in evaluating dual-purpose cow performance over the reproductive cycle in specific production situations.

17. Inputs for the simulation Crossbred of Holstein x Brahman 2 nd lactation Age --- 65 mo CI --- 420days Dry periods—150 days Weight --- 470 kg Calf BW--- 31.5 kg Temperature -Previous 26C ° -Current 26C ° Milk -Production 11.5 kg/day -Fat 4.1 % -Protein 3.9 % Rolling herd average --- 2500 kg/270 day lactation with the CI of 420 days

18. Feed information Lactating cows -Graze forage Star grass (Cynodon plectostachyus) - 2 kg of commercial supplement (Both energy and protein concentrates) Non-lactating -Only grazed forage

19. Chemical components of Star grass Juarez et al., 1999 Lactating (fertilized) NDF --- 71.6 CP --- 10 Lignin – 7.3 NDF digestion rate --- 7.0 %/h Dry (unfertilized) NDF --- 78.3 CP --- 6.6 Lignin – 7.6 NDF digestion rate --- 5.0 %/h

20. Source, Reynoso-Campos et al.,2004

23. Source, Reynoso-Campos et al.,2003

24. Comparison of ME allowable milk with and without ME contribution from mobilized body tissue

25. Conclusion by Reynoso et al The CNCPS analyzes and integrates the nutritional and productive performance of cows on a dynamic basis throughout a calving interval. Changes in the predicted nutritional status of animals reflect dynamic, cyclic processes of tissue mobilization and repletion associated with variation in production requirements and nutrient availability during the CI

26. Hints from the Reynoso’s paper for our Yucatan case The CNCPS is a useful tool to monitor energy balance through the calving interval. The CNCPS can show the tissue mobilization and repletion in the prediction of nutrient requirement

27. My conclusion Energy balance, protein balance, and body condition score are different from physiological stages (early or late lactation, and early or late pregnancy), and feed quality and quantity. Not accounting for the fluxes of body tissue leads to unrealistic predictions of dietary requirements. It is important to think about forage availability, and energy requirements for each physiological stage