1. Animal Science 400 Nutrition Management Decision-making: An Intensification Strategy for Beef Cattle Systems in Tizimín, Yucatán, México May 2006 Kotaro Baba

2. www.elca.org

3. Issue and problem, México, USA and beef production Migration and population increase Demand for animal product (Delgado et al.,1999) NAFTA Cow-calf production

4. www.realestateyucatan.com

6. Cow-calf production system

7. Target audiences of our project 1. The owners of the beef reproduction ranches in the study site 2.Local professionals

8. Source Magaña UADY

9. The end of June, the early rainy season

10. The end of October, The early dry season

11. d The end of March, the late dry season

12. The forage growing cycle of the year Source, Magaña, UADY

13. Irrigation Pumps from under ground The cost of irrigation is expensive.

14. Forage quality Tropical forage contains a lot of cell walls (Van Soest., 1994) -High temperature, the length of the day -High NDF, lignin, low CP Season is known to have a large effect on NDF, lignin, CP(Licitra et al., 1998)

15. Reproduction, Calving Interval (CI) Brahman in Texas (Browing Jr,1995) -one calf per year (12-13 mo) Brahman in our study site -14 month for mature cows -15-17 mo for 1 st lactation cows (Magaña et al., 2002)

16. Problem statement seasonal variation in the supply and quality of forage is a primary constraint affecting beef cattle productivity in Tizimín herds. Extended Calving interval, economic losses.

17. Body Condition scoring Beef cattle scale 1(Thin)-9(Fat) Use body reserve for early lactation (high energy requirement) and when the feed supply is inadequate Restore reserve after the energy supply is improved These should be included in nutritional management, (Reynoso-Campos., 2003), the amount of the energy for these, is not small in our case and many cases.

18. Body Condition scoring (continued) Strong link between BCS and reproductive performance At least the cows need a BCS 5, and 6 for breeding heifers for next calving (Herd et al., 1995)

19. Source Virginia State University and Virginia cooperative extension This cow’s BCS is five. www.ext.vt.edu

20. What is her BCS?

21. Problem-solving approach The energy intake is low The postpartum intervals from parturition to the nadir of negative energy balance were correlated with the number of days from parturition to first ovulation (Canfield and Butler 1989,1990, Beam and Butler, 1997) effective reproductive management requires analysis of energy balance and dietary supplementation strategies to replenish catabolized tissue reserves and to shorten CI. indicate which season is best for calving, and which season should be avoided for calving.

23. Objectives of our project Determine nutrient requirements and appropriate dietary supplementation strategies throughout the year for key management groups of females to efficiently achieve productivity and reproductive goals Management goals include prompt recovery from the postpartum energy balance nadir to allow ovulation and conception to occur, and to assure adequate body tissue reserves over the reproductive cycle to minimize the calving interval

24. What information is needed? Energy balance throughout the CI How can we know the energy balance throughout the calving interval? Use the CNCPS as a tool. (Rueda et al., 2003, Reynoso-Campos et al., 2004, Nherera 2005) in the tropics

25. Procedures Use panel of experts to describe current situation –Describe each group in the beef herd –Describe forage composition available during each season of the year Predict nutrient balances for each group in the herd when consuming forages available during each forage growth season

26. Procedures Management group for the simulation Physiological stage -Early lactation stage (first 90 d) -Mid late lactation stage(150 d) -Early dry -Late dry (last 90 d) Parity - 1 st lactation cows -2 nd lactation cows -Mature cows -Breeding heifers

27. Seasons Season 1(calving on June 1, the early rainy season) Season 2(calving on August 1, the late dry season) Season 3(calving on October 1, the early dry season) Season 4(calving on February 1, the late dry season)

28. .Forage composition for the CNCPS simulation Yucatán assumptions SeasonCP(%)NDF (%) Lignin % in DM Ash%in DM NDF rate % /hou r Ether extrac t % in DM Season 1967612.78.63 Season 28727127.22.6 Season 3774811.57.22.2 Season 45779115.11.6

29. Forage composition for the CNCPS simulation assumptions the average values of Juarez et al, and Rueda et al SeasonCP(%)NDF (%) Lignin % in DM Ash%in DM NDF rate % /hour Ether extract % in DM Season 19675.512.78.63 Season 28706127.22.6 Season 38716.511.57.22.2 Season 47737115.11.6

30. Inputs for the CNCPS, Maga ñ a et al. 2002, 2006 and assumptions by the Yucatán panel of experts. Item 1st lactation cows 2nd lactation cowsMature cows Body weight, kg400460500 Mature weight, kg500 Calf body weight, kg31.5 Calving interval, d 460(rainy) 500(dry)420 Milk production early lactation, kg4 (6.4)4.5(7.2)5(8) Milk production mid-late lactation, kg3(4.8)3.3(5.3)3.7(6)

31. BCS change The next slide will be BCS change in each season. the CNCPS inputs Based on Delgado 2000 with our assumptions.

32. Table 6 Season 1 (Calvingon June 1, the beginning of the rainy season) Season 2 (Calving on August 1 at the middle of the rainy season) Parity Calving ( 1 day) Early lactation (1-90 days after calving) Mid-late lactation (90-240 days after calving) Early dryLate dryParity Calving (1day) Early lactation (1-90 days after calving) Mid-late lactation (90-240 days after calving) Early dry Late dry 1 st 4.5 44 5 1 st 5.5 4.5456 2 nd 4.5 4 55.5 2 nd 6 5456 Mature4.54 55.5 mature 65566 Season 3 ( Calving on October 1, the beginning of the dry season) Season 4 ( Calving on Feb 1 the middle of the dry season, the data is originally BCS change for the dry season) Parity Calving ( 1 day) Early lactation (1-90 days after calving) Mid-late lactation (90-240 days after calving) Early dryLate dryParity Calving ( 1 day) Early lactation (1-90 days after calving) Mid-late lactation (90-240 days after calving) Early dry Late dry 1 st 6 54.5 5 1 st 5 3.5 45 2 nd 6 54.5 5.5 2 nd 5 4346 mature 654.5 5.5Mature6544.56

33. Analytical framework and preliminary results The results of the simulation (EB) are combinations of Energy requirements -Lactation (High especially in the early stage) -Pregnancy( low, but higher in the late stage) -BW or parity (growth rate, and maintenance) Energy supply -Grass (Season 1 is the best, and Season 4 is the worst) BCS change -Body tissue mobilization -Body tissue repletion

34. Simulation 1 Compare energy balance with and without body tissue contribution (with and without BCS change in each physiological stage)

35. Early lactation 3 mo in S4 S4 G=100% T sup 17.72 -Btis(6-5)2.21 T req 22.43 -.Maint- 16.72 -Lac - 5.714 EB- Mius 4.72, The 2.21 Mcal helps the cow Mid-late lactation -1 mo in S4 -2 mo in S1 -2 mo in S2 G4:G1:G2=1:2:2 T sup 19.99 From BT(BCS5-4) -1.22 T req 19.32 Maint- 15.05 Lac - 4.23 Pre - 0.04 EB - (0.67) Early dry -3 mo in S3 G3=100 % T sup 19.59 T req 17.34 Maint-15.14 Pre - 0.79 to BT- 1.09 BCS(4-4.5) EB- (2.56) Late dry -1 mo in S3 -2 mo in S4 G3:G4=1:2 T sup 18.428 T req 22.89 - Maint-15.28 - Pre - 4.3 to BT- 3.35 BCS(4.5-6) EB= (-4.46 )

36. Simulation 2, Which season is good for calving, and which season should be avoided? I do not know exactly yet. More simulations are needed. To have a calf per year, cows must get pregnant at 75 days after calving (The Brahman’s pregnant period in our study site is 290 d) Energy Balance -Energy supply is different in seasons -Energy requirement is different in physiological stages BCS 5, at least needed at calving Prompt recovery is necessary from the postpartum energy balance nadir to allow ovulation and conception to occur

37. E-Lac - 2 mo in S1 - 1 mo in S2 G1:G2=2:1 Mi- lac -1 mo in S2 - 4 mo in S3 G2:G3=1:4 E-Dry - 3 mo in S4 G4=100% L-Dry -1 mo in S4 -2 mo in S1 G4:G1=1:2

38. Simulation 3, with Molasses (M) and Poultry Manure Some farmers feed 1 kg of M and PM for cows in the lactation stage, and some cows in the dry season, I am asking Fernando Duarte. Both are by-product feeds - Molasses CP 4%, Fat 4.2%, Sugar 70% DM -Poultry Manure CP 15.8 %, Fat 0.5%, and Sugar 1.9 % DM (Tedeschi et al., 2002) M & PM are added for the entire CI to see the difference with and without M & PM

40. Conclusion of simulation 1, 2 and 3 The CNCPS predicts the energy balance included the fluxes of the body tissue Supplementation strategies would be needed for all the seasons to achieve a 12 mo CI. I can not still indicate the best season for the calving Calving Season 4 looks not very good to achieve the 12 mo CI Season 4 grass (High NDF and lignin content forage) constraints feed intake. In our simulation, molasses and poultry manure help cows in the dry season, but 1 kg of M and PM is insufficient.

41. Goals for shortening the CI Reach nadir as soon as possible after calving. Have cows in optimum BCS at calving. Need to achieve zero energy balance over the reproductive cycle.

42. Thank you