evaluation of beef cow-calf nutrition in yucatan, mexico: ms thesis progress report animal science...

Evaluation of beef cow-calf nutrition in

Yucatan, Mexico:MS thesis progress report

Animal Science

Kotaro Baba

January 2006

Situation

• Beef cattle farming is the main industry in Tizimín

• beef production systems in Yucatan are constrained by:– Declining forage quality as the forage prod

uction system progresses– Low quality and amount in the dry season – Long calving intervals and percentage of c

ows calving each year

Thesis objectives

• Predict nutrient balances during each stage of the reproductive cycle with forages available during each stage of the annual forage production cycle.

• Use this information to:– Identify weak links and their effect on the

calving interval– Identify cost effective management

strategies that can shorten the calving interval

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

Distribution of calving of Zebu and crossbred cows by month

0

50

100

150

200

250

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

month

calv

ing

fre

qu

en

cy

Conception rate of the Zebu cows at 120 days pospartum by parity

0

0.1

0.2

0.3

0.4

0.5

0.6

1 2 3 4 5 6 more than 7Parity

Forage growth periodsForage growing cycle in Yucatan, (Source Magaña UADY)

0

200

400

600

800

1000

1200

1400

1600

1800

2000

1 2 3 4 5 6 7 8 9 10 11 12month

DM

/kg

/ha

nn1nn2nn3nn4

Grasses grazed by forage growth periods

• Season 1 grass ( June 1- July 31)• Season 2 grass ( August 1-September 30)• Season 3 grass ( October 1- January 30)• Season 4 grass ( February 1-May 31)

Representative farms

• Farm 1: Calving on June 1

• Farm 2: Calving on August 1

• Farm 3: Calving on October 1

• Farm 4: Calving on February 1

• Physiological stages -Early lactation -Mid-late lactation -Early dry -Late Dry

• Parity and age - 1 st lactation cows

- 2nd lactation cows -Mature cows

-heifers

Inputs for the CNCPS

SBW

-1st =400 kg

-2nd=460 kg

-Mature=500 kg

Calf BW

-male 33 kg

-female 30 kg

Weaning weight

-male 210 kg (dry season)

-female 180 kg (dry)

- male 220 kg (rainy)

- female 220 kg (rainy)

Inputs for the CNCPS

Milk production early lactation -1 st= 4 kg -2nd=4.5 kg -mature=5kgMid late lactation-1 st =3 kg-2 nd=3.3 kg-Mature 3.7 kg

Milk fat=4 %Milk CP=3.5 %True protein=3.3 %

CI -1st (rainy) 460 days -1st(dry) 500 days -The others 420 days

BCS change in the rainy season

Rainy season

parity calvingearly

lactationMid-late

lactation Early dry late dry

1st7 6 4 5 6

2nd6 5 4 5 7

≧38 7 6 6 7

BCS change in the dry season

Dry season

parity calvingearly

lactationMid-late

lactation Early dry late dry

1st6 3.5 3 4 5

2nd5 4 3 4 6

≧37 5 4 5 6

Rations for simulations

• Rations -season of the year and physiological period.

Example,

Early lactation period =90 days

Farm 1 (calving on June 1)

The ration ; 60 days(June1-July 31 with season 1 grass): 30 days( August 1- August 31, season 2 grass)=2:1, (6 kg:3 kg for example)

Simulation 1: grazed grass composition

based on CNCPS feed library

Predicted composition of forages grazed during each of 4 growth

periods• Assume forage quality progressively

declines from beginning of growth in rainy season (season 1) to accumulated forage grazed in the dry season (season 4).

• Used CNCPS feed library to estimate composition of forage grazed during each season.

Estimated composition of grazed forage during each of 4 seasons1

ForageCP% of DM

NDF% in

DM

Lignin% in NDF

Ash% in DM

NDF rate

%/hr

Ether extract% in DM

Season 1 grass

9 67 6 12.7 8.6 3

Season 2 grass

8 72 7 12 6.8 2.6

Season 3 grass

7 74 8 11.5 4.2 2.2

Season 4 grass

5 77 9 11 3 1.6

1Based on CNCPS Feed Library

Simulation 1:early lactation with Grasss 1 and 2

Early lactation Mature with season 1 grass

Inputed DMI 9.94 kg

Predicted DMI 9.94 kg

Inputed Milk 5 kg

ME allowable Milk 6.1 kg

MP allowable Milk 5.7 kg

ME Balance0.33 Mca

l

MP Balance -6.82 g

Day to BCS change 694 days


Inputed DMI 9.46 kg

Predicted DMI 9.46kg

Inputed Milk 5 kg

ME allowable Milk 2.9kg


ME Balance-3.27 Mc

al

MP Balance -112g

Day to BCS change 0

Simulation 1:early lactation with Grasses 3 and 4

Early lactation Mature with season 3grass

Inputed DMI 7.37 kg


Inputed Milk 5 kg

ME allowable Milk -3.9kg


ME Balance-11.06 M

cal

MP Balance -331 g



Inputed DMI 5.46 kg


Inputed Milk 5 kg

ME allowable Milk -10.7kg

MP allowable Milk -1.5 kg

ME Balance-18.87 M

cal

MP Balance -427g

Day to BCS change 0

Farm 1; Mature lactating cows calving on June 1

Early lactation (June 1-August 31); consuming grasses 1and 2 in ratio of 2:1

Grass1 :Grass 2 =6.5 kg:3.25 kg

Inputed DMI 9.75 kg


Inputed Milk 5 kg

ME allowable Milk 5 kg

MP allowable Milk 5 kg

ME Balance-0.91 Mcal

MP Balance -44.3 g

Mid-late lactation (Sep 1-January 31); consuming grasses 2 and 3 in ratio of 1:4

Grass 2 :Grass 3 =(1.57 kg):(6.28 kg)

Inputed DMI 7.85 kg


Inputed Milk 3.7 kg

ME allowable Milk -2.7 kg


ME Balance-6.28 Mcal

MP Balance -126 g

Farm 1; Mature lactation cows calving on June 1

Farm 1 early dry mature cows (Feb 1-April 30); consuming grass 4, 100%

Grass 4(100%)=6

.83 kg

Inputed DMI 6.83 kg


--- ---

ME Balance-14.41 M

cal

MP Balance 　 -193 g

Farm 1 late dry mature cows (May 1-July 31); consuming grasses 4 and 1in ratio of 1:2

Grass 4 :Grass 1 =3.375 kg:6.75 kg

Inputed DMI 10.125 kg

Predicted DMI 10.192 kg--- ---

ME Balance -3.77 Mcal

MP Balance 　

Energy balance change for mature cows, Farm 1 calving on June 1

-20

-15

-10

-5

0

5

Jun Jul

Aug

Sep

Oct

Nov

Dec

Jan

Feb

Mar Ap

rM

ay Jun

Jul

Aug

Mca

l

Conclusions: simulation 1

• Negative energy balance through the entire calving interval; does not agree with observations of panel of experts.

i) assumptions on milk amount and composition? ii) Do cows eat more than the predicted intake by the CNCPS? iii) Forage composition assumed.

Simulation 2:grazed grass composition based on data collected by Juarez at

Veracruz and Rueda in Western Brazil

Predicted composition of grazed forages: simulation 2

• Assume forage quality progressively declines from beginning of growth in rainy season (season 1) to accumulated forage grazed in the dry season (season 4).

• Used data from Mexico Gulf Coast (Juarez et al.) and Brazil Amazon region (Rueda et al.) to estimate composition of forage grazed during each season.

NDF Lignin CPNDF rate, %/hour

Rainiest 71.7 5.6 7.8 6.6

Less rainy

68.6 6.1 8.1 6.6

mean 70.15 5.85 7.95 6.6

Composition of grass grazed, Brazil Amazon region1

1Rueda et al., J. Animal Science 81:2923-2937.

Grass composition, Gulf of Mexico1

NDF

% of DM

LIGNIN

% of NDF

CP

% of DM

NDF rate,

%/hour

66.8 5.6 9.4 7.3

70.6 5.9 7.8 7.2

74.2 7.5 7.0 5.1

1Juarez et al., J. Dairy Science 82:2136-2145. Averaged by 3 NDF ranges; 64-69, 70-72, and 73-75

Simulation 2 forage composition assumptions

ForageCP% in

DM

NDF% in

DM

Lignin% in NDF

Ash% in DM

CHOB3 Kd

%/hr

Fat(Ether

extract)(%DM)

Season 1 grass

9 67 5.5 12.7 8.6 3

Season 2 grass

8 70 6 12 6.8 2.6

Season 3 grass

8 71 6.5 11.5 6.2 2.2

Season 4 grass

7 73 7 11 4.4 1.6

Simulation 2 (grasses one and two)


Inputted DMI 10.00 kg

Predicted DMI 10 kg

Inputted Milk 5 kg

ME allowable Milk

6.5 kg


ME Balance 0.77 Mcal

MP Balance 8.2 g

Day to BCS change

297 days




Inputted Milk 5 kg



ME Balance ‘-2.11 Mcal

MP Balance -91 g

Day to BCS change---

Simulation 2 (grass three and four)Early lactation Mature with

season 3 grass



Inputted Milk 5 kg

ME allowable Milk

3 kg


ME Balance-3.17 Mca

l

MP Balance -146 g

Day to BCS change

---



Predicted DMI 8.08kg

Inputted Milk 5 kg

ME allowable Milk -1.8 kg


ME Balance -8.65Mcal

MP Balance -275 g

Day to BCS change---

Simulation 2 (Farm 1; Lactating mature cows that calved on June 1)

Early lactation (June 1-August 31); consuming grasses 1and 2 in ratio of 2:1

Grass1 :Grass 2

=6.58 kg:3.29kg

Inputed DMI 9.87 kg


Inputed Milk 5 kg





Mid-late lactation (Sep 1-January 31); grasses 2 and 3 in ratio of 1:4

Grass2 :Grass3=(1.897kg):

7.59kg)



Inputed Milk 3.7 kg



ME Balance 0.1 Mcal


Simulation 2 (Farm 1; early and late dry Mature cows that calved on June 1)

Farm 1 early dry mature cows (Feb 1-April 30) consuming grass 4, 100%

Grass 4 (100%)=9.17 kg

Inputed DMI 9.17 kg


---

ME allowable gain 0

MP allowable gain N-A-N

ME Balance-4.19 Mca

l

Day to BCS change 0

Farm 1 late dry mature cows (May 1-July 31) consuming grasses 4 and 1 in ratio of 1:2

Grass 4 :Grass 1 =3.43 kg:6.86 kg



---

ME allowable gain 0.01

MP allowable gain Infinity



Energy balance change through the CI calving on June 1

-15

-10

-5

0

5

10

Mca

l

Energy balance change through the CI calving on June 1 for 1stlactation cows

-15

-10

-5

0

5

10

J un J ul AugSepOct NovDec J an FebMar Apr May J un J ul AugSepOctMcal

Energy balance change Farm 4 through the CI for mature cows calving on Feb 1

-15

-10

-5

0

5

10

Mca

l

Energy balance change for 1 st lactation cows farm 4 calving on Feb 1

-15

-10

-5

0

5

10Fe

bMa

rAp

rMa

yJu

n Jul

Aug

Sep

Oct

Nov

Dec

Jan

Feb

March Ap

rMa

yJu

nMcal

BCS change of the mature cows at farm 4

123456789

Effect of body condition score on conception

• BCS 4.5-5 is needed for mature cows, 6 for heifers at calving, for conception

(Herd et al, 1995 Randel, 1990)

• Need BCS inputs for Farm 1 and 3 simulations whose calving time is in the beginning of the dry season.

Conclusions.

• The CNCPS simulations are very sensitive to forage chemical composition (Juarez et al. J. Dairy Science)

• Farm 1 (Calving on June) looks closer to average of zero energy balance for the reproductive cycle than that of Farm 4(Calving on February 4)

• Farm 4 has two energy balance nadirs

Conclusions about forage composition for accurate simulation• Need actual values for forage consumed.

• Grass samples need to represent what cows are observed to select.

• Need samples for each month of year.

• Analysis should include NDF, lignin, CP, and available NDF digestion rate.

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.

evaluation of beef cow-calf nutrition in yucatan, mexico: ms thesis progress report animal science...

Documents

dry season season

rainy season season

dry season dry season

forage growth season

rainy slide

dry season female

days slide

forage growth periods