Evaluation of the Cornell Net Carbohydrates and Protein System for sheep in growing lambs in Yucatan

Luis Alberto Nabté Solis

Background• Increase in world human population Increase in

animal production

• Yucatan Production: Mostly beef cattle, however increase in sheep production.

• Productivity potential and efficiency• slaughter weight (35-40 kg), due to malnutrition,

usually takes over a year. These lambs do no command high prices because the market wants lambs of that weight but with aged under eight months and in regular amounts.

0

200,000,000

400,000,000

600,000,000

800,000,000

1,000,000,000

1,200,000,000

1,400,000,000

1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

Year

-2,000,000

3,000,000

8,000,000

13,000,000

18,000,000

23,000,000

28,000,000

33,000,000

Mex

ico

SheepStocks (Head) WorldCattleStocks (Head) World Sheep (Mexico)

  Cattle (Mexico)

•Sheep world population compared with cattle

Country Observations Peso (kg) DS

Reference Singles Doubles

México 69 y 32 2,6 ± 0,5 2,1 ± 0,5 Castillo et al., 1972

México 185 y 52 2,8 2,3 Valencia et al., 1973

México 32 2,4 ± 0,59 Castillo et al., 1977b

México 169 y 476 2,6 ± 0,4 2,1 ± 0,4 Avalos et al., 1977

147 2,63 González et al., 1978

México 46 y 16a 2,8 ± 0,5 2,1 ± 0,3 González et al., 1983

42 y 17b 2,6 ± 0,4 2,1 ± 0,3

Cuba 227 y 318 3,36 ± 0,7 2,74 ± 1,4 Limas et al., 1983

Cuba 75 y 91a 3,43 ± 0,7 2,83 ± 0,7 Fuentes et al., 1983a

México 717 y 176a 2,74 ± 0,5 2,22 ± 0,5 Valencia et al., 1983

715 y 168b 2,58 ± 0,5 2,07 ± 0,5

Cuba 69 y 93b 8,30 ± 0,6 2,83 ± 0,6 Fuentes et al., 1987

a Machos.b Hembras.

Title needed, other table

FAO, 2002

AntecedentsYucatan

0

50

100

150

200

250

300

J F M A M J J A S O N D

Month

Pre

cipa

tion

(mm

)

0

5

10

15

20

25

30

35

40

45

T °C

Mean prec(1940-2004)

Total Precipit(2000)

Mean precip

Mean T °C(1940-2004)

Temp Max(2000)

Temp Min(2000)

Rain and Temperature distribution

Forage production, effect of seasonality

Precipitation effect on forage production

…not only forage production is affected

• Animal performance affected by climatic conditions• Heat stress • Reduction in feed consumption• Water intake

• Change in body mass, body composition, and energy requirements of ruminants

• Influence of hot environments on protein and fat deposition and ultimately energy deposition has not been widely studied

Growth curve and difference in deposition of components

Energy and Body Frame effect on growth

Adaptation phenomena…

• Maintenance requirements reduction (up to 50%)• Visceral organs reduction

• Feed selectivity enhanced

• Body reserves useBody reserves use

• How to manage under these conditions…How to manage under these conditions…

Sheep breeds in Yucatan

• Pelibuey

• Blackbelly

• Dorper

• Probably closely related to the West African, Red African, African or Africana breed of Colombia and Venezuela

• Mature rams and ewes weigh 54 and 34 kg, respectively

• Litter size: relatively low at 1.24. First lambing: ~16 to 19 months of age. Lambing interval: less than 210 days. Lambs average 12 kg at 120 days of age

Sheep breeds in Yucatan

• Pelibuey

• Blackbelly

• Dorper

Barbados Blackbelly evolved from crosses of African hair sheep and European wooled breeds

Mature Barbados Blackbelly ewes have a high prolificacy. Studies have shown the average lambing rate to range between 1.50 to 2.30 lambs per ewe lambing, and an average lambing interval of eight to nine months. mature ewes 100 pounds, and rams 105 to 125 pounds

Good meat flavor

Sheep breeds in Yucatan• Pelibuey

• Blackbelly

• Dorper

South Africa 1930

A live weight of about 36 kg can be reached by the Dorper lamb at the age of 3- 4 months.

2.25 lambs in average per year.

Growth, multiple variables. So, how to analyze?

SheepGrowthNet Growth Rate

Initial Sheep

Carcass Yield

ProducerRevenues

Total ForageProductionFeed

ProductionFeed

Consumption

Feed AvailablePer Sheep

Relative Rainfall

ManagementPractices

EnvironmentalConditions

Energy convertedper unit of feed

Animal adaptationsand behavior

Models

• Several Models, INRA, CSIRO, ARC, NRC, CNCPS

• CNCPS-Cattle diverse animal, feed, and environmental production situations for all classes of beef, dairy, and dual-purpose cattle

• CNCPS-Sheep Developed based on CNCPS-C

• CNCPS calculates NE requirements for maintenance, growth, pregnancy, lactation, and body reserves, which then are converted to ME using ME efficiency coefficients for each of these physiological functions

• But, is appropriate to use it in Yucatan conditions?• Yes, with necessary calibration or validation!!!• Temperature, seasonality, forage availability

forage composition and kinetics, animal behavior responses e.g. DMI, breeds…

Model evaluations

• CNCPS-S Cannas et al. (2004) evaluation

• Sheep of diverse body sizes and physiological stages, fed diverse diets at various levels of nutrition

• Accurately predict nutrient requirements, body weight gains and losses

• So, concluded that is a useful tool to evaluate diets and animal performance in different production settings ranging from extensive grazing situations to highly productive sheep

• First step to be able to use the model:• Validation, evaluation

• CNCPS-C around the world in dairy cows, beef, and tropical dual purpose cattle.

• Different uses for models

• CNCPS-S, absence of evaluation under tropical conditions

• Objectives

• Evaluate CNCPS-Sheep predictions under Yucatan conditions in growing animals, using experimental data that had enough information to describe animal, feeds and the environment as required by the model.

• Identify limiting factors in CNCPS-Sheep model requiring further research and analysis.

Material and Methods.

• Model evaluation

• Data needed• Model inputs• Forage composition, animal weight, BCS, Body

Composition, DMI

• Data collection• Simulations• Statistical validation

Data neededInput Description

Animal type Category of animals for which the diet is evaluated

Age Mean age of the group of animals

Body Weight Current shrunk body weight or full body weight

Standard Reference Weight at BCS 2.5

FBW by a specific animal of certain breed, age, sex and rate of gain, skeletal development complete and BCS 2.5

Wool Depth Depth of the wool measured perpendicularly to skin surface.

Clean Wool Production Production of clean wool per year

Current Temperature current mean daily (24 h) air temperature (°C)

Previous Temperature previous month average daily air temperature (°C)

Wind Speed measured at ground level

Rainfall only for sheep kept outdoors

Horizontal distance daily distance walked by sheep every day on flat surfaces

Vertical distance the vertical component of the movement

Feed consumed Diet description and composition

BCS current body condition score scale 0-5

Data collection

• Experiment carried out by UADY-FMVZ

• Three groups of animals (Pelibuey and F1 crosses of Pelibuey x Dorper and x Katahdin)

• Two different diets will be supplied to each group of animals from weaning (15 kg) until slaughter (40 kg).

• One animal will be slaughtered by each group and diet at 15, 30 and 40 kg.

• Carcass characteristics, ultrasonography, and dissection of half carcass to quantify muscle, fat and bone.

• Feed analysis, chemical composition and kinetics of feeds

• Environmental data from meteorological stations

• Simulation with all data collected will be carried out choosing groups and animals

• Comparison between actual and simulation results

• Daily gain, body composition, body condition score, energy for maintenance and growth

• Statistical analysis• mean bias, the mean square prediction error

(MSPE), and the statistical measures of model performance

• Regression between the observed and the model-predicted

Expected results• Model accuracy and precision

• Model limiting factors

• Identification of critical points in the model and in the management methods

• Proposal of a tool to analyze hypothetical situations in sheep production

Thank you for your attention!!!