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.

Sheep world population compared with cattle

CountryObservations Peso (kg) DS Reference SinglesDoubles México69 y 322,6 ± 0,52,1 ± 0,5Castillo et al., 1972 México185 y 522,82,3Valencia et al., 1973 México322,4 ± 0,59Castillo et al., 1977 b México169 y 4762,6 ± 0,42,1 ± 0,4Avalos et al., ,63González et al., 1978 México46 y 16a2,8 ± 0,52,1 ± 0,3González et al., y 17b2,6 ± 0,42,1 ± 0,3 Cuba227 y 3183,36 ± 0,72,74 ± 1,4Limas et al., 1983 Cuba75 y 91a3,43 ± 0,72,83 ± 0,7Fuentes et al., 1983 a México717 y 176a2,74 ± 0,52,22 ± 0,5Valencia et al., y 168b2,58 ± 0,52,07 ± 0,5 Cuba69 y 93b8,30 ± 0,62,83 ± 0,6Fuentes et al., 1987 a Machos. b Hembras. Title needed, other table

FAO, 2002

Antecedents Yucatan

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 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 lambs in average per year.

Growth, multiple variables. So, how to analyze?

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 needed InputDescription Animal typeCategory of animals for which the diet is evaluated AgeMean age of the group of animals Body WeightCurrent 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 DepthDepth of the wool measured perpendicularly to skin surface. Clean Wool ProductionProduction of clean wool per year Current Temperaturecurrent mean daily (24 h) air temperature (°C) Previous Temperatureprevious month average daily air temperature (°C) Wind Speedmeasured at ground level Rainfallonly for sheep kept outdoors Horizontal distancedaily distance walked by sheep every day on flat surfaces Vertical distancethe vertical component of the movement Feed consumedDiet description and composition BCScurrent 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!!!