Department of Animal Production and Biotechnology, Hassan II Agronomy and Veterinary Medicine Institute, Madinate Al Irfane, 10 101, Rabat, Morocco
Receive Date: 11 June 2014,
Revise Date: 20 July 2014,
Accept Date: 31 July 2014
The objective of this study was to determine the relationship between body weight (BW) and heart girth (HG) in Sardi and Timahdite sheep in order to develop a prediction equation of BW from HG. The data used for this study included 476 records on BW and HG (227 in Sardi and 249 in Timahdite) collected on males and females of different ages in 33 private farms. The BW and the HG averaged 34.8 ± 21.2 kg and 74.0 ± 16.3 cm, respectively in Sardi and 39.2 ± 22.7 kg and 78.4 ± 16.4 cm, respectively in Timahdite. Correlation coefficients between BW and HG were 0.958 in Sardi and 0.944 in Timahdite indicating a strong relationship between the two variables. Six predictive models for BW were fitted to the data; simple linear regression, polynomial quadratic and cubic regressions and three non-linear regressions (Gompertz, allometric and Mitscherlich). These models were used for the pooled data (regardless of breed and sex), separately for all the animals of a breed regardless of sex (breed-specific) and separately for males and females irrespective of breed (sex-specific). To determine the best fitted regression model, coefficient of determination (R2 or Pseudo-R2), residual mean square (MSE) and Akaike information criterion (AIC) were used. The six models fitted the dataset well since their R2 or Pseudo- R2 varied from 0.892 to 0.969. Nevertheless, based on the previous selection criteria, it seemed that the polynomial cubic model was the best and the allometric model should be discarded. Extreme observations of the three best models were checked using studentized residuals and an absolute value greater than two standard deviations implies considerable deviation. Once the outliers discarded, the best models were run on the clean dataset and compared. Thus, for the pooled data, Sardi breed and females, the Mitscherlich model was appropriate, whereas for Timahdite breed and males, cubic and Gompertz models, respectively were the best. Therefore, a tape measure was developed for each animal category in order to assist livestock farmers in managing their sheep better.
Afolayan R.A., Adeyinka I.A. and Lakpini C.A.M. (2006). The estimation of live weight from body measurements in Yankasa sheep. Czech J. Anim. Sci.51(8), 343-348.
Atta M. and El Khidir O.A. (2004). Use of heart girth, wither height and scapuloischial length for prediction of liveweight of Nilotic sheep. Small Rumin. Res.55, 233-237.
Baffour-Awuah O., Ampofo E. and Dodoo R. (2000). Predicting the liveweight of sheep by using linear body measurements. Ghana Jnl Agric. Sci.33, 207-212.
Bassano B., Bergero D. and Peracino A. (2003). Accuracy of body weight prediction in Alpine Ibex (Capra ibex) using morphometry. J. Anim. Physiol. A: Anim. Nutr.87(3), 79-85.
Benyi K. (1997). Estimation of live weight from chest girth in pure and crossbred West African goats. Trop. Anim. Health Prod.29(2), 124-128.
Birteeb P.T. and Ozoje M.O. (2012). Prediction of live body weight from linear body measurements of west African long-legged and west African dwarf sheep in northern Ghana. Online J. Anim. Feed Res.2(5), 427-434.
Boujenane I. (1999). Les ressources génétiques ovines au Maroc, Actes Editions, Rabat, Maroc.
Boujenane I. (2005). Small Ruminant Breeds of Morocco. Pp. 5-54 in Characterization of Small Ruminant Breeds in West Asia and North Africa. L. Iniguez, Ed. International Center for Agricultural Research in the Dry Areas (ICARDA), Aleppo, Syria.
Cam M.A., Olfaz M. and Soydan E. (2010). Body measurements reflect body weights and carcass yields in Karayaka sheep. Asian J. Anim. Vet. Adv.5(2), 120-127.
Enevoldsen C. and Kristensen T. (1997).Estimation of body weight from body size measurements and body condition scores in dairy cows. J. Dairy Sci.80, 1988-1995.
Goe M.R., Alldredge J.R. and Light D. (2001). Use of heart girth to predict body weight of working oxen in the Ethiopian highlands. Livest. Prod. Sci.69, 187-195.
Kaps M. and Lamberson W. (2004). Biostatistics for Animal Science. CABI Publishing, Wallingford, UK.
Kunene N., Nesamvuni E.A. and Fossey A. (2007). Characterization of Zulu (Nguni) sheep using linear body measurements and some environmental factors affecting these measurements. South African J. Anim. Sci.37, 11-20.
Kunene N.W., Nesamvuni A.E. and Nsahlai I.V. (2009). Determination of prediction equations for estimating body weight of Zulu (Nguni) sheep. Small Rumin. Res.84, 41-46.
Kurnianto E., Sutopo S., Purbowati E., Setiatin E.T., Samsudewa D. and Permatasari T. (2013). Multivariate analysis of morphological traits of local goats in Central Java, Indonesia. Iranian J. Appl. Anim. Sci.3(2), 361-367.
Lawrence T.L. and Fowler V.R. (1997). Growth of Farm Animals. CABI Publishing, Wallingford, UK.
Mahieu M., Navès M. and Arquet R. (2011). Predicting the body mass of goats from body measurements. Livest. Res. Rural Dev.WebMD.
http://www.lrrd.org/lrrd23/9/mahi 23192.html. Accessed on 22 Feb. 2014.
Melesse A., Banerjee S., Lakew A., Mersha F., Hailemariam F., Tsegaye S. and Makebo T. (2013). Variations in linear body measurements and establishing prediction equations for live weight of indigenous sheep populations of southern Ethiopia. Scientific J. Anim. Sci.2(1), 15-25.
Mohammad M.T., Rafeeq M., Bajwa M.A., Awan M.A., Abbas F., Waheed A., Bukhari F.A. and Akhtar P. (2012). Prediction of body weight from body measurements using regression tree (RT) method for indigenous sheep breeds in Balochistan, Pakistan. J. Anim. Plant Sci.22(1), 20-24.
Musa A.M., Idam N.Z. and Elamin K.M. (2012). Heart girth reflect live body weight in Sudanese Shogur sheep under field conditions. World's Vet. J.2(4), 54-56.
Olatunji-Akioye A.O. and Adeyemo O.K. (2009). Liveweight and chest girth correlation in commercial sheep and goat herds in southwestern Nigeria. Int. J. Morphol.27(1), 49-52.
Ratkowsky D.A. (1990). Handbook of Nonlinear Regression Models. Marcel Dekker, New York, USA.
Ravimurugan T., Thiruvenkadan A.K., Sudhakar K., Panneerselvam S. and Elango A. (2013). The estimation of body weight from body measurements in Kilakarsal sheep of Tamil Nadu, India. Iranian J. Appl. Anim. Sci.3(2), 357-360.
Sarti F.M., Castelli L., Bogani D. and Panella F. (2003). The measurement of chest girth as an alternative to weight determination in the performance recording of meat sheep. Italian J. Anim. Sci.2, 123-129.
SAS Institute. (2002). SAS®/STAT Software, Release 6.11. SAS Institute, Inc., Cary, NC. USA.
Shirzeyli F.H., Lavvaf A. and Asadi A. (2013). Estimation of body weight from body measurements in four breeds of Iranian sheep. Songklanakarin J. Sci. Technol.35(5), 507-511