Statistical Analysis of Lamb Survival during the Rearing Period with the Use of Classification Trees and Logistic Regressions

Yıl 2022, Cilt: 5 Sayı: 4, 357 - 364, 01.10.2022

Dariusz Piwczyński Julia Piwczyńska Magdalena Kolenda

https://doi.org/10.47115/bsagriculture.1133500

Öz

The presented research aimed to statistically analyse the survival of 44,133 Polish Merino and Polish Merino in Old-Type lambs between birth and the 100th day of their life, using classification trees and logistic regression. The study included lambs born between 2008 and 2017 and used in 43 flocks in Pomerania and Kujawy region (Poland). The results showed that 9.27% of all controlled lambs did not survive till the 100th day of life. The statistical analysis of the case of lambs’ death during their first 100 days of life was carried out using multiple logistic regression as well as classification trees, using two algorithms CART and CHAID. The quality of multiple regression and decision tree models was compared considering the following criteria: percentage of misclassifications, average squared error and the area under the Receiver Operating Characteristic curve. The calculated quality criteria for tree models that were created during the research suggested that the classification trees formed based on CART algorithm were the most accurate in defining the variability of studied characteristics, i.e. survival of lambs up to the 100th day of age. For the best available classification model, the ranking of variable importance, developed based on the “Importance” measure, allowed to conclude that the type of lamb’s birth, season, following by the year of birth, subsequent lambing, lamb’s sex and its breed were the most significant differentiating factors. It was noted that the tree built with the use of CART algorithm was composed of 30 leaves. It was also shown that the highest frequency of lamb’s death during the rearing period was to be expected among triplets born in winter or summer (37.14% of all deaths), while the highest chance (98.42%) of surviving till the 100th day of life showed singletons, born from their mother’s 3rd to 6th litter, in the spring-winter season in the last year of the present research.

Anahtar Kelimeler

Lamb mortality, Classification tree, CART, CHAID, Logistic regression

Kaynakça

• Aksakal V, Macit M, Esenbuga N, Dogan KA. 2009. Effects of various ages of weaning on growth characteristics, survival rate and some body measurements of Awassi lambs. J Anim Vet Advan, 8(80): 1624-1630.
• Campbell A, Vizard A, Larsen J. 2009. Risk factor for post-weaning mortality of Merino sheep in south-eastern Australia. Aust Vet J, 87: 305-312.
• Casellas J, Caja G, Such X, Piedrafita J. 2007. Survival analysis from birth to slaughter of Ripollesa lambs under semi-intensive management. J Anim Sci, 85: 512-517.
• Cetin H, Akcapnar H. 2005. The effects of twice lambing in a year on the survival ability and growth of Merino lambs. Lalahan Hayv Araş Enst Derg, 45(2): 25-34.
• Ekiz B, Atnel A. 2006. The growth and survival characteristics of lambs produced by commercial crossbreeding Kivircik ewes with F2 rams with the German Black-Headed Mutton genotype. Turk J Vet Anim Sci, 30(6): 507-512.
• Everett-Hincks JM, Mathias-Davis HC, Greer GJ, Auvray BA, Dodds KG. 2014. Genetic parameters for lamb birth weight, survival and death risk traits. J Anim Sci, 92(7): 2885–2895.
• Freking BA, Leymaster KA. 2004. Evaluation of Dorset, Finnsheep, Romanov, Texel, and Montadale breeds of sheep: IV. Survival, growth, and carcass traits of F1 lambs. J Anim Sci, 82(11): 3144-3153.
• Ghiasi H, Sadeghi-Sefidmazgi A, Taherkhani R, Khaldari M, Piwczyński D. 2019. Application of classification tree method to determine factors affecting somatic cell count in Holstein cows. J Agr Sci Tech, 21(7): 1783-1792.
• Grzesiak W. 2003. Milk yield prediction in cows with artificial neural network. Pr Mat Zoot, 61: 71-89.
• GUS. 2021. Central Statistical Office - Farm animals in 2020. URL: https://stat.gov.pl/en/topics/agriculture-forestry/animal-production-farm-animals/farm-animals-in-2020,1,3.html (access date: June 02, 2022).
• Gut A, Wójtkowski J, Ślósarz P, Pietrzak J. 2008. Conservation breeding of old type Polish Merino Sheep. Rocz Nauk PTZ, 35(1): 19-23.
• Hatcher S, Atkins KD, Safari E. 2009. Phenotypic aspects of lamb survival in Australian Merino sheep. J Anim Sci, 87: 2781-2790.
• Kleemann DO, Walker SK. 2005. Fertility in South Australian commercial Merino flocks: relationships between reproductive traits and environmental cues. Theriogenology, 63: 2416-2433.
• Kliś P, Piwczyński D, Sawa A, Sitkowska B. 2021. Prediction of lactational milk yield of cows based on data recorded by AMS during the periparturient period. Animals, 11(2): 383. DOI: 10.3390/ani11020383.
• Mandal A, Prasad H, Kumar A, Roy R, Sharma N. 2007. Factors associated with lamb mortalities in Muzaffarnagari sheep. Small Rum Res, 71(1-3): 273-279.
• Milerski M. 2006. Analysis of lamb mortality in Sumava, Suffolk, Charollais, Romney, Merinolandschaft and Romanov sheep in the Czech Republic. Book of Abstracts, EAAP – 57th Annual Meeting, September 17-20, 2006, Antayla, Turkey, pp: 215.
• Morel PCH, Morris ST, Kenyon PR. 2009. Effects of birth weight on survival in twin born lambs. Proc New Zealand Soc Anim Prod, 69: 75-79.
• Petersson CJ, Danell Ö. 1985. Factors influencing lambs survival in four Swedish sheep breeds. Acta Agric Scand, 35: 217-232.
• Piwczyński D. 2007. Statistical analysis of lamb mortality using logistic regression. Rocz Nauk PTZ, 3(1): 19-26.
• Piwczyński D, Nogalski Z, Sitkowska B. 2013a. Statistical modeling of calving ease and stillbirths in dairy cattle using the classification tree technique. Livest Sci, 154: 19-27.
• Piwczyński D, Sitkowska B, Czajkowska A. 2013b. Application of data mining techniques in biological research. Biotechnology and Animal Food Quality. Part III. SAAIC – Erasmus intensive program, Bydgoszcz, Poland, pp: 89-98
• Piwczyński D, Sitkowska B, Wiśniewska E. 2012. Application of classification trees and logistic regression to determine factors responsible for lamb mortality. Small Rum Res, 103(2): 225-231.
• PSBA. 2009. Sheep and goats breeding in Poland in 2008, 2020. The Polish Sheep Breeders’ Association, Warsaw (in Polish).
• PSBA. 2021. Sheep and goats breeding in Poland in 2008, 2020. The Polish Sheep Breeders’ Association, Warsaw (in Polish).
• Salem IB, Rekik M, Hammami H, Hamouda MB, Aloulou R, Sâadoun L. 2009. Fateurs de variation non génétique de la productivité des brebis de race Noire de Thibar. Revue Élev Méd Vét Pays Trop, 62(1): 59-66.
• SAS Institute Inc. 2021. Getting started with SAS ® Enterprise Miner 15.1TM. Cary, NC: SAS Institute Inc.
• Schreurs NM, Kenyon PR, Mulvaney FJ, Morel PCH, West DM, Morris ST. 2010. Effect of birth weight and birth rank on the survival of single and twin lambs born to ewe lambs. Anim Prod Sci, 50(5-6): 460-464.