In recent years, an increase in the number of donkeysfarmed in Italy as a consequence of the growingdemand for donkey milk for direct consumption hasbeen observed. Some research has been carried out on jenny milk composition and on its nutritional properties, whereas milk production features are scarcely described for this species. In this work, the lactationcurve shape of donkeys for milk yield and compositionwas investigated. A total of 453 test-day records for milk yield, fat and protein percentage, and somatic cell count of 62 lactations measured on 46 multiparousjennies of the Ragusano breed were considered. Effectsof herd, age, and foaling season were assessed by usinga mixed model analysis. Average and individual lactation curves were fitted using the Wood incompletegamma function, the Cappio-Borlino modified gamma,and a third-order Legendre orthogonal polynomial model. Donkeys foaling between 6- and 10-yr-old had the highest test-day milk yield (about 1.85 kg/d). Donkeys foaling in winter and autumn had a higher daily milk yield compared with those foaling in summer and spring. Less defined results were obtained for composition traits. The general pattern of the donkey lactation curve is similar to the standard shape reportedfor the main dairy ruminant species, with a peak yieldoccurring at about 5 wk from parturition. Younger jenniestended to have lower production peaks and higherlactation persistency. Similarly to what is reported for dairy cattle, a large variability in individual patterns has been observed. No differences in goodness of fit have been observed between the models in the case of average lactation curves, whereas orthogonal polynomials were more efficient in fitting individual patterns.

The mathematical modeling of the lactation curve for dairy traits of the donkey (Equus asinus)

BORDONARO, Salvatore;Criscione A;MARLETTA, DONATA;
2013-01-01

Abstract

In recent years, an increase in the number of donkeysfarmed in Italy as a consequence of the growingdemand for donkey milk for direct consumption hasbeen observed. Some research has been carried out on jenny milk composition and on its nutritional properties, whereas milk production features are scarcely described for this species. In this work, the lactationcurve shape of donkeys for milk yield and compositionwas investigated. A total of 453 test-day records for milk yield, fat and protein percentage, and somatic cell count of 62 lactations measured on 46 multiparousjennies of the Ragusano breed were considered. Effectsof herd, age, and foaling season were assessed by usinga mixed model analysis. Average and individual lactation curves were fitted using the Wood incompletegamma function, the Cappio-Borlino modified gamma,and a third-order Legendre orthogonal polynomial model. Donkeys foaling between 6- and 10-yr-old had the highest test-day milk yield (about 1.85 kg/d). Donkeys foaling in winter and autumn had a higher daily milk yield compared with those foaling in summer and spring. Less defined results were obtained for composition traits. The general pattern of the donkey lactation curve is similar to the standard shape reportedfor the main dairy ruminant species, with a peak yieldoccurring at about 5 wk from parturition. Younger jenniestended to have lower production peaks and higherlactation persistency. Similarly to what is reported for dairy cattle, a large variability in individual patterns has been observed. No differences in goodness of fit have been observed between the models in the case of average lactation curves, whereas orthogonal polynomials were more efficient in fitting individual patterns.
2013
donkey milk; lactation curve; mathematical model
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11769/57381
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