Cappio-Borlino A, Pulina G, Rossi G. 1995. A non-linear modification of Wood’s equation fitted to lactation curves of Sardinian dairy ewes. Small Rumin Res 18:75–79.

Cappio-Borlino A, Macciotta NPP, Pulina G. 1997. The shape of Sarda ewe lactation curve analyzed by a compartmental model. Livest Prod Sci 51:89–96.

Carta A, Sanna SR, Casu S. 1995. Estimating lactation curves and seasonal effects for milk, fat and protein in Sarda dairy sheep with a test day model. Lives Prod Sci 44:37–44.

Dag B, Keskin I, Mikailsoy F. 2005. Application of different models to the lactation curves of unimproved Awassi ewes in Turkey. SAfr J Anim Sci 35:238–243.

Dijkstra J, France J, Dhanoa MS, Mass JA, Hanigan MD, Rook AJ, Beever JA. 1997. A model to describe growth patterns of the mammary gland during pregnancy and lactation. J Dairy Sci 80:2340–2354.

Franci O, Pugliese C, Acciaioli G, Parisi G, Lucifero M. 1999. Application of two models to the lactation curve of Massese ewes. Small Rumin Res 31:91–96.

Gabiña D, Arrese F, Arranz J, Beltran de Heredia I. 1993. Average milk yields and environmental effects on latxa sheep. J Dairy Sci 76:1191–1198.

Gootwine E. 2004. Placental hormones and fetal-placental development. Anim Reprod Sci 82–83:551–566.

Grossman M, Koops WJ. 1988. Multiphasic analysis of lactation curves in dairy cattle. J Dairy Sci 71:1598–1608.

Haenlein GFW, Wendorff LW. 2006. Sheep milk. Handbook of Milk of Non-Bovine Mammals. Park WY, Haenlein GFW, editorsBlackwell Publishing; Iowa: p. 137–194.

Keskink I, Dag B. 2006. Comparison of different mathematical models for describing the complete lactation of akkaraman ewes in turkey. Asian-Aust J Anim Sci 19:1551–1555.

Köpke U. 2005. Organic foods: Do they have a role? Diet diversification and health promotion. Elmadfa I, editorKarger; Publishers, Basel: p. 62–73.

León JM, Macciotta NPP, Gama LT, Barba C, Delgado JV. 2012. Characterization of the lactation curve in Murciano-Granadina dairy goats. Small Rumin Res 107:76–84.

Macciotta NPP, Vicario D, Cappio-Borlino A. 2005. Detection of different shapes of lactation curve for milk yield in dairy cattle by empirical mathematical model. J Dairy Sci 88:1178–1191.

Morant SV, Gnanasakthy A. 1989. A new approach to the mathematical formulation of lactation curves. Anim Prod 49:151–162.

Nauta WJ, Baars T, Bovenhuis H. 2006. Converting to organic dairy farming: consequences for production, somatic cell scores and calving interval of first parity Holstein cows. Livest Sci 90:185–195.

Olori VE, Brotherstone S, Hill WG, McGuirk BJ. 1999. Fit of standard models of lactation curves to weekly records of milk production of cows in a single herd. Livest Prod Sci 58:55–63.

Padel S. 2000. Strategies of organic milk production. Human- animal relationships: Stockman ship and housing in organic livestock systems. In : Proceedings of the 3th NAHWOA Workshop, Clermont-Ferrand; France. 121–135.

Pollott GE. 2000. A biological approach to lactation curve analysis for milk yield. J Dairy Sci 83:2448–2458.

Pollott GE, Gootwine E. 2000. Appropriate mathematical models for describing the complete lactation of dairy sheep. Anim Sci 71:197–207.

Portolano B, Spatafora F, Bono G, Margiotta S, Todaro M, Ortoleva V, Leto G. 1996. Application of the Wood model to lactation curves of Comisana sheep. Small Rumin Res 24:7–13.

Rotz CA, Kamphuis GH, Karsten HD, Weaver RD. 2007. Organic dairy production systems in Pennsylvania: A case study evaluation. J Dairy Sci 90:3961–3979.

Rochi B, Nardone A. 2003. Contribution of organic farming to increase sustainability of Mediterranean small ruminants livestock systems. Lives Prod Sci 80:17–31.

Refsgaard K, Halberg N, Kristensen ES. 1998. Energy utilization in crop and dairy production in organic and conventional livestock production systems. Agric Syst 57:599–630.

Ruiz R, Oregui LM, Herrero M. 2000. Comparison of models for describing the lactation curve of Latxa sheep and an analysis of factors affecting milk yield. J Dairy Sci 83:2709–2719.

Sakul H, Boylan WJ. 1992. Lactation curves for several US sheep breeds. Anim Prod 54:229–233.

Schoknecht PA, Nobrega SN, Patterson JA, Ehrhardt RA, Slepeti R, Bell AW. 1991. Relations between maternal and fetal plasma concentrations of placental lactogen and placental and fetal weights in fell-fed ewes. J Anim Sci 69:1059–1063.

Silvestre AM, Petim-Batista F, Colaço J. 2006. The accuracy of seven mathematical functions in modeling dairy cattle lactation curves based on test- day records from varying sample schemes. J Dairy Sci 89:1813–1821.

Statistical Analysis Systems Institute. 2002. User’s guide version eight. SAS Institute Inc; Cary, NC, USA:

Toro-Mujica P, García A, Gómez-Castro AG, Acero R, Perea J, Rodríguez-Estévez V, Aguilar C, Vera R. 2011. Technical efficiency and viability of organic dairy sheep farming systems in a traditional area for sheep production in Spain. Small Rumin Res 100:89–95.

Tzouramani I, Sintori A, Liontakis A, Karanikolas P, Alexopoulos G. 2011. An assessment of the economic performance of organic dairy sheep farming in Greece. Livest Sci 141:136–142.

Ünal N, Orman MN, Çolak C, Atasoy F, Mundan D, Aytaç M. 2007. Comparison of various models for lactation curves of Akkaraman and its crossbreds (Chios×Akkaraman F1 and Kivircik×Akkaraman F1) ewes. Lalahan Hay. Araşt. Enst Derg 47:7–13. (In Turkish)

Walker GP, Dunshea FR, Doyle PT. 2004. Effects of nutrition and management on the production and composition of milk fat and protein: a review. Aust J Agric Res 55:1009–1028.

Wasike CB, Kahi AK, Peters KJ. 2011. Modeling of lactation curves of dairy cows based on monthly test day milk yield records under inconsistent milk recording scenarios. Animal 5:1780–1790.

Wilmink JBM. 1987. Adjustment of test-day milk, fat and protein yield for age, season and stage of lactation. Livest Prod Sci 16:335–348.

Wolfová M, Wolf J, Krupová Z, Kica J. 2009. Estimation of economic values for traits of dairy sheep: I. Model development. J Dairy Sci 92:2183–2194.

Wood PDP. 1967. Algebraic model of the lactation curve in cattle. Nature 216:164–165.