TY  - JOUR
T1  - Influence of Types of Ration on Modeling of Lactation Curves in Tunisia
AU - Darej, C. AU - Moujahed, N. AU - Hammami, H. AU - Gillon, A. AU - Gengler, N. 
JO  - Research Journal of Dairy Sciences
VL  - 6
IS  - 2
SP  - 8
EP  - 14
PY  - 2012
DA  - 2001/08/19
SN  - 1993-5277
DO  - rjdsci.2012.8.14
UR  - https://makhillpublications.co/view-article.php?doi=rjdsci.2012.8.14
KW  - Lactation curve
KW  -test day model
KW  -incomplete gamma
KW  -types of ration
KW  -UCPA
KW  -Tunisia
AB  - Lactation curve traits were determined for Holstein-Friesian cows in five dairy 
  bovine farms in Tunisia two public farms and three Cooperative Units of Agricultural 
  Production (UCPA) using Wood’s incomplete gamma function to lactation records 
  by non-linear regression in 1967 model. A total of 49950 test day records during 
  the period between 1997 and 2007 were used in the analysis. Six types of basal 
  ration were identified in these farms (distributed during 1 month minimum) on 
  the base of the roughages used in the basal ration (R1: Concentrate (CC) + Dry 
  Forages (DF)+Silage (S); R2: CC+DF+S+Sugar Beet Pulp (SBP); R3: CC+DF+S+Summer 
  Green Forages (SGF) R4: CC+DF+S+Spring Green Forages (SPGF); R5: CC+DF+S+SPGF+SP; 
  R6: CC+DF+S+SPGF. The parameters of Wood model (a is the estimation of initial 
  milk yield, b and c are respectively the increasing and the decreasing slopes 
  of the curve) were estimated. The model included herd x year, herd x month, 
  DIM x age x season of calving as fixed effects, herd x test day as random effect 
  and random regression coefficients for animal herd x parity, herd x year, herd 
  x year and ration effects which were defined as modified quadratic Legendre 
  coefficients. Results suggested peak milk yield increased from 18.7-20.92 kg 
  and 22.92, respectively from the first lactation to the second and the third. 
  However, the highest persistency was observed in the first lactation. The R2 
  type rations including the sugar beet pulp, presented late peak milk and allowed 
  high peak milk yield production while this ration allows a low persistency.
ER  -