The research aimed to determine the most effective ratio of forage to concentrate on feed intake, body weight, and carcass traits of male Zel fattening lambs. The current study was performed using 20 lambs of 16-week-old for 90 days in a completely randomized design with four treatments and five replications. Experimental treatments were included different ratios of forage to concentrate (80:20, 70:30, 60:40, and 50:50). Traits were measured during the fattening period. The collected data were analyzed by LSmeans and regression procedure in SAS software. Effect of different ratios of forage to concentrate was significant on the feed intake, body weight traits (P<0.01), slaughter weight (P<0.05), weight gain during rearing (P<0.05), daily weight gain (P<0.05), feed intake (P<0.01), feed conversion ratio (P<0.01), the weight of digestive system contents (P<0.05), hot and cold carcass weight (P<0.05), carcass percentage (P<0.05) and back fat thickness (P<0.05). The linear change in the mentioned traits was due to the increase of the concentrate to forage ratio (P<0.01). As the percentage of concentrate in the ration increases, feed intake was increased. The concentrate is palatable and contains more energy and nutrients than forage. Therefore, lambs that consumed more concentrate had higher body and slaughter weight. Based on the results for optimal performance in fattening lambs, a ration with ratio of forage to concentrate equal (50:50) is recommended. Manuscript profile

Random regression models (RRM) are used for genetic estimations of milk traits in dairy cows. RRM utilize data on traits that are repeated during the time, such as milk trait, which allows of the evaluation of the test day production information. In this study, to estimate genetic parameters for milk production trait, test day records (TDR) were collected from the first lactation of Holstein cows from a Mazandaran Gavdasht herd during the years 2001 to 2012. The data included 14150 TDR of milk production trait of 1460 Holstein cows. Analysis of TDR was performed using the DFREML software. The random regression was fitted according to the Legendrepolynomials model from days of lactation. The minimum of heritability (0.04) was estimated for the early lactation period and increased in the late of lactation, about the month 9 of lactation to its peak (0.29). The phenotypic variance was not same during the lactation period and it was too much in the early and late of lactation. The maximum of genetic variance was at the month 10 (19.81) and the minimum at the early of the lactation period (2.51). The residual variances were constant. The maximum of the genetic and phenotypic correlations were observed between adjacent days for milk production trait. Using TDR, accuracy of genetic parameter estimation was increased. Manuscript profile