Growth performance, voluntary feed intake and grazing behavior of lambs grazing forages with different relative forage quality

The feed value of forages is a function of intake rate and nutritional quality (DM, CP, EE, ADF, NDF, DDM, TDN, DMI, IVTDMD, ME, RFV and RFQ) determined by chemical analyses and animal nutrition experiments. Growth, voluntary feed intake, grazing behavior, carcass yield and some meat quality (L*, a*, b* and drip loss) and blood (glucose, triglyceride, urea nitrogen, AST, ALT, ALP, Ca and P) parameters can be affected by the difference in relative forage quality (RFQ) of forages in grazing lambs. To test this situation, four plots with different RFQ (89, 105, 121 and 147) were constituted from grass and legume forages either as single or a mixture; 89RFQ (33.3% Festuca pratensis, Festuca arundinacea and Dactylis glomerata), 105RFQ (40% Medicago sativa, 20% Festuca pratensis, Festuca arundinacea and Dactylis glomerata), 121RFQ (80% Trifolium repens and 20% Lolium perenne) and 147RFQ (%100 Lotus corniculatus). First of all, dry matter (DMY) and crude protein (CPY) yields and some forage quality characteristics were examined in the plots (total of 12) established in three replications. Then, three male Karayaka lambs (9 per treatment, 36 in total) three months old and 22.8 ±0.14 kg body weight were randomly allocated to four treatments. The grazing experiment lasted for 60 days. 121RFQ (1203.7 kg da-1) plots, have higher DMY than other treatments (P<0.05). 121RFQ (212.1 kg da-1), had higher CPY than 89RFQ (85.2 kg da-1) and 105RFQ (143.8 kg da-1) also, CPY of 147RFQ (190.0 kg da-1) was higher than 89RFQ. The mean daily live weight gain (LWG) of 121GKK (95.8 g/day) lambs was higher than that of 105RFQ (54.6 g/day) lambs. 89RFQ (78.1 g/day) and 147RFQ (63.3 g/day) lambs had similar LWG. Dry matter intake (DMI) of 121FRQ lambs (926.1 g/day) was higher than that of other treatments (834.2, 815.8 and 719.7 g/day for 89RFQ, 105RFQ and 147RFQ, respectively) (P<0.05). The feed conversion ratio (FCR) of 121RFQ (9.88) lambs was found to be better than that of 105RFQ (14.89) lambs, and similar to 89RFQ (11.16) and 147 RFQ (11.74) lambs. Only the b* value of the Longissimus dorsi muscle was affected by RFQ level. In addition, it was concluded that the effect of feeding history on feeding behaviour was caused by factors related plants and the experiences of animals rather than the level of RFQ. As a result, although there is no relationship between RFQ and FCR, it was determined that high RFQ causes better FCR, except for 89GKK. It would be appropriate to choose plants with similar characteristics to 121RFQ treatment in pasture facilities.