THE USE OF FEED RESTRICTION FOR IMPROVING REPRODUCTIVE TRAITS IN MALE-LINE LARGE WHITE TURKEY HENS .2. OVARY MORPHOLOGY AND LAYING TRAITS

The influence of feed restriction during rearing was investigated in m ale-line Large White breeder hens with regard to effects on ovarian mo rphology, egg production, laying patterns, and egg characteristics. Tw o hundred poults were reared from 4 to 28 wk of age under four treatme nts as follows: full-fed controls (FF), low-protein diet (12% CP from 12 to 28 wk; LP), and reduced BW (10 to 20% lower BW than FF; R10 and R20). At photostimulation (28 wk), all birds consumed a commercial bre eder diet ad libitum for the remainder of the study (48 wk of age). Se ttable egg production (eggs per hen) to 48 wk for all hens, and those in lay was: FF, 39.4 (48.6); LP 42.7 (51.7); R10, 41.4 (52.8); R20, 40 .7 (55.4). Inferior egg production per bird in R10 and R20 hens reflec ted a reduced persistency of lay. At first egg, hens of all treatments had a mean of 4.9 postovulatory follicles (POF) not accounted for by an egg. Number of unreconciled POF correlated with abdominal fat pad w eight (P less than or equal to .01). Ovary weight correlated with BW ( P < .0001) and fat pad weight (P < .0004). Proportion of yolk and shel l in the egg and egg specific gravity were improved with feed restrict ion. Sequence length was longest in R20 treatment hens and pause lengt h shortest in R10 and R20 hens. Incidence of multiple-follicle sets wa s reduced in the R10 and R20 treatments. Feed restriction during reari ng can potentially improve laying characteristics by altering ovarian morphology without limiting shell quality or yolk size. Quantitative f eed restriction was most effective at improving egg quality, reducing average pause length, and reducing ovarian multiple-follicle sets. If problems with persistency of lay are addressed, the R10 and R20 treatm ents are the recommended rearing restriction treatments for male-line turkey breeder hen candidates.