Section 6
Chapter 5,274

Effect of supplementation with concentrates and lasalocid during late pregnancy and lactation on productivity of Rambouillet ewes and development of wool follicles in their lambs

Shetaewi, M.M.; Ross, T.T.

Journal of Animal Science 65(2): 351-358


ISSN/ISBN: 0021-8812
PMID: 3624089
DOI: 10.2527/jas1987.652351x
Accession: 005273958

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A total of 64 Rambouillet ewes was utilized in this study. Ewes were fed a 50:50 mixture of alfalfa and prairie hay ad libitum and either no concentrates (C), .4 kg concentrates .cntdot. head-1 .cntdot. d-1 (S) or .4 kg concentrates containing 73 ppm lasalocid .cntdot. head-1 .cntdot. d-1 (SL) during the last 50 d of pregnancy and through 60 d of lactation. A total of 163 skin samples was obtained from the mid-side region of the lambs at birth, 1 and 2 mo of age, and follicle traits were estimated by histological techniques. Wool growth per unit area (100 cm2) was estimated by clipping wool from both right and left mid-sides of all ewes 60 d postpartum. Birth weight of single lambs did not differ (P > .20) among treatments. Twin lambs of supplemented ewes were heavier (P < .01) at birth than those of control ewes and the difference between S and SL groups was not significant. Compared with the control, concentrate supplementation with or without lasolocid increased (P < .01) postnatal lamb survival and ewe productivity, expressed as kilograms of lamb weaned per ewe lambed. The C, S and SL groups weaned 12.50, 18.52 and 20.72 kg/ewe lambed (P < .01), respectively. Maternal concentrate supplementation did not influence secondary to primary wool follicle ratio (Sf/Pf) of single lambs (P > .20). Twin lambs of the S ewes tended to have higher Sf/Pf than controls. The SL twins had intermediate Sf/Pf values (P > .20). Means of Sf/Pf for twin lambs of C, S and SL groups at 2 mo of age were 6.5 .+-. 8, 8.2 .+-. .4 and 7.4 .+-. .8, respectively. Supplementation with and without losalocid had no effect on wool growth of ewes during late pregnancy and lactation.

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