Weight gains per acre of yearling steers on continuously grazed Russian wildrye were 96.2 lb, or six times the gain of 16.0 lb on native range over a 6-year period. Crested wheatgrass, native range, and Russian wildrye grazed in a rotation or free-choice system reduced the acreage requirement to 15 acres per animal-unit for 6 months from 28 acres required for native range and increased beef production per acre by 55 to 66%. The vegetation on each of the three pasture types was maintained in a more productive condition when they were grazed in rotation in individually fenced fields than when they were grazed free-choice as a single unit. Crested wheatgrass and Russian wildrye effectively extended the grazing season. C rested wheatgrass [Agropyron cristatum (L.) Gaertn. and A. desertorum (Fisch.) Schult.] and Russian wildrye (Elymus jurzceus Fisch.) are the most commonly used species for range reseeding in the Northern Great Plains. (Grazing studies conducted by various research institutions have shown that these grasses are well adapted for pasture use. Some grazing trials have deferred the use of native range during the spring by providing crested wheatgrass pasture (Sarvis,

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Milk production from ewes of five breeds of sheep (Suffolk, Hampshire, Rambouillet, Canadian Corriedale, and Romnelet) and the growth of lambs suckling these ewes were compared. Milk production was measured by weighing the lambs prior to and after nursing and crediting the gain in weight to milk produced. Ewes nursing twins produced more milk than those nursing singles (P <.01). Among ewes nursing singles, Suffolk produced the greatest amount of milk (P <.01). Milk production from ewes nursing twins was greatest (P <.05) in Canadian Corriedale and Suffolk ewes. It is suggested that the milk drawn by twin lambs is a measure of milk production while that drawn by single lambs is a measure of ad lib. consumption.Single lambs gained more body weight than twin lambs (P <.01) but differences between breeds were not consistent. Gain in body weight of lambs varied with the milk consumed and, also, may have been influenced by differences in creep-feed consumption.The significant correlation coefficients between milk production and body weight gain of twin lambs in four of the five breeds suggests that milk production is a major consideration in determining the body weight gain of lambs, although other factors also apparently influence body weight gain of the lambs. Since no differences were found in the protein or fat content of the milk (P >.05), it would appear that these factors had little influence on the body weight gain of the lambs or its correlation with milk production.

Heritabilities of weaning weight, yearling weight and clean fleece weight for range Romnelet sheep were estimated by the intra-sire regression of daughter on dam from data adjusted for year effects, age of dam, type of birth and rearing and age of lamb or yearling ewe. The data from which each estimate was calculated were collected over a 12-year period.The estimate for weaning weight based on 694 daughter-dam pairs (26 sire groups) was 0.28 ±.09. For yearling weight an estimate of 0.37 ±.11 was obtained from 394 daughter-dam pairs (34 sire groups). Five hundred and thirty-seven daughter-dam pairs (27 sire groups) provided an estimate of 0.48 ±.08 for clean fleece weight.