Jacqueline A. Musgrave

Effect of calving distribution on beef cattle progeny performance

Records collected between 1997 and 2010 were used to determine the effect of calving period on heifer (n = 1,019) and steer (n = 771) progeny from the Gudmundsen Sandhills Laboratory, Whitman, NE. Progeny were classified as being born in the first, second, or third 21-d period of the spring calving season within year. Heifer birth BW was lightest (P < 0.01) for heifers born in the first period. Birth to weaning ADG tended (P = 0.10) to be least for heifers born in the first calving period; however, weaning BW decreased (P = 0.03) with advancing calving period. Weaning to prebreeding ADG tended (P = 0.07) to be least for heifers born in the first period; however, prebreeding BW was greatest (P < 0.01) for calves born in the first period. Heifer ADG from the beginning of the breeding season to pregnancy diagnosis was greater (P = 0.03) for heifers born in the third vs. first calving period. Heifers cycling at the beginning of the breeding season decreased (P < 0.01) with advancing calving date (70, 58, and 39%, respectively) and 45 d pregnancy rates were lowest (P = 0.02) for heifers born in the third calving period (90, 86, and 78%, respectively). Birth date of the first calf of the heifer and birth BW decreased (P < 0.01) if the heifer was born in the first calving period. First calf progeny had the greatest (P ≤ 0.10) weaning BW if born to a heifer born in the first calving period. As steer calving period advanced, weaning BW decreased (P < 0.01). Calving period did not affect (P = 0.81) feedlot ADG. As calving period advanced, HCW, marbling score, and yield grade decreased (P < 0.01). The percentage of steers grading USDA small marbling was not affected (P = 0.13) by calving period; however, the percentage of steers grading USDA modest marbling or greater and the total carcass value declined (P ≤ 0.01) as calving period advanced. Heifer calves born during the first 21 d of the spring calving season had greater weaning, prebreeding, and precalving BW; greater percent cycling before breeding; and greater pregnancy rates compared with heifers born in the third period. First calf progeny also had an earlier birth date and greater weaning BW. Steer calves born during the first 21 d of the calving season had greater weaning, final, and carcass weights; greater marbling scores; a greater percentage grading USDA modest or greater; and greater carcass value. Calving period of progeny significantly impacts performance.

The effects of supplementing dried distillers grains to steers grazing cool-season meadow1

Two summer experiments were conducted with 28 (BW = 291 ± 22 kg; Exp. 1) and 48 (BW = 280 ± 22 kg; Exp. 2) steers to determine the effect of supplementing dried distillers grains plus solubles (DDGS) on growth when grazing subirrigated Sandhills meadow. Steers were stratified by BW and assigned randomly to a treatment. In Exp. 1, there were 2 treatments: nonsupplemented or 0.6% of BW (1.75 kg) DDGS supplementation daily. In Exp. 2, there were 3 treatments: 0, 0.6 (1.68 kg), or 1.2% of BW (3.36 kg) DDGS supplementation daily. In both experiments, steers were individually supplemented for the duration of the study (Exp. 1 = 92 d; Exp. 2 = 91 d). Both experiments were analyzed as completely randomized designs with individual steer as the experimental unit. In Exp. 1, ending BW (P = 0.52) and ADG (P = 0.16) were not different. In Exp. 2, ADG (P 0.06). However, in Exp. 2, supplementing DDGS to steers grazing subirrigated Sandhills meadow increased carcass weight (P = 0.02) with increasing level of DDGS supplementation. In Exp. 2, supplementing DDGS during summer grazing did not affect QG or YG. Results from Exp. 2 indicate that supplementing DDGS at levels greater than 0.6% of BW during summer meadow grazing increases ADG, with BW maintained through finishing.

171 Effect of Backgrounding and Feedlot System Strategies on May-Born Steer Performance.

Mayborn steers were backgrounded to achieve either a high or low rate of gain. The high rate of gain was achieved by offering steers meadow hay ad libitum and 4 lb/d of a 33% CP (DM) supplement, while the low rate of gain consisted of steers grazing meadow and offered 1 lb/d of the same supplement. After backgrounding, onehalf of the steers from each group entered the feedlot in May as shortyearlings, while the remainder grazed upland range until entering the feedlot as longyearlings in midSeptember. Hot carcass weight was greater for steers backgrounded to achieve a high rate of gain, but they also consumed more during the feedlot phase and had fewer carcasses grade USDA average Choice or greater compared with steers backgrounded to achieve a low rate of gain. Longyearling steers had increased marbling scores and percentage of carcasses grading USDA average Choice or greater compared with shortyearling steers. Furthermore, longyearlings had increased carcass weight and risk for overweight carcasses.

Technical Note: Collection and preparation techniques change nutrient composition of masticate collected from esophageally fistulated cattle

Two experiments determined effects of collection and preparation techniques on nutrient composition of masticate samples from esophageally fistulated cattle. In Exp. 1, 12 esophageally fistulated cattle were maintained on 2 precollection diets, high CP (24% CP; = 6) or low CP (7.7% CP; = 6), for 8 d. On d 9, the esophageal plug was removed, screen bottom bags were attached, and each cow was offered fresh grass. Immediately after fresh grass sample collection was complete, dry grass (hay) was offered and a sample was collected. Blood samples were collected and analyzed for serum urea nitrogen concentration. Masticate samples of both fresh and dry grass were divided and each was either squeezed by hand until no more saliva could be removed or remained unsqueezed. In Exp. 2, 10 esophageally fistulated cattle were fitted with either screen ( = 5) or solid ( = 5) bottom collection bags after removal of the esophageal plug and presented grass hay, fresh grass, alfalfa hay, or fresh alfalfa. In Exp. 1, the precollection diet did not affect ( = 0.49) CP content of masticate even though serum urea nitrogen tended to be greater ( = 0.08) for high- vs. low-CP precollection diets. Forage harvest type offered (fresh vs. hay) interacted ( = 0.01) with preparation technique (squeezed vs. unsqueezed) for CP, where CP decreased in squeezed fresh samples ( < 0.001) but not in squeezed grass hay samples ( = 0.98). In Exp. 2, ingestion greatly increased levels of ash ( < 0.001). Crude protein was greater ( < 0.004) before ingestion for all samples except grass hay ( = 0.43). Levels of NDF were similar before and after ingestion ( > 0.15) for all samples except fresh alfalfa, which was greater after ingestion ( = 0.002). Ingestion status did not affect in vitro OM disappearance (IVOMD; > 0.34) except for grass hay, which was greater after ingestion ( < 0.001). Bag type (screen vs. solid) did not affect ash and NDF ( > 0.31), except for fresh alfalfa, which were greater ( < 0.03) for solid bottom bags. Bag type did not affect alfalfa CP ( = 0.71) but did affect grass CP, which was lower ( = 0.02) for solid bottom bags. Bag type did not affect IVOMD ( > 0.33). More ( = 0.01) fresh forage than hay was recovered through the esophageal opening. Previous diet did not impact masticate samples but squeezing impacted CP levels of high-quality forage and therefore should not be performed. Nutrient values should be reported on an OM basis.

Temporary calf removal during late lactation reduces calf performance without affecting milk production

ABSTRACT The objectives of this study were to investigate the effects of temporary calf removal on milk production, cow performance, and calf performance in springcalving beef cows. Each year for 2 yr, 60 crossbred (1/4 Hereford, 1/4 Angus, 1/4 Simmental, and 1/4 Gelbvieh) multiparous beef cows and their calves were assigned to 1 of 5 separation treatments: 0, 4, 8, or 12 d of separation or permanent wean. Treatments were imposed on September 10. On October 18 and December 4, milk production was determined and cows were weighed and scored for body condition. Milk was sampled and analyzed for nutrient composition on September 2 and December 5. Milk production on October 18 and December 4 was not affected (P > 0.10) by temporary separation. No differences (P > 0.10) in milk nutrient composition occurred. Cow BW change from September 10 to December 4 responded in a cubic (P