286 The influence of age and winter environment on Rumax Bovibox and Bovibox HM supplement intake behavior of winter grazing beef cattle on mixed-grass rangelands

This study evaluated the influence of cow age and temperature adjusted for windchill (Twindchill) on supplement intake behavior of cattle winter grazing northern mixed-grass prairie rangelands. A commercial herd of 291 (yr-1) and 316 (yr-2) bred cows were winter grazed on a 329-ha rangeland pasture for 2 years. Cows were assigned to one of six age classifications and were provided free-choice access to Rumax Bovibox HM (2018–2019) and Rumax Bovibox (2019–2020) protein blocks. The target daily intake range was 0.45–0.91 kg∙cow-1∙d-1. Supplement was provided in a SmartFeedPro self-feeder system to measure individual animal supplement intake and behavior. Average daily supplement intake (expressed as kg∙cow-1∙d-1) and variation in supplement intake displayed Twindchill × cow age × yr interactions (P ≤ 0.05). There was no effect of age on daily supplement intake at below average and above average Twindchill in yr 1 (P ≥ 0.07). Age displayed a quadratic effect on daily supplement intake at average Twindchill in yr-1 (P < 0.01) but was limited to 3- and 4-yr-old cattle consuming more supplement per day than yearlings (P ≤ 0.02). During yr-2, cow age had a quadratic effect on supplement intake for all Twindchill conditions (P < 0.01) where 3-yr-old cattle consumed more supplement per day than yearlings, 5–7- and ≥ 8-yr-olds (P ≤ 0.01). Cow age exhibited quadratic effects on variation in supplement intake across all Twindchill conditions during both years (P < 0.01). However, the quadratic effects of age in yr-1 were limited to yearlings having higher variation in supplement intake than all other ages (P < 0.01). In summary, both cow age and the winter environmental conditions interacted to influence animal supplement intake behavior and, as a result, nutrient delivery efficacy in winter grazing beef cattle.

179 Using a 100% Dried Distillers Grains Cube as a Supplement for Steers Grazing Mixed Grass Prairie in Oklahoma

This research was conducted to determine effects of supplementation and implanting on BW gain by steers grazing mixed grass prairie (n = 12 pastures, 19.9 ± 0.7 ha) in northwest Oklahoma. Three main plot treatments were: 1) Negative Control (NC), no supplementation, 2) Positive Control (PC), supplemented with DDGS cubes, 1.8 kg/steer on alternate days in late summer, 3) High Supplement (HS), 1/3 increase in stocking rate with 0.75% BW supplemental DDGS cubes all season. Steers (n = 125, BW = 223.1 ± 23.2 kg) were stocked at 2.2 ha/steer for PC and NC, 1.3 ha/steer for HS. Grazing was from May 17 – September 27 (132 d). All steers were implanted with 200 mg progesterone and 20 mg estradiol benzoate (SYN, Synonvex S, Zoetis Animal Health) on May 17. On July 18 three reimplant treatments were applied: 1) no reimplant; 2) SYN; or 3) 40 mg trenbolone acetate and 8 mg estradiol (Revalor G, Merck Animal Health). Data were analyzed using the PROC MIXED in SAS as a split-plot experimental design. In early summer HS had 0.26 kg greater (P < 0.01) ADG than NC and PC. Late summer gains of PC were 0.33 kg/d more (P ≤ 0.01) than NC; and HS gained 0.49 and 0.16 kg/day more (P ≤ 0.04) than NC and PC, respectively. Gain per hectare for PC (46 kg/ha) were greater (P < 0.01) than NC (35 kg/ha) and more than doubled (P < 0.01) with HS (89 kg/ha). Reimplanting had no effect on ADG (P ≥ 0.28). Late season supplementation with PC resulted in supplemental efficiency of 2.7 kg supplement/kg added gain compared with NC. Increased stocking rates with season long supplementation in HS resulted in supplemental efficiency of 3.8 kg supplement/kg added gain per hectare. Based on these data, a 100% DDGS cube is an effective supplement option to increase BW gain during the late summer or increase carrying capacity and gain during the summer grazing period in northwestern Oklahoma.

Little Brown Birds

This chapter narrates the author's trip to western North Dakota's Bakken region, where he was mapping out habitat fragmentation caused by the recent surge in oil development. The research was really just an excuse to go out birding for a few days. Two birds are confined to the northern mixed-grass prairie: the Baird's sparrow and the Sprague's pipit. Both are small, brown birds, not terribly charismatic — what birders call LBJs or “little brown jobs” — and both are declining in population. The chapter then discusses how oil development occurs with seeming abandon in the Bakken and is only lightly regulated. Despite a history of progressivism and socialism in the American prairies, North Dakota today is essentially a one-party state — an explicitly oil-friendly Republican Party has held the governorship and both houses of the state legislature for years. Unlike resistance in parts of the East Coast, there have been no large-scale protests in North Dakota, save resistance to the pipeline by the Standing Rock reservation.