A 2-yr study was conducted to determine the effects of rate of N fertilization on productivity and nutritive value of stockpiled "Tifton 85" bermudagrass for lactating-cow and calf performance. On 31 October 2012 (year 1) and 11 November 2013 (year 2), 16 Angus × Simmental cows (mean initial BW for both years, 647 ± 23 kg) and their calves (mean age for both years, 16 ± 3 d) were assigned randomly to 0.76-ha paddocks (2 cow-calf pairs/paddock) of stockpiled "Tifton 85" bermudagrass pasture that had been cut to a 10-cm stubble height in early August and fertilized with either 56 (56N), 112 (112N), or 168 (168N) kg N/ha (2 paddocks/treatment), or to replicate 0.41-ha paddocks (2 cow-calf pairs/paddock) of dormant pasture with free-choice access to August-cut "Tifton 85" bermudagrass hay plus 2.7 kg whole cottonseed daily (HAY). Cows were allowed access to strips of ungrazed forage by moving polytape every 3 to 4 d to maintain a DM harvest efficiency of approximately 75%. In year 1, forage mass (6,113 kg DM/ha), IVDMD (60.9%), and grazing d/ha (314) were not different (P > 0.05) among the stockpile treatments over a 116-d grazing period; mean forage IVDMD (60.1%) and CP (12.7%) in the stockpiled treatments were greater (P < 0.05) than the HAY treatment. Stockpiled forage CP concentration was greater (P < 0.05) for the 168N than 56N and 112N treatments and was greater (P < 0.05) for the 56N than 112N treatment. In year 2, mean forage CP concentration was greater (P < 0.05) for the 168N (14.5%) than 56N (11.3%), 112N (12.0%), and HAY (9.0%) treatments; mean stockpiled forage IVDMD (59.5%) was greater (P < 0.05) than the HAY treatment (46.3%); and mean forage mass for the 168N treatment (5,017 kg DM/ha) was 378 kg and 298 kg DM/ha greater (P < 0.05) than the 112N and 56N treatments, respectively. Mean cow BW (611 ± 147 kg), body condition scores (5.5 ± 0.6), and milk production (9.0 ± 6.0 kg/d) were not different (P > 0.05) among treatments. Mean blood urea-N (BUN) concentrations (11.2 mg/mL) were not different among treatments, but mean BUN across treatments for the last sampling date was greater (P < 0.05) than the first and second sampling dates. Mean 205-d adjusted weaning weight (249 kg ± SD) was not different among treatments. Economic evaluation revealed that input costs/cow were 66%, 61%, and 56% greater for HAY than 56N, 112N, and 168N, respectively. Stockpiled forages were of sufficient nutritive quality to support lactation without supplementation.

No abstract

A 2-yr study was conducted to determine effects of N fertilization level on fiber digestion kinetics and protein degradability characteristics of stockpiled Tifton 85 bermudagrass (T85). Six 0.76-ha pastures of stockpiled T85 were cut to a 10-cm stubble height on August 1 of each yr and fertilized with 56 (56N), 112 (112N), or 168 (168N) kg N/ha (2 pastures/treatment). Fiber digestion kinetics included the 72-hr potential extent of NDF digestion (PED), rate of NDF digestion, and lag time. In yr 1 and 2, PED decreased over the stockpile season. Rates of NDF digestion did not differ ( > 0.05) among N fertilization treatments in either yr. In yr 1, rate of NDF digestion was greatest ( < 0.05) in October/November, and decreased beginning in December. In yr 2, rate of NDF digestion decreased ( < 0.05) in January compared with November, but digestion rates were similar for November and January 21 sampling dates. Lag time was greater ( < 0.05) for the 112N than 56N and 168N treatments, and increased ( < 0.05) across sampling dates in yr 1. In yr 2, lag time increased ( < 0.05) from 9.0 to 17.7 h across the season. In yr 1 and 2, a negative correlation ( < 0.05) between forage lignin concentration and both PED ( = -0.91 and -0.87 in yr 1 and 2, respectively) and rate of NDF digestion ( = -0.60 and -0.25 in yr 1 and 2, respectively) was observed. There was a trend ( = 0.06) for lignin concentration to be positively correlated with lag time ( = 0.39) in yr 1, and a strong relationship was observed in yr 2 ( = 0.91; < 0.05). The RDP fraction as a % of CP was ≥ 90% throughout both years. Concentration of RDP (% of total DM) decreased across the stockpiling season through January in yr 1 and 2. Results suggest that kinetic parameters of NDF digestion in stockpiled T85 were influenced more by temporal changes over the stockpile season than by N fertilization level. Supplement formulations based on kinetic parameters of fiber digestion may require periodic adjustment to insure that energy-yielding components of NDF are sufficient to meet animal requirements throughout the stockpile season. The CP fraction in stockpiled T85 contains sufficient RDP to support fibrolytic activity and growth of ruminal microorganisms throughout the stockpile season. Toward the latter end of the season, supplementation with sources of digestible fiber and RDP could be expected to increase MP supply to the host animal.

No abstract

The objective of this study was to quantify the effect of shipping to feedyards in western Kansas from the Southeast on the immune response of beef steers using complete blood counts. Angus- and Hereford-sired steers (n = 24, BW = 266.3±24.9 kg) from E.V. Smith Research Center in Shorter, AL, were weaned on June 14, 2018. The following day, blood was collected for analysis. These calves were a subset from a larger project involving grazing. As such, calves were then maintained in drylots for 14 d until grazing was available. Once grazing was initiated, these calves were placed in drylot pens with a diet consisting of dry hay with supplemented with 1% of BW of dried distiller’s grains with solubles. After 80 d, half of the calves were shipped (n = 12, SC) to Hy-Plains Feedyard, LLC. in Montezuma, KS. Immediately prior to shipment, immediately post-shipment, and after 24-hr rest, blood was collected. Blood was also collected from the unshipped calves (UC) at similar time points. Whole blood collected at each time point was analyzed for complete blood counts. The data was analyzed using the Mixed Procedure in SAS. No significant differences (P > 0.05) were detected post-weaning or pre-shipping. Immediately post-shipment, white blood cell, and neutrophil counts were greater in SC while lymphocytes counts were less (P < 0.05) than UC; however, these were not different after 24-hr rest (P > 0.05). Hematocrit and monocyte count were elevated in SC both immediately post-shipping and after 24 hr of rest (P <0.05), while reticulocyte count was lower in SC at those same time points (P < 0.05). Basophil counts were lower in SC at the 24-hr rest time point (P = 0.03). Results of this study indicate that SC did not completely rehydrate after 24 hr of rest and complete blood counts show differences in immune response due to shipping