PSXV-22 Effect of inclusion of dried citrus pulp in the receiving supplement for newly received stocker cattle

Citrus pulp is a source of flavonoids which have been found to have antioxidant properties. Thus, the objective of this experiment was to investigate the effects of feeding dried citrus pulp on performance of newly received calves. Crossbred beef heifers (n = 254, initial body weight = 248 ± 5.9 kg) were obtained on 3 dates (block, 8 pens/block). Treatments were: 1) a corn and distillers’ grains based receiving supplement (control) or 2) a receiving supplement that contained 20% dried citrus pulp (replacing a portion of the corn). Upon arrival from regional livestock markets, cattle had access to hay and water and rested overnight then were processed the next day in which they received an identification tag, were vaccinated with a clostridial and a 5-way modified live bovine respiratory viral, dewormed, weighed, branded, and ear notched for detection of persistent infection with bovine viral diarrhea virus. Each truckload was assigned randomly to pens resulting in 8 pens with 9 to 12 heifers/pen. Pens were assigned randomly to 1 of the 2 treatments. Cattle were offered bermudagrass hay and water for ad libitum intake and were offered up to 1.8 kg/day of their appropriate receiving supplement. Overall average daily gain for the 42-day receiving period was increased (P < 0.01) for calves fed the supplement that included dried citrus pulp (1.01 kg/day) compared to the calves fed the control supplement (0.90 kg/day). However, the percentage of calves treated for clinical bovine respiratory disease was increased (P < 0.05) for calves fed the citrus pulp containing supplement (14% morbidity) compared to control calves (7% morbidity). The supplementation of dried citrus pulp to calves improved growth performance, but did not reduce the incidence of clinical bovine respiratory disease during the receiving period; however, clinical morbidity was low for both treatments.

Evaluation of nitrogen-delivery methods for stocker cattle grazing annual ryegrass

A 2-yr grazing experiment was conducted to evaluate efficacy of nitrogen (N) fertilization, interseeded legumes and protein supplementation for N delivery to stocker cattle grazing annual ryegrass (Lolium multiflorum). Each yr, 90 steers (initial BW, 241 ± 13 kg) were assigned to the following N-delivery methods, with or without monensin fed in a free-choice mineral supplement as a 5 x 2 factorial arrangement of treatments: ryegrass fertilized with 112 kg N/ha (NFERT); ryegrass interseeded with crimson clover (CC, Trifolium incarnatum); ryegrass interseeded with arrowleaf clover (AC, Trifolium vesiculosum); ryegrass plus distillers dried grains with solubles (DDGS) supplemented at 0.65% BW daily; and ryegrass plus whole cottonseed (WCS) supplemented at 0.65% BW daily. Pastures within the interseeded-clover and protein-supplementation treatments were fertilized with 56 kg N/ha at time of establishment. Steers were weighed every 28 d, and forage mass (FM, kg DM/ha) was measured concurrently using the destructive harvest/disk meter double-sampling method. Each of 30 0.81-ha paddocks was stocked initially with 3 ‘tester’ steers, and stocking density (steers/ha) was adjusted using ‘put-and-take steers’ based on changes in FM and steer BW in order to maintain a uniform forage allowance (FA) of 1 kg DM/kg steer BW. Grazing was discontinued on May 11, 2016 in Yr 1 and May 10, 2017 in Yr 2 following 140 and 84 d of grazing, respectively. Data were analyzed as a completely randomized design with repeated measures for which pasture (n = 3) was the experimental unit. Ionophore inclusion did not affect (P > 0.10) any variable measured. Mean FM differed (P < 0.0001) between yr and among N-delivery methods (P < 0.10), and mean FA differed (P = 0.005) among N-delivery methods. Steer ADG differed among N-delivery methods (P = 0.02) and between yr (P < 0.001), whereas total gain/ha differed (P < 0.0008) among N-delivery methods, but not between yr (P = 0.78). Stocking density differed among N-delivery methods (P = 0.02) and between yr (P < 0.0001), and grazing-days/ha differed between yr (P < 0.0001) and among N-delivery methods (P = 0.001). Results indicate that supplementation with a high-protein by-product feed for cattle grazing annual ryegrass maintained ADG, total gain/ha and grazing-days/ha compared with N-fertilized annual ryegrass, and increased ADG, total gain/ha and grazing-days over interseeded legumes.

62 Effects of forage allowance and supplementation on performance of steers grazing wheat pasture

A 72-d trial was conducted to estimate the combined effect of forage allowance and a fiber-based energy supplement in stocker cattle grazing wheat. Eight pastures (2.7 to 5.1 ha) each contained seven test steers (initial BW = 210 ± 36 kg). Weekly, additional steers were stocked in each pasture in a put and take method to achieve forage allowance of either 2.5 or 5.5 kg forage DM / kg steer BW (4 pastures each). Two pastures in each forage allowance were fed daily with a supplement containing 50% wheat midds and 50% soybean hulls at the rate of 1.5 kg per steer. Forage mass was measured twice weekly using a calibrated rising plate meter. Cattle were weighed weekly on calibrated scales. Data were analyzed using linear regression with pasture as the experimental unit. Mean ADG was 1.36 kg/d. One pasture in the high forage allowance, non-supplemented treatment was removed because we were unable to maintain the designed forage allowance. The interaction of forage allowance and supplement was not significant (P = 0.37) for ADG, and supplementation did not affect ADG (P = 0.20), however increased forage allowance tended to improve ADG (P = 0.06, 0.21 kg ADG per kg forage allowance). To further investigate forage DMI, a 14-d trial began on day 36. Three of the seven test steers in each pasture were randomly chosen and administered 7 ± 0.1 g of TiO2 daily at 0700 as an external marker to estimate fecal output. Forage DMI (at an assumed 72% DM digestibility) averaged 2.1% of midpoint BW, below our expectation. Additional forage allowance tended to improve estimated forage DMI (P= 0.06), but supplement had minimal effect (P = 0.30).

63 Effects of forage allowance and supplementation on performance of steers grazing wheat pasture

A 72-d trial was conducted to estimate the combined effect of forage allowance and a fiber-based energy supplement in stocker cattle grazing wheat. Eight pastures (2.7 to 5.1 ha) each contained seven test steers (initial BW = 210 ± 36 kg). Weekly, additional steers were stocked in each pasture in a put and take method to achieve forage allowance of either 2.5 or 5.5 kg forage DM / kg steer BW (4 pastures each). Two pastures in each forage allowance were fed daily with a supplement containing 50% wheat midds and 50% soybean hulls at the rate of 1.5 kg per steer. Forage mass was measured twice weekly using a calibrated rising plate meter. Cattle were weighed weekly on calibrated scales. Data were analyzed using linear regression with pasture as the experimental unit. Mean ADG was 1.36 kg/d. One pasture in the high forage allowance, non-supplemented treatment was removed because we were unable to maintain the designed forage allowance. The interaction of forage allowance and supplement was not significant (P = 0.37) for ADG, and supplementation did not affect ADG (P = 0.20), however increased forage allowance tended to improve ADG (P = 0.06, 0.21 kg ADG per kg forage allowance). To further investigate forage DMI, a 14-d trial began on day 36. Three of the seven test steers in each pasture were randomly chosen and administered 7 ± 0.1 g of TiO2 daily at 0700 as an external marker to estimate fecal output. Forage DMI (at an assumed 72% DM digestibility) averaged 2.1% of midpoint BW, below our expectation. Additional forage allowance tended to improve estimated forage DMI (P= 0.06), but supplement had minimal effect (P = 0.30).

155 The effect of number of cattle per pen on stocker cattle health and performance

The objectives of this study were to: 1) to examine the effect of number of stocker cattle in a receiving pen on BRD morbidity and mortality; and 2) to examine the effect of number of stocker cattle in a receiving pen on cattle performance. Crossbred steers of unknown origin and history (n = 200) were purchased from auction barns in the southern portion of the United States. Cattle were stratified by weight and assigned to either a small (10 head/pen) or large (50 head/pen) treatment on arrival. Calves were assigned to 1 of 3 large pens or 1 of 5 small pens. Cattle were observed daily for clinical signs of BRD and treated if rectal temperature ≥40°C. Body weight was collected on d 0, 14, 28, 42, and 56. Rectal temperature was collected at arrival. Days-at-risk for BRD was the number of days from arrival until a calf: (1) was first diagnosed with BRD; (2) died; or (3) finished the trial. Treatment effects on BRD incidence and performance were tested using Poisson distribution and logistic regression using GLIMMIX or linear regression using MIXED procedure of SAS, respectively, accounting for clustering by pen. Mortality was analyzed using the LOGISTIC function with Firth’s penalized likelihood. There were 8,698 total days at risk and overall incidence density was 7.82 BRD cases per 1,000 calf days. Overall morbidity totaled 32.5% with 5.5% mortality. No difference among treatment was observed for morbidity, mortality, or performance. Cattle with fever on arrival were 1.125 times more likely to contract BRD (P ˂ .0001). The number of BRD treatments received had an effect on ADG at d 0–14 (P ˂ .0001), 0–28 (P ˂ .0001), and 0–60 (P ˂ .0001), with ADG decreasing as number of treatments increased. In summary, fever on arrival affected BRD incidence, and number of treatments cattle received affected growth throughout the trial.

113 Mineral Supplementation Effects in Stocker Cattle Performance Grazed on Wheat Seeded Native Pastures

One way to extend the grazing season in the southeast United States is to plant cool-season forages into native pastures to provide additional forages for the winter and spring grazing. The objective of this study was to evaluate the effects of two different medicated (Monensin) supplementation types, with or without protein, on stocker calves grazing native pasture overseeded with wheat through the months of February to May. Cross-bred steers (n = 36; BW = 291.76 kg ± 29.92) and heifers (n = 29; BW = 288.17 kg ± 25.22), sired primarily by Hereford bulls, were assigned to two treatment groups at two locations blocked by sex and weight. All mineral supplementation was provided ad libitum. The first supplementation consisted of a commercial loose mineral (Advanced Mineral Performance Technology (AMPT); ADM; Quincy, Illinois), and the second was a commercial protein block (MoorMan’s, Mintrate Blonde Block RU; ADM; Quincy, IL) containing 42.0% Crude Protein. Average Daily Gain was compared using PROC MIX with the main effects: treatment, pasture, gender, and their interactions. The starting weights of the treatment groups were not different (P = 0.996). No significant interactions (P < 0.05) were detected and only the main effects will be reported. Steers gained more (P < 0.0001) than heifers (1.25 kg ± 0.025 kg vs. 0.96 kg ± 0.029 kg, respectively). ADG for the mineral was 1.14 kg ± 0.027 kg, compared to 1.06 kg ± 0.028 kg for the protein block (P < 0.05). Differences in ADG was observed between pastures (P < 0.07). At 124 days the final body weight of heifers averaged 119.56 kg and the steers averaged 154.70 kg. These results indicate that the mineral improved ADG over the block supplementation.

154 The effect of number of cattle per pen on stocker cattle health and performance

The objectives of this study were to: 1) to examine the effect of number of stocker cattle in a receiving pen on BRD morbidity and mortality; and 2) to examine the effect of number of stocker cattle in a receiving pen on cattle performance. Crossbred steers of unknown origin and history (n = 200) were purchased from auction barns in the southern portion of the United States. Cattle were stratified by weight and assigned to either a small (10 head/pen) or large (50 head/pen) treatment on arrival. Calves were assigned to 1 of 3 large pens or 1 of 5 small pens. Cattle were observed daily for clinical signs of BRD and treated if rectal temperature ≥40°C. Body weight was collected on d 0, 14, 28, 42, and 56. Rectal temperature was collected at arrival. Days-at-risk for BRD was the number of days from arrival until a calf: (1) was first diagnosed with BRD; (2) died; or (3) finished the trial. Treatment effects on BRD incidence and performance were tested using Poisson distribution and logistic regression using GLIMMIX or linear regression using MIXED procedure of SAS, respectively, accounting for clustering by pen. Mortality was analyzed using the LOGISTIC function with Firth’s penalized likelihood. There were 8,698 total days at risk and overall incidence density was 7.82 BRD cases per 1,000 calf days. Overall morbidity totaled 32.5% with 5.5% mortality. No difference among treatment was observed for morbidity, mortality, or performance. Cattle with fever on arrival were 1.125 times more likely to contract BRD (P ˂ .0001). The number of BRD treatments received had an effect on ADG at d 0–14 (P ˂ .0001), 0–28 (P ˂ .0001), and 0–60 (P ˂ .0001), with ADG decreasing as number of treatments increased. In summary, fever on arrival affected BRD incidence, and number of treatments cattle received affected growth throughout the trial.