J.A. Parish

Evaluation of Four Different Methods of Calf Birth Weight Data Collection1

Abstract Reporting accurate calf birth weight is important for accurate calculation of birth weight and calving ease expected progeny differences. Calf birth weight information is used by many cow-calf producers as an indicator trait for calving ease in animal selection and culling decisions to minimize the risk of dystocia in their herds. The objectives of this study were to 1) evaluate the accuracy of the following birth weight collection methods: estimation via visual appraisal, estimation using hoof circumference tapes, measurement with handheld hanging spring scales, and measurement using digital scales; and 2) determine if visual birth weight estimations change in accuracy with increasing operator experience as the calving season progresses. Within the first 24 h of life, birth weight estimates and measurements were collected on each calf (n = 587) born at the Mississippi Agricultural and Forestry Experiment Station, Leveck Animal Research Center (Mississippi State, MS) and the Prairie Research Unit (Prairie, MS) during routine calf tagging and processing over a spring and autumn period at each location. Results indicate that birth weight records can vary because of the birth weight collection method used. When birth weight levels were examined, visual estimates and hoof tape measurements tended to underestimate high birth weights, whereas hoof tape measurements tended to overestimate low birth weights. Birth weight data collection via either spring or digital scales resulted in more accurate measurements.

Comparison of chicory and annual ryegrass for spring stockering of beef steers1

ABSTRACT The perennial forage herb, ‘Puna II’ chicory (Cichorium intybus L.; CHY) was evaluated as an alternative to ‘Marshall’ annual ryegrass (Lolium multiflorum Lam.; ARG) for spring stocker cattle grazing. Replicated (n = 4) 0.81-ha ARG and CHY pastures were established in September 2004 in a randomized complete block design. British-Continental crossbred steers (mean BW = 215 kg; 5 testers/paddock) were rotationally stocked (14-d grazing, 14-d rest) for a 56-d period starting in mid-April, for 3 yr. Forage IVDMD and ADF concentrations were not different between ARG and CHY pastures in April or May, but were lesser (P

Evaluation of 3 bermudagrass cultivars for stocker programs with beef steers1

Three bermudagrass (Cynodon dactylon) cultivars were evaluated for nutritive value and calf growth performance for 84 d in 2 yr each. Replicated (n = 3) 1.62-ha common (CMN), Sumrall 007 (SMRL), and Tifton 44 (T44) bermudagrass pastures in a randomized complete block design were rotationally stocked (14-d grazing, 14-d rest) with 6 to 12 British-Continental steers (initial BW = 255 ± 26 kg) using put-and-take management based on herbage mass. Steers were supplemented with soybean hulls at 1% of BW (as fed). Forage ADF concentration was greater (P = 0.01) for SMRL (31.7 ± 0.4%) than for CMN (29.7 ± 0.4%). Forage IVDMD (P = 0.13), NDF (P = 0.07), and CP (P = 0.15) concentrations were comparable among cultivars. Forage CP concentration differed (P < 0.01) by grazing period. Least squares means for CP concentrations were 11.1 ± 0.5%, 12.4 ± 0.6%, 9.7 ± 0.5%, and 8.1 ± 0.5% for d 0, 28, 56, and 84, respectively. Neither ADG (P = 0.56) nor steer BW gain per hectare (P = 0.77) was different among cultivars. Steer BW gain per hectare was greater (P < 0.01) in 2006 (372 ± 23.9 kg/ha) than in 2007 (295 ± 23.9 kg/ha). Steer ADG was unchanged (P = 0.39) among 28-d periods in 2006 but decreased progressively (P < 0.01) in 2007. Forage nutritive value and calf performance grazing CMN was comparable to that on SMRL or T44 bermudagrass. Steer BW gains on bermudagrass monocultures supplemented with soybean hulls at 1% of BW did not differ among cultivars.

Mississippi Farm to Feedlot Program 13-year summary: Effects of steer age and morbidity on feedlot performance and carcass traits1

ABSTRACT Records of steers (n = 6,392) consigned to the Mississippi Farm to Feedlot Program from 1993 to 2006 were used to assess effects of steer age and morbidity on feedlot performance and carcass traits and to describe characteristics of steers fitting certain carcass specifications by finishing net return quartile ranking. Morbidity rate, days treated, treatment cost, and mortality rate were dramatically greater (P

Assessment of 3 sudangrass cultivars for summer stockering of beef steers1

Three sudangrass [Sorghum bicolor (L.) Moench ssp. drummondii (Nees ex Steud.) de Wet & Harlan] cultivars were evaluated for calf growth performance and nutritive value for 56 d during summer for 2 yr. Replicated (n = 3) 2.17-ha Piper (PIP), Monarch V (MONV), and HayKing/Pro-Max (HKPM) sudangrass pastures were rotationally stocked with British-Continental crossbred calves (initial BW = 233 ± 28.5 kg) using put-and-take management. Forage IVDMD (P = 0.14), herbage mass (P = 0.14), stocking rate (P = 0.65), forage allowance (P = 0.54), ADG (P = 0.83), and BW gain per hectare (P = 0.46) were comparable among cultivars. Year × grazing period interactions (P ≤ 0.03) were detected for IVDMD, NDF, ADF, CP, stocking rate, forage allowance, ADG, and BW gain per hectare. Forage IVDMD and CP concentrations were greater (P < 0.01) on d 0 than on d 56, and forage NDF and ADF concentrations were greater (P < 0.01) on d 56 than on d 0 in both 2005 and 2006, but the magnitude of these changes varied by year. Thus, as forage matured, nutritive value decreased. This led to decreased (P < 0.01) ADG and gain per hectare in the second half of the grazing season each year. Least squares means for ADG were 1.05 and 0.42 ± 0.04 kg/d in 2005 and 1.07 and 0.72 ± 0.04 kg/d in 2006 for the first and second 28-d grazing periods, respectively. Grazing management and diet modifications may be warranted to avoid decreases in animal performance on sudangrass pastures later in the grazing season.

Effects of steer breed composition on feedlot performance and carcass traits1

Records of steers (n = 3,554) of known breed composition were used to assess the effect of breed composition on feedlot performance and carcass traits. Feedlot ADG was greater (P ≤ 0.01) for Angus and Red Angus than for Brangus and Polled Hereford steers. Longissimus muscle area ranged from 81.6 cm2 for Beefmaster carcasses to 85.7 cm2 for Red Angus carcasses and was affected by breed (P < 0.01). Marbling score was greatest (P = 0.03) in Angus carcasses and greater (P < 0.05) in Brangus than in Polled Hereford and Beefmaster carcasses. All following results are relative to a British base. Direct additive effects for backfat thickness in Continental (P < 0.01), American (P < 0.01), and Zebu (P < 0.05) breeds were − 0.6, − 0.2, and − 0.1 cm. Marbling score and USDA QG direct additive effects (P < 0.01) were large negative values for American, Continental, and Zebu. The Continental direct additive effect (P < 0.01) for LM area was 9.7 cm2 . Calculated YG direct additive effects (P < 0.01) were − 0.2 and − 1.0 for American and Continental breeds, respectively. Direct heterosis effects (P < 0.01) in British × American steers were present for ADG and marbling score, whereas Continental crosses tended to exhibit direct heterosis effects (P < 0.05) for LM area and backfat thickness. Steer breed composition influenced finishing performance and carcass traits. This information is important for breed selection, finishing, and marketing decisions.

Evaluation of different methods of cattle hip height data collection 1

Reporting accurate cattle hip height is important for calculation of frame score and expected progeny differences. The objectives of this study were to 1) evaluate the accuracy of the following hip height collection methods: visual appraisal using a premeasured board placed on the opposite side of the animal from the observer (VIS), measurement of the difference in distance down to the hips from the distance down to the floor with a descending tape placed above the animal (TPE), and measurement using an altitude stick (STK); 2) determine if head restraint affects hip height data accuracy; and 3) assess reproducibility of hip height measurements using different observers. Hip heights were collected on cows (n = 329) and calves (n = 341). Cow hip height was greater (P < 0.01) for TPE than VIS and STK (135.3, 133.8, and 133.8 ± 0.2 cm, respectively). There was a significant interaction for restraint × chute score (CS) for cows (P < 0.01) and calves (P < 0.03). Hip height was greater (P < 0.01) for calves with heads unrestrained (110.2 ± 0.2 cm) compared with restrained (108.3 ± 0.2 cm) in a squeeze chute. As CS increased (1, 2, 3), calf hip height (110.4 ± 0.1; 109.7 ± 0.2; 107.7 ± 0.3 cm, respectively) decreased (P < 0.01). Pearson correlation coefficients between observers were significant (P < 0.01) and all 0.86 or greater, indicating that the measurements were quite reproducible. Hip height measurements can vary due to collection method, head restraint, and CS.

Effect of a DNA-based immunostimulant on growth, performance, and expression of inflammatory and immune mediators in beef calves abruptly weaned and introduced to a complete ration

The effect of a DNA immunostimulant on inflammatory and immune responses, performance, and health in calves following abrupt weaning and introduction to a concentrate diet was tested. Sixty-four single source Angus crossbred steers were weaned on day 1 and assigned to receive a DNA immunostimulant (TRT) or saline (CON) on days 0, 2, 4, and 6. On day 0, steers received clostridial and respiratory vaccines and anthelmintic; they were then transported 2 h, allocated to pens (n = 8 per pen), and introduced to total mixed ration. Daily intake, ADG, and feed efficiency were measured. Serum haptoglobin, tumor necrosis factor-alpha (TNF-α), and interleukin-1 beta (IL-1β) were assayed by ELISA or AlphaLISA on days 0, 2, 4, 6, 14, and 28; serum-neutralizing antibodies (SNA) to bovine herpesvirus-1 and bovine viral diarrhea virus-1 (BVDV-1) were quantified on days 0, 28, 68, and 135. In a subset of cattle (n = 6 to 8 per treatment group), the percent macrophages and activated gamma delta (γδ) T cells in blood was determined by flow cytometry on days 2 and 6, and expression of mRNA for TNF-α, interferon-gamma (IFN-γ), IL-4, and IL-10 by stimulated blood mononuclear cells was assessed by real-time reverse transcriptase PCR on day 6. After 70 d, cattle were shipped 1,205 km to a feedlot and performance and health were followed. There was a significant effect of time on serum TNF-α, IL-1β, haptoglobin, and SNA (P < 0.001); the range in concentration among cattle on each day was large. The ratio of IFN-γ to IL-4 expression was significantly higher (P = 0.03) for TRT cattle, suggesting that treatment activated T-helper type 1 cells. There was a trend toward an improved feed conversion (P = 0.10) for TRT steers over the 70-d backgrounding period. There was no effect of treatment on feedlot performance or carcass merit (P > 0.10). During backgrounding, 1 TRT steer died of enterocolitis. In spite of backgrounding, cattle experienced an outbreak of bovine respiratory disease (BRD) in the feedlot and 1 of 31 TRT cattle and 5 of 32 CON cattle died of BRD. The immunostimulant modified some immune responses during backgrounding. Large variability in inflammatory responses during backgrounding indicated that events around weaning induce systemic inflammation that varies substantially among cattle.

Influence of years of Mississippi Farm to Feedlot Program participation on feedlot performance and carcass traits1

ABSTRACT The Mississippi Farm to Feedlot Program is an extension program intended to evaluate cattle feedlot and carcass performance and to develop recommendations for producers based on program results to improve farm management practices. Records of steers (n = 1,719) consigned to the Mississippi Farm to Feedlot Program from 1993 to 2006, representing 9 unique farms of origin, were used to evaluate feedlot performance and carcass characteristics within farm over time. Program participation years were categorized into distinct groups: yr 1 to 3 (period 1; P1), yr 4 to 6 (P2), and yr 7 to 9 (P3). Across farms, age at feedlot entry was similar (P = 0.12) among periods. Yet initial BW increased (P