Guillermo Scaglia

Effects of Time of Supplementation on Beef Stocker Calves Grazing Ryegrass. II. Grazing Behavior and Dry Matter Intake1

Grazing behavior of ruminants can be affected by different management practices, such as time of supplementation. Steers grazing ryegrass and supplemented with corn gluten feed (CGF) were evaluated for 2 consecutive years. Each year, 72 crossbred fall-weaned steers (BW = 227.6 ± 0.6 kg) were blocked by BW and biological type to 12 groups, which were then allotted to one of the following treatments (3 replicates): 1) control, nonsupplemented; 2) morning (0700 h) supplementation with 0.5% BW of CGF; 3) noon (1200 h) supplementation with 0.5% BW of CGF; or 4) afternoon (1600 h) supplementation with 0.5% BW of CGF. Electronic pedometers were attached to 1 steer/pasture during two 14-d periods (from d 45 to 59 and d 75 to 89 of grazing) to monitor behavior, and bite rate was also recorded. In the second year of the study, forage growth was estimated at 14-d intervals (7 periods) and, together with forage mass estimates, was used to determine forage DMI and allowance. Both were affected by period (P < 0.0001) during the grazing season, with lower forage growth rates in period 4. Dry matter intake was affected by treatment (P < 0.05). Steers receiving the supplement in the morning consumed less forage than those in the other treatments. Time of supplementation affected the grazing behavior of steers receiving the supplement in the afternoon, although this was not reflected in the forage DMI. These data suggest that time of supplementation may have affected grazing behavior, although level of supplement, type of supplement, or both need to be investigated.

The effect of bermudagrass hybrid on forage characteristics, animal performance, and grazing behavior of beef steers.

Bermudagrass (Cynodon dactylon [L.] Pers.) is a major feed source for ruminants across the southeastern United States. In 4 consecutive yr, 3 different bermudagrass hybrids, Alicia, Jiggs, and Tifton-85, were evaluated under a low stocking rate as forage and hay sources. The nutritive value, in situ DM digestibility, and performance and grazing behavior of beef steers under similar management were evaluated. Sampling day had an effect (P < 0.05) on all forage variables. Percentages of CP and TDN decreased while concentration of ADF, NDF, lignin, and nonfiber carbohydrates (NFC) increased as grazing season advanced. Alicia had lower nutritive value, showing greater lignin (5.3%) and indigestible fraction (44.9%) compared to Jiggs (4.9 and 35.6%, respectively) and Tifton-85 (4.5 and 40.1%, respectively). Tifton-85 contained the lowest concentration of NFC (11.8%). Steers grazing Jiggs and Tifton-85 had greater ADG (0.51 and 0.55 kg, respectively) and BW gain per hectare (258 and 279 kg, respectively) than those on Alicia (0.36 kg and 184 kg/ha, respectively); results that are probably explained by the lower nutritive value characteristics of the latter. Most grazing behavior variables were affected (P < 0.05) by time of the day (TOD) and grazing period. Two major grazing events were observed at dawn and dusk. Grazing time (32 min) was lowest (P = 0.003) while standing (140 min) and lying (98 min) time were greater (P = 0.001 and 0.04, respectively) from 1100 to 1559 h, probably as an effect of temperature and humidity at that time of the day. During summer, the temperature humidity index (THI) is above 72 (mild heat load) for the entire season and above 79 (severe heat load) during most of the daylight hours from June to August. Heat load likely affected animal performance and grazing behavior; however, some characteristics associated with these bermudagrass hybrids, especially with Alicia, such as its percentages of lignin and indigestible fraction may also partially explain the poor animal performance. In the conditions of the study, environmental variables (temperature and humidity), as well as the type of bermudagrass hybrid, affected animal performance and grazing behavior of recently weaned beef steers.

Cross-Cultural Consumer Acceptability and Purchase Intent of Forage-Finished Rib-Eye Steaks

UNLABELLED Rib-eye steaks, from 3 forage-finished systems (S1, S2, and S3) and 1 commercial steak (C), either cooked by 1-sided-grilling or 2-sided-grilling, were evaluated for sensory acceptability [overall appearance (ORA) and overall appearance of fat (OAF) for raw steaks; overall appearance (OCA), overall beef aroma (OBA), overall beef flavor (OBF), juiciness, tenderness and overall liking (OL) for cooked steaks] and purchase intent by Hispanic, Asian and U.S. consumers. They also indicated preferred degree of doneness and cooking methods. Cross-cultural differences in preferences and consumer acceptability of rib-eye steaks were observed. Grilling was the most preferred cooking method. Hispanics and Asians preferred medium and/or medium well, while U.S. consumers preferred medium and/or medium rare. For cooked steaks, the population effect was significant for all sensory attributes; Asians generally scored lower than did Hispanics and U.S. consumers. C and S3 generally had higher scores for all sensory attributes across 3 populations. Purchase intent for all forage-finished steaks was higher for Hispanics and U.S. consumers compared to Asians (50.0% to 77.8% compared with 43.2% to 65.9%). Attributes influencing purchase intent of forage-finished steaks differed among populations: tenderness (odds ratio = 1.4) for Hispanics, OCA (odds ratio = 1.5) for Asians, and OBF (odds ratio = 1.3) for U.S. consumers. Overall, this study demonstrated that the type of forage-finished system and ethnic differences influenced sensory acceptability and purchase intent of forage-finished rib-eye steaks. PRACTICAL APPLICATION Demand for forage-finished beef has increased worldwide due to its potential health benefits. Little is known regarding the cross-cultural effects on the consumer acceptance of forage-finished beef. We evaluated sensory acceptance and purchase intent of raw and cooked forage-finished rib-eye steaks using Hispanic, Asian, and U.S. (White and African American) populations. This study demonstrated that consumer acceptability and purchase intent of forage-finished rib-eye steaks differed among Hispanic, Asian, and U.S. populations. This information can be used to guide development and marketing strategies for beef products.

Performance and economic analyses of year-round forage systems for forage-fed beef production in the Gulf Coast.

On a global scale, most beef is produced from grazing pastures or rangelands. Certain limitations exist, however, such as not having adequate animal rates of gain for marbling and availability of adequate forage nutritional value and quantity for constant animal weight gains. In the last 20 yr, there has been an increased interest in forage-fed beef for multiple reasons (health related, environmental concerns, and welfare issues). Starting on June 5, 13, 14, and 8 in 4 consecutive yr, 54 steers (initial BW=259±5.6 kg; average of 9 mo of age) were randomly allotted to 3 yr-round forage systems. Each system occupied 6 ha/replicate and had the same stocking rate. System 1 had annual ryegrass (Lolium multiflorum) for winter grazing and bermudagrass (Cynodon dactylon) for summer grazing; while Systems 2 and 3 added rye and a clover mix to the ryegrass and diversified the use of pastures in the fall (dallisgrass [Paspalum dilatatum] and clovers [Trifolium spp.]). System 3 added the use of annual summer forages. During their respective growing season for each forage or forage mix, mass and height did not limit animal performance; however, there was a sampling date effect (P<0.05) for nutritive value variables since it decreased as forages became mature. The ADG observed (0.44 kg) for all systems (P=0.78) during summer was lower than expected and might have been limited by the observed temperature as well as forage nutritive value. Systems 1 and 2 had more grazing days (P=0.03) during summer (155 and 146 d, respectively) compared to System 3 (132 d) due to the greater pasture area of bermudagrass in those systems. Steers in System 3 were fed more hay for a longer period of time (P<0.05) than on the other 2 systems. System 1 and 2 produced more hay per hectare than System 3 (P<0.05). No differences (P>0.05) were detected between systems in ADG year round, during the winter season, or carcass characteristics. Return over total direct costs and total specified expenses were greater for Systems 1 and 2, while System 3 was the lowest. Hay making and bale sales played a major role in explaining the economic results of this study. Where possible, year-round forage systems are a viable alternative for forage-fed beef production; however, the low gains during summer and forage availability during the transition period when hay is necessary deserve further research to find alternatives to improve productivity during those times of the year.

Effects of Time of Supplementation on Beef Stocker Calves Grazing Ryegrass. I. Performance and Economic Analysis1

Abstract An opportunity for improving the profitability of beef production in the Southeast lies in stockering weaned calves on high-quality, cool-season annual or perennial pastures. The large supply of weaned calves available in this region offers the opportunity for businesses to concentrate on stockering systems and retained ownership. Optimized nutrient utilization for these forage-fed cattle can be through the timing of supplementing nutrients within a day. In each year of this consecutive 2-yr experiment, 72 crossbred steers (initial BW = 227.6 ± 0.6 kg) weaned in October were blocked by BW and biological type into 12 groups, which were later allotted to one of the following treatments (3 replicates): 1) control, nonsupplemented; 2) morning (0700 h) supplementation with 0.5% BW of corn gluten feed (CGF); 3) noon (1200 h) supplementation with 0.5% BW of CGF; or 4) afternoon (1600 h) supplementation with 0.5% BW of CGF. Steers were weighed at 14-d intervals and supplementation level was adjusted accordingly. Forage mass, height, and nutritive value were estimated every 14 d. Differences in ADG ( P P = 0.042) on kilograms produced per hectare when morning supplementation was compared with noon supplementation. Ruminal environment may have been affected since forage variables and ADG were not different across timing of supplementation. Under the conditions of this experiment, supplementation did not enhance animal performance, beef production per hectare, or profitability. However, noon supplementation may be detrimental to these aspects in a winter grazing enterprise.

P re- and postweaning calf performances in crossbred cattle from Hereford, Braford, and Bonsmara sires and Angus and Brangus dams 1

Growth traits were evaluated on 560 calves (288 male and 272 female calves) to determine the source and extent of tropical adaptation affecting calf preweaning and postweaning growth performances. Calves with Brangus dams were sired by Braford (BFBN; n = 115; 38% Brahman), Hereford (HEBN; n = 92; 19% Brahman), and Bonsmara (BOBN; n = 139; 19% Brahman and 31% Africander) sires. Calves with Angus (AN) dams were sired by Hereford (HEAN; n = 95) and Bonsmara (BOAN, n = 119; 31% Africander) sires. Growth performances of BFBN and HEBN calves were similar (P > 0.15) for an array of growth traits. However, BFBN and HEBN either tended to (P < 0.10) or had (P < 0.05) greater adjusted birth BW, postweaning ADG, and adjusted 452-d BW when compared with BOBN. Calves with AN dams and Bonsmara sires had greater preweaning ADG (P < 0.05), adjusted 205-d BW (P < 0.01), and adjusted 452-d BW (P < 0.01) than HEAN calves. Among calves with Brangus dams, extent (BFBN vs. HEBN) of tropical adaptation was not important in terms of growth, but source (BFBN vs. BOBN and HEBN vs. BOBN) of tropical adaptation did not favor those calves with Africander breeding. However, for calves with AN dams, the use of Bonsmara sires (BOAN) imparted a growth advantage relative to the HE sires (HEAN). It is important that tropical adaptation, in terms of Brahman and Africander breeding, be imparted to the calf directly but more importantly, that Brahman breeding is imparted maternally.

Growth and reproductive performances in F1 crossbred heifers from Hereford, Braford, and Bonsmara sires and Angus and Brangus dams12

The objective of this research was to evaluate source and extent of tropical adaptation affecting heifer BW and productivity traits. The F1 heifers with Brangus (BN) dams were sired by Braford (BFBN; n = 44), Hereford (HEBN; n = 29), and Bonsmara (BOBN; n = 58) sires. The F1 heifers with Angus (AN) dams were sired by Hereford (HEAN; n = 32) and Bonsmara (BOAN, n = 40) sires. The F1 heifer breeds did not differ (P > 0.22) for pregnancy and weaning rate. Calving rate was similar (P > 0.26) among F1 heifer breed types, but there was a tendency (P 0.17) for BFBN and HEBN F1 cows and for HEBN and BOBN F1 cows but was greater (P 0.25) among BFBN, HEBN, and BOBN F1 cows but was greater (P 0.35) of any particular breed type based on calf:dam weaning BW ratios.