Endocrine and hematological responses of beef heifers divergently ranked for residual feed intake following a bovine corticotropin-releasing hormone challenge

2016 ◽  
Vol 94 (4) ◽  
pp. 1703-1711 ◽  
Author(s):  
A. K. Kelly ◽  
B. Earley ◽  
M. McGee ◽  
A. G. Fahey ◽  
D. A. Kenny
Keyword(s):  
Feed Intake ◽  
Residual Feed Intake ◽  
Corticotropin Releasing Hormone ◽  
Beef Heifers ◽  
Releasing Hormone

scholarly journals Feed efficiency and meat quality of crossbred beef heifers classified according to residual feed intake

2015 ◽  
Vol 16 (3) ◽  
pp. 632-642 ◽  
Author(s):  
Simone Frotas dos REIS ◽  
Daiane Aparecida FAUSTO ◽  
Sergio Raposo de MEDEIROS ◽  
Pedro Veiga Rodrigues PAULINO ◽  
Sebastião de Campos VALADARES FILHO ◽  
...  
Keyword(s):  
Meat Quality ◽  
Feed Intake ◽  
Feed Efficiency ◽  
Residual Feed Intake ◽  
Beef Heifers ◽  
System A ◽  
Fat Thickness ◽  
Ad Libitum ◽  
Sorghum Silage

AbstractThis study aimed to evaluate feed efficiency and meat quality of 31 three-crossbred beef heifers during 84 days in a feedlot system. A 60:40 concentrate and sorghum silage ration on DM basis (ME = 2.73Mcal/kg of DM, CP = 11.90% DM) was fed ad libitum. Based on residual feed intake (RFI) calculations, the heifers were ranked in three groups of feed efficiency: High RFI (average mean = 0.776; n = 9), medium RFI (average mean = -0.010; n = 11), and low RFI (average mean = - 0.624; n = 11). High RFI heifers consumed 4.56% more DM per day than low RFI heifers (P <0.05). The ADG did not differ (P> 0.05) among RFI groups (1.40kg/day). No differences (P>0.05) were detected for digestibility of the nutrients: DM (64.00%), CP (60.01%), crude fat (72.90%), NDF (54.80%) and non-fibrous carbohydrate (NFC) (78.91%). There were no differences between low and high RFI groups for slaughter weight (475.00 vs. 479.55kg), hot carcass weight (259.09 vs. 261.44kg), Longissimus dorsi (LD) area (69.02 vs. 68.11 cm2), back-fat thickness (5.74 vs. 6.26 cm), shear force (5.45 vs. 5.19kg), sensorial traits of LD muscle, LD color (intensities L=40.47 a*=24.74 and b*=16.13) or commercial cuts yield. Low RFI heifers presented similar meat quality and carcass traits as high RFI heifers, however low RFI heifers consumed less DM (kg/d).

Methane and carbon dioxide emissions and grazed forage intake from pregnant beef heifers previously classified for residual feed intake under drylot conditions

2020 ◽  
Author(s):  
Ghader Manafiazar ◽  
Thomas K. Flesch ◽  
Vern S. Baron ◽  
Lisa McKeown ◽  
Brittany Byron ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Co2 Emissions ◽  
Feed Intake ◽  
Carbon Dioxide Emissions ◽  
Residual Feed Intake ◽  
Beef Heifers ◽  
Once Daily ◽  
Forage Intake ◽  
Carbon Dioxide Co2 ◽  
Fecal Sampling

Objectives were to quantify the effect of post-weaning residual feed intake (RFI) on subsequent grazed forage intake, methane (CH4) and carbon dioxide (CO2) emissions. Beef heifers classified for RFI adjusted for off-test backfat (RFIfat; 55 high and 56 low) at nine mo of age were monitored seven mo later for CH4 and CO2 emissions using the GreenFeed Emissions Monitoring system. Fifty-six of these heifers were also monitored as high and low RFIfat groups using Open Path Fourier-Transform Infrared Spectroscopy (OP-FTIR). Heifers were dosed with one kg of C32 labelled pellets once daily for 15 d, with twice daily fecal sampling the last eight d to determine individual grazed forage intake using the n-alkane method. Low RFIfat pregnant heifers consumed less forage (10.25 vs. 10.81 kg DM d-1; P < 0.001), and emitted less daily CH4 (238.7 vs. 250.7 g d-1; P = 0.009) and CO2 (7578 vs. 8041 g d-1; P < 0.001) compared with high RFIfat animals. Results from the OP-FTIR further confirmed that low RFIfat heifers emitted 6.3% less (g d-1; P = 0.006) CH4 compared to their high RFIfat cohorts. Thus, selection for low RFIfat will decrease daily CH4 and CO2 emissions from beef cattle.

Methane and carbon dioxide emissions from yearling beef heifers and mature cows classified for residual feed intake under drylot conditions

2020 ◽  
Vol 100 (3) ◽  
pp. 522-535 ◽  
Author(s):  
G. Manafiazar ◽  
V.S. Baron ◽  
L. McKeown ◽  
H. Block ◽  
K. Ominski ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Feed Intake ◽  
Carbon Dioxide Emissions ◽  
Body Weight Gain ◽  
Residual Feed Intake ◽  
Individual Performance ◽  
Feed Consumption ◽  
Beef Heifers ◽  
Air Temperatures ◽  
Rapid City

This study quantified methane (CH4) and carbon dioxide (CO2) production from beef heifers and cows classified for residual feed intake adjusted for off-test backfat thickness (RFIfat) and reared in drylot during cold winter temperatures. Individual performance, daily feed intake, and RFIfat were obtained for 1068 crossbred and purebred yearling heifers (eight trials) as well as 176 crossbred mature cows (six trials) during the winters of 2015–2017 at two locations. A portion of these heifers (147 high RFIfat; 167 low RFIfat) and cows (69 high RFIfat; 70 low RFIfat) was monitored for enteric CH4 and CO2 emissions using the GreenFeed Emissions Monitoring (GEM) system (C-Lock Inc., Rapid City, SD, USA). Low RFIfat cattle consumed less feed [heifers, 7.80 vs. 8.48 kg dry matter (DM) d−1; cows, 11.64 vs. 13.16 kg DM d−1] and emitted less daily CH4 (2.5% for heifers; 3.7% for cows) and CO2 (1.4% for heifers; 3.4% for cows) compared with high RFIfat cattle. However, low RFIfat heifers and cows had higher CH4 (6.2% for heifers; 9.9% for cows) and CO2 yield (7.3% for heifers; 9.8% for cows) per kilogram DM intake compared with their high RFIfat pen mates. The GEM system performed at air temperatures between +20 and −30 °C. Feed intake of heifers and mature cows was differently affected by ambient temperature reduction between +20 and −15 °C and similarly increased their feed intake at temperatures below −15 °C. In conclusion, low RFIfat animals emit less daily enteric CH4 and CO2, due mainly to lower feed consumption at equal body weight, gain, and fatness.

Relationships among performance, residual feed intake, and temperament assessed in growing beef heifers and subsequently as 3-year-old, lactating beef cows1

2013 ◽  
Vol 91 (5) ◽  
pp. 2254-2263 ◽  
Author(s):  
T. E. Black ◽  
K. M. Bischoff ◽  
V. R. G. Mercadante ◽  
G. H. L. Marquezini ◽  
N. DiLorenzo ◽  
...  
Keyword(s):  
Feed Intake ◽  
Residual Feed Intake ◽  
Beef Heifers

490 Estimating enteric methane emission from beef heifers with different residual feed intake using greenfeed and respiration chambers

2017 ◽  
Vol 95 (suppl_4) ◽  
pp. 239-240
Author(s):  
A. W. Alemu ◽  
D. Vyas ◽  
G. Manafiazar ◽  
J. A. Basarab ◽  
K. A. Beauchemin
Keyword(s):  
Methane Emission ◽  
Feed Intake ◽  
Residual Feed Intake ◽  
Beef Heifers ◽  
Enteric Methane

Effect of post-weaning residual feed intake classification on grazed grass intake and performance in pregnant beef heifers

2015 ◽  
Vol 95 (3) ◽  
pp. 369-381 ◽  
Author(s):  
G. Manafiazar ◽  
J. A. Basarab ◽  
V. S. Baron ◽  
L. McKeown ◽  
R. R. Doce ◽  
...  
Keyword(s):  
Body Weight ◽  
Feed Intake ◽  
Average Daily Gain ◽  
Residual Feed Intake ◽  
Backfat Thickness ◽  
Automated System ◽  
Adaptation Period ◽  
Beef Heifers ◽  
Fat Thickness ◽  
And Performance

Manafiazar, G., Basarab, J. A., Baron, V. S., McKeown, L., Doce, R. R., Swift, M., Undi, M., Wittenberg, K. and Ominski, K. 2015. Effect of post-weaning residual feed intake classification on grazed grass intake and performance in pregnant beef heifers. Can. J. Anim. Sci. 95: 369–381. There is limited knowledge of how cattle tested for feed efficiency under drylot conditions perform when they graze on summer pasture. Residual feed intake adjusted for end of test backfat thickness (RFIfat) was determined on 171 beef crossbred heifers under drylot conditions over 2 yr using an automated system. Upon completion of the test, the 10 lowest and 10 highest RFIfat (–0.54±0.17 vs. 0.58±0.15 kg DM d−1) heifers in 2012, and the 14 lowest and 14 highest RFIfat (−0.47±0.16 vs. 0.53±0.19 kg DM d−1) heifers in 2013 were selected and placed on meadow bromegrass pasture to investigate the effect of RFIfat ranking on their grass intake and performance on the pasture. The pasture adaptation period (8 d in 2012 and 19 d in 2013) was followed by a pasture feed intake experiment during which heifers were dosed twice daily (0815 and 1415) with 500 g of C32-labeled feed pellet for 13 d (day 0 to 12) and fecal sampled twice daily (0815 and 1415) from day 8 to 12. Forage DM intake on pasture for each heifer was determined using the double alkane (C31/C32) methodology. High and low RFIfat heifers were similar in body weight (BW), backfat and rump fat thickness, and average daily gain (ADG) during the grazing trial period, except backfat thickness at the end of test period. However, low RFIfat heifers consumed 5.3% less forage when expressed as kg DM d−1 (8.20±0.08 vs. 8.66±0.09, P<0.001) and 5.1% less when expressed as a percentage of body weight (1.86±0.02 vs. 1.96±0.02% of BW, P<0.001) compared with high RFIfat heifers. RFIfat measured under drylot conditions in growing heifers was positively correlated to grazed RFIfat determined in pregnant heifers (rp=0.30, P=0.04). These results suggest that beef heifers classified as low RFIfat during the post-weaning drylot period had lower dry matter intake as heifers in their first pregnancy grazing tame pasture, with no negative impact on their body weight, back-fat thickness, and ADG compared with their high RFIfat herdmates.

scholarly journals Relationships between feed efficiency and puberty in Bos taurus and Bos indicus-influenced replacement beef heifers

2020 ◽  
Vol 98 (10) ◽  
Author(s):  
Luara B Canal ◽  
Pedro L P Fontes ◽  
Carla D Sanford ◽  
Vitor R G Mercadante ◽  
Nicolas DiLorenzo ◽  
...  
Keyword(s):  
Breeding Season ◽  
Feed Intake ◽  
Feed Efficiency ◽  
Bos Taurus ◽  
Average Daily Gain ◽  
Bos Indicus ◽  
Residual Feed Intake ◽  
Feed Ratio ◽  
Beef Heifers ◽  
Efficiency Test

Abstract The objective of this experiment was to investigate the relationship between residual feed intake (RFI) and parameters associated with reproductive efficiency in growing beef heifers. One hundred and seventy-nine replacement beef heifers (Bos taurus and Bos indicus-influenced) were enrolled in a retrospective cohort design. Heifers were assigned to a 70-d feed efficiency test, and results were utilized to retrospectively classify heifers into low (n = 51), medium (n = 66), or high (n = 62) RFI groups based on their individual RFI values. Blood samples were collected weekly throughout the feed efficiency test and breeding season, which were analyzed for plasma concentration of progesterone to determine age at puberty (PUB). By design, residual feed intake differed among RFI groups where high (1.21 ± 0.08 kg/d) had greater (P &lt; 0.01) RFI than medium (0.00 ± 0.08 kg/d) and low RFI groups (–1.49 ± 0.09 kg/d), and medium had greater (P &lt; 0.01) RFI than low RFI heifers. Yet, no differences were observed between breed types for RFI (P = 0.53). Average daily gain (ADG) differed between breed types where Bos taurus heifers had greater ADG (P = 0.02) than B. indicus-influenced heifers. Furthermore, ADG tended (P = 0.08) to differ among RFI groups, where medium RFI heifers tended to have reduced ADG compared with low and high RFI heifers. No differences were determined between breed types for gain-to-feed ratio (G:F; P = 0.20; however, G:F differed among RFI groups and was greater (P &lt; 0.01) in low vs. high, and low vs. medium RFI heifers. The percentage of cycling heifers by the start of the breeding season differed (P = 0.03) by RFI group, where a greater percentage of low RFI heifers were cycling compared with high RFI heifers. A difference was determined on PUB between breed types (P = 0.03), where Bos taurus (393.40 ± 4.64 d) heifers had a reduced PUB compared with B. indicus-influenced (406.90 ± 5.07 d) heifers. In addition, PUB differed by RFI group where low (385.96 ± 6.20 d; P &lt; 0.01) and medium (398.47 ± 5.47 d; P = 0.02) RFI heifers had a reduced PUB compared with High RFI heifers (416.03 ± 5.58 d). In conclusion, more feed efficient heifers attained PUB earlier than less feed efficient heifers. Therefore, selection of heifers for feed efficiency may positively impact reproductive performance of replacement beef heifers.

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