scholarly journals PSV-18 The role of leptin in feed efficiency and behavior attributes of commercial beef heifers

2020 ◽  
Vol 98 (Supplement_3) ◽  
pp. 162-162
Author(s):  
Nayan Bhowmik ◽  
Kris A Ringwall ◽  
Carl R Dahlen ◽  
Kendall C Swanson ◽  
Jeffrey A Clapper ◽  
...  
Keyword(s):  
Feeding Behavior ◽  
Breeding Season ◽  
Feed Intake ◽  
Feed Efficiency ◽  
Repeated Measures ◽  
Fixed Effects ◽  
Beef Heifers ◽  
Frame Size ◽  
And Behavior ◽  
Plasma Leptin

Abstract Leptin is a 16-kDa-peptide hormone product of the leptin gene (LEP) that is predominantly synthesized by adipose tissues and has known involvement in regulation of feed intake, energy expenditure, reproduction, and immune functions. The objective was to determine the association of leptin genotype (LEP c.73C >T), leptin diplotype (LEPD) and plasma leptin hormone (LEPH) concentration with growth, feed intake, feed efficiency, and behavior characteristics in developing beef heifers. A total of 336 commercial beef heifers were genotyped for the LEP c.73C >T marker. Four single nucleotide polymorphism markers including LEP c.73C >T, ARS-BFGL-NGS-59298 (intron 1), BovineHD0400026029 (upstream) and BovineHD0400026063 (downstream) of LEP were considered for haplotype analysis. Eleven LEPD were identified for this study using parsimony-based analyses. Circulating levels of LEPH were measured on 333 heifers prior to their first breeding season and used to assign low or high concentration group based on population median. Data were analyzed using the mixed procedure of SAS for repeated measures, fixed effects of ancestral breed group (n = 4), dam age category (n = 4), frame size group (n = 4), project cycle nested within birth year (n = 6), week of feed trial × year, LEP (n = 3) or LEPD (n = 11) or LEPH (n = 2), as well as week × LEPH (only for LEPH). There were no significant differences between LEP genotypes (P ≥ 0.11) or LEPD (P ≥ 0.33) for any of the studied traits. Heifers with low LEPH ate fewer meals per day (P = 0.02) and had more DMI per meal (P = 0.04) compared to those with high plasma leptin. Further research is needed to better understand plasma LEPH concentration and its role in feeding behavior attributes. However, circulatory LEPH before the breeding season may serve as a predictor for feeding behavior.

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 < 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 < 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 < 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 < 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.

scholarly journals 43 Feed efficiency and behavior are associated with gut microbiome in three breeds of pigs

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 24-24
Author(s):  
Francesco Tiezzi ◽  
Matteo Bergamaschi ◽  
Jeremy Howard ◽  
Christian Maltecca
Keyword(s):  
Body Weight ◽  
Feeding Behavior ◽  
Feed Intake ◽  
Gut Microbiome ◽  
Feed Efficiency ◽  
Negative Impact ◽  
Positive Impact ◽  
Occupation Time ◽  
Large White ◽  
And Behavior

Abstract Feed efficiency and behavior are important traits in the pork industry for economic, welfare, and environmental aspects. The gut microbiota plays an important role in nutrient digestibility and it is likely to influence these traits. The aim of this study was to characterize the feed efficiency, feeding behavior and gut microbiome relationships of pigs belonging to three different breeds. Individual body weight, feed intake and rate of Duroc (n = 222), Landrace (n = 244), and Large White (n = 221) pigs were recorded. Rectal fecal samples were collected from each animal at three time points (T1, start of trial; T2, mid-trial; T3, end of trial) and used for microbiome 16S rRNA gene sequencing. Individual feed intake and body weight were edited to obtain average daily gain (ADG), average daily feed intake (ADFI), feed conversion ratio (FCR), average daily feeding rate (ADFR), average feed intake per visit (AFIV), average daily number of visits to feeder (ANVD), average daily occupation time (AOTD), average occupation time per visit (AOTV). The impact of gut microbiome on the traits studied was present and seemed to depend on the breed and the time point of recording. At T1, Oscillibacter and Phascolarctobacterium had negative impact on ANVD and ADFI in Duroc, Ruminococcus had negative impact on ADFI in Landrace and Parvimonas, Escherichia and Anaerovibrio had negative impact on ADFI and ANVD in Large White. At T2, Lactobacillus showed a positive impact on ADFR in Landrace and on ADFI in Large White. At T3, Ruminococcus, Faecalibacterium and Dorea had a positive impact on ADFI in Duroc, Staphylococcous had positive impact on ADFR in Landrace and Peptoniphilus had negative impact on ADFI in Large White. Gut microbiome may have an heterogenous impact on the regulation of feeding behavior and feed efficiency depending on the host genotype.

Genetic parameters and breed differences for feed efficiency, growth, and body composition traits of young beef bulls

2004 ◽  
Vol 84 (2) ◽  
pp. 177-185 ◽  
Author(s):  
F. S. Schenkel ◽  
S. P. Miller ◽  
J. W. Wilton
Keyword(s):  
Body Composition ◽  
Genetic Correlation ◽  
Feed Intake ◽  
Feed Efficiency ◽  
Fixed Effects ◽  
Residual Feed Intake ◽  
Backfat Thickness ◽  
Daily Weight Gain ◽  
Feed Conversion ◽  
Beef Bulls

Genetic associations between feed efficiency, growth, and live ultrasound measured body composition traits were studied in purebred beef bulls of six breeds in Ontario bull test stations from 1991 to 2000. Feed traits included average daily feed intake (FI), feed conversion ratio (FCR), and residual feed intake [feed intake adjusted for production alone (RFIp) or production and backfat thickness (RFIb)]. Growth traits were average daily weight gain (ADG), mid-test metabolic weight (MW), hip height (HH), and scrotal circumference (SC). Body composition traits included ultrasound backfat thickness (BF), longissimus muscle area (LMA), and predicted percentage of intramuscular fat (IFAT). Bulls were measured every 28 d for weight and individual feed intake, and at the end of test for ultrasound body composition traits. Number of records per trait ranged from 2284 (FI) to 13 319 (ADG). Fixed effects of test group, breed and end of test age (within breed), and random effects of animal and herd of origin were modeled using REML bivariate analyses for all traits. Heritability estimates were moderate for all traits (0.30 to 0.55), except for IFAT (0.14). The genetic correlation between RFIp and RFIb was high (0.99) within breeds, but breeds ranked differently with respect to RFIp and RFIb. Genetic correlations of RFIb with ADG and backfat thickness were essentially zero, which indicate that selection on residual feed intake could be implemented to reduce feed intake and improve feed conversion without compromising growth or changing levels of subcutaneous fat. Key words: Central test, genetic correlation, heritability, residual feed intake

PSVI-20 Extent of genetic variation in feeding behavior and genetic associations with performance and feed efficiency in crossbred growing cattle

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 233-234
Author(s):  
David N Kelly ◽  
Roy D Sleator ◽  
Craig P Murphy ◽  
Stephen B Conroy ◽  
Donagh P Berry
Keyword(s):  
Genetic Variation ◽  
Feeding Behavior ◽  
Energy Intake ◽  
Feed Efficiency ◽  
Fixed Effects ◽  
Feeding Rate ◽  
Feeding Time ◽  
Genetic Associations ◽  
Event Duration ◽  
Growing Cattle

Abstract To the best of our knowledge, the genetic variability in feeding behavior, as well as relationships with performance and feed efficiency, has not been investigated in a cattle population of greater than 1,500 animals. Our objective was to quantify the genetic parameters of several feeding behavior traits, and their genetic associations with both performance and feed efficiency traits, in crossbred growing cattle. Feed intake and live-weight data were available on 6,088 bulls, steers and heifers; of these, 4,672 cattle had backfat and muscle ultrasound data, and 1,548 steers and heifers had feeding behavior data. Genetic (co)variance parameters were estimated using animal linear mixed models; fixed effects included test group, heterosis, recombination loss, dam parity, age in months at the end of test, and the two-way interaction between age in months at the end of test and sex. Heritability was estimated to be 0.51 (0.097), 0.61 (0.100), 0.44 (0.093), 0.48 (0.094), and 0.47 (0.095) for feed events per day, feeding time per day, feeding rate, feed event duration, and energy intake per feed event, respectively. Coefficients of genetic variation ranged from 0.11 (feeding time per day) to 0.22 (feed event duration). Genetically heavier cattle with a higher energy intake per day, and faster growth rate, had a faster feeding rate and a greater energy intake per feed event. Genetic correlations between feeding behavior and feed efficiency were generally not different from zero, however, there was a genetic correlation of 0.36 (0.11) between feeding time per day and residual energy intake. Significant heritable and exploitable genetic variation exists in several feeding behavior traits in crossbred growing cattle which are also correlated with several performance traits. As some feeding behavior traits may be relatively less resource intensive to measure, they could be useful as predictor traits in beef cattle genetic evaluations.

scholarly journals PSVIII-38 Late-Breaking Abstract: Estimating genetic parameters of feed efficiency traits in American mink

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 347-347
Author(s):  
Pourya Davoudi ◽  
Duy Ngoc Do ◽  
Guoyu Hu ◽  
Siavash Salek Ardestani ◽  
Younes Miar
Keyword(s):  
Body Weight ◽  
Genetic Correlation ◽  
Feed Intake ◽  
Feed Efficiency ◽  
Fixed Effects ◽  
Genetic Parameters ◽  
American Mink ◽  
Genetic Correlations ◽  
Final Body Weight ◽  
Selection For

Abstract Feed cost is the major input cost in the mink industry and thus improvement of feed efficiency through selection for high feed efficient mink is necessary for the mink farmers. The objective of this study was to estimate the heritability, phenotypic and genetic correlations for different feed efficiency measures, including final body weight (FBW), daily feed intake (DFI), average daily gain (ADG), feed conversion ratio (FCR) and residual feed intake (RFI). For this purpose, 1,088 American mink from the Canadian Center for Fur Animal Research at Dalhousie Faculty of Agriculture were recorded for daily feed intake and body weight from August 1 to November 14 in 2018 and 2019. The univariate models were used to test the significance of sex, birth year and color as fixed effects, and dam as a random effect. Genetic parameters were estimated via bivariate models using ASReml-R version 4. Estimates of heritabilities (±SE) were 0.41±0.10, 0.37±0.11, 0.33±0.14, 0.24±0.09 and 0.22±0.09 for FBW, DFI, ADG, FCR and RFI, respectively. The genetic correlation (±SE) was moderate to high between FCR and RFI (0.68±0.15) and between FCR and ADG (-0.86±0.06). In addition, RFI had low non-significant (P > 0.05) genetic correlations with ADG (0.04 ± 0.26) and BW (0.16 ± 0.24) but significant (P < 0.05) high genetic correlation with DFI (0.74 ± 0.11) indicating that selection for lower RFI will reduce feed intake without adverse effects on the animal size and growth rate. The results suggested that RFI can be implemented in genetic/genomic selection programs to reduce feed intake in the mink production system.

scholarly journals 195 Association of insulin, glucagon, and glucagon-like peptide-1 with production traits of growing and finishing beef heifers fed forage- and concentrate-based rations

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 26-27
Author(s):  
Andrew P Foote ◽  
Harvey C Freetly
Keyword(s):  
Feed Intake ◽  
Fixed Effects ◽  
Mixed Model ◽  
Body Weight Gain ◽  
Production Traits ◽  
Beef Heifers ◽  
Mineral Supplement ◽  
Negatively Associated ◽  
Alfalfa Hay ◽  
Glucagon Like Peptide

Abstract The objective of this study was to determine the association of insulin, glucagon, and glucagon-like peptide (GLP-1) with production traits of growing and finishing beef heifers fed a forage- (FOR) and concentrate-based (CONC) ration. This experiment was conducted over 2 years. Shortly after weaning, heifers (n = 74 and 62, for year 1 and 2, respectively) were placed on a ration containing (DM basis) 69.8% corn silage, 30% alfalfa hay, and 0.2% salt. Feed intake was measured for 84 d using Calan gates and BW were measured at 7-time points to calculate ADG using a quadratic regression of BW on time. Cattle were then transitioned to a concentrate-based finishing ration containing (DM basis) 67.8% dry-rolled corn, 20% wet distillers grains with solubles, 8% alfalfa hay, and 4.2% vitamin/mineral supplement. Blood samples were collected on day 42 of each period. Data were analyzed as a mixed model with fixed effects of sire breed, period, and the random variable of year. Hormone concentration was included as an interaction with period to determine the association of the hormones with production traits. Dry matter intake (DMI), average daily body weight gain (ADG), gain:feed (G:F), and all three hormones were greater in the CONC period (P < 0.01). Insulin was negatively associated with DMI only during the CONC period (P = 0.04) and positively associated with G:F (P = 0.01). GLP-1 was positively associated with CONC DMI (P < 0.01), FOR ADG (P < 0.01), and positively associated with FOR G:F and negatively associated with CONC G:F (P < 0.01). Glucagon was positively associated with residual feed intake (P = 0.04). While these data do not infer causality, they do indicate that more in-depth understanding of the role of gut peptide and insulin signaling in feed efficiency needs to be evaluated.

scholarly journals 165 Impact of mycotoxin contamination of feed on growth performance and blood metabolites of growing pigs

2019 ◽  
Vol 97 (Supplement_2) ◽  
pp. 93-93
Author(s):  
Jesus A Acosta ◽  
Gwendolyn M Jones ◽  
John F Patience
Keyword(s):  
Growth Performance ◽  
Feed Intake ◽  
Repeated Measures ◽  
Fixed Effects ◽  
Control Diet ◽  
Blood Parameters ◽  
Growing Pigs ◽  
Blood Metabolites ◽  
Mycotoxin Contamination ◽  
The Impact

Abstract The objective of this study was to evaluate the impact of deoxynivalenol (DON), derived from contaminated corn, on growth performance and blood metabolites. A total of 32 growing pigs (initial BW 73.1 ± 1.2 kg; L337 × Camborough, PIC, Hendersonville, TN) were randomly allotted in individual pens to 1 of 2 treatments: a non-contaminated control diet (CTL) and a diet containing 1.8 mg DON/kg (CTL+DON). Upon analysis, CTL+DON also contained 1.9 mg zearalenone/kg and 1.0 mg total fumonisins/kg. On d 1, blood samples were obtained at 60, 120 and 240 min following resumed access to feed. Pigs had ad libitum access to feed thereafter and for 28 d in total. Data were analyzed using the MIXED procedure of SAS with initial BW, sex and treatment as fixed effects, and blood parameters the repeated measures. Compared with CTL, pigs fed CTL+DON had decreased final BW (102.9 vs 87.5 kg; P < 0.001), ADG (1.06 vs 0.51 kg; P < 0.001) and ADFI (2.97 vs 1.54 kg; P < 0.001). Mycotoxins did not affect G:F (0.35 vs 0.32; P = 0.234 for CTL and CTL+DON, respectively). Compared to CTL, pigs fed CTL+DON had increased levels of blood cholecystokinin, a hormone involved in satiety and digestion (32.1 vs 43.3 pg/mL; P = 0.048), increased ghrelin, a hormone that stimulates appetite and promotes fat deposition (345 vs 654 pg/mL; P = 0.011), a tendency for decreased blood urea nitrogen (19.6 vs 17.1 mg/dL; P = 0.076), and increased creatine kinase (2,826 vs 4,920 IU/L; P = 0.027). No treatment differences were observed for circulating creatinine, glucose, albumin, or alkaline phosphatase. In conclusion, mycotoxin contamination substantially impaired feed intake and growth. Pigs offered mycotoxin-contaminated feed had altered blood parameters related to appetite regulation and nutrient metabolism. However, it was not possible to determine if these differences were due to the mycotoxin contamination or to reduced feed intake.

scholarly journals Immune and metabolic responses of beef heifers supplemented with Saccharomyces cerevisiae to a combined viral-bacterial respiratory disease challenge

2018 ◽  
Vol 3 (1) ◽  
pp. 135-148 ◽  
Author(s):  
Alyssa B Word ◽  
P Rand Broadway ◽  
Nicole C Burdick Sanchez ◽  
Shelby L Roberts ◽  
John T Richeson ◽  
...  
Keyword(s):  
Respiratory Disease ◽  
Repeated Measures ◽  
Fixed Effects ◽  
Treatment Time ◽  
Metabolic Responses ◽  
Total Leukocyte Count ◽  
Average Dose ◽  
Recording Device ◽  
Beef Heifers ◽  
Vaginal Temperature

Abstract Two treatments were evaluated in heifers to determine the effects of a yeast supplement on immune and metabolic responses to a combined (tandem viral-bacterial) respiratory disease challenge. Thirty-two beef heifers (325 ± 20.1 kg BW) were selected from a larger population previously assigned to one of two treatments: Control (CON), receiving no yeast supplement in the diet, or yeast (YST), CON diet plus a combination live yeast (2.5 g·heifer−1·d−1) and yeast cell wall (2.5 g·heifer−1·d−1) supplement (Phileo Lesaffre Animal Care, Milwaukee, WI). Heifers were maintained on treatments for 31 d prior to the challenge. On day −3 all heifers were fitted with an indwelling vaginal temperature recording device, received an intranasal challenge with 2 × 108 plaque-forming units of bovine herpesvirus-1 (BHV-1), and placed in outdoor pens. On day 0, all heifers were fitted with an indwelling jugular catheter, challenged intratracheally with an average dose of 3.0 × 107 colony-forming units (cfu) of Mannheimia haemolytica in 100 mL media, and were transferred into individual stanchions in an enclosed, environmentally controlled barn. Whole blood samples were collected at −72 h and at 0, 2, 4, 6, 8, 12, 24, 36, 48, 60, and 72 h (hematology) and at 0, 1, 2, 3, 4, 5, 6, 7, 8, 12, 24, 36, 48, 60, and 72 h (serum isolation) relative to M. haemolytica challenge (0 h). Data were analyzed using the MIXED procedure of SAS specific for repeated measures with fixed effects of treatment, time, and the treatment × time interaction. Vaginal temperature and cortisol concentrations were similar between treatments (P ≥ 0.39). Although total leukocyte count following BHV-1 challenge was similar between treatments (P = 0.21), there was a tendency (P = 0.07) for CON heifers to have greater neutrophil counts than YST heifers. Serum haptoglobin concentration was similar between treatments (P = 0.13). Heifers in the YST treatment had similar serum glucose concentrations (P = 0.25) and decreased serum concentrations of urea nitrogen compared to CON (P = 0.03). Dietary treatment did not affect serum nonesterified fatty acid concentrations (P = 0.37). Nasal lesion score severity (0–4) tended (P = 0.07) to be decreased in YST compared to CON (2.5 vs. 3.19 ± 0.26), while water intake tended to be increased in YST (P = 0.06). Feeding a yeast supplement had little effect on the acute-phase response but improved metabolic outcomes in heifers during a respiratory disease challenge.

PSVIII-14 Effect of Certillus, a direct-fed microbial, on milk yield, milk components, and feed intake in primi- and multiparous lactating Holstein cows

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 426-427
Author(s):  
Excel Rio S Maylem ◽  
Martina Vargiu ◽  
Caleb Melton ◽  
Jesse Thompson ◽  
John O’Neill ◽  
...  
Keyword(s):  
Milk Production ◽  
Feed Intake ◽  
Feed Efficiency ◽  
Repeated Measures ◽  
Milk Fat ◽  
Holstein Cows ◽  
Fat Percentage ◽  
Milk Components ◽  
Daily Milk Production ◽  
Daily Milk

Abstract To determine the effect of Certillus on milk production, milk components and feed efficiency, primiparous (n = 13) and multiparous (n = 12) Holstein cows were assigned to one of two dietary groups starting from 8 to 120 days of lactation. The controls (n = 13) received regular TMR ration, and treated cows (n =12) received control TMR plus 2 x 109 cfu/head of Certillus (Church & Dwight Co., Inc., Waukesha, WI). Cows were housed in an open-air free-stall barn with 16 Insentec electronic feeders (8 feeders/group) to record daily feed events and intake (DMI). Cows were provided with ad libitum TMR fed twice daily and were milked twice daily. Milk samples were taken weekly during successive a.m./p.m. milkings and analyzed for percentage milk fat, protein, lactose, and milk urea nitrogen (MUN). Data were analyzed using a repeated-measures 2 x 2 factorial ANOVA. Daily milk production (4%FCM) was influenced (P &lt; 0.05) by treatment x parity, week and parity, averaging 11% greater (P &lt; 0.05) in Certillus-fed than control cows. Milk fat percentage increased (P &lt; 0.005) from 4.02 to 4.41 + 0.09% with Certillus feeding. Milk lactose was influenced (P &lt; 0.05) by week and treatment x parity. Milk protein was affected by week (P &lt; 0.001) only. Certillus decreased (P &lt; 0.05) MUN levels such that MUN was 1.0 mg/dL greater (P &lt; 0.001) in Certillus-fed than control cows. Feed intake was reduced by 9% (P &lt; 0.01) and feed efficiency (kg 4%FCM/kg DMI) was improved by 14% (P &lt; 0.05) in Certillus-fed versus control cows. We conclude that Certillus may hold potential as an effective direct-fed microbial to increase feed efficiency and milk production.

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).

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