Efficiency of Feed Use in Beef Cattle

Feed efficiency is an important trait in the future sustainability of pig production, however, the mechanisms involved are not fully elucidated. The objective of this study was to examine nutrient digestibility, organ weights, select bacterial populations, volatile fatty acids (VFA's), enzyme and intestinal nutrient transporter gene expression in a pig population divergent in feed efficiency. Male pigs (n = 75; initial BW 22.4 kg SEM 2.03 kg) were fed a standard finishing diet for 43 days before slaughter to evaluate feed intake and growth for the purpose of calculating residual feed intake (RFI). Phenotypic RFI was calculated as the residuals from a regression model regressing average daily feed intake (ADFI) on average daily gain (ADG) and midtest BW 0.60 (MBW). On day 115, 16 pigs (85 kg SEM 2.8 kg), designated as high RFI (HRFI) and low RFI (LRFI) were slaughtered and digesta was collected to calculate the coefficient of apparent ileal digestibility (CAID), total tract nutrient digestibility (CATTD), microbial populations and VFA's. Intestinal tissue was collected to examine intestinal nutrient transporter and enzyme gene expression. The LRFI pigs had lower ADFI ( P < 0.001), improved feed conversion ratio ( P < 0.001) and an improved RFI value relative to HRFI pigs (0.19 v. −0.14 SEM 0.08; P < 0.001). The LRFI pigs had an increased CAID of gross energy (GE), and an improved CATTD of GE, nitrogen and dry matter compared to HRFI pigs ( P < 0.05). The LRFI pigs had higher relative gene expression levels of fatty acid binding transporter 2 ( FABP2) ( P < 0.01), the sodium/glucose co-transporter 1 ( SGLT1) ( P < 0.05), the glucose transporter GLUT2 ( P < 0.10), and the enzyme sucrase-isomaltase (SI) ( P < 0.05) in the jejunum. The LRFI pigs had increased populations of lactobacillus spp. in the caecum compared with HRFI pigs. In colonic digesta HRFI pigs had increased acetic acid concentrations ( P < 0.05). Differences in nutrient digestibility, intestinal microbial populations and gene expression levels of intestinal nutrient transporters could contribute to the biological processes responsible for feed efficiency in pigs.

Section: Introductionmentioning

confidence: 99%

Pigs that are divergent in feed efficiency, differ in intestinal enzyme and nutrient transporter gene expression, nutrient digestibility and microbial activity

Vigors

Sweeney

O’Shea

et al. 2016

“…Residual feed intake (RFI) is an alternative measure for characterising feed efficiency (Koch et al, 1963) and is equivalent to a restricted selection index for decreased feed intake, holding other energy deposition constant (Kennedy et al,1993;Van der Werf et al, 2004). However, RFI prediction still requires the records of individual feed intake, thereby limiting its application in the breeding programme of the dairy industry (Connor, 2014).…”

Section: Introductionmentioning

confidence: 99%

Genetic and phenotypic correlations among feed efficiency, production and selected conformation traits in dairy cows

Manafiazar

Goonewardene

Miglior

et al. 2016

The difficulties and costs of measuring individual feed intake in dairy cattle are the primary factors limiting the genetic study of feed intake and utilisation, and hence the potential of their subsequent industry-wide applications. However, indirect selection based on heritable, easily measurable, and genetically correlated traits, such as conformation traits, may be an alternative approach to improve feed efficiency. The aim of this study was to estimate genetic and phenotypic correlations among feed intake, production, and feed efficiency traits (particularly residual feed intake; RFI) with routinely recorded conformation traits. A total of 496 repeated records from 260 Holstein dairy cows in different lactations (260, 159 and 77 from first, second and third lactation, respectively) were considered in this study. Individual daily feed intake and monthly BW and body condition scores of these animals were recorded from 5 to 305 days in milk within each lactation from June 2007 to July 2013. Milk yield and composition data of all animals within each lactation were retrieved, and the first lactation conformation traits for primiparous animals were extracted from databases. Individual RFI over 301 days was estimated using linear regression of total 301 days actual energy intake on a total of 301 days estimated traits of metabolic BW, milk production energy requirement, and empty BW change. Pair-wise bivariate animal models were used to estimate genetic and phenotypic parameters among the studied traits. Estimated heritabilities of total intake and production traits ranged from 0.27 ± 0.07 for lactation actual energy intake to 0.45 ± 0.08 for average body condition score over 301 days of the lactation period. RFI showed a moderate heritability estimate (0.20 ± 0.03) and non-significant phenotypic and genetic correlations with lactation 3.5 % fat-corrected milk and average BW over lactation. Among the conformation traits, dairy strength, stature, rear attachment width, chest width and pin width had significant (P < 0.05) moderate to strong genetic correlations with RFI. Combinations of these conformation traits could be used as RFI indicators in the dairy genetic improvement programmes to increase the accuracy of the genetic evaluation of feed intake and utilisation included in the index.

“…Selection for residual feed intake (RFI), defined as the difference between observed feed intake and feed consumption predicted for maintenance and production requirements, was first proposed to improve feed efficiency in beef cattle (Koch et al, 1963). In pigs, some studies have focused on relationships between RFI and appetite and feeding activity (De Haer et al, 1993;Rauw et al, 2006;Gilbert et al, 2009;Young et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Divergent selection for residual feed intake in group-housed growing pigs: characteristics of physical and behavioural activity according to line and sex

Meunier-Salaün

Guérin

Billon³

et al. 2014

The aim of the study was to assess the impact of selection for residual feed intake (RFI) on the behavioural activity of lines divergently selected for RFI during seven generations. In all, six successive batches from the seventh generation of selection were raised in collective pens equipped with a single-place electronic feeder (SEF) from 10 weeks of age to 100 kg BW. Each batch included four groups of 12 pigs: high RFI (RFI + ) castrated males, RFI + females, low RFI (RFI − ) castrated males, RFI − females. At 17 weeks of age, health criteria were evaluated using a gradient scale for increased severity of lameness, body lesions, bursae and tail biting. Individual behavioural activities were recorded by 24-h video tape on the day after health evaluation. The investigative motivation towards unfamiliar objects was quantified at 18 weeks of age. The daily individual feeding patterns were computed from SEF records during the 4 weeks surrounding 12, 17 and 22 weeks of age. All pigs spent significantly most of their time lying in diurnal (80% of total scan) and nocturnal (>89%) periods. The RFI − pigs showed a lower proportion of health problems ( P < 0.01) than RFI + pigs. The RFI − pigs used the SEF less than the RFI + pigs, in diurnal (5.3% v. 6.4% of video scans, P < 0.05) and nocturnal periods (3.6% v. 4.5% of video scans, P < 0.05). This was confirmed by a significantly lower daily number and duration of visits to the SEF computed from the SEF data. The feeding activity measured from the video recording was significantly correlated ( R > 0.34; P < 0.05) with feeding patterns computed from the SEF. The RFI − pigs spent less time standing over the 24-h period (9.7% v. 12.2% of scans, i.e. 35 min/day, P < 0.05). In terms of energy costs, this amounted to 14% of the line difference in terms of daily metabolizable energy intake. The castrated males used the SEF more than females, especially at night (4.7% v. 3.4% of total scans, P < 0.05), whereas females displayed greater investigation of their environment (7.7 ± 0.3% v. 6.6 ± 0.2% of total scans, P < 0.05) and the novel objects (10.7% v. 4.9% of total scans, P < 0.05). In conclusion, the lower physical activity associated with reduced energy expenditure in RFI − pigs compared with RFI + pigs contributed significantly to their improved efficiency and was not related to worsened health scores.Keywords: pig, genetic, residual feed intake, physical activity, behaviour ImplicationsSelection for reduced residual feed intake (RFI) to improve the feed efficiency of pigs diminishes daily feed intake. In this study, physical activity is also reduced, and the energy saving associated with the lower physical activity in the low RFI pigs explains 14% of the feed intake difference between two lines divergently selected for RFI, significantly contributing to the better feed efficiency of the low RFI pigs. This highlights the potential of phenotyping physical activity in pigs to better quantify energy expenditure, together with the impact of improved efficiency on animal behavi...