The economic importance of genetically improving feed efficiency has been recognized by cattle producers worldwide. It has the potential to considerably reduce costs, minimize environmental impact, optimize land and resource use efficiency, and improve the overall cattle industry’s profitability. Feed efficiency is a genetically complex trait that can be described as units of product output (e.g., milk yield) per unit of feed input. The main objective of this review paper is to present an overview of the main genetic and physiological mechanisms underlying feed utilization in ruminants and the process towards implementation of genomic selection for feed efficiency in dairy cattle. In summary, feed efficiency can be improved via numerous metabolic pathways and biological mechanisms through genetic selection. Various studies have indicated that feed efficiency is heritable, and genomic selection can be successfully implemented in dairy cattle with a large enough training population. In this context, some organizations have worked collaboratively to do research and develop training populations for successful implementation of joint international genomic evaluations. The integration of “-omics” technologies, further investments in high-throughput phenotyping, and identification of novel indicator traits will also be paramount in maximizing the rates of genetic progress for feed efficiency in dairy cattle worldwide.

This study aimed to clone the cDNA of PepT1, an H⁺-dependent oligopeptide transporter, from kid goats and examine effects of physiological development (suckling, weaning, and post-weaning) of the animal and feeding system (supplemental feeding vs. grazing) on peptide transport capability. A 2395 bp cDNA sequence of pept1 (GenBank: MH308024) was cloned and phylogenetic analysis revealed a high homology and structure similarity with PepT1 of sheep and cattle. The pept1 was expressed throughout the gastrointestinal tract of kid goats immediately after birth and during development. Relative abundance of pept1 decreased in all segments except the middle-jejunum during suckling, whereas its expression in most segments of small intestine increased with age after weaning and remained stable thereafter. Middle-jejunum was the predominant expression site and probably the main peptide absorption site. Supplemental feeding enhanced pept1 expression because it increased protein intake compared with grazing. No feeding system × age interaction was observed in most segments; the expression was age related during suckling and diet related during weaning and post-weaning, indicating that feeding system and age had independent effects on pept1 expression. These results indicate that PepT1 plays an important role for protein nutrition in neonatal goats, and its expression can be affected by feeding system.

This study was conducted to evaluate the effect of different monochromatic light-emitting diode colours on the behaviour and welfare of broiler chicks. A total of 750 one-day-old chicks were used and lighting was set up as follows: pure blue (PB, 440–450 nm), bright blue (460–470 nm), sky blue (480–490 nm), greenish blue (500–510 nm), and green (530–540), while fluorescent white (400–700 nm) was used as a control. Birds were placed into 30 independent light proof pens and each light treatment was replicated five times with 25 birds in each pen. Video was recorded and behaviour was evaluated twice per day and observed five consecutive days in a week. Broiler welfare was evaluated using the characteristics of gait score, tibia dyschondroplasia, tonic immobility duration, and heterophil:lymphocyte ratio. In results, sitting, walking, and ground pecking behaviour were influenced by the light colour from 0 to 7 d. Extending the rearing period from 8 to 21 d resulted in increased sitting behaviour and decreased walking and pecking behaviour in chicks in the PB treatment (P < 0.05). When the growth period was extended further (22–42 d), sitting behaviour increased when chicks were exposed to PB light (P < 0.05). The effect of light colour did not significantly influence welfare of broiler chicks. Thus, the present results suggest that PB light colour decreased broiler chickens movement and thus increased duration of sitting behaviour. These results would be helpful to choose light colour for broiler producers.

This study was conducted to evaluate feeding periods of dietary conjugated linoleic acid (CLA) supplementation on growth performance, nutrient digestibility, blood profiles, and meat quality in finishing pigs. A total of 150 finishing pigs [(Yorkshire × Landrace) × Duroc] with an average body weight (BW) of 83.13 ± 1.91 kg were randomly allocated into one of three treatments (10 pens per treatment, five pigs per pen) based on their BW. Dietary treatments consisted of supplementing the basal diet with 1.0% CLA during 2, 3, and 4 wk prior to finishing. Pigs fed CLA diets 2 wk before finishing had a higher overall average daily gain (ADG) and gain-to-feed ratio (G/F) than those fed CLA diets 4 wk before finishing (P < 0.05). In the whole experiment, pigs fed CLA diets 2 wk before finishing had a higher serum low-density lipoprotein (LDL) than those fed CLA diets 3 and 4 wk before finishing. However, pigs that received CLA diets 4 wk before finishing had higher triglyceride levels (P < 0.05). Feeding 1% CLA diets 4 wk before finishing improved meat color and firmness. Taken together, feeding 1% CLA diet 4 wk before finishing increased ADG, G/F, and serum LDL, but reduced serum triglyceride.

A total of 90 finishing pigs [(Yorkshire × Landrace) × Duroc] with an average body weight (BW) of 50.02 ± 1.78 kg were used in a 10 wk experiment. The pigs were distributed into three dietary treatments replicated six times with five pigs (two barrows and three gilts) per pen. The treatment diets were a positive control (PC; high-energy diet), a negative control (NC; low-energy diet), and an NC + 0.05% ferritin diet (TRT1). The supplementation of ferritin in a low-energy diet tended (P = 0.06) to increase the BW at week 5 compared with pigs fed low-energy diets without ferritin. At week 5 and overall period, the gain-to-feed ratio of pigs fed high-energy diets was higher (P < 0.05) compared with pigs fed low-energy diets. The pigs receiving a ferritin-supplemented diet had a comparable growth performance to pigs fed high-energy diets. At week 10, fecal Lactobacilli counts of pigs fed high-energy diets were higher (P < 0.05) compared with pigs fed low-energy diets. The supplementation of low-energy diets with ferritin resulted in comparable growth performance to pigs fed high-energy diets and had no adverse effect on digestibility and fecal gas emissions. Thus, it seems beneficial to include ferritin in low-energy diets of finishing pigs.

The goal of this study was to investigate effects of different levels of silicate supplementation in weaning to finishing pigs. A total of 96 piglets [(Landrace × Yorkshire) × Duroc] with initial body weight of 11.30 ± 0.02 kg were used for 16 wk (six replicate pens with four pigs per pen). Dietary treatment consisted of 0% (CON), 0.1% (T1), 0.5% (T2), and 1.0% (T3) silicate in the basal diet. Inclusion of 0.1% dietary silicate increased (P < 0.05) body weight, average daily gain, and gain-to-feed ratio in 0–16 wk. In addition, inclusion of 0.1% dietary silicate increased (P < 0.05) crude protein digestibility in 8 and 16 wk, whereas it decreased (P < 0.05) Escherichia coli count and ammonia emissions throughout the study period. Additionally, inclusion of dietary silicate increased (linear, P < 0.05) white blood cell in 4 wk, whereas it increased (quadratic, P < 0.05) white blood cell counts in 8 and 16 wk. Blood urea nitrogen decreased (quadratic, P < 0.05), and lymphocyte and foot and mouth antibodies increased (quadratic, P < 0.05) when silicate level increased. In conclusion, supplementation of 0.1% silicate in the diet showed positive effects in weaning to finishing pigs.

The objective of the study was to analyse the association of growth hormone (GH1) and C-reactive protein (CRP) loci polymorphisms with reproductive traits in native Pulawska gilts and sows. In the GH1 locus, two mutations were identified: one in the second intron [single-nucleotide polymorphism (SNP) = rs340429823 in.742C>T, MspI], and one in the second exon (SNP = rs340087546 c.566G>A, HaeII). In the CRP locus, two mutations were found in exon 2 (SNP = rs340175625, NM_213844.2: c.1271A>G, BstNI; and SNP = rs80928546, NM_213844.2: c.788C>T, HinfI). Analysis of sexual activity showed that intensity of external estrus signs differed significantly (P ≤ 0.05) and was the most manifested in gilts with the CT (GH1_MspI) genotype during the second estrus. In case of the CRP gene, statistically significant differences (P ≤ 0.05) were found in terms of the duration of farrowing. The longest farrowings were reported for the GG (CRP_HinfI) and the TT (CRP_BstNI) genotypes and the shortest for the AA (CRP_HinfI) and CC (CRP_BstNI). The most numerous first litters were produced by sows with the AA genotype (CRP_HinfI), with significant differences (P ≤ 0.05) between the AA and GG genotypes. In turn, the CC homozygotes (CRP_BstNI) differed significantly (P ≤ 0.05) in terms of the number of piglets born and reared to day 21 in the second litters compared to the other genotype groups.

Yanbian yellow cattle breeding is limited by its slow growth. We previously found that the miRNA miR-6523a is differentially expressed between Yanbian yellow cattle and Han Yan cattle, which differ in growth characteristics. In this study, we evaluated the effects of miR-6523a on growth hormone (GH) secretion in pituitary cells of Yanbian yellow cattle. Bioinformatics analyses using TargetScan and RNAhybrid, as well as dual luciferase reporter assays, showed that miR-6523a targets the 3′ untranslated region of somatostatin receptor 5 (SSTR5). We further found that the mRNA and protein expression levels of GH in pituitary cells were significantly higher in cells treated with miR-6523a mimic than in the control group (P = 0.0082 and P = 0.0069). The GH mRNA and protein expression levels were lower in cells treated with miR-6523a inhibitor than in the control group, but the difference was not significant (P = 0.064 and P = 0.089). SSTR5 mRNA and protein levels were inhibited by miR-6523a mimic compared with the control group (P = 0.0024 and P = 0.0028) and were elevated slightly by miR-6523a inhibitor (P = 0.093 and P = 0.091). These results prove that miR-6523a regulates GH secretion in pituitary cells by SSTR5. More broadly, these findings provide a basis for studies of the roles of miRNAs in animal growth and development.

A total of 80 free-range Iberian pigs reared with acorns and grass in eight different free-range systems (n = 10) in the southwest of the Iberian Peninsula were used to determine the relationship between fatty acid, tocopherol, and neophytadiene subcutaneous fat composition. The pigs were fed extensively for 79.1 ± 9.5 d from 110.9 ± 11.9 kg live weight at the beginning of the final fattening phase to 175.0 ± 15.9 kg slaughtered weight. Quercus suber and Quercus rotundifolia acorns were characterised by a high content of C18:1n-9 (58.3 and 63.1%, respectively) and γ-tocopherol [43.7 and 43.0 mg kg⁻¹ dry matter (DM), respectively], while grass exhibited a high content of C18:3n-3 (42.5%), α-tocopherol (366.5 mg kg⁻¹ DM) and neophytadiene (136.2 relative area units). The C18:1n-9 (54.4%–57.7%) and γ-tocopherol (2.7–4.1 mg kg⁻¹ DM) contents in subcutaneous fat from Iberian pigs differed (p < 0.001) between the free-range systems studied. Pasture intake had a significant effect (p < 0.01) on subcutaneous fat content of C18:3n-3 (0.5%–0.8%), α-tocopherol (7.8–13.1 mg kg⁻¹ DM) and neophytadiene (2.6–6.3 relative area units). However, the results demonstrated no correlations between accumulated levels of these compounds throughout the free-range period. In conclusion, the absence of correlations corroborated the heterogeneity of extensive rearing systems, with variations between years and geographical areas where the Iberian pigs were reared.

This study examined the presence and the antibiotic resistance patterns of Enterococcus faecalis isolated from the feces of 285 animals. Polymerase chain reaction tests verified the presence of E. faecalis from 49 pigs, 20 cows, 174 sheep, 17 horses, 21 chickens, and four dung beetles. Bacterial strains from different animals showed differences in susceptibility and resistance to the tested antimicrobials. The isolates exhibited resistance to ampicillin (6.32%), ciprofloxacin (40.00%), nitrofurantoin (1.40%), erythromycin (54.04%), streptomycin (82.11%), tetracycline (45.26%), amoxicillin (64.91%), penicillin (92.28%), and vancomycin (0.35%). The resistant strains also possessed varying complements of resistance genes including tem (77.89%), tetM (33.68%), gyrA (37.54%), parC (34.74%), aph(3′)-III (22.46%), aac(6′)/aph2″ (10.88%), and ant(6′)-I (8.42%). Genes for vancomycin resistance (vanB and vanC) and erythromycin resistance (mefA) were not detected. These results indicate high levels of antibiotic resistance among the isolates, although no positive correlation was observed between resistance genes and antibiotic resistance spectrum.

The present study was designed to investigate comparative expressions of follicle-stimulating hormone beta subunit (FSHβ) and nuclear receptor coactivator 1 (NCOA1) genes by real-time polymerase chain reaction, using polymerase chain reaction single-strand conformation polymorphism methods to investigate the effects of gene polymorphisms on reproductive traits, including total number of kits born (TNB) and number of born alive (NBA) in pink-eyed white mink. Four single-nucleotide polymorphisms were identified in the FSHβ and NCOA1 genes. The g.1228G>A polymorphism of FSHβ was associated with NBA and TNB (P < 0.01). The g.151536T>C polymorphism of NCOA1 was associated with NBA and TNB (P < 0.01). The NCOA1 mRNA levels in hypothalamus, ovary, and uterus during the first half of gestation were higher than during the middle term and last half of gestation (P < 0.01). The FSHβ mRNA levels in the hypothalamus and uterus were higher during the first half of gestation than during the middle term and last half of gestation (P < 0.05). In conclusion, the g.1866T>C polymorphism of FSHβ and the g.151536T>C polymorphism of NCOA1 could be molecular markers for reproductive traits, and expressions of FSHβ and NCOA1 might be involved in the regulation of embryo attachment mechanisms in pink-eyed white mink breeding.

Two simulated rumens (Rusitecs) were used to assess the effects of flaxseed (FS) and (or) vitamin E (VE) on rumen fermentation, fatty acid (FA) biohydrogenation, and microbial protein synthesis. Ground FS replaced 0% or 15% of barley grain, along with VE at 0 or 1000 IU d⁻¹ in a 2 × 2 factorial experiment. Flaxseed lowered neutral detergent fiber (P = 0.001) and acid detergent fiber (P = 0.01) and increased (P = 0.001) nitrogen (N) disappearance. Flaxseed also increased (P = 0.01) total volatile FA and decreased (P = 0.001) acetate production. When both FS and VE were included, the acetate:propionate ratio decreased (P = 0.04). Biohydrogenation of FA was not influenced by VE, but total FA and C18:0 in effluent were increased (P = 0.001) and C16:0 decreased (P = 0.001) by FS. With VE, total microbial N (MN) was increased (P = 0.001). In the concentrate, production of MN in feed-particle-bound bacteria was increased (P = 0.001) by VE. Vitamin E did not alter FA biohydrogenation but did promote MN production. The stable and relatively high pH in the Rusitec may have prevented the typical shift from C18:1 trans-11 to C18:1 trans-10 with concentrate diets. Future studies simulating subclinical acidosis in the Rusitec may illuminate ruminal mode(s) of action of VE on FA biohydrogenation.

Previously, we investigated the impact of a mixed Lactobacillus buchneri, Lactobacillus plantarum, and Lactobacillus casei inoculant on fermentation and aerobic stability of barley silage over two years in 2009 and 2010. In 2009, a classical response to inoculation was obtained with an increase in acetic acid concentration of silage ensiled in both mini- and bag silos. In 2010, this classical response was not observed in mini-silos but was observed in bag silos. The objective of this study was to determine if molecular microbial ecology could explain the differential responses to the inoculation of barley silage between the two years. The Illumina MiSeq sequencing results showed that inoculation increased Lactobacillus and lowered Pediococcus, Weissella, and Leuconostoc in both types of silos in 2009. However, a similar trend was not observed in mini-silos, but was instead observed in bag silos in 2010. Inoculation did not alter the core fungal community in either silo type in either year. Cladosporium, Leptosphaeria, and Cryptococcus were abundant in fresh forage, but were superseded by Pichia and Kazachstania after ensiling. Our results suggest that changes in silage chemistry corresponded to differences observed in microbial ecology. Inoculation may have less impact when using more mature crops with shorter ensiling times.

The objective of this study was to evaluate the inclusion rate of pea hay in barley or oat hay diets for beef cattle. Six ruminally cannulated heifers (407 ± 38 kg) were used in a 6 × 6 Latin square (25 d periods) with a 2 × 3 factorial design. Treatments included whole-crop barley or oat hay with pea hay blended in to achieve inclusion rates of 0%, 15%, or 30% (dry matter basis) of the forage. Pea hay inclusion increased dry matter intake (DMI; P = 0.03) by 0.75 kg d⁻¹ relative to diets without pea hay, but the response was not linear or quadratic. Inclusion of pea hay linearly increased mean ruminal pH (P = 0.039), the concentration of butyrate in ruminal fluid (P = 0.013), plasma urea nitrogen (N) concentration (P = 0.001), and quadratically increased ruminal ammonia concentration (P < 0.001). Pea hay inclusion reduced crude protein (CP) digestibility by 2.87% relative to cereal-only treatments (P = 0.025), but did not affect N intake, microbial N, or N excretion. Overall, pea hay inclusion increased DMI, increased ruminal butyrate concentration, but reduced CP digestibility without affecting N balance.

Two experiments were conducted to evaluate the effects of adding multi-enzyme on the available energy concentration and standardized ileal digestibility (SID) of amino acids of double-low rapeseed expellers (RSE) and rapeseed meal (RSM) fed to growing pigs. In Experiment 1, a total of 36 growing barrows were fed six diets in a replicated 3 × 2 factorial design. Diets included a corn–soybean meal basal diet, RSE diet, and RSM diet with or without multi-enzyme (1000 U g^-1 of cellulase, 10 000 U g^-1 of xylanase, 2000 U g^-1 of glucanase, and 10 000 U g^-1 of protease). In Experiment 2, a total of 30 crossbred pigs were randomly allotted to five diets consisting of a nitrogen-free diet and four cornstarch-based diets containing RSE or RSM with or without multi-enzyme. Multi-enzyme supplementation significantly improved (P < 0.05) the metabolizable energy (ME) value and apparent total tract digestibility (ATTD) of ether extract, neutral detergent fiber, and acid detergent fiber, and it tended to increase (P < 0.10) the ATTD of gross energy and digestible energy in ingredients. With the exception of phenylalanine, multi-enzyme supplementation increased (P < 0.05) the SID of crude protein (CP) and all amino acids (AA) in ingredients. Multi-enzyme supplementation enhanced fiber degradation and increased the ME value and SID of CP as well as most AA in double-low rapeseed co-products fed to pigs.

Cette étude vise à estimer le poids du fœtus zébu peulh à partir des mesures échographiques des diamètres de l’abdomen (DA), du bipariétal (DBP), du cordon ombilical (DCO), de la corne utérine (DCU) et des longueurs du fémur (LF), du tibia (LT), et du dos (LD). Elle a concerné soixante et un (n = 61) utérus gravides recueillis après abattage de femelles gestantes. Toutes les gestations étaient simples. Les examens ont été réalisés en bain d’eau au moyen d’une sonde convexe de 3,5 MHz. Les utérus ont été ensuite disséqués afin de rapporté le poids des fœtus au moyen d’une balance. Les données ont été analysées au moyen du système de régression curvilinéaire. Les formules d’estimation du poids à partir des paramètres biométriques ont été de type y = ax^b, où y est le poids (g), a et b_constantes, et x est le paramètre biomètrique (mm). Toutes les structures morphologiques étudiées ont présenté des corrélations positives et hautement significatives avec le poids du fœtus (p < 0,0001). Toutefois, les DA (R² = 0,94), DBP (R² = 0,80), et la LF (R² = 0,81) semblent être les plus appropriés pour l’estimation du poids du fœtus. À défaut de ces paramètres, les autres structures étudiées peuvent servir de repère dans l’estimation du poids.

Little information exists regarding the optimal economic slaughter endpoint (OSE) for feedlot-finished cattle in Brazil. This study investigated the perceptions of Brazilian feeders regarding the optimal time for slaughter. A total of 52 interviews were conducted involving nutritionist-consultants (n = 23), feedlot owners (n = 21), and packer-owned feedlots (n = 8). The results showed that 65% of the interviewees used weight and fat cover, both estimated visually, to determine the moment for slaughter. Identifying the ideal time for slaughter was considered a challenge for respondents, and 85% of them recognized that their current slaughter endpoint identification method needed improvements. Regarding decision support systems, 58% of respondents reported they would purchase a computer program to help identify OSE, and 73% would be interested in incorporating a prototype of such a system into their feedlots. Carcass dressing (38%) and price (25%) were the main factors driving the feeder’s choice of meatpacker, followed by carcass premiums (10%). Meat quality was found to be an irrelevant criterion for Brazilian meatpackers in awarding both premiums (5%) and deductions (3%). Slaughter endpoint is determined subjectively by the Brazilian feeders, based on a visual evaluation of both weight and fatness.

Research interviews with agribusiness professionals are carried out in several countries for updating and developing technologies. This study aimed to investigate the perception of Brazilian feeders regarding management and marketing tools used in the feedlot industry. Interviews were conducted with groups: nutritionist-consultants (n = 23), feedlot owners (n = 21), and packer-owned feedlots (n = 8). Roughly 58% of the interviewees worked with two cycles of animals per year. Roughly 80% of animals on feedlots were males, with 73% of the respondents having fed only intact males and 75% of the animals were Nellore breed. Among the criteria used for pen formation, weight was the most common (75%). The use of computational tools for feedlot management (71%) and diet formulation (69%) were found to be common, although interviewees did not use any software to characterize feeder animals. In 44% of the respondent feedlots, animals that reached the desired weight and degree of finish were removed for slaughter, whereas the unfinished animals remained in the same pen. We found that a need, therefore, exists to develop efficient strategies for forming homogeneous pens upon animal entry onto feedlots, and maintaining homogenous pens upon the exit of animals for slaughter.

This study aims to determine the effect of adding different proportions of Broussonetia papyrifera (BP)-fermented feed on Hu sheep. A total of 40 male Hu sheep (weighting 20.6 ± 2.20 kg) were collected and then divided into group I, II, III, and IV, with 0%, 5%, 10%, and 15% of BP-fermented feed to based diet, respectively. After the trial period of 10 and 50 d, the sheep were slaughtered by conventional methods for the chemical analyses. It showed that adding 10% fermented feed could significantly increase the growth performance of the Hu sheep. Adding the fermented feed can improve the protein level, main flavor amino acid content, and fatty acid in the muscle. Based on the headspace solid-phase microextraction and gas chromatography – mass spectrometry methods, a total of 125, 120, 119, and 117 kinds of volatile compounds were identified in group I, II, III, and IV, among which the relative content of the acid compound, ester compound, ketone compound, and aldehydes in group II, III, and IV were higher than that in control group, respectively. Addition of BP-fermented feed could significantly improve growth performance and meat quality of Hu sheep.

The objectives of this study were to identify the phenotypic and genetic relationships and heritability (h²) of feeding behaviours (FB) in replacement beef females. Between 2005 and 2017, heifers (N = 1394) were tested for feed intake using an electronic feed bunk system. The various FB were feeding duration (DUR; min d⁻¹), head down time (HD; min d⁻¹), feeding frequency (FREQ; events d⁻¹), time-to-bunk (TTB; min). Dry matter intake (DMI; kg d⁻¹), and residual feed intake adjusted for off-test ultrasound back fat thickness (RFI_FAT) were also reported. The h² estimates for DUR, HD, FREQ, TTB, DMI, and RFI_FAT were 0.25 ± 0.05, 0.26 ± 0.06, 0.27 ± 0.05, 0.29 ± 0.06, 0.26 ± 0.05, and 0.40 ± 0.07, respectively. These are the first h² to be presented for these FB among developing replacement heifers on a high-forage diet.

An autosomal recessive defect caused by a loss of function mutation in the bovine apolipoprotein B (APOB) gene causes cholesterol deficiency with strong effects on calf survival and development. This study examined the distribution of cholesterol deficiency haplotype (CDH) in the APOB gene in Canadian Holstein cows and its impacts on milk production and milk cholesterol content. The CDH in 917 cows from 29 herds was determined via polymerase chain reaction (PCR). A longer insertion of approximately 7 kb potentially characterizing the mutation was amplified. The average carrier frequency of herds in Quebec based on PCR results was 14.6%. Cholesterol deficiency haplotype status had non-significant (P > 0.05) effects on milk cholesterol content, other milk components, and milk yield.