Performance,health, and physiological responses of newly received feedlot cattle supplemented with pre- and probiotic ingredients

Nutritional strategies that optimize immunity of feedlot cattle are warranted due to increasing regulations with the use of feed-grade antimicrobials. This study evaluated physiological, health, and performance responses of cattle receiving a synbiotic supplement (yeast-derived prebiotic + Bacillus subtilis probiotic), which replaced feed-grade antimicrobials or were fed in conjunction with monensin during the initial 45 days in the feedlot. Angus-influenced steers (n = 256) were acquired from an auction facility on day −2, and transported (800 km) to the feedlot. Shrunk BW was recorded upon arrival (day −1). Steers were allocated to 1 of 18 pens (day 0), and pens were assigned to receive (n = 6/treatment) a free-choice diet containing: (1) monensin and tylosin (RT; 360 mg/steer daily from Rumensin and 90 mg/steer daily from Tylan; Elanco Animal Health, Greenfield, IN, USA), (2) yeast-derived ingredient and B. subtilis probiotic (CC; 18 g/steer daily of Celmanax and 28 g/steer daily of Certillus; Church and Dwight Co., Inc., Princeton, NJ, USA), or (3) monensin in addition to yeast-derived and B. subtilis ingredients (RCC) as in RT and CC. Steers were assessed for bovine respiratory disease (BRD) and DMI daily. Steer BW was recorded on days 45 and 46, and averaged for final BW. Blood samples were collected on days 0, 7, 17, 31, and 45. Feed intake was greater (P ≤ 0.05) in CC vs. RCC and RT during the initial 3 weeks upon feedlot arrival. No treatment differences were noted (P ≥ 0.41) for average daily gain, BW, and feed efficiency. Incidence of BRD did not differ (P = 0.77) between treatments (average 80.1%). A greater proportion (P ≤ 0.03) of RT steers diagnosed with BRD required a second antimicrobial treatment compared with CC and RCC (57.3, 37.3, and 38.6%, respectively). Removal of steers from the trial due to severe morbidity + mortality was greater (P = 0.02) in RT vs. CC (22.4 and 7.0%), and did not differ (P ≥ 0.16) among RCC (12.9%) vs. RT and CC. Plasma glucose concentrations were greater (P ≤ 0.02) in CC vs. RCC and RT on day 7. Plasma concentrations of nonesterified fatty acids were greater (P ≤ 0.02) in RT and RCC vs. CC on day 7, and in RT vs. CC on day 17. Steers receiving the synbiotic supplement had improved response to BRD treatment, suggesting heightened immunocompetence from partially enhanced metabolism and the nutraceutical effects of B. subtilis and yeast compounds.     

日粮添加复合饲用益生菌对肉牛生长性能及肠道微生物的影响

[目的]为研究添加饲用益生菌对肉牛生长性能、血液生理生化指标及肠道微生物区系的影响.[方法]在青海地区选取西门塔尔牛与荷斯坦牛的杂交1代18头,按每组平均体重相近的原则随机分为2组,每组9头,试验组饮食添加地衣芽孢杆菌、枯草芽孢杆菌和酿酒酵母的复合饲用益生菌.[结果]试验结果表明:试验组显著地提高了胸围日增长量(P=0...     

Effects of organic complexed or inorganic Co,Cu, Mn and Zn supplementation during a 45-day preconditioning period on productive and health responses of feeder cattle

This experiment evaluated production and health parameters among cattle offered concentrates containing inorganic or organic complexed sources of supplemental Cu, Co, Mn and Zn during a 45-day preconditioning period. In total, 90 Angus×Hereford calves were weaned at 7 months (day −1), sorted by sex, weaning BW and age (261±2 kg; 224±2 days), and allocated to 18 drylot pens (one heifer and four steers per pen) on day 0; thus, all pens had equivalent initial BW and age. Pens were randomly assigned to receive a corn-based preconditioning concentrate containing: (1) Cu, Co, Mn and Zn sulfate sources (INR), (2) Cu, Mn, Co and Zn complexed organic source (AAC) or (3) no Cu, Co, Mn and Zn supplementation (CON). From day 0 to 45, cattle received concentrate treatments (2.7 kg/animal daily, as-fed basis) and had free-choice access to orchardgrass (Dactylis glomerata L.), long-stem hay and water. The INR and AAC treatments were formulated to provide the same daily amount of Co, Cu, Mn and Zn at a 50-, 16-, 8- and ninefold increase, respectively, compared with the CON treatment. On day 46, cattle were transported to a commercial feedlot, maintained as a single pen, and offered a free-choice receiving diet until day 103. Calf full BW was recorded on days −1 and 0, 45 and 46, and 102 and 103 for average daily gain (ADG) calculation. Liver biopsy was performed on days 0 (used as covariate), 22 and 45. Cattle were vaccinated against respiratory pathogens on days 15, 29 and 46. Blood samples were collected on days 15, 29, 45, 47, 49, 53 and 60. During preconditioning, mean liver concentrations of Co, Zn and Cu were greater (P⩽0.03) in AAC and INR compared with CON. No treatment effects were detected (P⩾0.17) for preconditioning feed intake, ADG or feed efficiency. No treatment effects were detected (P⩾0.48) for plasma concentrations of antibodies against Mannheimia haemolytica, bovine viral diarrhea types 1 and 2 viruses. Plasma haptoglobin concentrations were similar among treatments (P=0.98). Mean plasma cortisol concentration was greater (P⩽0.04) in CON compared with INR and AAC. No treatment effects were detected (P⩾0.37) for cattle ADG during feedlot receiving. Hence, INR and AAC increased liver concentrations of Co, Zn and Cu through preconditioning, but did not impact cattle performance and immunity responses during preconditioning and feedlot receiving.     

Supplementing a yeast-derived product to enhance productive and health responses of beef steers

This experiment evaluated the impacts of supplementing a yeast-derived product (Celmanax; Church & Dwight Co., Inc., Princeton, NJ, USA) on productive and health responses of beef steers, and was divided into a preconditioning (days 4 to 30) and feedlot receiving phase (days 31 to 69). In all, 84 Angus × Hereford steers were weaned on day 0 (BW=245±2 kg; age=186±2 days), and maintained in a single group from days 0 to 3. On day 4, steers were allocated according to weaning BW and age to a 21-pen drylot (4 steers/pen). Pens were randomly assigned to (n=7 pens/treatment): (1) no Celmanax supplementation during the study, (2) Celmanax supplementation (14 g/steer daily; as-fed) from days 14 to 69 or (3) Celmanax supplementation (14 g/steer daily; as-fed) from days 31 to 69. Steers had free-choice access to grass-alfalfa hay, and were also offered a corn-based concentrate beginning on day 14. Celmanax was mixed daily with the concentrate. On day 30, steers were road-transported for 1500 km (24 h). On day 31, steers returned to their original pens for the 38-day feedlot receiving. Shrunk BW was recorded on days 4, 31 and 70. Feed intake was evaluated daily (days 14 to 69). Steers were observed daily (days 4 to 69) for bovine respiratory disease (BRD) signs. Blood samples were collected on days 14, 30, 31, 33, 35, 40, 45, 54 and 69, and analyzed for plasma cortisol, haptoglobin, IGF-I, and serum fatty acids. Preconditioning results were analyzed by comparing pens that received (CELM) or not (CONPC) Celmanax during the preconditioning phase. Feedlot receiving results were analyzed by comparing pens that received Celmanax from days 14 to 69 (CELPREC), days 31 to 69 (CELRECV) or no Celmanax supplementation (CON). During preconditioning, BRD incidence was less (P=0.03) in CELM v. CONPC. During feedlot receiving, average daily gain (ADG) (P=0.07) and feed efficiency (P=0.08) tended to be greater in CELPREC and CELRECV v. CON, whereas dry matter intake was similar (P⩾0.29) among treatments. No other treatment effects were detected (P⩾0.20). Collectively, Celmanax supplementation reduced BRD incidence during the 30-day preconditioning. Moreover, supplementing Celmanax tended to improve ADG and feed efficiency during the 38-day feedlot receiving, independently of whether supplementation began during preconditioning or after feedlot entry. These results suggest that Celmanax supplementation benefits preconditioning health and feedlot receiving performance in beef cattle.     

The repeatability of feed intake and feed efficiency in beef cattle offered high-concentrate,grass silage and pasture-based diets

Breeding values for feed intake and feed efficiency in beef cattle are generally derived indoors on high-concentrate (HC) diets. Within temperate regions of north-western Europe, however, the majority of a growing beef animal’s lifetime dietary intake comes from grazed grass and grass silage. Using 97 growing beef cattle, the objective of the current study was to assess the repeatability of both feed intake and feed efficiency across 3 successive dietary test periods comprising grass silage plus concentrates (S+C), grazed grass (GRZ) and a HC diet. Individual DM intake (DMI), DMI/kg BW and feed efficiency-related parameters, residual feed intake (RFI) and gain to feed ratio (G : F) were assessed. There was a significant correlation for DMI between the S+C and GRZ periods (r = 0.32; P < 0.01) as well as between the S+C and HC periods (r = 0.41; P < 0.001), whereas there was no association for DMI between the GRZ and HC periods. There was a significant correlation for DMI/kg BW between the S+C and GRZ periods (r = 0.33; P < 0.01) and between the S+C and HC periods (r = 0.40; P < 0.001), but there was no association for the trait between the GRZ and HC periods. There was a significant correlation for RFI between the S+C and GRZ periods (r = 0.25; P < 0.05) as well as between S+C and HC periods (r = 0.25; P < 0.05), whereas there was no association for RFI between the GRZ and HC periods. Gain to feed ratio was not correlated between any of the test periods. A secondary aspect of the study demonstrated that traits recorded in the GRZ period relating to grazing bite rate, the number of daily grazing bouts and ruminating bouts were associated with DMI (r = 0.28 to 0.42; P < 0.05 - 0.001), DMI/kg BW (r = 0.36 to 0.45; P < 0.01 - 0.001) and RFI (r = 0.31 to 0.42; P < 0.05 - 0.001). Additionally, the number of ruminating boli produced per day and per ruminating bout were associated with G : F (r = 0.28 and 0.26, respectively; P < 0.05). Results from this study demonstrate that evaluating animals for both feed intake and feed efficiency indoors on HC diets may not reflect their phenotypic performance when consuming conserved forage-based diets indoors or when grazing pasture.     

Physiologic and innate immunity responses to bacterial lipopolysaccharide administration in beef heifers supplemented with OmniGen-AF

Nutritional alternatives to strengthen animal immunocompetence are critical for welfare and productivity in livestock systems, such as beef cattle operations. This experiment evaluated physiological and innate immunity effects of supplementing an immunomodulatory feed ingredient (Omnigen-AF; Phibro Animal Health, Teaneck, NJ, USA) to beef heifers administered bacterial lipopolysaccharide (LPS). In total, 8 non-pregnant, non-lactating nulliparous Angus×Hereford heifers (676±4 days of age) were ranked by BW (473±8 kg), and assigned to crossover design containing two periods of 34 days each. Heifers were housed in individual pens and had ad libitum access to meadow foxtail (Alopecurus pratensis L.) hay, water and a granulated commercial vitamin+mineral mix. Within each period, heifers received (as-fed basis) 227 g/day of dried distillers grains including (OMN) or not (CON) 56 g of Omnigen-AF for 34 days. On day 28 of each period (0800 h), heifers received an intravenous bolus dose (0.5 μg/kg of BW, diluted in 5 ml of 0.9% sterile saline) of bacterial LPS (Escherichia coli 0111:B4). Hay DM intake was recorded daily from day 0 to 34. Blood was collected at −1, 0, 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 24, 48, 72, 96, 120 and 144 h relative to LPS administration. Heifer intravaginal temperature was recorded every 10 min from −0.5 to 10 h relative to LPS administration. No treatment effect was detected (P=0.35) for hay DM intake during the experiment. No treatment effects were detected (P⩾0.64) for intravaginal temperature and plasma concentrations of tumor necrosis-α, cortisol and haptoglobin, which increased (time effect, P<0.01) for OMN and CON heifers and peaked at 4.5, 2, 4 and 48 h, respectively, after LPS administration. No treatment effects were detected (P⩾0.35) for whole blood mRNA expression of chemokine ligand 5, tumor necrosis-α, cyclooxygenase 2 and interleukin 8, which also increased (time effect, P<0.01) for OMN and CON heifers and peaked at 0.5, 1.5, 2 and 2.5 h, respectively, after LPS administration. Whole blood mRNA expression of interleukin 8 receptor and L-selectin were also similar (P⩾0.61) between OMN and CON heifers, and decreased (time effect, P<0.01) for both treatments reaching nadir levels at 1 and 2.5 h, respectively, after LPS administration. Collectively, OMN supplementation did not modulate the physiological and innate immunity responses of beef heifers to bacterial LPS administration.     

Relative contribution of ruminal buffering systems to pH regulation in feedlot cattle fed either low- or high-forage diets

The relative contribution of ruminal short-chain fatty acid (SCFA) absorption and salivary buffering to pH regulation could potentially change under different dietary conditions. Therefore, the objective of this study was to investigate the effects of altering the ruminal supply of rapidly fermentable carbohydrate (CHO) on absorptive function and salivation in beef cattle. Eight heifers (mean BW±SD=410±14 kg) were randomly allocated to two treatments in a crossover design with 37-day periods. Dietary treatments were barley silage at 30% low forage (LF) or 70% high forage (HF) of dietary dry matter (DM), with the remainder of the diet consisting of barley grain (65% or 25% on a DM basis) and a constant level (5%) of supplement. The LF and HF diets contained 45.3% and 30.9% starch, and 4.1% and 14.0% physically effective fiber (DM basis), respectively. Ruminal pH was continuously measured from day 17 to day 23, whereas ruminal fluid was collected on day 23 to determine SCFA concentration. Ruminal liquid passage rate was determined on day 23 using Cr-ethylenediaminetetraacetic acid. Eating or resting salivation was measured by collecting masticate (days 28 and 29) or saliva samples (days 30 and 31) at the cardia, respectively. On days 30 and 31, the temporarily isolated and washed reticulo-rumen technique was used to measure total, and Cl⁻-competitive (an indirect measure of protein-mediated transport) absorption of acetate, propionate and butyrate. As a result of the higher dietary starch content and DM intake, the ruminal supply of rapidly fermentable CHO, total ruminal SCFA concentration (118 v. 95 mM; P<0.001) and osmolality (330 v. 306 mOsm/kg; P=0.018) were greater in cattle fed LF compared with HF. In addition, feeding LF resulted in a longer duration (2.50 v. 0.09 h/day; P=0.02) and a larger area (0.44 v. 0.01 (pH×h)/day; P=0.050) that pH was below 5.5. There was no diet effect on total and Cl⁻-competitive absorption (mmol/h and %/h) of acetate, propionate, butyrate and total SCFA (acetate+propionate+butyrate), but eating salivation was less (131 v. 152 ml/min; P=0.02), and resting salivation tended to be less (87 v. 104 ml/min; P=0.10) in cattle fed an LF diet. In summary, lower ruminal pH in cattle with greater rapidly fermentable CHO intake was attributed to an increase in SCFA production and decrease in salivation, which were not compensated for by an increase in epithelial permeability.     

Identification of polymorphisms influencing feed intake and efficiency in beef cattle

Feed efficiency is an economically important trait in beef cattle. Net feed efficiency, measured as residual feed intake (RFI), is the difference between actual feed intake and the predicted feed intake required for maintenance and gain of the animal. SNPs that show associations with RFI may be useful quantitative trait nucleotides for marker-assisted selection. This study identified associations between SNPs underlying five RFI QTL on five bovine chromosomes (BTA2, 5, 10, 20 and 29) with measures of dry matter intake (DMI), RFI and feed conversion ratio (FCR) in beef cattle. Six SNPs were found to have effects on RFI (P < 0.05). The largest single SNP allele substitution effect for RFI was -0.25 kg/day located on BTA2. The combined effects of the SNPs found significant in this experiment explained 6.9% of the phenotypic variation of RFI. Not all the RFI SNPs showed associations with DMI and FCR even though these traits are highly correlated with RFI (r = 0.77 and r = 0.62 respectively). This shows that these SNPs may be affecting the underlying biological mechanisms of feed efficiency beyond feed intake control and weight gain efficiency. These SNPs can be used in marker-assisted selection but first it will be important to verify these effects in independent populations of cattle.     

The effects of grain treatment, grain feed level and grass silage feed value on the performance of and meat quality from, finishing beef cattle

A completely randomised design study involving 132 continental crossbred beef steers was undertaken to evaluate the effects of method of grain treatment and feed level, and grass silage feed value on animal performance, carcass characteristics and meat quality of beef cattle. Winter wheat was harvested and the grain was stored either ensiled crimped and treated with 4.5 l/t of a proprietary acid-based additive (crimped), ensiled whole and treated with 20 kg feed-grade urea per t (urea) or stored conventionally in an open bin treated with 3 l propionic acid per t. Two grass silages, of contrasting feed value (L and H) were ensiled. For the conventional, crimped and urea treatments, grain dry matter (DM) concentrations were 802, 658 and 640 g/kg, respectively. For the L- and H-feed value silages, DM concentrations were 192 and 240 g/kg and D values were 671 and 730 g/kg DM, respectively. The silages were offered as the sole forage supplemented with either conventional, crimped or urea-treated grain-based concentrate at either 3.5 or 6.0 kg DM per steer per day. The grain supplement consisted of 850 and 150 g/kg DM of grain and citrus pulp, respectively. For the conventional, urea and crimped treatments, DM intakes were 8.85, 9.43 and 9.04 kg/day (standard error (s.e.) = 0.129); estimated carcass gains were 0.60, 0.55 and 0.61 kg/day (s.e. = 0.020), respectively. For the low- and high- feed value grass silages, estimated carcass gains were 0.56 and 0.61 kg/day (s.e. = 0.014), respectively. For the low and high grain feed levels, estimated carcass gains were 0.56 and 0.61 kg/day, respectively. Grain treatment, grain feed level or silage feed value did not alter (P > 0.05) meat quality, lean colour or fat colour. There were significant silage feed value × grain feed level interactions (P < 0.05) for final live weight (LW) and daily live-weight gain (DLWG). Increasing grain feed level increased final LW and DLWG when offered with the low-feed value silage, however, grain feed level had no effect on final LW or DLWG when offered with the high-feed value silage. It is concluded that urea treatment of grain increased silage intake and feed conversion ratio (kg DM intake per kg carcass) and tended to decrease carcass gain. Crimping provides a biologically equally effective method to store grain as conventional methods. Improving grass silage feed value had a greater impact on animal performance than increasing grain feed level by 2.4 kg DM per day.     

Performance,carcass characteristics and meat quality of Nellore cattle supplemented with supranutritional doses of sodium selenite or selenium-enriched yeast

The enrichment of meat with selenium is important to improve the intake of selenium by humans. The effects of supranutritional doses of sodium selenite or selenium-enriched yeast on performance, carcass characteristics and meat quality were evaluated using 63 Nellore cattle in a completely randomized design with two sources (sodium selenite and selenium-enriched yeast), three levels (0.3, 0.9 and 2.7 mg Se/kg DM) and control treatment (without addition of selenium). Final body weight (BW), average daily gain, dry matter intake and gain to feed ratio (G : F) at the end of 84 days of supplementation were not influenced by treatments (P>0.05). Values of pH, ribeye area, back fat thickness and marbling score were also not influenced by treatments (P>0.05). Dressing percentage was greater (P=0.02) in Nellore cattle supplemented with organic Se (58.70%) compared to animals supplemented with inorganic Se (57.94%). Hot carcass weight increased (P=0.05) with the increasing of Se levels in the diet. Colour, shear force (SF), cooking and drip loss remained unchanged (P>0.05); however thiobarbituric acid reactive substances was 15.51% higher with inorganic Se compared with organic Se. The selenium concentration in the meat of animals receiving organic selenium was higher (P<0.001) than that of animals receiving sodium selenite, at all levels (0.3; 0.9 and 2.7 mg/kg DM). The meat of animals receiving 2.7 mg of organic Se/kg of DM presented concentration of 372.7 μg Se/kg in the L.dorsi muscle, and the intake of 150 g of this meat by humans provides approximately 100% of the recommended Se intake (55 μg Se/day for adults). Therefore, the use of supranutritional doses of 2.7 mg Se/kg of DM, regardless of source, is a way of naturally producing selenium-enriched meat without compromising performance, carcass characteristics and quality of Nellore bovine meat.     

The effect of dietary addition of nitrate or increase in lipid concentrations,alone or in combination,on performance and methane emissions of beef cattle

Adding nitrate to or increasing the concentration of lipid in the diet are established strategies for reducing enteric methane (CH₄) emissions, but their effectiveness when used in combination has been largely unexplored. This study investigated the effect of dietary nitrate and increased lipid included alone or together on CH₄ emissions and performance traits of finishing beef cattle. The experiment was a 2×4 factorial design comprising two breeds (cross-bred Aberdeen Angus (AAx) and cross-bred Limousin (LIMx) steers) and four dietary treatments (each based on 550 g forage : 450 g concentrate/kg dry matter (DM)). The four dietary treatments were assigned according to a 2×2 factorial design where the control treatment contained rapeseed meal as the main protein source, which was replaced either with nitrate (21.5 g nitrate/kg DM); maize distillers dark grains (MDDG, which increased diet ether extract from 24 to 37 g/kg DM) or both nitrate and MDDG. Steers (n=20/dietary treatment) were allocated to each of the four treatments in equal numbers of each breed with feed offered ad libitum. After 28 days adaptation to dietary treatments, individual animal intake, performance and feed efficiency were recorded for 56 days. Thereafter, CH₄ emissions were measured over 13 weeks (six steers/week). Increasing dietary lipid did not adversely affect animal performance and showed no interactions with dietary nitrate. In contrast, addition of nitrate to diets resulted in poorer live-weight gain (P<0.01) and increased feed conversion ratio (P<0.05) compared with diets not containing nitrate. Daily CH₄ output was lower (P<0.001) on nitrate-containing diets but increasing dietary lipid resulted in only a non-significant reduction in CH₄. There were no interactions associated with CH₄ emissions between dietary nitrate and lipid. Cross-bred Aberdeen Angus steers achieved greater live-weight gains (P<0.01), but had greater DM intakes (P<0.001), greater fat depth (P<0.01) and poorer residual feed intakes (P<0.01) than LIMx steers. Cross-bred Aberdeen Angus steers had higher daily CH₄ outputs (P<0.001) but emitted less CH₄ per kilogram DM intake than LIMx steers (P<0.05). In conclusion, inclusion of nitrate reduced CH₄ emissions in growing beef cattle although the efficacy of nitrate was less than in previous work. When increased dietary lipid and nitrate inclusion were combined there was no evidence of an interaction between treatments and therefore combining different nutritional treatments to mitigate CH₄ emissions could be a useful means of achieving reductions in CH₄ while minimising any adverse effects.     

Effects of polymorphic microsatellites in the regulatory region of IGF1 and GHR on growth and carcass traits in beef cattle

Growth hormone (GH), insulin-like growth factors 1 and 2 (IGF1 and IGF2) and their associated binding proteins and transmembrane receptors (GHR, IGF1R and IGF2R) play an important role in the physiology of mammalian growth. The objectives of the present study were to estimate the allele and genotype frequencies of microsatellite markers located in the 5'-regulatory region of the IGF1 and GHR genes in beef cattle belonging to different genetic groups and to determine effects of these markers on growth and carcass traits in these animals under an intensive production system. For this purpose, genotyping was performed on 384 bulls including 79 Nellore, 30 Canchim (5/8 Charolais + 3/8 Zebu) and 275 crossbred animals originating from crosses of Simmental (1/2 Simmental, n = 30) and Angus (1/2 Angus, n = 245) sires with Nellore females. The effects of substituting L allele for S allele of GHR microsatellite across Nellore, Canchim and 1/2 Angus were significant for weight gain and body weight (P < 0.05). The IGF1 microsatellite allele substitutions of 229 for 225 within Nellore group and of 225 for 229 within 1/2 Angus were not significant for any of the traits.     

Estimation of genetic parameters for BW and body measurements in Brahman cattle

Body weight and body measurements are commonly used to represent growth and measured at several growth stages in beef cattle. Those economically important traits should be genetically improved. To achieve breeding programs, genetic parameters are prerequisite, as they are needed for designing and predicting outcomes of breeding programs, as well as estimating of breeding values. (Co)variance components were estimated for BW and body measurements on Brahman cattle born between 1990 and 2016 from 17 research herds across Thailand. The traits measured were BW, heart girth (GR), hip height (HH) and body length (BL) and were measured at birth, 200 days, 400 days and 600 days of age. The number of records varied between traits from 18 890 for birth BW to 876 for GR at 600 days. Estimation of variance components was performed using restricted maximum likelihood using univariate and multivariate animal models. Pre-weaning traits were influenced by genetic and/or permanent environmental effects of the dam, except for BL. Heritability estimates from birth to 600 days of age ranged from 0.28±0.01 to 0.50±0.06 for BW, 0.27±0.01 to 0.43±0.09 for GR, 0.28±0.01 to 0.58±0.08 for HH and 0.34±0.01 to 0.51±0.08 for BL using univariate analysis. Heritability estimates for the traits studied increased with age. A similar trend was observed for the phenotypic and genetic correlations between subsequent BW and body measurements. A positive correlation was observed between different traits measured at a similar age, ranging from 0.22±0.01 to 0.72±0.01 for the phenotypic correlation and 0.25±0.04 to 0.97±0.11 for the genetic correlation. Also, a positive correlation was observed for similar traits across different age classes ranging from 0.07±0.03 to 0.76±0.02 for the phenotypic correlation and 0.24±0.11 to 0.92±0.05 for the genetic correlation. Therefore, all correlations between body measurements at the same age and across age classes were positive. The results show the potential improvement of growth traits in Brahman cattle, and those traits can be improved simultaneously under the same breeding program.     

Synthetic rubber surface as an alternative to concrete to improve welfare and performance of finishing beef cattle reared on fully slatted flooring

The aim of this study was to compare a fully slatted concrete floor (concrete slatted (CS)) with the same floor on which synthetic rubber slats were placed on the concrete slats (rubber slatted (RS)) as housing solution for finishing beef cattle. The present study involved five commercial beef cattle farms in which the floor of at least three pens was kept as fully slatted, and in an equal number of pens a rubber cover was placed on the floor, tightly matching the gap profile of the concrete slats to allow the drainage of manure. A total of 326 finishing beef bulls were used (153 on CS and 173 on RS), and regardless of the floor treatment animals were housed in groups of 6 to 12 bulls/pen with a space allowance of 3.1±0.2 m²/bull. Bulls had similar initial live weights (422.3 kg on CS and 425.0 kg on RS), but bulls on RS were heavier at the end of the finishing period with a higher average daily gain than bulls kept on CS (1.53 v. 1.46 kg/day; P<0.05). The proportion of bulls treated for locomotor problems was lower in RS pens compared with CS. Rubber covering prevented the occurrence of bursitis, but it increased the odds for hoof overgrowth at end of the finishing period. Hoof overgrowth detected in vivo in bulls on RS was confirmed at the slaughterhouse by the longer dorsal wall and diagonal lengths of the hoof as well as by a more acute toe angle. Compared with bulls on CS, bulls on RS showed less inactivity and resting time, increased social interactions, decreased abnormal lying down and unsuccessful attempts to lie down, as well as shortened the time for lying down. Bulls in RS pens were dirtier compared with those in CS pens, likely due to the draining gaps being reduced to 11.6±1.2% of the total pen surface compared with the 16.9±1.7% in CS pens. This study gave further evidence about the positive effects of the RS floor on growth performance and welfare of finishing beef cattle, although compromising cleanliness and hoof overgrowth.     

Genetic correlation of longevity with growth, post-mortem, docility and some morphological traits in the Pirenaica beef cattle breed

Survival or longevity is an economically relevant trait in cattle. However, it is not currently included in cattle selection criteria because of the delayed recording of phenotypic data and the high computational demand of survival techniques under proportional hazard models. The identification of longevity-correlated traits that can be early registered in lifetime would therefore be very useful for beef cattle selection processes. The aim of this study was to estimate the genetic correlation of survival (SURV) with: growth - birth weight (BW), weight at 120 days (W120), weight at 210 days (W210); carcass - cold carcass weight (CCW), conformation (CON), fatness (FAT) and meat colour (COL); teat morphology - teat thickness (TT), teat length (TL) and udder depth (UD); leg morphology - forward (FL) and backward legs (BL); milk production (MILK) and docility (DOC). In the statistical analysis, SURV was measured in discrete-time intervals and modelled via a sequential threshold model. A series of independent bivariate Bayesian analyses between cow survival and each recorded trait were carried out. The posterior mean estimates (and posterior standard deviation) for the heritability of SURV was 0.05 (0.01); and for the relevant genetic correlations with SURV were 0.07 (0.04), 0.12 (0.05), 0.10 (0.05), 0.15 (0.05), -0.18 (0.06), 0.33 (0.06) and 0.27 (0.15) for BW, W120, W210, CCW, CON, FAT and COL, respectively.     

Administration of dexamethasone per os in finishing bulls. I. Effects on productive traits, meat quality and cattle behaviour as indicator of welfare

The study investigated the effects of prolonged oral administration of dexamethasone at a low daily dosage of 0.75 mg/head per day (Dexa) on beef cattle productive traits, behaviour and meat quality. In all, 14 finishing Marchigiana bulls were used in a trial that begun 56 days prior to slaughter, of which six bulls received treatment from day 5 to day 53, whereas the remaining animals were used for Control. The animals treated showed an increased average daily gain (1515 v. 1177 g/head per day; P < 0.05; s.e.d. = 48.54) and improved warm carcass dressing percentage (60.8% v. 59.7%; P < 0.05; s.e.d. = 0.32). Behavioural observation did not permit a clear distinction between treated and Control animals since feeding and social behaviour were similar in both groups. The bulls treated spent less time lying (16.5% v. 34.6%; P < 0.05; s.e.d. = 4.38) and grooming (6.7% v. 11.9%; P < 0.05; s.e.d. = 1.23), and this may indicate poorer welfare. No evidence of treatment was observed in other carcass traits, and redness was the only meat quality parameter slightly affected by corticosteroid administration.     

Effects of pre-weaning concentrate feeding on calf performance, carcass and meat quality of autumn-born bull calves weaned at 90 or 150 days of age

A study was conducted to evaluate the effect of pre-weaning concentrate feeding in early-weaned (EW, day 90) or traditionally weaned (TW, day 150) autumn-born beef calves on growth, feed intake and feed efficiency, and carcass and meat quality. Twenty-eight male calves were either EW or TW, and offered a starter concentrate (S) or no additional feed (NS) during the pre-weaning period. Therefore, four management strategies were tested: EWS, EWNS, TWS and TWNS. Growth patterns were affected by management strategy. From day 90 to 150, TWNS calves presented a substantially lower average daily gain (ADG) than their counterparts, which had similar performance. During the finishing phase (from day 150 to slaughter at 450 kg live weight), EWS calves had the lowest ADG. Daily feed intake or efficiency in the finishing phase was unaffected by previous management. Serum IGF-I concentrations at day 90 and slaughter did not differ with management strategy, but early weaning and pre-weaning concentrate feeding increased IGF-I concentrations at day 150. Circulating leptin concentrations were unaffected by age at weaning and pre-weaning concentrate feeding, except for leptin concentrations at slaughter, which were higher in S calves than in NS calves. Total concentrate intake from birth to slaughter and the concomitant feed costs were higher for EWS and EWNS calves than for TWNS and TWS ones. However, cow feed costs were lower for cows whose calves had been early weaned. Concerning carcass quality, early weaning improved dressing percentage and increased fatness score, and particularly TWNS calves presented a poorer conformation. Meat quality was not affected by management strategy. Considering the economic performance, TWS, EWNS and EWS strategies yielded a similar economic margin, whereas TWNS would be the least advisable strategy when calves are fattened in the farm until slaughter.     

Effects of lactoferrin feeding on growth,feed intake and health of calves

Abstract

Lactoferrin (LF) exhibits a broad spectrum of anti-microbial properties and may have regulatory functions in the immune system. In the present study, 40 calves (20 males, 20 females) were used to examine the effects of supplemental bovine LF added to colostrum and milk replacer (at 0.16%) on health, weight development and feed intake during a 70-day experimental period. The calves were allocated to a treatment group (n = 20) and a control group (n = 20); the groups were balanced in terms of sex, live weight and date of birth. Body weight and feed intake were measured at regular intervals. Blood and colostrum samples were collected to determine the content of IgG. In addition, colostrum and milk replacer samples were analysed for their LF concentrations. Significantly higher IgG values were observed in the LF treated than in the control group during the entire feeding experiment from week 2 to week 6. Calves receiving LF had less days of disease with less serious cases of diarrhoea than the control group. Body weight and feed intake were not significantly different between the treatments; in male calves LF-treated animals tended towards higher weight gains. This study indicates that LF is advantageous for health and may therefore be a beneficial supplement in the diets for neonatal calves.     

Intestinal parasite infections in pigs and beef cattle in rural areas of Chungcheongnam-do, Korea

The present study was performed to investigate the infection status of intestinal parasites in pigs and beef cattle in rural areas of Chungcheongnam-do, Korea. From November 2009 to April 2010, a total of 241 fecal samples of pigs and beef cattle (136 and 105, respectively) were examined by direct smear and centrifugal sedimentation methods. The overall positive rates of intestinal parasites among pigs and beef cattle were 73.5% and 4.8%, respectively, and the double-infection rate was 10.3% in pigs. Of 136 specimens from pigs, Balantidium coli, Ascaris suum, and Entamoeba spp. infections were found in 88 (64.7%), 24 (17.6%), and 5 cases (3.7%), respectively. Of 105 beef cattle, Entamoeba spp. infections were detected in 5 cases (4.8%). From these results, it is shown that pigs raised on rural farms in Chungcheongnam-do had a high B. coli infection rate and a moderate A. suum infection rate. These results demonstrate that environmentally resistant cysts or eggs could be widespread on the farms examined, and thus an effective hygienic management system is needed to prevent them from serving as the source of infection for human beings.