Calf Growth Research Articles

Effect of Bacillus subtilis C-3102 supplementation in milk replacer on growth and rumen microbiota in preweaned calves.

We aimed to assess the effect of feeding Bacillus subtilis C-3102 on the growth and rumen microbiota in the preweaned calves. Twelve newborn Japanese Black calves were randomly allocated to either the control (n = 6) or the treatment (n = 6) groups in the present study. Calves in the treatment group were offered B. subtilis C-3102 supplemented milk replacer throughout the preweaning period. Rumen fermentation during the first 21 days of life seemed to be slightly suppressed by feeding B. subtilis C-3102. This fermentation shift was probably attributed to the lower abundance of the core members of rumen microbiota until 21 days of age in the calves fed B. subtilis C-3102. However, feeding B. subtilis C-3102 did not influence the abundance of the core members of rumen microbiota at 90 days of age. Distribution of Sharpea spp. and Megasphaera spp., which potentially contribute to low methane production and are regarded as beneficial rumen bacteria, was higher in the rumen of calves fed B. subtilis C-3102 at 90 days of age. These results suggest that B. subtilis C-3102 supplementation in milk replacer could potentially contribute to the improvement of feed efficiency after weaning via the establishment of beneficial rumen bacteria.

The effect of different suckling feeding modes on the growth and development of calves in postnatal ontogenesis

One of the key areas of development of the cattle breeding industry in Russia is the creation of effective technological methods. They allow to carry out the improvement and establishment of new resource-saving systems for breeding young animals at an accelerated pace. It is essential to meet the modern requirements of meat production as an ecologically safe product. The aim of the research was to enhance the fattening qualities of Hereford bull calves while using mode-setting suckling of various ratios as an element of resource saving. The study was performed on "SAVA-Agro-Yapryk" OOO of the Tuymazinsky district of the Republic of Bashkortostan. The determination of the efficiency of the use of free and mode-setting suckling of various ratios made it possible to identify an effective method of raising young meat cattle. A three-fold mode suckling is used with separate keeping of young animals and mother cows. This makes it possible to keep the optimal microclimate parameters in the calf house, contributes to the rapid early adaptation of calves to the consumption of coarse feed and concentrates. It has a positive effect on the growth and development of calves and their meat productivity at the age of 18 months according to the parameters of removable fat mass, carcass mass and interior fat mass. All this promotes an increase in the sale of beef and an improvement in the level of production profitability to 13.93%.

Supplementation of dairy calves with digestive enzymes and fermentation products of Aspergillus oryzae and Aspergillus niger

The effect of supplementation with Aspergillus oryzae and A. niger fermentation products and digestive enzymes on weight gain, growth, and health of Holstein (n=11) and Jersey (n=9) calves was evaluated. All calves, individually housed, were fed unpasteurized waste milk at 0600 (2 L) and 1800 (2 L) for 49 days. All calves were fed ad libitum a calf starter that contained 18% CP; 2.5% fat; 8% CF; 14% ADF; 1.5% Ca; 0.5% P; 0.20 mg/kg Se; 2,273 IU/kg vitamin A; and 66 g/Tm of Lasalocid. Treated animals (five Holsteins and four Jerseys) were fed 2 g of commercial mixture of A. oryzae and A. niger fermentation products and the digestive enzymes α amylase, pectinase, endoglucanase, β glucanase, xylanase, and mannanase. Weight and height were recorded weekly using a Nasco© measuring tape and measuring stick, repectively. There was no interaction of treatment by breed by period (P=0.9636). Treatment did not affect weight gain across periods (P≥0.7215). As expected, Holsteins were heavier than Jerseys (P=0.0284) and both breeds increased in weight over time (P<0.0001). Treatment did not affect the height at the hip (P=0.7971) or withers (P=0.4248). Holstein’s height at the hip for the treatment group (HT) was 80.8 cm ± 2.31 at 49 days and 80.5 cm ± 3.25 for the control group (HC). Jersey treatment group (JT) ended with 85 cm ± 1.98 whereas the control group (JC) ended with 82.1 cm ± 2.17 at the hip. Height at the withers for HT measured 75.3 cm ± 2.62 compared to 80.5 cm for HC. Moreover, calves in JT at the end of the experiment measured 79.9 cm ± 1.23 compared to JC 76.7 cm ± 2.59. Health status did not benefit from the supplementation of A. oryzae and A. niger in combination with enzymes (P=0.1444). Supplementation with A. oryzae and A. niger fermentation products and digestive enzymes did not increase weight gain, growth, or health status in Holstein and Jersey calves fed waste milk under the tropical conditions in Puerto Rico.

RATE OF GROWTH AND SAFETY OF CALVES WITH DIFFERENT DURATION OF REARING IN INDIVIDUAL HUTCHES

As a result of the studies, it was found that from birth to 6 months of age calves reared in individual hutches up to 60 days of age grew more intensively compared to reared up to 30 and 45 days of age. Their live weight was by 3.3% (P<0.05) higher compared to their herd mates’ kept in hutches up to 30 days of age; the average daily increase in live weight was by 4.0% (P<0.05) higher, and the relative growth rate – by 3.0 p. p. in young animals kept in individual hutches up to 45 days of age, by 1.6%, 2.7% 2.0 p. p, respectively. The safety of calves in all experimental groups was 100%.

Growth and bacterial dynamics of beef calves during transition from milk/pasture to a high-concentrate diet added with tannins or medium-chain fatty acids

Context Rumen fermentation modulation with feed additives during the transition period to high-concentrate diets might help to avoid bacterial dysbiosis. Aims Assessing the effects of the addition of tannins and medium-chain fatty acids (MCFA) to the adaptation diet of beef calves to a high-concentrate ration on the rate of intake, animal performance and rumen bacterial composition. Methods Eighteen 7-month-old beef calves were abruptly weaned and transitioned over a 28-day period from a milk/grass regime to one of the following diets: a non-supplemented high-concentrate diet plus wheat straw, both given ad libitum (C); C plus 20 g/kg of a 65:35 chestnut and quebracho tannin extract; and C plus 6 g/kg of a commercial mixture of MCFA. Concentrate and straw rate of intake were recorded. Rumen fluid was collected on Days 0, 1, 7, 14, 21 and 28 at 0, 3, 6 and 9 h after feeding to characterise rumen fermentation. Samples from 0 h were analysed to assess the bacterial population using Ion Torrent sequencing. Key results The rate of intake of concentrates and straw, as well as daily gains and final weights, were similar (P > 0.05) among diets. The addition of tannins or MCFA did not modify (P = 0.98) the rumen bacterial population, which was affected by sampling day (P < 0.001). The additives inclusion did not affect relative abundances of the main bacterial taxa (P < 0.05), most of them differing across days (P < 0.001). Diversity indexes (Shannon and richness) declined over sampling days (P < 0.05), although some genera emerged after concentrate inclusion. Conclusions At the doses used in the present experiment, tannins and MCFA did not exert any effect on intake, animal performance and bacterial population. Abrupt transition to high-concentrate diets modified the rumen environment and bacterial community, indicating bacterial adaptation to new environmental conditions. Implications Abrupt transition of 7-month-old calves from milk/pasture to a high-concentrate diet did not impair rumen microbiota or performance; therefore, the use of feed additives seems unnecessary.

Utilizing an electronic feeder to measure individual mineral intake, feeding behavior, and growth performance of cow-calf pairs grazing native range.

Crossbred Angus cow–calf pairs (n = 28 pairs) at the Central Grasslands Research Extension Center (Streeter, ND) were used to evaluate an electronic feeder to monitor individual mineral intake and feeding behavior and their relationship with growth performance and liver mineral concentrations. Cows and calves were fitted with radio frequency identification ear tags that allowed access to an electronic feeder (SmartFeed system; C-Lock Inc., Rapid City, SD) and were provided ad libitum minerals (Purina Wind and Rain Storm, Land O’Lakes, Inc., Arden Hills, MN). Mineral intake, number of visits, and duration at the feeder were recorded over a 95-d monitoring period while pairs were grazing native range. Liver biopsies were collected from a subset of cows on the final day of monitoring and analyzed for mineral concentrations. Data were analyzed with the GLM procedure in SAS for mineral intake and feeding behavior with age class (cows vs. calves), intake category (high vs. low), and the interaction between class and category in the model. Correlations were calculated among cow feeding behavior and calf intake and growth performance with the CORR procedure, and a comparison of liver mineral concentrations among cows of high (>90 g/d; average 125.4 g/d) and low (<90 g/d; average 33.5 g/d) mineral intake was performed using the GLM procedure. High-intake calves (>50 g/d; average 72.2 g/d) consumed greater (P < 0.001) amounts of minerals than low-intake calves (<50 g/d; average 22.2 g/d) intake calves. Cows and calves attended the mineral feeder a similar (P = 0.71) proportion of the days during the experiment (overall mean of 20%, or once every 5 d). On days calves visited the feeder, they consumed less (P < 0.01) minerals than cows (222 ± 27 vs. 356 ± 26 g/d, respectively). Over the grazing period, calves gained 1.17 ± 0.02 kg/d, whereas cows lost 0.35 ± 0.02 kg/d. Calf mineral intake was correlated with cow duration at the mineral feeder (r = 0.403, P = 0.05). Cows with high mineral intake had greater (P < 0.01) concentrations of Se (2.92 vs. 2.41 ug/g), Cu (247 vs. 116 ug/g), and Co (0.51 vs. 0.27 ug/g) compared with low mineral intake cows, but liver concentrations of Fe, Zn, Mo, and Mn did not differ (P ≥ 0.22). We were able to successfully monitor individual mineral intake and feeding behavior with the electronic feeder evaluated, and the divergence in mineral intake observed with the feeder was corroborated by concentrations of minerals in the liver.

Эффективность комплексного применения антиоксиданта дигидрокверцетина и пребиотика арабиногалактана при выращивании телят в молочный период

Studies were conducted on two groups of calves during the growing period from 1 to 6 months in conditions of unfavorable respiratory and gastrointestinal diseases. Calves of the experimental group with a diet were given dihydroquercetin and arabinogalactan at a dose of 1 and 75 mg/ kg of live weight / day, respectively. DHQ and AG, in accordance with their biological properties, provided a high level of antioxidant protection, the formation of microbiocenosis and intestinal immunity, correction and control of mineral homeostasis in the body of calves. As a result, there was a normalization and increase in the intensity of protein, nitrogen, lipid, carbohydrate, energy and mineral metabolism, improved the functional state of the liver and increased pathogenetic resistance, which generally had a positive effect on the formation of productive health, viability and resistance of the body to the action of biotic and abiotic environmental factors, safety and average daily growth of calves.

Effect of season and temperature before and after calving on the future milk production of born heifers

Effect of season and temperature before and after calving on the future milk production of born heifers

Effect of sole maize and maize –lablab silage on the ruminal volatile fatty acids (VFAS) of grazing calves in the dry season

Silages of sole maize and mixtures of maize-lablab were made at harvest in plastic bags. The experimental Unit consists of twelve cross-bred yearling bulls (White Fulani x N’dama) calves weighing 71-72kg and were randomly allotted to three dietary treatments: Grazing + sole maize silage, Grazing + mixtures of maize-lablab silage and Unsupplemented grazing as control. The experimental design was a completely randomized design and lasted 84days. Silage diets were given between 07:30 and 11:00 hours daily before grazing. Rumen fluid was collected at the end of the study to evaluate the co-efficient of ruminal fluid. The crude protein content in sole maize silage was half of that in mixture of maize-lablab silage. Inclusion of lablab in maize stover silage increased the mineral content as well as the lignin fraction. The mean pH value of sole maize silage (3.80) was less (P &lt; 0.05) than 4.25 obtained with addition of lablab. The buffering capacity (5.37%) of sole maize silage significantly (P &lt; 0.05) increased to 5.71% in mixture of maize-lablab silage. Lactic acid contents differed was influenced significantly (P &lt; 0.05) with a mean value of 8.4% and 8.5% respectively in the sole maize silage and with lablab inclusion. Total volatile fatty acid (VFA) ranged from 56.7 μmoles/ml in calves without supplementation to 95.2 μmoles/ml in the calves fed mixture of maize-lablab silage. Mixture of Maize-lablab silage had the highest values for all the minerals determined in the feed materials while sole maize had the least. It was concluded from this trial, that forage legumes are relatively good sources of degradable nitrogen and fermentable energy, so their inclusion in the diet is likely to increase the rumen population of cellulolytic microbes and also proves that, mixture of maize-lablab silage could be used as supplement to enhance the growth and survival of calves during the dry season, when animal feeds are relatively scarce.

The effect of individual versus pair housing of dairy heifer calves during the preweaning period on measures of health, performance, and behavior up to 16 weeks of age

Pair housing of dairy heifer calves during the preweaning period helps meet the natural social needs of the calf and has been shown to improve growth and starter intake during the preweaning period as compared with individual housing. However, there is little evidence to suggest that pair-housed calves maintain their social and growth advantages past the weaning phase. The objective of this study was to investigate the effect of pair housing on measures of calf performance, health, and behavior up to 16 wk of age. Healthy Holstein and crossbred heifer calves were enrolled in the study after colostrum feeding, with the first calf randomly assigned to 1 of 2 housing treatments: pair (PR; 2 hutches with common outdoor space) or individual (INDV; 1 hutch plus outdoor space). All calves were bucket fed 4 L of milk replacer twice daily and weaned at 50 d of age. Weaned calves (6/group) remained with their treatment group until exit from the study at 16 wk. A venous blood sample was collected from each calf between 24 h and 7 d of age to test for serum total protein (g/dL). Body weights (kg) were obtained at birth, weaning, and 16 wk. Each enrolled calf was scored for health each week and calf health treatments were also collected. A hair sample was collected from the left shoulder at birth and 16 wk to assess hair cortisol (pg/mL). At enrollment, each calf was fitted with a triaxial accelerometer on the left hind leg for continuous recording of standing and lying time (min/24 h) for 16 wk. Latency to find feed, water, and lie down (min) at entrance to the weaned pen were recorded by continuous video observation. Open field testing with a novel object was performed at 5, 10, and 16 wk. Behaviors analyzed by video observation included latency to approach the object (s), vocalizations (n), and time spent immobile, walking, or running (s/10 min). Linear mixed models were used to determine the effect of treatment (INDV or PR) on calf growth, activity, and behavioral outcomes, which accounted for time, breed, the interaction of time and treatment, the random pen, and variability in testing day and repeated measurements within calf when appropriate. Twenty-four Holstein and crossbred calves (PR: n = 12, 6 pairs; INDV: n = 12) were enrolled from November 2 to December 23, 2018. The PR calves were 7.1 kg heavier at weaning and gained 0.15 kg/d more during the preweaning period as compared with INDV calves. In the 24 h after movement to the postweaning pen, PR calves lay down for longer periods of time (14.3 vs. 11.0 ± 0.4 h/d), and PR calves urinated more during novel object testing at 5 wk of age. Our study demonstrated benefits, such as better growth and increased lying time, of pair housing calves during the preweaning period.

Influence of starter crude protein content on growth and body composition of dairy calves in an enhanced early nutrition program

Our objectives were to determine the effect of starter crude protein (CP) content on body composition of male Holstein calves from birth to 10 wk of age in an enhanced early nutrition program, and to compare the enhanced program to a conventional milk replacer program. Calves (n = 45) were purchased on the day of birth and assigned to a randomized block design. Eight calves were harvested at baseline and remaining calves were divided among the following 3 dietary treatments: (1) low rate of milk replacer [LMR; 20.6% CP, 21.7% fat; 1.25% of body weight (BW) as dry matter (DM)] plus conventional starter (CCS; 21.5% CP, DM basis); n = 11 calves; (2) high rate of milk replacer (HMR; 29.1% CP, 17.3% fat; 1.5% of BW as DM for wk 1, 2% of BW as DM wk 2-5, 1% of BW as DM wk 6) plus conventional starter; n = 12 calves; and (3) enhanced milk replacer (HMR) plus high-CP starter (HCS; 26% CP, DM basis); n = 14 calves. A subset of calves (n = 8) was harvested on d 2 to provide baseline data. Calves began treatments on d 2 or 3 of age. Calves were weaned at d 42. Starter was available ad libitum. Calves from each treatment were harvested at 5 (n = 18) and 10 (n = 19) wk of age and divided into 4 fractions: carcass; viscera; blood; and head, hide, feet, and tail. Fractions were analyzed for energy, CP, lipid, and ash. Average weekly starter intake did not differ between enhanced treatments. Gain of BW was greater for calves fed HMR than for LMR, but was unaffected by starter CP. Carcass weights at 5 wk were greater for HMR but did not differ between starter CP content. At 10 wk, carcass weights were heavier for HMR and had a greater percentage of empty BW for HMR + CCS than for HMR + HCS. At 10 wk, the weights of reticulorumen and liver were greater for calves fed HMR + HCS than for those fed HMR + CCS. At 5 wk, empty BW gain for HMR contained more water and less fat and ash than in calves fed LMR. At 10 wk, empty BW gain for calves fed HMR + HCS contained a greater percentage of water and less fat than for calves fed HMR + CCS. Plasma β-hydroxybutyrate was greater after weaning for calves fed HMR + HCS than for those fed HMR + CCS. After weaning, calves fed HMR had greater plasma total protein concentration than those fed LMR, and total protein was greater for calves fed HMR + HCS than those fed HMR + CCS. Plasma urea N was greater for calves fed HMR treatments, and postweaning was greater for calves fed HMR + HCS. A high-CP starter had minimal effect on empty BW gain before weaning, but after weaning it tended to increase mass of reticulorumen and liver.

Short communication: Associations of serum biomarkers of stress and inflammation measured at arrival with health, mortality, and growth of calves transported within the first 4 days of life

The objective of this study was to assess the association between serum concentrations of haptoglobin (Hp), cortisol, and l-lactate following transport of dairy heifer calves within their first week of life with health, mortality, and growth during the preweaning period. Blood samples were collected at arrival and included a cohort of 168 Jersey and Jersey-cross calves from 8 different sources located in Minnesota. All calves were raised at a single facility in New Mexico. Incidence of respiratory disease (BRD) and mortality during the preweaning period (60 d of life) were extracted from the farm's software database. Individual body weight was measured at birth and at weaning to estimate average daily gain. No simple linear correlations were found between the biomarkers. The incidence of BRD during the preweaning period was 7.7%. While cortisol and l-lactate serum concentrations were not associated with BRD, Hp was negatively associated with BRD. Receiving operating characteristic curve analysis was performed to determine the optimal threshold value for Hp [threshold ≤0.63 μmol/L (63 μg/mL), area under the curve = 0.65]. A Cox's proportional hazards model revealed that calves with Hp concentration ≤0.63 μmol/L were more likely to be diagnosed with BRD (hazard ratio = 5.0, 95% confidence interval = 1.3-19.0). A mixed linear model showed that calves with Hp concentration ≤0.63 μmol/L tended to have lower average daily gain (454.4 vs. 479.9 g/d) during the preweaning period than calves with Hp >0.63 μmol/L at arrival. Overall mortality of the cohort was 3.5%, and Hp was not associated with mortality. Although circulating concentrations of l-lactate and cortisol measured at arrival were not associated with BRD incidence during the preweaning period of heifer calves transported within the first 4 d of life, calves with serum Hp concentration >0.63 μmol/L were less likely to be diagnosed with BRD and tended to grow more than calves with Hp ≤0.63 μmol/L. Further research is needed to replicate these results in a larger cohort and to better understand the possible influence of greater inflammatory status at arrival on health and growth of calves transported to a calf-raising facility.

Effect of increasing the amount of hay fed on Holstein calf performance and digestibility from 2 to 4 months of age

A good transition from a mainly liquid diet to a solid diet of concentrates and forages is important considering the small size and development of the calf's rumen. However, the optimal amount of hay or other high-fiber ingredients in the diet of recently weaned calves is not well defined. The objective of this trial was to determine the effects of feeding 0, 5, or 10% chopped grass hay (6.5% crude protein, 64.6% neutral detergent fiber) with a textured, high-starch starter (20.5% crude protein, 38.4% starch, 14.1% neutral detergent fiber; protein pellet, whole corn, and oats) on performance and digestion in Holstein steer calves between 2 and 4 mo of age. Forty-eight calves (initial body weight = 90.7 ± 2.15 kg) were housed in group pens (4 per pen) and fed diets and water for ad libitum intake. Feed offered and refused was measured daily. Calf body weight, hip width, and body condition score (1-5 scale) were measured initially and at 28 and 56 d. Fecal samples were collected from the pen floor with care not to sample bedding material and composited by pen during d 5-9, 26-30, and 47-51 to estimate apparent total-tract digestibility using acid-insoluble ash. Data were analyzed as a completely randomized design with repeated measures and pen as the experimental unit. As grass hay increased, dry matter intake (kg/d) decreased linearly but tended to change quadratically. Dry matter intake as a % of body weight changed quadratically with increasing hay, increasing from 0 to 5%, and decreasing from 5 to 10% hay. Average daily gain (1.15, 1.12, and 0.95 kg/d), feed efficiency (0.336, 0.319, and 0.309 kg of average daily gain/kg of dry matter intake), and hip width change (4.6, 4.7, and 4.1) decreased linearly with 0, 5, and 10% hay, respectively. Overall estimates of dry matter, organic matter, neutral detergent fiber, acid detergent fiber, and crude protein digestibility changed quadratically with hay, increasing from 0 to 5%, and decreasing from 5 to 10% hay, whereas digestibility of starch, sugar, and fat decreased linearly with increasing hay. Digestibility of dry matter, organic matter, neutral detergent fiber, and acid detergent fiber increased from 2 to 3 mo of age, and decreased from 3 to 4 mo of age. Digestibility of starch decreased linearly and digestibility of fat and crude protein increased linearly with age. Digestive capacity did not appear mature by 4 mo of age. Feeding 5% chopped hay supported optimal digestion and growth in calves 2 to 4 mo of age, which agrees with previously published research.

Adding monoglycerides containing short and medium chain fatty acids to milk replacer: effects on health and performance of preweaned calves

The aim of this trial was to investigate the effects of a blend of monoglycerides of short- and medium-chain fatty acids (SMCFA) on health status and growth of preweaned male calves from 16 to 72 days of age. The in vivo study was conducted as a complete randomised block design. Twenty Italian Holstein calves received starter administered ad libitum and 6 L of milk replacer/day (12% powder concentration) and were divided into treated (T) and control (C) groups. A preliminary in vitro antibiotic activity test of SMCFA was performed on several bacterial strains showing a minimum inhibiting concentration ranging from 0.8 to 12.5%. The group T received SMCFA (11 g/day) within the milk replacer while, to obtain isoenergetic liquid diets, the group C received additional 18 g/day of milk replacer powder. Body weight and morphological measurements of the calves were performed weekly. Health scores were checked daily. Faecal and blood samples were collected every two weeks for routine clinical investigations including serum concentration of non-esterified fatty acids and β-Hydroxybutyric acid. At the end of the trial calves were slaughtered and gastrointestinal tract (GIT) organs weighed. The group T reported a better health status and did not require Ab therapy. No differences in biometrical measurements, feed efficiency, blood parameters, and GIT measures were found between the two groups. At 44 days of age, group T showed higher β-Hydroxybutyric acid concentration compared to group C (p < .05). The SMCFA improved the calf health status avoiding the use of antimicrobics. HIGHLIGHTS The monoglycerides of short and medium chain fatty acids improve calf health status. The monoglycerides of short and medium chain fatty acids reduce the need for antibiotic treatment. The monoglycerides of short and medium chain fatty acids reduce the negative impact of enteropathogens.

Sire Effects on Post-Weaning Growth of Beef-Cross-Dairy Cattle: A Case Study in New Zealand.

Simple SummaryCattle born in the dairy industry are a very important source of beef. This study evaluated the growth of calves born to dairy cows and sired by a range of Angus and Hereford bulls. The sire had effects on live weights of their progeny at all ages. Growth trajectories differed among beef sires and the differences in live weights between the lightest and heaviest sires increased as live weight increased. Live weight at early age could explain a large proportion of live weights at later ages. Thus, using beef sires selected for growth has the potential to increase the live weight of cattle born on dairy farms for meat production. Little is known about the growth performance of beef sires used over dairy cows in New Zealand. This experiment aimed to evaluate the growth of Angus and Hereford sires via progeny testing of beef-cross-dairy offspring born to dairy cows and grown on hill country pasture. Live weights at 131, 200, 400, 600 and 800 days were analysed from a dataset of 5208 records from 1101 progeny of 73 sires. The means of the progeny group means for live weight were 118.6 kg at 131 days, 159.1 kg at 200 days, 284.2 kg at 400 days, 427.0 kg at 600 days and 503.6 kg at 800 days, and the overall daily growth rate was 0.58 kg/day from 131 to 800 days. The sire affected (p < 0.05) the live weight of their progeny at all ages. Differences in live weights between the lightest and heaviest progeny group means increased from 19 kg at 131 days to 90 kg at 800 days. Even though growth of calves was likely restricted to 200 days, live weight at 200 days explained 51–56% of the variation in live weights at 400 and 600 days (p < 0.05). Thus, the use of beef sires selected for growth has the potential to increase the live weight of cattle born on dairy farms for meat production.

Low doses of lactoferrin supplementation in weaning calves

Low doses of lactoferrin supplementation in weaning calves

Textured vs pelletted feed impact on dairy heifers pre-weaning

Textured vs pelletted feed impact on dairy heifers pre-weaning

Feeding selenium-biofortified alfalfa hay during the preconditioning period improves growth, carcass weight, and nasal microbial diversity of beef calves.

We previously reported that feeding Se-biofortified alfalfa hay to weaned beef calves in a preconditioning program decreases morbidity and mortality during the feedlot period. To understand the mode of action by which supranutritional Se supplementation supports calf health, we examined the effect of agronomic Se-biofortification on nasal microbiome and fecal parasites. Recently weaned Angus-cross beef calves (n = 30) were randomly assigned to two groups and fed an alfalfa hay-based diet for 9 weeks in a preconditioning program. Alfalfa hay was harvested from fields fertilized with sodium selenate at a rate of 0 or 90 g Se/ha. Calculated Se intake from dietary sources was 1.09 and 27.45 mg Se/calf per day for calves consuming alfalfa hay with Se concentrations of 0.06 and 3.47 mg Se/kg dry matter, respectively. Feeding Se-biofortified alfalfa hay for 9 weeks was effective at increasing whole-blood Se concentrations (556 ± 11 vs 140 ± 11 ng/mL; P < 0.001) and increasing body weight (PTreatment, = 0.03) in weaned beef calves. Slaughter yield grades were higher for calves that had been fed Se-enriched alfalfa hay during the preconditioning period (PTreatment = 0.008). No significant differences were observed in fecal parasite load, which remained low. The nasal microbiome and microbiota diversity within calves and across calves expanded from weaning (week 0) to the feedlot period (week 12), which was promoted by feeding Se-biofortified alfalfa hay. Especially concerning was the expansion of nasal Mycoplasmataceae in the feedlot, which reached over 50% of the total microbiota in some calves. In conclusion, we identified dietary Se-biofortified alfalfa hay as a potential promoter of nasal microbiome genome and microbiota diversity, which may explain in part high-Se benefits for prevention of bovine respiratory disease complex in beef calves.

Growth and development of calves of different genetic background in the pre-weaning period

Development of a living organism, including periods of its development, follows certain laws. All mammals have a pre-weaning period. In calves, the pre-weaning period lasts 6 months. This period is known to be one of the most important, since at this time the body, firstly, adapts to new environmental conditions, and secondly, starts to live on typical feeds. The calf growth depends on many factors, including genetic ones. The study of the dynamics of live weight in calves in the pre-weaning period with regard to their genetic background is of practical relevance. The farm uses bulls of both Holstein black-motley cattle of domestic selection and Holstein breed of foreign selection. A general pattern in monthly live weight increase has been found for descendants of all the bulls. At the same time, the growth rate in groups of calves sired by different bulls differed by months of rearing. In calves sired by the bull Mers, the absolute weight gain by months of rearing ranged from 10.0 kg (4 months) to 36.0 kg (6 months), that is, the growth failure in the previous period was compensated for by increased growth rate in the next month. At the same time, calves sired by the bulls Gavano, Cassio and Bentley showed a uniform absolute weight gain by months of rearing. In general, calves sired by the bulls Cassio and Gavano grew better. They were superior to other calves in the absolute weight gain over the entire period, which attained 138.5 and 132.2 kg, and it was higher by 6.3–20.9 and 5.3–14.6 kg or 4.5–15.1% and 4.0–11.0%, respectively.

Effect of the balanced carbohydrate complex Felucene on growth and development of bull calves

The use of balanced multicomponent supplements is highly promising. In this regard, we believe it will be relevant to use a balanced carbohydrate complex under the trade names Felucene K 2-4 and Felucene K 2-6 for agricultural animals of a specified age in accordance with the instruction for use. The inclusion of the studied supplements in the ration of young cattle in various doses made it possible to trace changes in growth and development of young Hereford breed. The experiments showed the best result demonstrated by animals of experimental group III, who received the supplement K 2-4 at a dose of 100 g and K 2-6 at a dose of 150 g per animal per day, respectively. Further research is planned to study post-slaughter indicators in order to assess the quality of meat products.