Calf Growth Research Articles

Short communication: Effects of transition milk and milk replacer supplemented with colostrum replacer on growth and health of dairy calves

Transition milk (TM, defined here as the second through fourth milkings after calving) supplies additional fat, protein, and immunoglobulins to the calf compared with milk replacer at industry-suggested feeding rates (∼14% solids). Our objective was to determine whether 9 feedings of TM on d 2 through 4 of life increase the growth rate and overall health of calves. Holstein heifer calves on a commercial farm were randomly assigned to 1 of 3 diets (n = 35/diet): milk replacer (MR; Purina Warm Front BOV MOS Medicated Milk Replacer, St. Louis, MO), TM, or a 50:50 blend of MR and colostrum replacer (MCR; Alta HiCal Colostrum Powder Replacer, the Saskatoon Colostrum Company Ltd., Saskatoon, SK, Canada). The TM was harvested from Holstein cows on the farm, pooled, and pasteurized at 71.7°C for 15 s. Nutrient composition on a dry matter basis of TM was 25.9% fat, 41.8% protein, and 14% solids; MR was 10.3% fat, 27.8% protein, and 14% solids; and MCR was 14.6% fat, 38.6% protein, and 15% solids. All calves received IgG-enriched colostrum replacer for the first 2 feedings after birth. Subsequently, calves were fed 1.9 L of MR, TM, or MCR 3 times per day for 3 d (starting on d 2). After initial diets ended, calves were fed and managed similarly. Body weights (d 1, 7, 14, 21, and 56), blood samples (d 1, 7, 14, and 21), and daily health scores (scale of 0 to 3, with 0 representing normal or healthy and 3 representing severe symptoms or ill) were collected through weaning at 56 d. All except 1 calf achieved successful transfer of passive immunity, with serum IgG values greater than 10.0 mg/mL. From birth through weaning, calves fed TM and MCR gained 3 kg more total body weight than those fed MR (34.3, 34.3, and 31.3 kg, respectively). Increased metabolizable energy (using NRC 2001 recommendations) in TM accounts for 0.68 kg of the increased gain compared with MR. Treatment did not alter health scores for ears, eyes, or feces. Haptoglobin concentrations were lower in TM and MCR than in MR calves (4.63, 3.62, and 7.54 µg/mL, respectively), whereas lipopolysaccharide binding protein concentrations were not different. In conclusion, compared with MR alone, feeding TM or MR with colostrum replacer for 3 d increased growth rate of calves throughout the preweaning period.

Factors associated with calf mortality and poor growth of dairy heifer calves in northeast Germany

A cross-sectional study was conducted on fifty German dairy farms to identify risk factors for high mortality and poor growth in calves. Between 2012 and 2014, farm visits took place and a questionnaire on farm management practices was completed by in-person interview. In addition, heart girth measurements of calves around weaning were performed to estimate average daily weight gain. Furthermore, blood and faecel samples of calves were collected and a score addressing calf welfare was determined. The epidemiological associations between risk factors and high mortality and poor growth were estimated using two regression models. The factors significantly associated with high calf mortality (> 5%) were a high rate of calves with failure of passive transfer (> 25%) and the metaphylactic use of halofuginone lactate. A small amount of concentrates consumed around weaning, relocating calves more than twice until weaning and a low incidence risk of milk fever (< 5%) were found to be significantly associated with poor growth (median: 675 grams). Although the fifty farms cannot be considered as a representative sample for North-East Germany, the results indicate that the farm management has a big impact on growth and survival of dairy calves and needs to be addressed more thoroughly when raising the future dairy cow.

Efficacy of a stabilized liquid potassium sorbate preservative to reduce bacterial proliferation in colostrum or tank milk stored by refrigeration or at room temperature

Though critical to calf health and growth, colostrum exposure of dairy calves to infectious agents, potentially resulting in calfhood illness and/or reduced absorption of colostral antibodies. While FDA-approved preservatives such as potassium sorbate may represent 1 approach to reduce bacterial proliferation in stored colostrum or milk, efficacy studies are relatively limited. Objectives of this study were to describe the effect of a stabilized liquid potassium sorbate preservative product (Dam Fresh™, Solution BioSciences, Inc (SBS), Inc. Morristown, NJ) on 1) bacterial proliferation in bovine colostrum and milk when stored by refrigeration and at room temperature, and 2) immunoglobulin G (IgG) levels in colostrum. We hypothesized that the preservative would reduce bacterial proliferation in stored milk and colostrum while having no negative effect on colostrum IgG levels.

Perspective on the evaluation of dairy calf rearing operations

The basis for evaluation of calf rearing operations is to determine the role of the operational activities in affecting calf growth and development. The evaluation process should include the following; understanding and establishment of expectations for physiological growth and development, unbiased observation of the existing operation, compilation of operational activities and facilities as they relate to observed performance, identification and explanation of strengths and weaknesses, prioritization of corrective measures including impact on the operational function and economics, and a plan for education and implementation of corrective measures with expected outcomes. The evaluative process can help improve the calf rearing operation by focusing the operational activities on quality care of the calf to enable optimal genetic expression.

Effects of feeding frequency and protein source in milk replacer for Holstein calves

Whey proteins are a primary component of milk replacers (MR) and are considered the gold standard for calves. Alternative protein sources may decrease MR cost if calf performance is similar. A blend of bovine plasma protein and modified wheat protein might be a good partial replacement for whey protein. Usually MR is fed twice daily, but feeding 3 times daily might increase efficiency of nutrient use, especially with MR containing alternate proteins. Therefore, our objective was to determine the effects of 2 MR, containing either entirely whey protein (CON) or a combination of whey protein, bovine plasma protein, and modified wheat protein (WBP), when fed in either 2 or 3 meals daily on calf growth and health. Female and male Holstein calves (n = 103) housed in individual hutches were studied for the first 63 d of life, with additional measurements obtained at wk 12 of life in group housing. The MR contained 25% CP, 17% fat, and a Lys:Met ratio of 3.1:1. Individual treatments arose from the 2 × 2 factorial arrangement of MR formulation and frequency of feeding. After colostrum, calves were fed MR (12.5% solids) at daily rates of dry matter dependent on age. Amounts were as follows: d 3 to 10 = 0.52 kg/d (2× = 0.259 kg, 3× = 0.173 kg per feeding); d 11 to 20 = 0.68 kg/d (2× = 0.341 kg, 3× = 0.227 kg per feeding); d 21 to 42 = 0.84 kg/d (2× = 0.42 kg, 3× = 0.28 kg per feeding); d 43 to 46, 47, 49, and 51 = 0.42 kg/d, with both 2× and 3× changed to 1 feeding daily and skip days (d 48 and 50) between where calves were not given MR; and d 52 = calves weaned. Starter was fed and intake was measured from d 1 until d 63. Intakes, health scores, attitude scores, and fecal scores were measured daily. Body weight (BW) and growth measurements were obtained weekly until wk 8 and again at wk 12. Blood samples were obtained at 0, 24, and 48 h and then on d 5, 14, 28, and 42 of age. Starter intake was greater for calves fed WBP versus CON during wk 7 to 9. Final BW and hip width at wk 12 were greater for calves fed WBP than for calves fed CON. Calves fed 2× had greater mean and final BW to wk 6 and greater feed efficiency (gain:feed ratio) than calves fed 3×. Blood variables supported the generally similar growth outcomes. Health outcomes did not differ between diets or feeding frequencies. Overall, calves fed WBP had increased starter intake and greater BW gains during wk 7 to 12 than calves fed CON, and calves fed 2× had increased growth and feed efficiency compared with those fed 3×.

Effects of inorganic selenium injection on the performance of beef cows and their subsequent calves

Sixty-seven pregnant Angus cows and their subsequent calves were used in a randomized design to evaluate the effect of inorganic Se injection from 80 d of gestation until weaning on cow reproductive parameters, BW and BCS evolution, milk yield and quality, calf growth and calf hematology parameters. The treatments were as follows: 1) Se+: cows were administered Se as sodium selenite at doses of 0.05 mg/Kg of BW at 80, 140, 200, 260 d of gestation and 30, 90, 150 and 240 d of lactation. Calves from Se + cows were Se as sodium selenite subcutaneously injected with a dose of 0.05 mg/Kg of BW at 70, 104, 144 d of age; 2) Control: cows and calves were administered sterile NaCl solution (9 g/l) at the same volume and intervals as Se + treatment. At the start of the experiment, forage Se concentration was 58.6 ppb ± 7.6 ppb, and cow whole blood Se concentration was similar (P > 0.10) between treatments (Se+, 29.3 ± 0.3 ppb; Control, 28.1 ± 0.5 ppb). After Se injection, cow whole blood Se concentration was increased (P < 0.01) in Se + cows in relation to control cows until the end of the experiment. Calf whole blood Se concentration was increased (P < 0.01) at birth and 30 d of age in calves from Se + cows compared to calves from Control cows. However, calf whole blood Se concentration was not different (P > 0.10) between treatments at d 70 after birth. After the first Se injection (70 d of age), calf whole blood Se concentration was increased (P < 0.01) at 104 and 144 d of age in calves from Se + cows compared to calves from Control cows. Cow BW and BCS did not differ (P > 0.10) between treatments throughout the experiment. Ovarian follicle diameter measured by ultrasound 47 d postpartum was greater (P = 0.03) in Se + cows compared to Control cows. Pregnancy rate to fixed time artificial insemination (FTAI), overall pregnancy rate (P > 0.10) and pregnancy loss (P = 0.19) did not differ between groups. Selenium injection did not affect (P > 0.10) milk yield and composition. Calf morphometric parameters, BW at birth and growth rate during lactation were not affected (P > 0.10) by treatments. No significant effect (P > 0.10) was observed between treatments on hematological results of blood samples from calves at weaning. Results of this study shown that inorganic Se injection was an efficient tool to improve Se-status in cow-calf operation under extensive management. Selenium injection increased follicle diameter in postpartum beef cow, however, did not affect the rest of the variables studied.

Effects of rumen-protected methionine or methionine analogs in starter on plasma metabolites, growth, and efficiency of Holstein calves from 14 to 91 d of age

During weaning, methionine (Met) supply decreases as liquid feed intake is reduced and ruminal function is developing. During this transition, the calf starter should both promote ruminal development and provide adequate nutrients post-ruminally. In mature ruminants, rumen-protected Met (RPM) and the Met analogs, 2-hydroxy-4-(methylthio)-butanoic acid (HMTBa) and HMTBa isopropyl ester (HMBi), are used to increase Met supply, stimulate ruminal fermentation, or exert both effects, respectively. To evaluate the effects of these forms of Met on calf performance during development of ruminal function, 74 Holstein calves were raised until 91 d of age, in 2 enrollment periods. Calves were individually housed from birth and, at 14 d of age, balanced for sex and randomly assigned to receive a starter with no added Met (CTRL, n = 20) or one supplemented with RPM (Smartamine M, Adisseo USA Inc., Alpharetta, GA; n = 16), HMTBa (RumenSmart, Adisseo; n = 19), or HMBi (MetaSmart, Adisseo; n = 19). Milk replacer [28% crude protein (CP), 15% fat] was offered up to 1.6 kg of dry matter (DM)/d and fed 3 times daily. Weaning was facilitated from d 49 to 63. The 4 starters (25% CP, 2.5 Mcal of metabolizable energy/kg of DM) were offered ad libitum, and supplement inclusion was set to provide an additional 0.16% DM of Met equivalents, and equal amounts of HMTBa within the analogs. Body weight and stature were measured, and blood was collected and analyzed for plasma urea nitrogen, β-hydroxybutyrate, and free AA on a weekly basis. Supplementation of RPM and HMBi increased free plasma Met, but no differences in growth or feed efficiency compared with calves fed the CTRL starter could be attributed to the additional Met supply alone. The addition of HMBi in the starter increased feed intake and body weight during the last weeks of the experiment. On the contrary, HMTBa failed to increase plasma Met and depressed intake and growth after weaning, likely because the level included in the diet was too high and intake was greater than previous studies, exacerbating the level of HMTBa ingested. No differences were observed in stature, feed efficiency, or non-AA plasma measurements among groups. These results demonstrate that RPM and HMBi are effective sources of metabolizable Met; however, Met was apparently not limiting calves fed the basal diet in this study. The increased feed intake observed with the inclusion of HMBi in the starter during the weaning and early postweaning period might be mediated by its metabolism in the rumen, and further research is needed to determine the mechanisms involved.

Feeding an amino acid–formulated milk replacer for Holstein calves during 2 time periods

The milk-fed calf has a requirement for essential amino acids (EAA) instead of crude protein (CP). However, most milk replacers (MR) are still formulated to a CP concentration, and although limited amounts of Lys or Met may be added, these MR are not formulated solely on an AA basis. Previous work has demonstrated that feeding a modified MR balanced for specific EAA concentrations of a 24% CP MR, but reducing CP to 22%, resulted in improved growth performance in calves compared with a 24% CP MR. The 56-d objective was to determine if the hypothesis that an EAA MR formulated to the specific EAA concentrations of a 24% CP MR, but reducing CP to 22 (22AA) compared with a standard 22% CP MR would result in similar or enhanced growth performance, while reducing feed costs. Two 56-d studies using forty 3- to 5-d-old Holstein bull calves per study received in 1 lot starting on May 8, 2018 (late-spring cooler) and June 22, 2018 (summer with heat stress) were blocked by body weight (BW) and randomly assigned to 1 of 2 MR treatments. Milk replacer treatments consisted of a standard 22:20 (CP:fat; 22CP) and a 22:20 MR with greater EAA concentrations of a 24% CP MR (22AA). All MR, containing decoquinate and diflubenzuron, were fed at 0.57 kg/d per calf split into 2 feedings at 0630 h and 1800 h for 0 to 14 d via bucket, increased to 0.85 kg/d through 35 d split in 2 feedings, and fed once per day at 0.41 kg/d in the morning with weaning after 42 d. Calves were housed in straw-bedded hutches with ad libitum access to water and 25% CP pelleted calf starter (CS). All data were analyzed as a randomized complete block design with block within study considered random and week as a repeated measurement. Initial BW was similar across all treatments (39.9 ± 2.32 kg). Average daily temperature (i.e., heat stress intensity) tended to be greater for calves in study 2 compared with study 1 (20.5 and 22.9°C for study 1 and 2, respectively). The interaction of study and MR effects were nonsignificant. Calf BW, BW gain, average daily gain, CS intake, total dry matter intake (MR plus CS), feed conversions, and EAA intake (MR plus CS) were similar for calves fed both MR. Study 2 (summer heat stress) resulted in more scours incidences compared with study 1, and 22AA MR formulation tended to increase scours possibly due to synthetic AA addition or greater carbohydrate (lactose) inclusion when AA replaced protein sources. Feed costs as MR and total feed costs were lower for calves fed 22AA MR compared with calves fed 22CP MR. The increased Leu, Lys, Met, Thr, and Val concentrations in the 22AA MR compared with the 22CP MR resulted in similar calf growth performance, but the feed cost was lower for calves fed the 22AA MR, which achieved similar growth performance at a lesser cost under current study conditions, but not enhanced as hypothesized.

Associations between maternal milk protein genotypes with preweaning calf growth traits in beef cattle.

The objectives of this study were to investigate milk casein polymorphisms in dams and to determine the impacts of maternal casein genotypes on growth traits of their sucking calves. Milk samples from 433 dams of the breeds German Angus (GA) and German Simmental (GS) were typed at the milk protein loci α s1-casein (αs1-CN), β-casein (β-CN), α s2-casein (αs2-CN), and κ-casein (κ-CN) via isoelectric focusing. Associations between casein genotypes in maternal milk with growth traits of their 1,872 calves were analyzed until the age of weaning using linear mixed models, considering either genotypes of individual casein loci (model 1) or composite α s1-β-α s2-κ-CN genotypes within the casein cluster (model 2). Besides environmental effects such as sex, age of the dam, and calving year-season, genetic effects (breed group and maternal and paternal effects) were considered in statistical models. The composite casein genotype BBǀA2A2ǀAAǀAB (order of genes on bovine chromosome 6: α s1-ǀβ-ǀα s2-ǀκ-CN) was associated with greater average daily weight gains (ADG) and heavier age-adjusted weaning weights (WW) of calves (P < 0.05). The effects of composite genotypes on birth weight of calves were similar (P > 0.05; model 2). With regard to individual casein loci, greater ADG and WW were observed for calves from dams with the genotypes κ-CN BB and α s1-CN BB, respectively (P < 0.05; model 1). Age-adjusted WW was largest for calves from dams carrying the κ-CN genotype BB (215 kg) compared with calves representing the maternal AB and AA genotypes (both 204 kg). Results from the present study suggested selectable casein genotypes due to their nutritional value of milk (value in terms of offspring performances), offering new perspectives for breeding strategies in beef cattle to improve preweaning calf performance.

Quantification of cow milk yield and pre-weaning calf growth response in temperate pasture-based beef suckler systems: A meta-analysis

The objectives of this study were to quantitatively summarize factors associated with cow milk yield (MY) and calf growth response in pasture-based beef cow-calf suckler systems and to discern how cow genotype and parity influenced these responses. A dataset of 344 treatment mean observations was compiled from 69 studies that reported data on cow MY, and calf pre-weaning average daily live weight gain (ADG) and/or weaning weight (WW). Data were analysed using linear mixed effects models with study and region included as random effects. Models were developed for cow MY, calf ADG and WW response and each model was evaluated based on different model fit statistics. The final cow MY model included cow origin (Dairybeef or Beef), cow maturity (early-maturing (EM) or late-maturing (LM) genotypes) and parity. Dairybeef produced 35.4% more milk (8.64 vs. 6.38 kg/day) than Beef cows, and LM produced 20.9% more milk (8.20 vs. 6.78 kg/day) than EM genotypes (P < 0.001). Multiparous cows had a 14.8% higher MY (8.11 vs. 7.06 kg/day) compared to primiparous cows (P < 0.001). Lactation curve persistency was better (P < 0.05) for Beef and EM compared to Dairybeef and LM genotype cows, respectively. The final models of calf ADG and WW included cow origin, cow maturity and parity. Calves from Dairybeef and LM cows were 14 and 20 kg heavier (P < 0.001) at weaning (210-day adjusted) compared to those from Beef and EM genotype cows, respectively. Calves from multiparous cows were 13 kg heavier at weaning than those from primiparous cows (P < 0.001). The response in calf ADG associated with a 1 kg increase in cow daily MY was 47 and 53 g for Dairybeef and Beef cows, respectively (P < 0.001). Corresponding responses for EM and LM cows were 51 and 55 g (P < 0.001). In conclusion, the relationships between cow MY and calf pre-weaning growth, as well as the quantitative impact of cow genotype and parity were determined for pasture-based beef suckler systems; the coefficients generated can be used for improving beef cow-calf management strategies, beef cattle breeding programmes and bio-economic modelling purposes.

Bone Morphology and Strength in the Mid-Diaphysis of the Humerus and Metacarpus in Dairy Calves Prior to Weaning.

Simple SummaryCalf growth and nutrition has been thoroughly researched in relation to future milk production. The effect of nutrition on growth has been overlooked, however, and the emergence of humeral fractures in first lactation heifers has driven the need for further research. The aim of this study was to understand the relationship of calf growth with bone measures such as size and density prior to weaning. Liveweight, height, body length, girth and leg length were measured at one, six and twelve weeks of age. At these intervals, the middle of the metacarpus was also scanned using a CT scanner. At the six and twelve weeks measures, a subset of calves were euthanised and the humerus was collected and scanned in the middle of the bone. Differences in growth between the metacarpus and humerus were observed over time. Liveweight was the main driver of the majority of bone measures in both the metacarpus and humerus. The strong relationship between weight and bone shows the importance of adequate preweaning nutrition to ensure adequate future bone growth.Calf growth rate in relation to future milk production has been thoroughly studied; however, the observation of growth arrest lines in bones from heifers with humeral fractures has highlighted the need to understand bone growth in relation to calf growth. The aim of this study was to describe the relationship of peripheral quantitative computed tomography (pQCT)-derived measures of bone strength and morphology with gross measurements of size and growth in pre-weaning dairy calves. Liveweight, height, body length, girth and leg length were measured at one, six and twelve weeks of age. At these intervals, the mid-diaphysis of the metacarpus was also scanned in the live animal using pQCT. At six and twelve weeks old, a subset of calves were euthanised and the humerus was collected and scanned at the mid-diaphysis using pQCT. Differences in growth patterns were observed between the metacarpus and humerus over time. Weight was the best predictor for measures of periosteal circumference and stress strain index (R2 = 0.49–0.58) in the metacarpus, and also the best predictor for measures of stress strain index at all ages in the humerus (R2 = 0.94). The strong relationship with weight and bone measures emphasises the need for adequate preweaning nutrition for future bone growth.

Novel Encapsulated Calcium Butyrate Supplement Enhances On-Farm Dairy Calf Growth Performance and Body Conformation in a Pasture-Based Dairy Production System.

Simple SummaryThe problem addressed in this study was that of enhancing healthy gut development in calves with the aim of promoting early weaning through faster growth using encapsulated calcium butyrate (ECAB, ButiPEARL™, Kemin Industries, Inc., Des Moines, IA, USA). Results showed that supplementation of neonatal calves with ECAB at 4 kg/ton of calf starter feed, under a pasture-based dairy production system, had a significant effect on calf growth and development, presumably through improved rumen and small intestine development, gut health, feed digestibility, and nutrient absorption. This first of its kind on-farm, pasture-based, dairy farmer-driven study makes a significant novel contribution to our understanding of the impact of supplementing neonatal heifer calves with ECAB on pre-weaning and post-weaning growth performance and body conformation traits in purebred Friesian and crossbred Friesian × Swedish Red and Friesian × Jersey. The practical implication is accelerated calf growth and improved lifetime performance.The effect of supplementing neonatal heifer calves with varying levels of ECAB on pre-weaning growth performance was investigated. Post-weaning growth was also measured, to determine any carry-over effect of pre-weaning supplementation of ECAB. Forty-eight heifer calves (7 ± 0.4 days old, average liveweight of 39.3 ± 5.3 kg) were utilized in a complete randomised experimental design, comprising 16 calves per pen, randomly allocated to one of the following three treatments: (1) Basal commercial calf starter mix without ECAB (Control); (2) control plus 4 kg/ton of ECAB (Low); and (3) control plus 6 kg/ton of ECAB (High). Calves were group-fed ad libitum for 77 days (11 weeks, pre-weaning period) with free choice access to water and 5.5 L of milk per head per day through an automated feeder. Calves were weighed weekly during the pre-weaning period, after which all calves were then weaned onto the same ryegrass pasture as one group. At approximately 9 months of age, calves were weighed to estimate post-weaning body weight gain. During the pre-weaning period, average daily dry matter feed intake was similar for 4 kg/ton and 6 kg/ton calves (649 g versus 688 g, respectively) and both were greater than that of the control calves (382 g). Average daily gain (ADG) was significantly higher for 4 kg/ton calves compared to 6 kg/ton calves or control calves (0.83 ± 0.03 kg, 0.74 ± 0.03 kg and 0.71 ± 0.03 kg, respectively; p = 0.0001). Similarly, 4 kg/ton calves had significantly increased chest girth (95.9 ± 0.7 cm), withers height (88.9 ± 0.5 cm), body length (82.9 ± 0.6 cm), and body condition score (1.99 ± 0.12) compared to 6 kg/ton calves (93.4 ± 0.7 cm, 87.4 ± 0.7, 81.5 ± 0.6 cm, and 1.67 ± 0.10, respectively) or control calves (92.9 ± 0.7 cm, 88.2 ± 0.5 cm, 80.1 ± 0.6 cm, and 1.30 ± 0.08, respectively). There was significant treatment × week interaction for all pre-weaning growth parameters. Breed differences were detected but there was no treatment × breed interaction. Post-weaning, 4 kg/t calves and 6 kg/t calves had significantly higher ADG compared to control calves (0.80 ± 0.03 kg, 0.85 ± 0.03 kg versus 0.70 ± 0.03 kg, respectively; p = 0.0047). It is concluded that under the conditions of this study, supplementing heifer calves with ECAB during pre-weaning period resulted in improved growth performance and there appears to be a post-weaning carry-over effect.

Introduction of biotechnology in animal breeding, as a factor of improving its efficiency

The article presents the results of the introduction of the biotechnological method to improve the reproduction of the herd of Holstein cattle. Comparative data on the growth of calves obtained in different ways are given: from artificial insemination and transplantation of embryos during the growing period - from birth to the age of 18 months. It was found that calves obtained from the biotechnological method grew faster than their peers obtained from artificial insemination. The difference was 18.3 kg in favor of the heifers of the experimental group. The largest average daily gain in live weight was observed during the period from 12 to 18 months - 50 g is naturally in favor of the heifers of the experimental group. The difference in live weight during the first insemination between the heifers of the studied groups was 10.0 kg or 2.5%. The fertility rate was +2.0 absolute percent. The insemination index was excellent and amounted to a difference between experimental groups of +0.6 absolute growth. The conditional profit from the cultivation of Holstein heifers obtained by the method of embryo transplantation amounted to 267.8 thousand rubles. Profitability was 22.4 percent.

Feeding various forages and live yeast culture on weaned dairy calf intake, growth, nutrient digestibility, and ruminal fermentation

The objective of this study was to determine effects of various forages and live yeast culture on intake, growth, nutrient digestibility, and ruminal fermentation of weaned dairy calves. Holstein calves (n = 45) were randomly assigned to 2 × 3 factorial treatments: live yeast culture or no yeast and alfalfa haylage (AH), corn silage (CS), or grass hay (GH). Calves were weaned at 6 wk of age, housed individually, and studied from 7 to 16 wk of age. Rations, consisting of an 18% crude protein texturized grower (yeast or no yeast) and assigned forage, were offered as separate components until 9 wk of age. After 9 wk, diets were offered as a total mixed ration (TMR). Concentrate intake was capped at 2.25 kg of dry matter (DM)/d, and forage was offered ad libitum. The TMR contained equal forage neutral detergent fiber (8 ± 0.5%) on a DM basis for each basal diet. Calves were fed TMR to limit concentrate intake, and additional forage was offered ad libitum after 8 h if the entire TMR allotment was consumed. Total fecal collection (12 calves) was conducted for 4 d at 11 and 15 wk of age. Feeds and feces were evaluated for DM, neutral detergent fiber, acid detergent fiber, and starch to calculate digestibility. On the last day of fecal collection, rumen samples were collected to evaluate pH and volatile fatty acid (VFA) profile. Metabolizable energy and DM intake was least for calves consuming GH compared with other forages. Forage intake (% of DM intake) increased as calves aged (AH = 20 to 44.4%, CS = 24.5 to 37.6%, GH = 11.3 to 32.3% at 10 and 16 wk of age, respectively). Calves on CS had the greatest average daily gain and empty body weight gain, and calves on GH had the least. Calves on GH tended to have the lowest final body weight. There were no differences in structural growth. Digestibility of DM decreased with age. Fiber digestibility was least for calves on CS, and starch digestibility was least for calves on AH. Mean and minimum rumen pH increased with age. Forage offered changed VFA profile and there was an interaction between yeast and forage on VFA profile. These results indicated that recently weaned calves perform well on AH, CS, or GH and have minimal benefit from yeast supplementation. Feeding GH reduced weight gain, but all calves achieved a level of gain to meet growth goals for breeding and freshening. Furthermore, the ability to consume large portions of the ration as forage allows for more economical diets to be fed.

Increasing grass hay inclusion level on weaned dairy calf growth, intake, digestibility, and ruminal fermentation

The objective was to determine effects of increasing grass hay (GH) inclusion level on weaned dairy calf growth, intake, digestibility, and ruminal fermentation. Holstein calves (n = 45) were randomly assigned to 1 of 3 total mixed rations with increasing GH [10, 17.5, or 25% on a dry matter (DM) basis; LGH, MGH, or HGH, respectively]. Calves were weaned at 6 wk of age, housed individually, and studied from 7 to 16 wk of age. Rations, consisting of texturized calf starter (20% crude protein) and coarsely chopped GH, were offered ad libitum as separate components from 7 to 9 wk of age. After 9 wk, feed was offered as a total mixed ration containing the assigned level of GH and fed according to the clean bunk feeding strategy as a means of limiting refusals. Initial 9-wk body weight was 81.6 ± 9 kg (mean ± standard deviation). Intake and growth were measured weekly. Blood samples were collected at 9, 10, 12, 14, and 16 wk of age for analysis of plasma glucose and β-hydroxybutyrate. Total fecal collection (12 calves; 4 per treatment) was conducted at 11 and 15 wk of age for 4 d consecutively. Rumen samples were collected over the final 24 h of each fecal collection period to evaluate pH and volatile fatty acid profile. Feeds and feces were evaluated for DM, neutral detergent fiber, acid detergent fiber, and starch to estimate total-tract digestibility. Intake and weight gain were analyzed from 7 to 9 wk and 9 to 16 wk, representing pretreatment and treatment periods. No differences were observed between treatments from 7 to 9 wk. However, differences were found from 9 to 16 wk. Final body weight, average daily gain, DM intake, and metabolizable energy intake all decreased with increased GH. However, skeletal frame measurements did not vary between treatments. Plasma β-hydroxybutyrate tended to decrease with increased GH. No differences were observed in DM or starch digestibility, but neutral detergent fiber and acid detergent fiber digestibility increased with increased GH. Mean rumen pH and total volatile fatty acid did not change with increasing GH inclusion; however, there was an interaction with time indicating that ruminal fermentation patterns throughout the day were different for calves offered MGH and HGH versus those offered LGH. These results indicate that feeding levels of GH >10% reduce growth and intake before 16 wk and alter ruminal fermentation patterns.

Extended colostrum feeding for 2 weeks improves growth performance and reduces the susceptibility to diarrhea and pneumonia in neonatal Holstein dairy calves

The objective of this study was to determine the effect of partial replacement of whole milk with colostrum on the growth performance and health status of Holstein dairy calves. Neonatal heifer calves (n = 144; 2 d of age; 39.3 ± 0.82 kg of body weight, BW; mean ± SE) were assigned randomly to 3 groups with partial replacement of pasteurized whole milk with pasteurized colostrum at 0 (C0; 0 kg/d of colostrum + 5 kg/d of whole milk), 350 g (C350; 0.350 kg/d of colostrum + 4.650 kg/d of whole milk), or 700 g (C700; 0.700 kg/d of colostrum + 4.300 kg/d of whole milk) for 14 d; there were no refusals of liquid feed. From d 15 onward, the calves were fed with 5 kg/d of pasteurized whole milk, weaned on d 61, and monitored until d 81 of life. Throughout the study, the calves had free access to fresh clean water and calf starter. Partial replacement of whole milk with colostrum increased liquid feed dry matter intake (DMI) but decreased milk DMI; however, intakes of starter DMI, total DMI, metabolizable energy, crude protein, and ether extract were not affected by treatments. Overall, the C700 calves recorded greater weaning weight, final BW, heart girth change, feed efficiency, and average daily gain (ADG). The calves fed milk had a higher chance of having rectal temperature ≥39.4°C and general appearance score ≥2 compared with those receiving colostrum in their milk. Diarrhea was more prevalent in C0 versus C700 calves. The occurrence of pneumonia tended to be higher in milk-fed calves compared with C350 and C700 animals. Colostrum feeding resulted in fewer days with a rectal temperature ≥39.4°C, general appearance ≥2, diarrhea, and pneumonia. We computed Cliff's delta (effect sizes) of the extended colostrum feeding (C350 vs. C0, C700 vs. C0, and C700 vs. C350) on starter and milk DMI, ADG, BW, and feed efficiency. In C350 calves, the effect sizes (Cliff's delta) for milk DMI, ADG, BW, and feed efficiency were positive and small, but negative in C700 calves. Compared with C350 treatment, C700 treatment resulted in greater final BW with moderate effect size. Positive and moderate effects of feeding colostrum (C700 vs. C0) were observed on postweaning ADG and final BW. The findings showed that the inclusion of 700 g of colostrum in 5 kg of milk may be beneficial to the growth and health of dairy calves.

The effect of milk feeding strategy and restriction of meal patterning on behavior, solid feed intake, and growth performance of male dairy calves fed via computer-controlled milk feeders

Dairy calves are often offered milk allowance at a flat rate during the first 6 wk of life, although an initial high allowance followed by a stepwise reduction (step-down strategy) may correspond better to the calves' nutritional needs. The amount of milk offered per feeding is typically constant. However, during natural suckling, the daily number of milk meals (suckling frequency) declines with age, which may reflect increased consumption of solid feeds. Thus, allowing calves to pattern their meals on a computer-controlled feeder by placing less restriction on meal frequency may stimulate dairy calves' ingestion of solid feeds. This experiment investigated the effects of milk feeding strategy and milk feeding frequency on calves' feeding behavior, intake, and growth. Sixty-four male Holstein Friesian calves, purchased from conventional dairy farms, were housed in groups of 8 and fed milk replacer (MR) via computer-controlled milk feeders. From 14 d old, calves were assigned to either a conventional flat-rate milk allowance (CON: 6.5 L/d of MR from d 14 to 42; 4 L/d from d 43 to 49; 2 L/d from d 50 to 56 of age) or to stepwise reduction in milk allowance (STEP: 8 L/d of MR from d 14 to 28; 5 L/d from d 29 to 42; 4 L/d from d 43 to 49; 2 L/d from d 50 to 56 of age). Within each group of 8, 4 calves were randomly allocated to each of 2 milk feeding frequencies, either restricted portion size (RES: maximum milk portion size of 2.3 L/portion) or unrestricted portion size (UNRES). Concentrates, hay, and water were available ad libitum. Feeding behavior was recorded via video for 24 h on 26 and 40 d of age. On d 26, where STEP calves were offered 1.5 L/d more milk than CON calves, no difference was seen regarding the time spent eating concentrate (16.9 vs. 20.3 min/d). However, STEP calves spent more time eating concentrate on d 40, where these calves had 1.5 L/d less milk than CON (36.1 vs. 27.2 min/d). Thus, a lower daily milk allowance stimulated feeding on concentrate d 40, but not d 26. As predicted, UNRES calves spent more time eating concentrate (27.6 vs. 21.9 min/d) and more time eating hay (38.4 vs. 30.0 min/d) than RES calves. However, higher appetite for solid feeds by UNRES calves may not be explained by milk intake per se. Rather, this is likely due to their opportunity to have larger milk meals, which appeared to increase their appetite for milk (as indicated by longer time spent in the milk feeder; 64.0 vs. 48.8 min/d) as well as for solid feeds. Among CON calves, the UNRES treatment resulted in higher ADG 2 wk postweaning, but not among STEP calves. These findings partially support that relaxing restriction on milk portions helps calves to transition from milk to solid feeds before weaning off milk. However, more research is needed to determine how restriction on milk portions interacts with milk feeding strategy when a higher total milk allowance is offered.

Dietary supplementation with oregano essential oil and monensin in combination is antagonistic to growth performance of yearling Holstein bulls

Our previous work indicated that feeding oregano essential oil (OEO) in combination with monensin (MON) may not be mutually beneficial to dairy calf growth performance. To evaluate this observation further, a 240-d long-term growth experiment was conducted using 12 young growing Holstein bulls using a 2 × 2 factorial treatment arrangement. Main factors were OEO and MON arranged in 4 individual treatments: (1) ration fed without OEO or MON (control), (2) OEO fed at 26 mg/kg of dry matter (DM), (3) MON fed at 25 mg/kg of DM, and (4) OEO and MON fed in combination (OEO+MON). Holstein bulls were 70 d of age and similar in body weight (BW; 93.3 ± 4.54 kg) and individually fed for 240 d. The targeted feeding rates of OEO and MON were blended into 200 g of concentrate and top dressed each morning to a corn stalklage-based ration. Body weights, frame measurements, and blood samples were collected monthly. Interactions of OEO by MON were detected for BW, BW gain, average daily gain, and a trend for feed conversion. Bulls fed OEO or MON demonstrated greater final BW (368, 385, 381, and 358 kg for control, OEO, MON, and OEO+MON, respectively), and BW gains (278, 292, 285, and 265 kg) and average daily gain (1.16, 1.22, 1.19, 1.11 kg/d) were greatest for bulls fed OEO or MON compared with bulls fed OEO+MON; bulls fed the control were intermediate and similar to bulls fed MON. Intake of DM was greater for bulls fed OEO (6.55, 6.99, 6.60, and 6.42 kg/d) compared with bulls fed remaining treatments. Frame growth gain measurements for heart girth, abdominal girth, withers height, body length, and cannon bone circumference were similar for bulls fed all treatments. Serum triglyceride (0.23, 0.25, 0.28, and 0.24 mmol/L) concentrations were greater for bulls fed MON compared with bulls fed the control and OEO+MON, and bulls fed OEO were intermediate and similar. Cholesterol (2.06, 2.29, 2.20, and 2.07 mmol/L) concentrations were greater for bulls fed OEO compared with bulls fed the control and OEO+MON, and bulls fed MON were intermediate and similar. Serum antioxidant measurements were similar for bulls fed all treatments. Serum IgA, IgG, and IgM concentrations were similar for bulls fed all treatments. Feeding OEO or MON separately can improve growth performance of growing Holstein bulls. We do not know why the combination of OEO and MON is antagonistic to growth performance of Holstein bulls. However, these technologies should not be fed in combination to growing dairy cattle.

Oral vitamin A supplementation during neonatal stage enhances growth, pre-adipocyte and muscle development in Korean native calves

Recently, many studies reported the critical importance of marbling development during late pregnancy and neonatal stage by influencing the preadipocyte hyperplasia. Our previous study demonstrated that 100,000 IU/day oral vitamin A supplementation during late-stage pregnancy enhances birth weight and gene expression-related muscle and preadipocyte development in offspring. This study investigated the effects of the oral supplementation of vitamin A on growth, and preadipocyte and muscle development in Korean native calves at the postnatal neonatal stage. Twenty-seven newborn calves were then randomly divided into two groups encompassing similar number of bulls and heifers (body weight of 31.6 ± 3.98 kg; age: from five days of birth to two-months age; control: 9 bulls and 4 heifers; treatment: 10 bulls and 4 heifers). All calves were treated with (treatment group) or without (control group) oral vitamin A supplementation (20,000 IU vs. 45,000 IU vitamin A/day, retinyl acetate) for two months until weaning. Vitamin A supplementation resulted in higher BW on day 45 (p < 0.05), as well as an upward tendency toward day 60 (weaned) in the treatment group (p = 0.079). Serum vitamin A showed an increasing trend on day 45 and 60 (p = 0.098 and p = 0.060, respectively) with vitamin A supplementation. However, no significant difference was found in complete blood counts analysis in treatment group compared to the control group. The mRNA expression results in longissimus dorsi muscle revealed that vitamin A supplementation promoted the levels of mRNA expression markers (p < 0.05) related to preadipocyte development (Pref-1, Zfp423, CTNNB1, ERK1, ERK2) and muscle development (MyoD, Myf6, Myogenin). High vitamin A supplementation during the postnatal period in newborn calves (45,000 IU/day) enhanced calf growth performance. In addition, according to the mRNA expression in two-month-old calves, positive impacts were observed on preadipocyte and muscle development with vitamin A supplementation. Collectively, vitamin A supplementation to calves can be beneficial for future production properties.

Association between Egyptian calves performance and growth hormone and IGF-1 levels under different housing types

This study was planned to examine the climatic effects of three housing types on the performance of Egyptian calves and its relationship with growth hormone (GH) and Insulin-like growth factor-1 (IGF-1). To achieve this goal, 18 weaned calves, three months old, and had average body weight (BW) 79.81 ± 7.42 kg were used to obtain animals' performance data throughout 540 days of age. Animals were divided into three equal groups, as follows: 1st, semi-open type shaded roofed with concrete slab and topped with three rows of rice straw bales (CS); 2nd, semi-open type shaded roofed with a layer of an iron sheet (PS); 3rd, opened type without shading or roof and exposed to the direct solar radiation (WS). Results indicated that thermo-regulatory, hematological parameters, GH, and IGF-1 levels were found to be significantly (P< 0.01) affected by the housing types provided. The CS housing type showed significant (P< 0.01) improvement in average daily gain (ADG) and feed conversion compared to other types. Closed positive correlations were observed among age, BW, ADG, and IGF-1 concentration. However, GH concentration recorded negative correlations with the previous traits. Reproductive performance parameters were improved significantly with CS housing type compared to others. It could be concluded that using CS housing type provides more comfortable climatic conditions for Egyptian calves than other housing types under middle Egypt conditions. Also, data of IGF-1 concentration may be a useful aid in selection strategies for improved growth and reproductive efficiency.