Holstein Calves Research Articles

Measurement of joint angles for the objective assessment of limb conformation in dairy calves

Poor limb conformation in cattle is believed to be closely associated with claw and limb disorders. Limb conformation is part of genetic evaluation and is assessed visually. In this descriptive study, the assessment of conformation in calves was evaluated objectively using joint angle measurements. A total of 100, 30- to 90-d-old, heifer calves of the Brown Swiss (n = 50) and Holstein (n = 50) breeds were photographed from both sides and the front and rear. Carpal, tarsal, autopodium and fetlock joint angles of the fore- or hind limbs were measured on the images using anatomic reference points and the ImageJ/Fiji® program. Each angle was measured 3 times, and the mean was used for analysis. Values from both sides were pooled. Deviations from defined standard angles were classified as slight or moderate. The positions of the front and hind feet were measured and scored. On average, the calves had moderate "knock-kneed" carpal conformation, and the autopodium of the front limb had a slight lateral deviation. In the rear view, the calves had slight, but close to moderate, "cow-hocked" tarsal conformation, and the autopodium of the hind limbs was parallel, but close to slightly deviated. Holstein calves were moderately, and Brown Swiss calves were slightly "cow-hocked". A moderate lateral deviation occurred in the metacarpal-digit angle in the front view and a slight lateral deviation occurred in the metatarsal-digit angle in the rear view. The front feet position score was >17° in 69% of the calves, and the hind feet position score was <17° in 90% of the calves. In the side views, the calves were slightly "over at the carpus" and slightly "straight-hocked" and had average fetlock conformation. In the mean values, most measured joint angles did not correspond to the straight or parallel classifications in our calves; moderate "knock-kneed" and slight "cow-hocked", and "toed-out" classifications were most common. The limb angles measured were based on anatomical features and therefore are unlikely to change substantially with increasing age. These aspects should be considered when assessing linear traits and investigating the relationship between limb conformation and claw diseases.

Relative merits of offering a milk replacer, glucose-electrolyte, or whey-based diet on the blood composition and health of unweaned calves after transport

The objective of this randomized controlled trial was to assess the relative merits of offering unweaned calves 3 different types of diets to meet energy and water deficits that can occur during journeys. A total of 6 young unweaned male Holstein calves were randomly selected from within 2 body weight ranges (median 48 and 42 kg) from each of 29 loads (total n = 174 calves) transported from an auction market or a collection center to a calf sorting center before transport to a veal unit. The calves were then randomly allocated to one of 3 dietary treatments (n = 58 calves/dietary treatment). They were offered either a milk replacer diet (M), a glucose-electrolyte diet (G) or a whey-based diet with added electrolytes (W). The ability of these diets to provide sufficient nutrient energy to restore vigor, and avoid hypoglycemia and clinical signs of dehydration without increasing the risk of diarrhea was assessed. A clinical assessment of dehydration, health, and vigor was made, and the calves were blood sampled before feeding and at 2 h and 4 h after feeding. The plasma glucose concentration was increased 2 h and 4 h after feeding the M and W diets. The increases in plasma glucose concentration were greater 2 h and 4 h after (1) feeding the M than after the W diet and (2) feeding the M and W diets than after the G diet. Back-transformed means and 95% CI for the ratio of the plasma glucose concentration at 4 h compared with 0 h for the M, G, and W diets were 1.2 mM (CI = 1.21, 1.35), 0.95 mM (CI = 0.92, 0.97), and 1.09 mM (CI = 1.06, 1.14), respectively. We found no effect of diet on the change in serum total protein concentration between before feeding and 2 h and 4 h after feeding. The serum osmolality was lower 2 h after feeding the G diet. The fall in serum osmolality was greater 2 h after feeding the G diet than after feeding the M and W diets. The changes in the serum osmolality between before feeding and 2 h after feeding for the milk replacer, glucose-electrolytes and whey-based diets were -0.68 mOsmol (CI = -3.27, 1.91); -5.23 mOsmol (CI = -7.82, and -2.64); and -0.13 mOsmol (CI = -2.77, 2.51), respectively. The diet offered at the sorting center had no effect on subsequent growth on the veal-rearing farm between arrival and slaughter (milk replacer, 1.22 kg/d [CI = 1.17, 1.28]; glucose-electrolyte diet, 1.23 kg/d [CI = 1.18, 1.28]; whey-based diet 1.28 kg/d [CI = 1.23, 1.33]). The M diet provided the calves with nutrients and water to replace energy and water deficits that had accumulated before arrival at the sorting center, and these dietary benefits were still apparent 4 h after feeding. The benefits of the W diet were similar to those of the M diet, but the M diet was better able to assist the calves in maintaining their plasma glucose concentration 4 h after feeding than the W diet. The G diet had some short-term benefits in providing energy and assistance to the calves to recover from dehydration, as indicated by a decrease in serum osmolality. However, the G diet was clearly inferior to the M and W diets in providing sufficient energy to assist the calves in recovering from the effects of transport and fasting. During the 4 h after feeding, no adverse effects of offering the calves the M or W diets were observed. The benefits of the W diet in replacing energy and water deficits were similar to those of the M diet, but the M diet was better able to assist the calves in maintaining their blood glucose concentration 4 h after feeding than the W diet.

Holstein calves fed a milk replacer with a direct-fed microbial and a starter containing a botanical extract or a direct-fed microbial alone or in combination

Botanical extracts (BE; Apex, Adisseo, North America) have demonstrated enhanced DMI and improved gut health, while direct fed microbials (DFM), such as Lactobacillus acidophilus fermentation product (EX: Excell, Pacer Technology, Inc.), has demonstrated improved gut health and growth performance of growing Holstein calves. The hypothesis was this combination may be synergistic to neonatal calf growth performance and intestinal health. Eighty, 2-5-d old Holstein bull calves were blocked by BW and randomly assigned to one of 8 treatments arranged in a 2 × 4 factorial using a randomized complete block design. The main factors were milk replacer (MR) without (Control) and with EX added at 5 g/d fed and calf starter (CS). The CS containing no additives (Control); CS containing BE at 496 mg/kg; CS containing EX at 2.50 g/kg; and CS containing BE and EX at the same inclusion rates. The MR were fed 2x/d at 0630 and 1800 h along with free choice CS (amounts and orts weighed d) and water. Weaning occurred after d 42 for the 56-d experiment. No MR by CS main effects interactions were detected for BW, ADG, CS intake, total DMI, feed efficiency or body frame gain parameters. The BW gain (38.0 and 39.3 kg for control and EX, respectively) for MR main effect was similar for calves fed both MR, while CS main effects (38.7, 39.7, 39.2, and 37.2 kg for control, BE, EX, and BE&EX, respectively) was similar among all CS. Gains in body length (10.6 and 10.8 cm), hip width (4.5 and 4.5 cm), withers height, (10.5 and 10.6 cm) heart girth (18.6 and 19.9 cm) and body length (9.1 and 7.9 cm) were similar for calves fed both MR, while CS main effects for hip height (10.5, 10.2, 10.3, and 10.9 cm), hip width (4.7, 4.6, 4.4, and 4.3 cm) withers height (10.7, 10.9, 10.3 and 10.6 cm), heart girth (19.9, 18.9, 18.9, and 19.4 cm), and body length (11.7, 9.1, 8.3, and 8.4 cm) were similar. Total days of a fecal score = 0 was greater for calves fed Control MR and BE CS compared with calves fed Contol MR and the combination of BE&EX with calves fed the remaining treatments being intermediated and similar. This study demonstrated little calf growth performance and health benefits when feeding a BE or EX alone or in combination compared with calves fed control.

Bacteria colonization and gene expression related to immune function in colon mucosa is associated with growth in neonatal calves regardless of live yeast supplementation

BackgroundAs Holstein calves are susceptible to gastrointestinal disorders during the first week of life, understanding how intestinal immune function develops in neonatal calves is important to promote better intestinal health. Feeding probiotics in early life may contribute to host intestinal health by facilitating beneficial bacteria colonization and developing intestinal immune function. The objective of this study was to characterize the impact of early life yeast supplementation and growth on colon mucosa-attached bacteria and host immune function.ResultsTwenty Holstein bull calves received no supplementation (CON) or Saccharomyces cerevisiae boulardii (SCB) from birth to 5 d of life. Colon tissue biopsies were taken within 2 h of life (D0) before the first colostrum feeding and 3 h after the morning feeding at d 5 of age (D5) to analyze mucosa-attached bacteria and colon transcriptome. Metagenome sequencing showed that there was no difference in α and β diversity of mucosa-attached bacteria between day and treatment, but bacteria related to diarrhea were more abundant in the colon mucosa on D0 compared to D5. In addition, qPCR indicated that the absolute abundance of Escherichia coli (E. coli) decreased in the colon mucosa on D5 compared to D0; however, that of Bifidobacterium, Lactobacillus, and Faecalibacterium prausnitzii, which could competitively exclude E. coli, increased in the colon mucosa on D5 compared to D0. RNA-sequencing showed that there were no differentially expressed genes between CON and SCB, but suggested that pathways related to viral infection such as “Interferon Signaling” were activated in the colon mucosa of D5 compared to D0.ConclusionsGrowth affected mucosa-attached bacteria and host immune function in the colon mucosa during the first 5 d of life in dairy calves independently of SCB supplementation. During early life, opportunistic pathogens may decrease due to intestinal environmental changes by beneficial bacteria and/or host immune function. Predicted activation of immune function-related pathways may be the result of host immune function development or suggest other antigens in the intestine during early life. Further studies focusing on the other antigens and host immune function in the colon mucosa are required to better understand intestinal immune function development.

Evaluation of hormones as candidate early biomarkers of Holstein bull performance around the first semen collection at artificial insemination centres

AbstractArtificial insemination (AI) centres select bulls as calves according to their genetic breeding values and raise them until the first semen collection; yet, a high dropout rate of reared bulls is a problem for AI centres. Potential hormonal indicators of bull sexual maturation (cortisol, dehydroepiandrosterone (DHEA), testosterone, oestradiol, insulin‐like growth factor 1 (IGF‐1)) were observed and evaluated in relation to the performance parameters to perhaps identify candidate biomarkers allowing an early selection of bulls as suitable sires. Blood samples from 102 German Holstein calves at 4 ± 1, 8 ± 1 and 12 ± 2 months of age from six AI centres were analysed using validated immunoassays for cortisol, DHEA, testosterone, oestradiol and IGF‐1. Semen analyses included native and thawed diluted semen. Bulls were classified at the first semen collection into groups with good versus poor performance (GP vs. LP). After 2 years, the subsequent differentiation was done in high (HPP), medium (MPP) and low performance persistency (LPP). Age at first semen collection was an important factor for sperm quality. Cortisol concentrations decreased with age, but the cortisol/DHEA ratio decreased with age only in GP bulls (p &lt; .05). Oestradiol and testosterone concentrations both correlated with libido behaviour (p &lt; .05). Testosterone and IGF‐1 concentrations were higher at the time of first semen collection in GP bulls and increased with age (p &lt; .05). In conclusion, testosterone and IGF‐1 concentrations at first semen collection are associated with performance at first semen collection and future performance persistency, and might be useful early biomarkers for consistent sperm producing bulls on AI centres.

Long-chain fatty acids mediate hepatic metabolic flux in preruminating dairy calves fed flaxseed oil, high oleic soybean oil, or milk fat

Nutrition and physiological state affect hepatic metabolism. Our objective was to determine if feeding flaxseed oil (∼50% C18:3n-3 cis), high oleic soybean oil (∼70% C18:1 cis-9), or milk fat (∼50% C16:0) alters hepatic expression of PC, PCK1, and PCK2 and the flow of carbons from propionate and pyruvate into the TCA cycle in preruminating calves. Male Holstein calves (n = 40) were assigned to a diet of skim milk with either: 3% milk fat (MF; n = 8), 3% flaxseed oil (Flax; n = 8), 3% high oleic soybean oil (HOSO; n = 8), 1.5% MF + 1.5% high oleic soybean oil (MF-HOSO; n = 8), or 1.5% MF + 1.5% flaxseed oil (MF-Flax; n = 8) from d 14 to d 21 postnatal. At d 21 postnatal, a liver biopsy was taken for gene expression and metabolic flux analysis. Liver explants were incubated in [U-13C] propionate and [U-13C] pyruvate to trace carbon flux through TCA cycle intermediates or with [U-14C] lactate, [1-14C] palmitic acid, or [2-14C] propionate to quantify substrate oxidation to CO2 and acid soluble products. Compared with other treatments, plasma C18:3n-3 cis was 10 times higher and C18:1 cis-9 was 3 times lower in both flax (Flax and MF-Flax) treatments. PC, PCK1, and PCK2 expression and flux of [U-13C] pyruvate as well as [U-13C] propionate were not different between treatments. PC expression was negatively correlated with the enrichment of citrate M+5 and malate M+3, and PCK2 was negatively correlated with citrate M+5, suggesting that when expression of these enzymes is increased, carbon from pyruvate enters the TCA cycle via PC mediated carboxylation, and then OAA is converted to phosphoenolpyruvate via PCK2. Acid soluble product formation and PC expression were reduced in HOSO (MF-HOSO and HOSO) treatments compared with flax (MF-Flax and Flax), indicating that fatty acids regulate PC expression and carbon flux, but that fatty acid flux control points are not connected to PC, PCK1, or PCK2. In conclusion, fatty acids regulate hepatic expression of PC, PCK1, and PCK2, and carbon flux, but the point of control is distinct.

Growth and body composition of dairy calves fed only milk replacer at 3 intakes

Determination of energy requirements for growth depends on measuring the composition of body weight (BW) gain. Previous studies have shown that the composition of gain can be altered in young dairy calves by composition of the milk replacer diet. Here, our objective was to determine body composition and the composition of empty body gain in young calves fed increasing amounts of a milk replacer containing adequate CP. Male Holstein calves underwent an adjustment period of 14 d after birth in which they were fed whole waste milk at 10% of BW. Calves were then stratified by BW and randomly assigned to either an initial harvest group (n = 11) or to groups fed 1 of 3 milk replacer amounts and harvested after 35 d of growth. All treatments consumed the same milk replacer containing 24.8% CP (dry matter [DM] basis; from all milk proteins) and 18.9% fat, reconstituted to 12.5% solids. Treatments were milk replacer fed at 1.25% of BW (DM basis; n = 6), 1.75% of BW (n = 6), or 2.25% of BW (n = 8), adjusted weekly as calves grew. Calves fed at 1.25% or 1.75% of BW were fed twice daily and those fed 2.25% of BW were fed 3 times daily. No starter was offered. Post harvest, the bodies of calves were separated into 4 fractions: carcass; total viscera minus digesta; head, hide, feet, and tail; and blood. The sum of those 4 fractions was empty BW, which increased linearly as amount of milk replacer increased. Final heart girth and body length, but not withers height, increased linearly as intake increased. Gain:feed increased linearly with increasing milk replacer. Feeding more milk replacer increased the amounts of lean tissue and fat in the body. The percentages of water and protein in the final body decreased linearly, whereas fat percentage and energy content increased linearly as intake increased. As gain increased, the percentage of protein in gain decreased and the percentage of fat increased, resulting in an increase of energy content of EBW gain. Efficiency of energy use (retained energy:gross energy intake) increased linearly but retained energy:metabolizable energy available for growth was not different among treatments. Efficiency of protein use increased quadratically as feeding rate increased; there was no further increase at 2.25% of BW. Plasma insulin-like growth factor 1, insulin, and glucose increased linearly, whereas urea-N decreased linearly, as milk replacer intake increased. Our data document changes in body composition that affect estimates of retained energy in the bodies of calves harvested at a common age. These data are important for calculations of energy requirements for young calves.

Injecting Fusobacterium necrophorum into the peripheral circulation or hepatic portal vein of preruminant Holstein calves failed to induce liver abscesses*

Injecting Fusobacterium necrophorum into the peripheral circulation or hepatic portal vein of preruminant Holstein calves failed to induce liver abscesses*

Cardiopulmonary function, anesthetic effects, quality of arousal, hematology, and blood biochemistry during continuous intravenous infusion of a combination solution of xylazine, butorphanol, and propofol in calves.

General anesthesia in calves is easier to perform under field conditions, total intravenous anesthesia (TIVA) than using inhalation anesthesia. In the present study, cardiopulmonary function, anesthetic effects, quality of arousal, hematology, and blood biochemistry were assessed during continuous infusion of a combination solution of 0.01% xylazine, 0.001% butorphanol, and 0.2% propofol (XBP) at doses of 6 (G6; 10μg/kg/min xylazine, 1μg/kg/min butorphanol, 200μg/kg/min propofol) and 9mL/kg/h (G9; 15μg/kg/min xylazine, 1.5μg/kg/min butorphanol 300μg/kg/min propofol). For both groups, five castrated Holstein calves received intravenous injections of xylazine (0.2mg/kg) and propofol (2mg/kg), followed by a continuous infusion of XBP for 60min to maintain anesthesia. Respiratory management consisted of tracheal intubation followed by spontaneous inhalation of pure oxygen. Cardiopulmonary, anesthesia, hematology, and blood biochemistry variables were assessed at rest (baseline) and every 5 or 15min after the start of the XBP infusion. Quality of arousal was assessed based on the swallowing reflex recovery time from the stop of XBP infusion, and the sternal position time and standing time after atipamezole administration. XBP produced adequate sedation, analgesia, and muscle relaxation in all calves and maintained stable anesthesia for 60min. As XBP infusion time passed, rectal temperature and heart rate became lower, and mean arterial blood pressure increased. In both groups, hematologic and blood biochemical effects were mild. The quality of arousal was not different, and all calves were standing. The results of the present study suggested that XBP is useful for TIVA in calves.

Short- and long-term effects of different forage types supplemented in preweaning dairy calves on performance and milk production into first lactation

We investigated the short- and long-term effects of different forage types supplemented in preweaning dairy calves on growth performance, blood metabolites, rumen fermentation, bacterial community, and milk production during first lactation. A total of 60 healthy 30-d-old female Holstein calves were blocked by birth date and body weight and randomly assigned to 1 of 3 groups (n = 20): normal milk and pelleted starter feeding (CON), supplemented with chopped oat hay (OAH; 75.0 g/d per calf [DM basis]), or alfalfa hay (ALF; 75.0 g/d per calf [DM basis]). The forage supplementation started when calves were 30 d old (d 1 of the experimental period) and ended when they were 73 d old (d 44 of the experimental period, when calves were weaned). Milk and feed intakes and fecal consistency scores were recorded daily. Growth performance, rumen fluid, and blood samples were collected biweekly. After weaning, all the calves were integrated with the same barn and diets. After calving, the milk production was recorded daily. During the experimental period, the OAH group had greater solid feed and total DM intakes and greater rumen pH than the CON group (P ≤ 0.04), but had lower forage intake and CP digestibility than the ALF group (P ≤ 0.04). The ALF group had higher rumen pH and blood BHB concentration (P ≤ 0.04), lower fecal score (P = 0.02), and greater ether extract digestibility (P = 0.02) than the CON group. The ALF and OAH groups had lower concentrations of ruminal total VFA (P = 0.01). Still, the ALF group had a greater proportion of acetate and a relative abundance of cellulose degradation-related bacteria (Lachnoclostridium_1 and Oribacterium) and a lower relative abundance of inflammation-related bacteria (Erysipelotrichaceae_UCG-009) in the rumen compared with CON. Interestingly, the average milk production from 6 to 200 DIM was greater in the ALF group (P < 0.01), even though no significant effects were found on the rumen fermentation parameters and blood metabolites at 200 DIM. Generally, alfalfa hay supplementation in preweaning dairy calves had positive effects in the short- and long-term for rumen development, health status, and future milk production.

Effects of different production systems on health, zootechnical and metabolic parameters in Holstein calves in the extreme south of Brazil

The aim of this study was to evaluate the incidence of diseases as well as metabolic and zootechnical parameters in Holstein calves maintained in individual or collective housing systems in the extreme south of Brazil. One hundred calves were included immediately after birth and monitored for 90 days. Animals were randomly divided into two groups: individual stalls group (ISG; n=50) and collective stalls group (CSG; n=50). ISG calves were individually housed in 1.2m² wood pens and received 6 L of milk/day and concentrate food and water ad libitum for 90 days. Calves in the CSG were housed in groups of up to 25 animals, in a total of two stalls containing one animal per 3 m2. CSG calves received up to 8 L of milk/day at 0-15 days, milk ad libitum at 15-40 days, 7.2 L of milk. /day at 40-60 days, and gradual weaning at 60-90 days with concentrate food and water ad libitum, using an automatic feeder. In both groups, Zootechnical parameters (weight, thoracic perimeter, height at the withers, and rump width) were measured weekly during the first 28 days and once every 15 days until weaning. Blood samples were retrieved weekly during the first 28 days. Metabolic parameters evaluated in this study were total calcium, beta-hydroxybutyrate (BHBA), free fatty acids (FFA), and glucose. The animals were monitored daily for clinical signs of diseases diarrhea and respiratory symptoms. General morbidity was higher in CSG 92% compared to ISG 74% (p&lt;0.05). We observed increased diarrhea-related morbidity and a higher rate of recurrence in the ISG (50% and 60%, respectively; p&lt;0.05) compared to those in the CSG (both 20%, p&lt;0.05 between groups). The morbidity due to bronchopneumonia was higher in the CSG (92%) than in the ISG (74%, p&lt;0.05). Recurrence of bronchopneumonia and mortality were similar between groups (p&gt;0.05). Glucose, FFA, and BHBA concentrations were higher in the ISG (p&lt;0.05) and total calcium higher in CSG (p&lt;0.05). Finally, the weight and thoracic perimeter were higher in the CSG than those in the ISG, whereas the height and, rump width, at the withers was higher in the ISG than that in the CSG (p&lt;0.05). In conclusion, animals raised in a collective system with automatic feeders exhibited less diarrhea and increased serum calcium as well as improved zootechnical development, although they had a higher incidence of bronchopneumonia.

294 Development of a model to predict forage intake and growth of bottle-fed Holstein calves

Abstract Models to predict intake and growth of preweaning calves have received less attention than postweaning calves. The objective was to develop a model to predict forage intake and growth of bottle-fed Holstein calves. Data on milk intake, alfalfa hay intake, and body weight (BW) of 40 Holstein calves from birth to 200 d of age were acquired from Abdelsamei (1989). Milk and forage intake equations were those used by Lancaster et. al. (2021; 10.1093/jas/skaa406). NASEM growth equation evaluation and new equation development were performed using a dataset compiled from the literature by Hildebrand et al. (2022; 10.1093/jas/skac064.321). The mean absolute error to predict milk intake was less for WOOD at peak milk less than 10.88 kg/d, and was less for NASEM at peak milk greater than 10.88 kg/d. A combination of NASEM and WOOD milk yield equations to predict milk intake resulted in CCC of 0.969 and MB of -0.74% and was used to predict milk intake in subsequent analyses. Prediction of forage intake by TED06, BAK76, TED09A, TED09B, and HOL82 had CCC of 0.878, 0.920, 0.729, 0.874, and 0.234 with MB of -17.49, -1.58, -64.40, -35.60, and -341.16%, respectively. Prediction of BW for the same intake equations with the NASEM growth equation had CCC of 0.876, 0.929, 0.819, 0.864, and 0.402 with MB of -21.54, -14.67, -30.10, -25.13, and -99.78%, respectively. With observed BW, prediction of forage intake by TED06, BAK76, TED09A, TED09B, and HOL82 resulted in CCC of 0.935, 0.936, 0.958, 0.964, and 0.640 with MB of -0.55, 6.57, -11.90, -8.83, and -92.26%, respectively, indicating high precision and moderate accuracy. With observed forage intake, prediction of BW by the NASEM growth equation resulted in CCC of 0.926 and MB of -17.08% indicating high precision and poor accuracy. Evaluation of the NASEM growth equation in Holstein cattle resulted in CCC of 0.329 and MB of 61.47%. A new growth equation was developed: EBG, kg/d = 0.78498 ± 0.24035*RE, Mcal/d^(0.78500 ± 0.06033)*EBW, kg^(-0.14323 ± 0.0742) with RMSE = 0.0599 ± 0.0207 and R2 = 0.8795 ± 0.1078. With observed forage intake, prediction of BW with the new growth equation resulted in CCC of 0.992 and MB of -0.11%. With the new growth equation, prediction of forage intake by TED06, BAK76, TED09A, TED09B, and HOL82 resulted in CCC of 0.914, 0.766, 0.881, 0.901, and 0.412 with MB of 15.47, 40.53, 18.11, 17.02, and -172.88%, respectively. Prediction of BW resulted in CCC of 0.978, 0.940, 0.968, 0.969, and 0.701 with MB of 2.83, 8.91, 3.87, 3.92, and -38.73%. In conclusion, prediction of forage intake and BW in Holstein calves were hindered by use of the NASEM growth equation, and a new growth equation more precisely and accurately predicted forage intake and body weight.

Hemoconcentration differs in neonatal dairy calves: considerations for assessment of transfer of passive immunity

Assessing transfer of passive immunity (TPI) is a critical management strategy to evaluate colostrum management and feeding; however, variability in hemoconcentration or serum or plasma volume in calves might influence TPI assessment. The objectives of this study were to 1) describe the variability in hemoconcentration as well as TPI in Holstein calves in New York State and 2) describe the effect of adjusting total protein (TP) for the degree of hemoconcentration by applying a sample average proportion of plasma in blood (PP) on TPI assessment. Records of TP and PP from 703 1 to 9 d of age Holstein calves from 19 commercial dairy farms were analyzed. The PP was determined by centrifugation of microhematocrit tubes and serum, and plasma TP was determined by digital refractometry. Transfer of passive immunity was categorized using unadjusted TP (uTP) as excellent = ≥ 6.2, good = 5.8–6.1, fair = 5.1–5.7, and poor = < 5.1 g/dL. Individual calf TP concentrations were adjusted to the sample average PP (aTP) and TPI categories were reassessed using aTP. The sample mean ± SD (range) PP was 68.8 ± 5.76 (50.5 to 86.0)%. The PP was lower on d 1 compared with d 7 of age. Using uTP to categorize TPI, 22 (3.1%) calves had poor, 113 (16.2%) calves had fair, 164 (23.6%) calves had good, and 397 (57.1%) calves had excellent TPI, respectively. After adjusting TP for hemoconcentration, TPI determined using aTP resulted in 52 (7.5%, + 4.4 percentage points) calves in poor, 137 (19.7%, + 3.5 percentage points) calves in fair, 122 (17.5%, - 6.1 percentage points) calves in good, and 385 (55.3%, - 1.8 percentage points) calves in excellent. The mean (range) proportion of calves with TPI determined using uTP by farm was 3.9 (0 to 16)% for poor, 19.0 (2 to 36)% for fair, 25.3 (10 to 42)% for good, 51.8 (26 to 83)% for excellent. When categorized using aTP, the proportion of calves by farm was 8.1 (0 to 21)% in poor, 20.5 (8 to 42)% in fair, 19.1 (6 to 33)% in good, 52.4 (27 to 83)% in excellent TPI. In conclusion, PP was variable in calves during the time of TPI assessment and this variability should be considered when assessing TPI at the calf- or herd-level.

The economic benefit of herd genotyping and using sexed semen for pure and beef-on-dairy breeding in dairy herds.

The cost benefits of herd genotyping and the benefits of using sexed semen have been affected by recent improvements in sexing technologies, the incorporation of direct health traits in the German total merit index for Holstein cattle, the deteriorating prices for purebred heifer calves and bull calves, and the introduction of herd genotyping programs. Inseminating the genetically superior dams with female-sexed Holstein semen increases the mean breeding value of the heifer calves and can produce more Holstein heifer calves than are needed for replacement. This provides an opportunity to increase the selection response in health and production traits at the farm level. A deterministic model is introduced that predicts the increase or decrease in net profit when a farmer takes part in a herd genotyping program and follows a certain insemination strategy. The types of semen that are allocated to cows and heifers are sexed semen or unsexed semen and Holstein semen or beef breed semen. The genetically superior heifers and cows are inseminated with female-sexed Holstein semen, intermediate dams with unsexed Holstein semen, and genetically inferior dams with unsexed or male-sexed beef breed semen. In general, participating in a herd genotyping program is beneficial for German Holstein breeders. The optimum proportions of cows and heifers that should be inseminated with a certain type of semen are sensitive to farm-specific peculiarities. A small price difference between crossbred bull calves and crossbred heifer calves often makes the use of male-sexed beef breed semen uneconomic. Under the conditions considered, it was found to be advantageous to inseminate approximately 50% of the heifers and 10% of the cows with the highest genetic merit with female-sexed Holstein semen. The optimum proportion of cows that should be inseminated with unsexed beef breed semen was found to be approximately 40%. In a herd with a low replacement rate, the selected heifers can exhibit their genetic superiority over a longer period of time, and a larger proportion of cows can be inseminated with beef breed semen. Participation in a herd genotyping program is, therefore, particularly beneficial for herds with low replacement rates.

No vaccine interference between bovine coronavirus and bovine herpesvirus-1 in a randomized trial when coadministrating two intranasal modified-live viral vaccines to neonatal calves.

Compare immune responses induced by 2 commercial intranasal (IN) modified-live viral (MLV) vaccines given individually or coadministered and evaluate prevention of infection and lung pathology following bovine herpesvirus-1 (BHV-1) challenge. 36 male Holstein calves (ages, 5 to 12 days). In a randomized complete block design, each calf received an IN injection of either vaccine diluent (Placebo), an MLV vaccine containing bovine herpesvirus-1 (BHV-1; N3), bovine coronavirus vaccine (BC), or both N3 and BC (BC + N3) with a booster 4 weeks later. Nasal secretions and blood were collected weekly. Three weeks after the booster, the calves were challenged with BHV-1, sampled for virus shedding, and euthanized 10 days later to quantify lung pathology. The study period was September 7, 2020, to April 6, 2021. Calves were seropositive for BHV-1 and BC before vaccination. No significant difference in BC-specific serum immunoglobin G and nasal immunoglobin A antibody responses in the BC versus BC + N3 group or BHV-1-specific serum immunoglobin G and nasal immunoglobin A antibody responses in the N3 versus BC + N3 group. Cytokine responses to BHV-1 and BC did not differ among groups. BHV-1 shedding after challenge was significantly reduced in N3 groups versus Placebo and BC. There was a significant reduction in lung pathology in the N3 + BC group versus Placebo. This study provides evidence an MLV vaccine containing BHV-1 and an MLV BC vaccine can be coadministered to neonatal calves without significantly altering immune responses to the 2 viruses or compromising the prevention of BHV-1 respiratory disease. Calves receiving the BC + N3 vaccine had a significant reduction in lung pathology after BHV-1 aerosol challenge.

Effect of Milk-Feeding Frequency and Calcium Gluconate Supplementation on Growth, Health, and Reproductive and Metabolic Features of Holstein Heifers at a Rearing Farm.

We compared the effects of milk-feeding in 288 Holstein calves (72 per group) which were fed twice (2F) or thrice (3F) daily, with or without the addition of hydrogenated fat-embedded calcium gluconate (G) supplemented in the starter food and in the daily diet up to the age of 9 months, on the calves' metabolism, growth, health, and reproductive efficiency up to first pregnancy. The calves received 6 L of milk replacer (130 g/L) and had ad libitum access to water and textured calf starter with or without gluconate. Gluconate supplementation promoted a "catch-up" in growth in supplemented calves compared to their counterparts that did not receive gluconate. Gluconate appeared to reduce animal metabolic stress during key events, such as weaning and transfer into open-door pens, reducing fructosamine (352.61 vs. 303.06 in 3FG and 3F, respectively; p = 0.028) and urea (3F revealed the highest values compared with the other three groups: 19.06 for 3F vs. 13.9 (2F), 13.7 (2FG), and 14.3 (3FG), respectively, p = 0.002) from weaning onwards. The feeding of dairy calves with milk replacer three rather than two times per day tended to be associated with better health from weaning to 4 months old; parameters such as ultrasound lung score and calf health score improved over time (p < 0.001). Thrice-daily feeding with milk replacer tended to reduce the number of artificial inseminations per pregnancy in heifers by 0.2 points (p = 0.092). We confirmed significant correlations between early health and growth parameters and reproductive efficiency and a positive correlation between body weight and average daily weight gain and the thickness of the back fat layer in young heifers (r = 0.245; p < 0.0001; r = 0.214; p < 0.0001 respectively). Our study was conducted on a commercial farm with reasonably effective animal management, so baseline welfare was likely satisfactory.

Health-associated changes of the fecal microbiota in dairy heifer calves during the pre-weaning period.

Neonatal calf diarrhea is a multifactorial condition that occurs in early life when calves are particularly susceptible to enteric infection and dysbiosis of the gut microbiome. Good calf health is dependent on successful passive transfer of immunity from the dam through colostrum. There are limited studies on the developing gut microbiota from birth to weaning in calves. Therefore, the objective of this study was to examine the effect of immune status and diarrheal incidence on the development of the fecal microbiota in Jersey (n = 22) and Holstein (n = 29) heifer calves throughout the pre-weaning period. Calves were hand-fed a colostrum volume equivalent to 8.5% of their birthweight, from either the calf's dam (n = 28) or re-heated mixed colostrum (≤2 cows, ≤1d; n = 23) within 2 h of birth. All calves were clinically assessed using a modified Wisconsin-Madison calf health scoring system and rectal temperature at day (d) 0, d7, d21, or disease manifestation (DM) and weaning (d83). Weights were recorded at d0, d21, and d83. Calf blood samples were collected at d7 for the determination of calf serum IgG (sIgG). Fecal samples were obtained at d7, d21/DM [mean d22 (SE 0.70)], and at weaning for 16S rRNA amplicon sequencing of the fecal microbiota. Data were processed in R using DADA2; taxonomy was assigned using the SILVA database and further analyzed using Phyloseq and MaAsLin 2. Significant amplicon sequence variants (ASVs) and calf performance data underwent a Spearman rank-order correlation test. There was no effect (p > 0.05) of colostrum source or calf breed on serum total protein. An effect of calf breed (p < 0.05) was observed on sIgG concentrations such that Holstein calves had 6.49 (SE 2.99) mg/ml higher sIgG than Jersey calves. Colostrum source and calf breed had no effect (p > 0.05) on health status or the alpha diversity of the fecal microbiota. There was a relationship between health status and time interaction (p < 0.001), whereby alpha diversity increased with time; however, diarrheic calves had reduced microbial diversity at DM. No difference (p > 0.05) in beta diversity of the microbiota was detected at d7 or d83. At the genus level, 33 ASVs were associated (adj.p < 0.05) with health status over the pre-weaning period.

The influence of a phytobiotic with &lt;i&gt;F. ulmaria&lt;/i&gt; extract and lactobacilli on the clinical and physiological status of calves

Purpose of the research: to study the effect of a phytobiotic additive on some clinical and physiological parameters of the body of calves during the dairy period (biochemical and morphological blood parameters, live weight gain and disease resistance). The subject of the study was a phytobiotic with the code name Fitostim, which is based on an extract of meadow-sweet (Filipendula ulmaria (L.) Maxim.) and a lyophilized culture of lactic acid microorganisms. The experiment used Holstein calves, divided into experimental (Fitostim + traditional diet) and control (traditional diet) groups of 12 animals each. Starting from 4 days of age, calves in the experimental group were administered Fitostim daily, individually, orally for 30 days at a dose of 3 grams per head, after dilution in milk. Blood tests for morphological (erythrocytes, leukocytes, hemoglobin, leukoformula) and biochemical parameters (IgG, total protein, albumin, ALT, AST, creatinine) were carried out on the 10th and 30th days of the experiment. By the end of the experiment, in the experimental group of calves, compared with the control, there was an increase in ALT (8.0±0.01 units/l) by 19.4 %, total protein (51.4±0.07 g/l) by 14.7 %, albumin (44.0±0.01 g/l) by 15.4 %, creatinine (41.5±0.001 µmol/l) by 10.9 %, immunoglobulin G (5.9±0.01g /l) by 18 %, leukocytes (7.1±0.02×109/l) by 31 %. The studied morphological blood parameters (leukocytes, erythrocytes, hemoglobin, leukoformula) did not go beyond the reference values. Recovery from enteritis in calves in the experimental group occurred earlier by 1.8±0.3 days than in calves in the control group. Safety of calves is 100 %. The average daily increase in body weight in calves in the experimental group was 0.811±0.12 kg, which was 17.1 % higher than the result in the control.

Intake of compound probiotics accelerates the construction of immune function and gut microbiome in Holstein calves.

The unstable gut microbiome and incomplete intestinal function of newborn calves are important factors for the high incidence of early diarrhea. This study presents an effective strategy to improve the overall immunity and gut microbiome in calves and provides new insights into the application of compound probiotics in mammals.

Influence of autolyzed yeast on the health of immunologically immature calves

Autolyzed yeast is a supplement option for calves due to its ability to stimulate the immune system and performance; however, there are few studies about the effect of different yeast derivatives. Autolyzed yeast is rich in immunomodulatory substances, such as mannan oligosaccharides and β-glucans. These substances enhance the innate and humoral immunity of calves, resulting in greater intestinal and respiratory health. Thus, the objective of the study was to evaluate whether supplementation with autolyzed yeast improves the health of calves, in the challenge of naturally acquired Eimeriosis and bovine respiratory disease (BRD). Twenty Holstein calves aged 15 days, which had already suckled colostrum, were studied for 36 days. At 15 days of life all animals had naturally acquired Eimeriosis. They were challenged with an intranasal BRD vaccine at 30 days of age. The Supplemented group (n=10) received autolyzed yeast (10 g animal -1 day -1), once a day in milk for 36 days, and the Control group (n=10) was not supplemented throughout the experiment. Blood neutrophil: lymphocyte ratio, oxidative metabolism of neutrophils (OM), serum immunoglobulins and haptoglobin, occurrence of diarrhea, BRD, and weight gain were measured. After vaccination, all animals increased the blood neutrophil: lymphocyte ratio, but only the control group showed a 20% reduction in OM three days after the vaccine. The supplement affected the immune response, preserving OM, increasing serum IgA levels by 10% (P=0.006), and reducing haptoglobin serum levels (P=0.05). In addition, the supplement attenuated diarrhea and BRD, which allowed for greater weekly weight gain (difference of 2 kg between treatments, P&lt;0.05), concluding that the autolyzed yeast showed some evidence that it can increase the health of calves challenged with Eimeriosis and the BRD vaccine.