Search Results (146)

Abdominal fat necrosis is a dystrophic–necrotic process that is relatively common in dairy cows. It is determined by productive strain (excess fat in the diet), negative energy balance after calving, a lack of physical activity, vitamin E and selenium deficiency, etc. Lipomatous masses are predominantly located in the omentum and mesentery in cattle, potentially causing intestinal obstruction. We report on an outbreak of abdominal fat necrosis that affected 135 of 220 cows and heifers (61.36%); this involved massive fat accumulation in the uterine and salpingian ligaments and severe reproductive disorders (reducing fertility to 20% in cows and 10% in heifers) caused by a hyperenergetic diet (supplementation with saturated fats). A transrectal ultrasound examination of the genital apparatus—both in heifers and in cows in the puerperium—revealed a diffuse pathological hyperechogenicity of the cervical folds, suggesting lipid infiltration, proliferation of the endocervical folds and hyperechogenic lipogranulomas located paracervically or in the uterine ligaments. An ultrasound examination of the ovaries showed the presence of parasalpingial lipogranulomas on the mesovarium, with a uniformly pixelated greasy appearance, that altered the topography of the salpinx, leading to the impossibility of oocyte retrieval. At the histopathological examination, in addition to the necrosis of adipocytes and the subacute–chronic inflammation of the abdominal and retroperitoneal adipose tissue, lipid infiltration of the uterine walls was also observed in the uterine ligaments and lymph nodes. Additionally, lipid infiltration was observed in the wall of the uterine artery. All muscular-type branches of the ovarian artery exhibited subendothelial (subintimal) amyloid deposits, severely reducing their lumen and leading to ischaemia. Amyloidosis was secondary to the systemic inflammatory process triggered by lipid deposition and necrosis. Fertility returned to normal 45–60 days after the exclusion of fat supplements from the diet and their replacement with a vitamin–mineral supplement rich in antioxidants. Full article

Our previous study has shown that supplementation of 0.50% benzoic acid (BA) increased growth performance, promoted rumen fermentation, and improved the composition and function of rumen microbiota. This research was designed to conduct a deeper exploration of the impacts of dietary supplementation with BA on the apparent digestibility of nutrients and the composition of rectal microbiota in weaned Holstein dairy calves. Sixteen Holstein heifer calves with similar body weights (91.2 ± 0.7 kg) were selected and randomly allocated into two groups, each comprising eight calves. Calves in the control group (CON group) were fed with a basal diet, while those in the benzoic acid group (BA group) were fed with the basal diet supplemented with 0.50% benzoic acid (on a dry matter basis). The experimental period started at 60 days of age and ended at 102 days of age, lasting for a total of 42 days. The calves were weaned at 60 days of age, with a transition period of 7 days. Feed samples were collected every two weeks, fecal samples were collected from 99 to 101 days of age, and blood samples were collected at 102 days of age. The results showed that supplementation with BA did not influence the digestibility of dry matter, crude protein, ether extract, neutral detergent fiber, acid detergent fiber, calcium, and phosphorus between the two groups. Compared with the CON group, BA supplementation tended to decrease the total cholesterol (TC) in the serum of the calves (p = 0.067). Supplementation with BA increased the relative abundances of the two beneficial bacteria, Bifidobacterium and Bifidobacterium pseudolongum (p < 0.05, LDA > 2), but decreased that of the harmful bacterium, Clostridium sensu stricto 1, in the rectum of dairy calves. The microbial functional prediction revealed that the fecal microbial metabolism involved in primary bile acid biosynthesis was higher in the calves from the BA group. In conclusion, the present study demonstrated that adding 0.50% BA to the diet did not influence the apparent nutrient digestibility, but improved rectal microbiota health, which finally promoted the growth performance in weaned Holstein dairy calves. Full article

Lipopolysaccharide (LPS) endotoxin is a well-characterized microbe-associated molecular pattern (MAMP) that forms the outer membrane of both pathogenic and commensal Gram-negative bacteria. It plays a crucial role in triggering inflammatory disorders such as mastitis, acidosis, and septicemia. In heifers, an LPS challenge induces a dynamic stress response, marked by elevated cortisol levels, increased body temperature, and altered immune function. Research indicates that LPS administration leads to a significant rise in cortisol post-challenge. Building on this understanding, the present study aimed to estimate genetic parameters for serum cortisol response to LPS challenge in Holstein heifers and its linear associations with production, health, reproduction, and conformation traits. Additionally, a genome-wide association study (GWAS) was conducted to identify genetic regions associated with cortisol response. A total of 252 animals were evaluated for cortisol response, with correlations estimated between cortisol levels and 55 genomic breeding values for key traits. Genetic parameters and heritability for cortisol response were estimated using Residual Maximum Likelihood (REML) in the Blupf90+ v 2.57 software. Single-Step GWAS (ssGWAS) employing a 10-SNP window approach and 42,123 SNP markers was performed to identify genomic regions that explained at least 0.5% of additive genetic variance. Finally, candidate genes and QTLs located 50 kb up and downstream of those windows were identified. The cortisol response showed significant but weak linear associations with cystic ovaries, body maintenance requirements, lactation persistency, milk yield, and protein yield (p-value ≤ 0.05) and showed suggestive weak linear associations with udder texture, clinical ketosis, heel horn erosion, and milking speed (p-value ≤ 0.15). Cortisol response showed significant additive genetic variance, along with moderate heritability of 0.26 (±0.19). A total of 34 windows explained at least 0.5% of additive genetic variance, and 75 QTLs and 11 candidate genes, comprising the genes CCL20, DAW1, CSMD2, HMGB4, B3GAT2, PARD3, bta-mir-2285aw, CFH, CDH2, ENSBTAG00000052242, and ENSBTAG00000050498, were identified. The functional enrichment analysis allowed us to infer two instances where these gene products could interfere with cortisol production: the first instance is related to the complement system, and the second one is related to the EMT (Epithelium–Mesenchymal Transition) and pituitary gland formation. Among the QTLs, 13 were enriched in the dataset, corresponding to traits related to milk (potassium content), the exterior (udder traits, teat placement, foot angle, rear leg placement, and feet and leg conformation), production (length of productive life, net merit, and type), and reproduction (stillbirth and calving ease). In summary, the cortisol response to LPS challenge in Holstein heifers seems to be moderately heritable and has weak but significant linear associations with important production and health traits. Several candidate genes identified could perform important roles, in at least two ways, for cortisol production, and QTLs were identified close to regions of the genome that explained a significant amount of additive genetic variance for cortisol response. Therefore, further investigations are warranted to validate these findings with a larger dataset. Full article

The objective of the study was to assess whether supplementing dairy heifers with Se-biofortified hay during the last 40 days of pregnancy and early lactation improves performance, metabolism, oxidative status, and immune response in the dams and their calves. Ten Jersey and eight Holstein pregnant dairy heifers were divided into two groups and supplemented with Se-biofortified or a control alfalfa hay from 40 days before to 2 weeks postpartum. The calves born to the heifers were also monitored during the first month of life. Supplementation of Se-biofortified hay improved milk yield in Holstein heifers only, but had minor effects on blood parameters measured and the liver transcriptome. Similarly, we did not detect any impact of feeding Se-biofortified hay to heifers on their offspring. The data indicated a better immune system and oxidative status in Holstein compared to Jersey heifers. Overall, our data did not support the hypothesis that supplementing Se-biofortified hay to pregnant heifers improves their performance and the health of dams and offspring, at least at the dose we provided. Full article

A previous study demonstrated that a 19-nucleotide edit, encoding a six amino acid substitution in the bovine CD46 gene, dramatically reduced bovine viral diarrhea virus (BVDV) susceptibility in a cloned Gir (Bos indicus) heifer. The present study aimed to replicate this result in American Angus (Bos taurus) using genetically matched controls and larger sample sizes. CRISPR/Cas9-mediated homology-directed repair introduced the identical CD46 edit, encoding the A₈₂LPTFS amino acid sequence, into exon 2 of CD46 in primary Angus fibroblasts. Thirty-three cloned embryos (22 CD46-edited and 11 unedited) were transferred to recipient cows. However, all pregnancies resulted in pre- and perinatal losses due to cloning-related abnormalities, preventing in vivo BVDV challenge. Consequently, ex vivo BVDV susceptibility assays were performed on primary fibroblast cell lines rescued from deceased cloned Angus calves. Infection studies revealed significantly reduced susceptibility in the edited lines, comparable to the resistance previously observed from the edited Gir heifer. These studies extend the applicability of this finding from Gir to the most common US beef breed, Angus, suggesting the potential for broad application of CD46 editing in BVDV control. Continued advancements in cloning technology will enhance the potential of gene-editing for producing disease-resistant livestock. Full article

The study objective was to compare the ability of Brix values and the D2Dx immunity test to predict the mortality risk of calves under 30 days of age. Heifer calves at 2–3 days of age were enrolled from two farms: Farm A, which has a low calf mortality rate (n = 849, 2.9% mortality), and Farm B, which has a high calf mortality rate (n = 698, 11.7% mortality). Serum samples were collected from the calves when they were 2–3 days of age. The D2Dx scores and Brix values of serum samples were compared between calves that died or survived between 3–30 days of age. For both farms, calves that survived their first 30 days of life had greater serum Brix values (9.05 vs. 8.48, p = 0.002 for Farm A; 9.26 vs. 8.99, p = 0.05 for Farm B) and D2Dx scores (0.0281 vs. 0.0036, p < 0.001 for Farm A; 0.0342 vs. 0.0286, p = 0.05 for Farm B) at 2–3 days of age compared with calves that died. On Farm A, the D2Dx score shows significantly better sensitivity (96% vs. 48%) and Area Under the Curve (0.87 vs. 0.69) than the Brix value in predicting calf mortality. However, similar results were not observed for the high-mortality farm (Farm B) due to other factors in addition to calf immune status that influenced calf survival. This study concludes that the D2Dx immunity test can be used to identify newborn dairy calves with low immunity and increased mortality risk; however, the prediction is most effective if no other risk factors are involved. Full article

This experiment aimed to assess the effects of both preweaning nutrition and postweaning growth rate on the resilience of dairy heifers from birth to 20 months of age. Immune competence and metabolic characteristics were assessed via repeated vaccine immune challenges throughout early life. Heifers were subject to either a high or low preweaning nutritional treatment (high: 8 L vs. low: 4 L of milk per day). Calves in these treatment groups were then equally divided into either a high or low postweaning growth rate treatment until 20 months of age. Nutritional intake, growth and metabolic data can be found in a companion paper, while the current paper outlines the responses to the three immune challenges. In the preweaning phase, heifers on a high milk volume had superior immune competence, demonstrated by higher monocyte and eosinophil counts. All other immune biomarkers were not different between treatments. By 8 months of age, the differences in monocytes were lost; however, the differences in preweaning eosinophil counts remained at 8 months and through to 13 months of age. At 13 months of age, there were also three-way interaction effects of preweaning nutrition, postweaning growth rate and vaccination for white blood cell count and neutrophil count; however, the trends in these responses appear random and do not align towards any clear advantages of pre- or postweaning nutrition. Metabolic responses to the immune challenges do not suggest any form of carryover effect from the preweaning phase and seemed to reflect the nutritional input at the time. Full article

Fetal programming suggests that maternal nutrition during gestation influences offspring growth, development, and productivity. This study evaluated the effects of prenatal protein-energy supplementation on the lifetime performance of Nellore cattle. Twenty-eight nulliparous heifers were inseminated and assigned to one of two groups: Non-Programmed; receiving only mineral supplementation; or Fetal Programmed (FP); receiving additional protein-energy supplementation throughout gestation. Cows in the FP group maintained significantly better body condition score during gestation (p < 0.01), and their calves exhibited greater body weight (BW) during the first 56 days (p < 0.05) and a tendency to grow to a greater BW up to 250 days (p < 0.10) in addition to improved morphological traits, such as increased rump width and length at 45 days of age (p ≤ 0.02). However, these advantages were not sustained in later growth stages, as no significant differences were observed in final body weight, ultrasound carcass traits, or overall feedlot performance. These findings suggest that while prenatal nutrition can influence early developmental traits, its long-term impact on offspring performance may be limited under consistent postnatal management. Nonetheless, the limited sample size, combined with the absence of molecular data and individual feed intake and efficiency measurements, constrains a more comprehensive interpretation of the programming effects on offspring performance. Further research is needed to explore the molecular mechanisms of fetal programming, particularly its epigenetic effects and interactions with postnatal nutrition, to optimize strategies for improving the efficiency and sustainability of beef cattle. Full article

Within the agricultural sector, dairy cattle farming systems are of the main ammonia emitters contributing to nitrogen (N) pollution. As a main strategy to mitigate N pollution, increased N use efficiency (NUE) of dairy cattle farms has been proposed. Dairy replacement heifers are an important aspect of dairy herds, and improving their NUE is a step toward addressing the issue holistically. The aim of the current review was to describe and assess heifer nutritional practices that affect NUE and examine protein supplementation to minimize N excretion in the environment. Heifer management practices related to growth and nutrition appear to have an important role on improving overall farm NUE. In particular, age at first calving, dietary crude protein level and rumen degradable protein level appear to be among the factors that affect N losses during the growth period. From a management point of view, frequent body weight monitoring at growth benchmarks and the use of mechanistic nutritional models are highly desirable to increase NUE under on-farm conditions. Full article

The cost-effective rearing of heifers depends on the provision of adequate nutrients at an appropriate age to meet nutrient requirements for growth and production. The objective of the present study was to investigate how the time of switching to a rumen-undegradable protein (RUP) source affects the ruminal fermentation and growth performance of Holstein dairy calves. A total of 36 Holstein female calves were randomly allocated to one of three dietary treatments on day 28 or 42 of life. In the first 28 days of life, they were on the same soybean meal (SBM)-based starter diet containing 22.2% crude protein with 37% RUP. The RUP content of the experimental diet was increased to 48% by a total replacement of the original SBM with xylose-treated soybean meal (XSBM). The following treatments were used: (1) starter diet containing SBM from d 28 (SBM28); (2) starter diet containing XSBM from d 28 (XSBM28); and (3) starter diet containing XSBM from d 42 (XSBM42). All the calves were fed a constant amount of milk (4 L/d), weaned on day 60, and then remained in the experiment until day 70 of life. The results showed that neither feed intake nor BW were influenced by the treatments in the pre-weaning period (days 28 to 60). The calves fed the XSBM28 and XSBM42 diets had greater daily gain and gain-to-feed ratio compared to those on the SBM28 diet post-weaning from day 61 to 70 (p < 0.05). The inclusion of XSBM in the starter diets from days 28 and 42 increased the calves’ height pre- and post-weaning (p < 0.05). The ruminal pH and concentrations of butyrate and iso-butyrate were higher at weaning when the calves were fed the XSBM diets. The calves fed the XSBM diets had less ammonia-N and total short-chain fatty acids at day 70 of life (p < 0.05) and a lower neutral detergent fiber digestibility in the post-weaning period (p < 0.05). The fecal scores and blood metabolites were not different among the treatments. The results showed that increasing the RUP content from 37% to 48% in the starter diets by a total replacement of SBM with XSBM during the pre-weaning period may improve the growth performance around weaning. A later replacement at 42 days of life appears equally effective compared to a replacement at 28 days of life. Full article

Cautery disbudding is a painful procedure and major welfare concern in organic dairy production, which lacks effective and easily implemented methods of pain control. Willow bark (WB) has been used to treat chronic pain in humans, but there is no scientific evidence that WB has an analgesic effect in dairy cattle. The objective of this study was to evaluate the effect of an oral WB bolus on heart rate, salivary cortisol concentration, ocular temperature, and lying behavior (time, bouts, and bout duration) of 42 Holstein and crossbred calves. Heifer calves were born at the University of Minnesota West Central Research and Outreach Center, Morris, MN organic dairy. Calves were disbudded from 4 to 7 weeks of age (42 ± 3 d) and randomly assigned to one of three treatments (n = 14 calves/treatment): hot iron disbudding with lidocaine (LID; 5 mL per horn bud), hot iron disbudding with oral WB (200 mg/kg), or sham disbudding (SD). Saliva samples and thermal images were collected 1 h before disbudding, at disbudding, and 5 min, 10 min, and every 30 min until 240 min after disbudding. Cardiac monitors recorded heart rates continuously throughout the 5 h study period. HOBO loggers recorded lying behavior during the 72 h following disbudding. The variables included in the statistical model for analyses were fixed effects of treatment, time, and the interaction between treatment and time, and calf was a random effect. The mean heart rate of LID calves (123.3 ± 2.8 beats/minute) and WB calves (124.5 ± 3.2 beats/minute) were higher than SD calves (110.8 ± 2.3 beats/minute). Salivary cortisol concentrations were higher for the LID calves (103.8 pg/mL) and for the WB calves (103.4 pg/mL) than for the SD calves (85.5 pg/mL). The ocular temperature was not affected by treatment group. There were fewer lying bouts 24 to 48 h after disbudding compared to the first 24 h after disbudding in both the LID and WB treatment groups. Treatment group did not affect lying time or lying bout duration. Neither LID nor WB alleviated the pain of calves throughout the post-disbudding period. The results highlighted the need to discover suitable options for pain mitigation of calves in organic livestock production. Full article

Background/Objectives:Neosporosis is a major cause of abortions in cattle worldwide. Primary results showed that the administration of a live attenuated vaccine during the mid-pregnancy stage of naturally infected cows may assist in preventing abortions. In this study, the effect of vaccination was evaluated in five dairy herds, with a follow-up of three consecutive pregnancies and re-vaccination during the subsequent pregnancies of some of the cows. Methods: A total of 1059 heifers were serologically tested during their first pregnancy, and 260 and 21 of them were re-tested during their second and third pregnancies. Vaccination was administered to 193 of 420 cows with antibody titers of 1:800 or higher, and 23 of them were re-vaccinated. Data were collected regarding the outcome of each pregnancy, the number of inseminations required and removal from the herd. Vertical transmission was evaluated in 136 pre-colostral calves born from 29 vaccinated and 107 unvaccinated dams. Results: The total seroprevalence using a cutoff titer of 1:800 was 33.1, 36.5 and 85.7% during the three consecutive pregnancies. The antibody titers of individual cows fluctuated over time. Abortion rates and the rate of removal from the herd were significantly higher in seropositive cows. The rate of vertical transmission increased in correlation with the dam’s antibody titer. Immunization resulted in lower abortion rates at two of the farms. Vaccine efficacy ranged from a negative effect to 54% at different farms, with an overall efficacy of 10.4%. The effect of vaccination on abortions, reproductive performance, antibody titers, vertical transmission and removal from the herd was not significant. Conclusions: These results demonstrate varying vaccine efficacies among farms and suggest that neosporosis is a multifactorial disease that cannot be solely controlled by vaccination. Full article

The objective of this study was to determine the enteric methane (CH₄) emission factor (EF) at the national level for Peruvian dairy cattle following the IPCC Tier II (2006, 2019) methodology. Data were collected from seven regions of Peru and classified according to the type of feeding as intensive, semi-intensive or extensive. It included farm information (geolocation) and livestock information for two seasons of the year. At the national level, lactating cows obtained the highest EF with 117 kg CH₄/head/year, followed by heifers from 15 to 24 months of age (91 kg), non-lactating cows (74 kg), heifers from 12 to 15 months of age (67 kg), calves (62 kg) and pre-weaned calves (16 kg). Additionally, the highest EF was reported for lactating cows in the intensive system (151.8 kg CH₄/head), which is 46.8 kg CH₄/head more per year than that reported in the semi-intensive and extensive systems in the same animal category. The combined uncertainty in all animal categories was low to very low (between 9.4 and 18.72%), except for that of lactating cows, which was low to medium (22.24 and 26.72%). These results allowed us to find the EF that exerts the most pressure according to the level of intensity in Peruvian dairy farming. Full article

Two experiments assessed the effects of providing a vitamin and mineral supplement to gestating beef heifers on concentrations of immunoglobulins (Ig) in colostrum and calf serum 24 h after feeding maternal colostrum (Exp. 1) or a colostrum-replacement product (Exp. 2). Angus-based heifers (n = 31, Exp. 1; n = 14, Exp. 2) were fed a basal diet (CON) or were fed a basal diet plus a vitamin and mineral supplement (VTM) from breeding (Exp. 1) or 60 d pre-breeding (Exp. 2) through calving. Colostrum was collected at calving, and serum was collected from calves 24 h after colostrum consumption to evaluate passive transfer. Serum was collected from calves in Exp. 1 to determine serum titers in response to vaccination at birth, pasture turn out, weaning, and 14 d after vaccination. Concentrations of IgG, IgM, or IgA in colostrum or in calf serum at 24 h were not impacted by dam treatment (p ≥ 0.21); however, concentrations of Ig in calf serum at 24 h were greater (p ≤ 0.01) in calves receiving maternal colostrum than those receiving a colostrum replacer. Calves born to VTM heifers had greater antibody titers at birth, pasture turn out, and weaning for infectious bovine rhinotracheitis (IBR), bovine viral diarrhea virus type 2 (BVD-2), and bovine respiratory syncytial virus (BRSV), respectively. Our results suggest that the programming of immune function in calves via prenatal nutrition appears to extend postnatally in CON and VTM offspring. Full article

This study investigates morbidity, mortality, and weight gain in pre-weaned female dairy calves, which pose economic and animal welfare challenges for farms, particularly in family-run operations in southern Brazil. We aimed to identify the rates and factors associated with these outcomes in Alto Uruguai, Rio Grande do Sul, Brazil, tracking 547 calves from 70 farms across 27 municipalities from July 2015 to September 2016. We assessed calf-rearing practices, nutrition, health, and the environment using farmer questionnaires, direct observations, and systematic weight and health monitoring of female calves from birth to weaning. The association between predictors and perinatal mortality (stillbirths and deaths within 24 h), postnatal mortality (deaths from 25 h after birth to weaning), calf morbidity, and weight gain was analysed through regression models. The participating farms had 25 (9–70) (median and range) lactating cows and produced 411 (96–1631) L/d of milk (median and range). Total mortality rate was 6.8% (median 0, range 0–50%/range), of which 2.4% (median 0, range 0–50%/range) was perinatal and 4.5% (median 0, range 0–40%/range) postnatal. Average morbidity was one case for every five calves born alive (106/538), 83% of which were reported as diarrhoea cases. Weight gain was 570 ± 212 g/d (mean and standard deviation). The postnatal mortality rate was highest in the first few weeks of life and among calves with at least one case of diarrhoea. Younger and winter/spring-born calves became sick more frequently. The calves of purebred bulls, fed with cow’s milk, which received at least 4 L of milk and 0.5 kg of feed daily, had greater weight gain. The calf mortality rate was at the lower end of the range reported in international research. The main disease affecting calves was diarrhoea, and weight gain was insufficient for calves to double their weight by the time they were weaned. The results of the present study suggest that the quality of the management adopted in calf rearing in many of the family-run dairy farms of southern Brazil may be compromising the welfare, health, performance, and survival of the calves and possibly the productivity of dairy herds. Full article