Influence of arrival weight, season and calf supplier on survival in Holstein beef calves on a calf ranch in California, USA

Evaluation of potential biomarkers to determine adequate colostrum provision in male dairy-beef calves upon arrival at the rearing facility beyond 14 days of age

Colostrum consumption is crucial for passive immunization and development of the newborn calf. However, the incidence on failed transfer of passive immunity in male calves destined to dairy-beef production remains high to date. In addition, the lack of an automated procedure to validate the immunization status upon arrival at rearing facilities in calves beyond 14 d of age impedes the identification of failed transfer of passive immunity, and therefore, of those calves at high risk of suffering diseases. For this study, 82 newborn male Holstein calves (43.3 ± 0.86 kg of body weight; mean ± standard error) from a commercial dairy farm were used to investigate potential serum biomarkers of colostrum provision. The potential biomarkers selected were IgG, IgG1, cholesterol, alkaline phosphatase, gamma-glutamyl transferase (GGT), and total protein (TP). Treatments were as follows: high-colostrum (HC; n = 49), in which calves received 4 L of colostrum within the first 2 h after birth and 2 L of colostrum in the next 3 feedings within the first 24 h after birth, for a total of 10 L of colostrum; and low-colostrum (LC; n = 33), in which calves received only 2 L of colostrum within the first 2 h after birth. After colostrum consumption, calves were allocated to individual hutches and fed 2 L of milk replacer twice daily at a concentration of 125 g/L as fed. Starter feed and water were offered ad libitum. At approximately 14 d of age (14.2 ± 0.81 d of age; mean ± standard error) calves were transported 2.5 h to a research unit at IRTA (Torre Marimon, Spain) simulating the arrival to a rearing facility. Blood samples were collected before feeding at birth, 48 h after birth, and at arrival to the rearing facility. Results on the serum concentrations of the potential biomarkers at arrival to the rearing facility showed that IgG, IgG1, GGT, and TP were greater for the HC calves compared with the LC calves. Serum concentrations of cholesterol and alkaline phosphatase did not show differences between treatment groups. Additionally, body weight losses from birth until arrival to the rearing facility were greater for the LC treatment compared with the HC. Because of their low cost, quickness, and ease of measurement, GGT and TP were good indicators of colostrum intake in calves arriving at rearing facilities beyond 14 d of age.

Overview of common practices in calf raising facilities

In this literature review, we overview some of the common management practices associated with calf rearing in specialized operations of the United States. Given the growing importance of dairy-beef calves entering the beef production of the United States, we overview aspects related to housing, nutrition, and health events during the pre- and post-weaning period. Based on data on dairy animals, we hypothesize how early life experiences could impact the feedlot performances of dairy-beef animals. Most of the large calf raising operations, where the majority of dairy-beef animals are raised, are located in the Central Great Plains and West regions of the United States. Approximately 80% of calves are individually housed, but the type of housing (e.g., outside hutch, inside a barn) varies based on location of calf-raising facilities. Milk-replacer is fed in more than 80% of operations, while milk (saleable or nonsaleable) is fed in approximately 30% of calf raising facilities (some operations fed more than one type of liquid diet). In addition to liquid feed, water and calf starter are offered ad libitum to calves. Adequate starter intake at weaning is crucial for feed transition from pre- to post-weaning period, which occurs at approximately 2 months of age. Then, calves are mainly housed in group pens and transition from calf-starter to total mixed ration (TMR). Health challenges such as scours and bovine respiratory disease (BRD) can hinder the performance of calves and are major causes of morbidity and mortality in calf ranches. Transportation at a very young age and comingling with animals from other dairies can increase the risk of diseases. Current research efforts are focusing on determining individual factors such as body weight (BW) at arrival or biomarkers of inflammation and stress that can be predictive of disease morbidity, mortality, and performance of calves. Future research should focus on how to utilize this information to optimize management and to develop targeted preventative strategies to reduce incidence of diseases and mortality and improve performance during the pre-weaned period. Also, more research is needed to understand how colostrum management, housing, and nutrition can impact the adult performance of dairy-beef animals.

Short communication: Predictors of time to dairy calf bucket training

The time required to adequately bucket-train a dairy calf to drink its milk allotment is unknown. Additionally, factors that could predict calves who are slow to learn have not been identified. A prospective observational study was conducted to describe timing of bucket training and possible calf birth and colostrum quality factors that might predict calves requiring extra time to train. On one dairy farm, 1,235 calves were enrolled at birth in a prospective cohort study. Calving ease score, calf presentation at birth, twinning, calf sex, and dam parity were recorded by farm personnel. An as-fed colostrum sample for each calf was collected and evaluated for total solids, total plate bacterial count, and coliform bacterial count. Calf serum total protein values were obtained by d 2 to 3 of life. Calves were observed before the morning milk feeding for attitude/posture, and after feeding for assistance needed to drink milk from their bucket. Attitude/posture was significantly associated with whether a calf required assistance or not. Almost 60% (n = 724) of calves consumed their morning milk allotment (2 L) after d 3 of life without assistance. Significant factors associated with the odds of requiring assistance with drinking after 3 d of age included calf sex, being born a twin, and the week the calf was enrolled. Knowing how long it takes to train a calf to drink from a bucket could be useful in allocating the time or labor required to successfully train calves.

Mortality risk factors for calves entering a multi-location white veal farm in Ontario, Canada

Mortality in preweaned dairy-breed calves, whether they are replacement dairy heifers, veal animals, or dairy beef animals, represents both a welfare issue and a source of economic loss for the industries involved. Studies describing morbidity and mortality in veal calves have illustrated different management practices and requirements in terms of housing and nutrition around the world. Studies examining the rearing of replacement dairy heifers have shown that rates of morbidity and mortality can vary dramatically between farms, perhaps reflecting differences in management strategies. It has been over 2 decades since morbidity and mortality in veal calves in Ontario were described. The objective of this retrospective population cohort study was to describe mortality and determine whether on-arrival information could be used to predict mortality risk. Predictors could be used to both better classify and group calves on arrival and provide feedback to suppliers about the characteristics of the highest- and lowest-risk calves. We collected data from 10,910 calves entering 7 barns of a single white veal farm, all in Ontario, from January 1 to December 31, 2014. Calves were followed until death or marketing (typically 140 to 150 d). We developed logistic regression models to determine the effects of weight on arrival, season of arrival, supplier, sex, barn, and purchase price on the risk of total mortality, early mortality (0-21d after arrival), and late mortality (>21d after arrival). We identified significant associations between season, barn, supplier, weight, and total mortality risk, with lighter-weight calves arriving in winter being at increased risk. Early mortality was significantly associated with weight, season, barn, and supplier, and tended to be associated with standardized price; lighter-weight calves arriving in winter at lower prices were at increased risk. Late mortality was significantly associated with season of arrival, barn, and supplier. On-arrival measures better predicted early mortality compared with late or total mortality. A further exploration of risk factors from the dairy farm of origin for veal calf mortality would serve to improve the productivity and welfare of calves of both sexes born on dairy farms.

Comparison of serum immunoglobulin G half-life in dairy calves fed colostrum, colostrum replacer or administered with intravenous bovine plasma

In calves, passive immunity of immunoglobulins can be acquired through ingestion of colostrum or colostrum replacers. Plasma can been used to supplement immunoglobulins in healthy or sick calves. Serum half-life of colostral derived immuglobulin G (IgG) is estimated to be 20 days. Half-life of IgG is important in determining response to antigens and timing of vaccination in calves. To date studies evaluating half-life of colostrum replacer or plasma derived IgG are lacking. The objectives of this study were to compare the serum half-life of IgG derived from colostrum, colostrum replacer and plasma in dairy calves reared up to 35 days of age. Thirty Jersey calves were randomly assigned to receive colostrum or colostrum replacer by oroesophageal tubing or plasma by intravenous administration. Serum samples were collected at 2, 5, 7, 10, 14, 21, 28 and 35 days. Serum IgG concentrations were determined by radial immunodiffusion. The results indicated that half-life for IgG in colostrum fed (28.5 days) or plasma transfused calves (27.3 days) was longer than colostrum replacer fed calves (19.1 days). Further studies are required to evaluate pathogen specific immunoglobulins in order to recommend vaccination timing in calves fed colostrum replacers.

Effect of feeding live yeast products to calves with failure of passive transfer on performance and patterns of antibiotic resistance in fecal Escherichia coli

Fifty-two newborn Holstein calves with serum IgG concentrations less than 0.73 g.dL(-1) were randomly assigned to one of four treatments: no added live yeast (control), 0.5 g of live yeast added to the grain for 84 d (SC; Saccharomyces cerevisiae), 0.5 g of live yeast added to the milk for 42 d (SB; S. cerevisiae, spp. boulardii), and 0.5 g of live yeast added to the grain for 84 d and to the milk for 42 d (SCSB). Calves were offered 440 g of milk replacer DM for the first 42 d and grain for ad libitum intake throughout the study. Plasma was analyzed weekly for concentrations of glucose and beta-hydroxybutyrate. Escherichia coli isolated from fecal samples collected every 2 weeks were used for determination of antibiotic resistance patterns. Calves receiving SC consumed more grain DM, had increased weight gain prior to weaning, and increased plasma glucose concentrations compared to controls. Days with diarrhea were reduced by feeding live yeast to calves. Antibiotic resistance in fecal E. coli was associated with the age of calves with highest levels of resistance observed in the 3 d calves. While calves receiving SCSB had higher levels of antibiotic resistance than controls, this effect was not associated with any of the other treatments. Improvements in performance of calves with failure of passive transfer were observed when live yeast was added only to the grain.

A Clinical Trial Evaluating Prophylactic and Therapeutic Antibiotic Use on Health and Performance of Preweaned Calves

The objective of this clinical trial was to evaluate the influence of prophylactic and therapeutic antibiotics on health and performance in preweaned dairy calves on a calf ranch. One hundred twenty 1-d-old calves were enrolled into 3 management systems for antibiotic use and raised until 4 wk of age. Sixty calves were not eligible to receive prophylactic or therapeutic antibiotics. Thirty calves were eligible to receive individual antibiotic treatment for disease, but no prophylactic antibiotics in milk replacer. The remaining 30 calves received milk replacer medicated with neomycin and tetracycline HCl, and could be treated with antibiotics. Health status and treatments were monitored and recorded daily. The primary study outcomes were weight gain, morbidity, and mortality. The most important factor associated with morbidity and mortality was passive immune transfer through colostrum. In-feed antibiotics delayed onset of morbidity, decreased overall morbidity, and increased weight gain. Nonantibiotic therapies for clinical disease were associated with increased mortality and morbidity compared with antibiotic treatments. The study has shown that minimizing or eliminating the use of antibiotics in the feed requires measures to ensure adequate passive transfer of immunity, but that in the face of inadequate passive transfer of immunity, animal welfare may be endangered by replacing medicated milk replacer with nonmedicated milk replacer, and therapeutic antibiotics with nonantibiotic alternatives.

Genetic and environmental factors influencing mortality up to weaning of Bruna dels Pirineus beef calves in mountain areas. A survival analysis1

Survival analysis techniques were used to analyze survival up to weaning of beef calves in the Pyrenean mountains areas of Catalonia, Spain. The Kaplan-Meier curve showed that the survival experience was not constant throughout the lactation period, as the mortality rate was more pronounced during the first month of life. The proportional hazards model analysis showed that several factors influenced the instantaneous mortality rate, with the herd-year effect having the strongest influence. Calves born in the first part of the breeding season, from September to February, had the lowest mortality risk (P < 0.001), showing that mortality risk increases as births accumulate. Calves from cows younger than 1,300 d of productive life had a higher risk of mortality (P < 0.05). Unassisted calvings presented the smallest risk of mortality, and mortality risk increased up to five times as birth became more difficult (P < 0.001). This risk also tended to increase slightly when calf birth weight was small (P < 0.10); for bigger calves, no increase of risk was detected, probably because calving difficulty was included in the model. These results suggest the need for improving the environment in the second part of the breeding period and paying more attention to births from younger cows. The survival curve fitted a parametric piecewise exponential function very well, with cut points at 16 and 32 d. The lower risk corresponded to the period of 33 to 180 d, the risk for the periods 17 to 32 d and 1 to 16 d being multiplied by 7 and 26, respectively. Confirming the robustness of the Cox model, the relative risks estimated for the different factors under this piecewise exponential model or a Weibull time-dependent model were similar to those reported above, as well as to those estimated under a frailty model, including the sire as a random effect. The modal estimates of sire variance under different baseline functions were close to 0.3, although the standard errors were very large. At weaning, the heritability estimate in the binary scale reached a value of only 0.037 because the survival at weaning was very high (96.9%) in this population. Nevertheless, in populations with a higher mortality, the inclusion of survival to weaning in the breeding objective might be justified. Overall, these results show that survival analysis is a powerful tool to analyze the mortality curve until weaning of beef calves.