Cracking the Code on Early Life Management of Crossbred Dairy-Beef Calves

Background

Beef-Dairy crosses continues to be a growing industry in Canada. Beef semen is being widely used in the dairy industry resulting in the production of dairy-beef calves. There has been a decline in the number of replacement heifers and cows on Canadian farms for years, resulting in less straight beef calves available to meet the demand of feedlots and processing facilities. Breeding beef on dairy provides dairy producers with a higher value calf, can help fill pens in feedlots and keep processing plants open. Auctions in Quebec reported 6.7% of calves sold in 2016 were beef on dairy and by 2021 have jumped to 40.7% of all calves sold in 2021. While this industry appears to be booming, feedlot producers are apprehensive due to the health and welfare concerns of these dairy-beef crosses. The increased rate of disease and loss with beef on dairy crosses compared to straight beef calves are a threat to the sustainability of producing dairy-beef calves as part of the beef industry. While current research on dairy-beef calves is focused on feedlot-performance, there is an industry need to evaluate the nutritional requirements and management practices during the early-life of dairy-beef calves. There are stark differences in how beef calves are raised compared to dairy-beef cross calves. Newborn dairy-beef calves are managed more like purebred dairy calves, but having both dairy and beef influences, these calves likely have different nutrient and management needs than straight beef or dairy calves. Optimizing early-life management and nutritional requirements of these calves may be the key to alleviating the significant health and welfare concerns associated with raising dairy-beef calves while improving feedlot productivity.

Objectives

• Explore strategies to optimize pre-weaning nutritional management of dairy-beef and purebred dairy calves
• Develop strategies to reduce antimicrobial use and improve the welfare of dairy-beef calves at calf rearing facilities
• Explore diets that lead to high levels of growth and feed efficiency post-weaning
• Evaluate the economic impact of employing strategies to maximize growth and health of dairy-beef calves

What they will do

This project will be broken into two studies:

First, they will look into pre- and post-weaning nutritional management. A total of 80 Holstein-Angus dairy-beef calves will receive a combination of high or low fat content milk replacer (30% vs 16.5%, DM basis) and high or low fat content in the solid feed (7% vs 2% of Ether Extract, DM basis), resulting in 4 treatments:

• High fat milk replacer and high fat solid diet
• High fat milk replacer and low fat solid diet
• Low fat milk replacer and high fat solid diet
• Low fat milk replacer and low fat solid diet

Calves will be fed milk according to their birth body weight (BW) (~20% of their birth BW) until they are six weeks old and then gradually weaned until week ten. They will receive their respective solid diet until eight months of age before they are transitioned into the same finishing diet. Animals will be slaughtered at 16 months of age. Feed intake and body weight will be continuously recorded throughout the study to evaluate their growth performance and feed efficiency. Calves will be assessed for fecal consistency, sickness, dehydration, and respiratory disease (via lung ultrasound). Fecal samples and nasal swabs will be taken to observe if the respective feeding strategy has any impact on the respiratory or gut microbial populations in these calves. Blood will be collected and evaluated for immunity and health hormones, as well as markers for metabolism and health. Muscle and adipose fat tissue biopsies will be taken to evaluate the effect of fat intake on these tissues. Intramuscular fat deposition will be of particular interest. Body composition will be estimated by pre-slaughter ultrasound and by examining carcass traits post slaughter. Additionally, gastrointestinal tract physiology, rumen pathology, liver abscesses as well as sensory analysis of meat will be recorded post slaughter.

In the second study, the team will look at the grower stage where different energy levels in the diet will be fed and evaluate overall calf performance. 24 Holstein and 24 Holstein-angus cross calves will receive either a low energy diet (mimicking current industry practice) or a higher energy post-weaning diet.

Calves will be fed this diet for 7 months (to reach a target weight of 700kg) at which point they will move to the feedlot and transition to the same feedlot diet. A control group of purebred angus steers will be added at this point. The same measures evaluated in the first study will also be analyzed here.

In both studies a greenfeed system will be used to determine methane emissions and feed efficiency.

Implications

Optimizing how we feed and manage dairy-beef calves could help reduce welfare concerns seen at the feedlot and increase the economic profitability of Canadian farms. This would not only reduce the need for an abundance of antibiotics but also provide a reliable year-round supply of calves to feedlots to manage the beef calf shortage.