Progress report for LNE21-432R
As sexed semen from proven dairy bulls is becoming more widely used, fewer cattle need to be bred to dairy bulls to produce adequate numbers of high genetic merit replacement heifers. Replacement rates of 20 to 40%, plus a safety margin, leave 40 to 70% of cattle available for crossbreeding with beef semen to produce beef x dairy (BxD) crossbred calves, while maintaining milk production in a herd. These calves have greater potential for growth and result in heavier carcasses with improved carcass characteristics compared with straightbred dairy calves, resulting in increased economic return to the producer. Dairies can increase profits by using sexed dairy semen for replacement heifer production and beef semen to produce BxD for the beef market. However, there is little information on appropriate nutritional management of BxD calves. Given that farms in the Northeast are using beef semen in dairy cows, implementing appropriate feeding strategies in early postnatal life will increase suitability of the BxD carcass for the beef market. Further, our preliminary data indicate that NE producers are interested in adopting this approach but requested additional nutrition, health, and breeding information. We hypothesize that improving postnatal nutrition for BxD calves will improve growth, carcass quality, and economic return. To test this hypothesis, multiparous Holstein dairy cows will be bred with beef semen to produce 40 BxD calves. After birth, calves will be assigned to one of two milk replacers: control (CON; 26:20 fat:protein milk replacer) or HIGH (32:30 fat:protein milk replacer). At 56 days of age, calves will be weaned onto a calf grower (GROWER; 14% protein) or an isonitrogenous, corn silage-based total mixed ration (TMR) to achieve a targeted gain of 3 lb/day. When calves reach 500 lb body weight, they will be finished by transitioning to a grain-based diet until slaughter at market weight. At the same time, we will survey dairies in the Northeast to quantify the number of dairies that are producing BxD calves, determine how they are managing those calves, and what support is required to improve their success. Educational materials will be created and presented to producers in a variety of formats, and extension personnel will conduct farm visits and consultations with producers. Further, the advisory committee will provide feedback on research findings, educational materials, and industry trends. Together, these data are critical to the wide-spread adoption of proper nutritional practices because specific nutritional management schemes to raise BxD calves are currently non-existent. Further, we seek to understand how dairies in the Northeast states are currently utilizing this approach and generate educational material aimed at increasing their success and economic return.
In 2020, Hoard’s Dairyman reported that use of beef semen by dairy producers to generate beef x dairy (BxD) calves had doubled over the past two years, because of an expected increased economic return compared with straightbred dairy calves raised for beef. However, data about management and growth of these animals, especially in the first six months of life is scarce. This study seeks to identify how different nutritional management strategies in early life impact future growth potential. These findings will support profitability of Northeast dairies, increasing returns to the farm and improving carcass quality for the BxD market.
- (Educator and Researcher)
- (Educator and Researcher)
The PI hired a graduate student to work on the project in August 2021. During this reporting period, the research team has begun collecting data on early postnatal growth of beef x dairy crossbred calves fed a high quality or standard milk replacer through weaning, and a total mixed ration or a commercial grower feed after weaning. In addition, the team has worked with staff at the Penn State Center for Survey Research to design and implement a survey distributed to dairy producers across the Northeast. Specific details are provided below:
Aim One: Determine the effects of nutritional plane before weaning and type of feed during growing on BxD calf growth. We hypothesize that feeding a high fat, high protein milk replacer before weaning and a grower feed during the grower period will improve calf growth during the growing and finishing periods.
Methods: Calf body weights and measurements [crown rump length (CRL), girth circumference, and hip height] are being taken at birth, weekly through day 56 of age, and monthly through finishing. Body weights will be used to calculate average daily gain and feed:gain ratios. The number of days on feed to reach the finishing phase (700 lb) and slaughter weight will be calculated to determine how early nutrition impacts later growth trajectory. Ultrasound for loin eye area (LEA), back fat (BF) thickness, and intramuscular fat (marbling) are being performed monthly from one month of age until slaughter weight. Muscle biopsies are being collected from the longissimus dorsi muscle at 14 and 56 days of age, at the start of the finishing phase, and muscle samples will be collected at slaughter. Muscle fiber number, cross-sectional area (CSA), and intramuscular fat quantity will be determined by immunohistochemistry.
Aim Two: Determine the effects of nutritional plane before weaning and type of feed during grower phase on BxD calf carcass quality and economic return. We hypothesize that feeding a high fat, high protein milk replacer before weaning and a grower feed during the grower period will reduce days to slaughter and improve carcass quality, resulting in greater economic return.
Methods: Animals will be slaughtered at a commercial slaughterhouse, where hot carcass weight (HCW), USDA Quality and Yield grade, BF thickness, LEA, and marbling score will be collected, and dressing percentage will be calculated. Feed and yardage costs associated with raising animals through finishing will be collected for all animals. Cattle will be sold on a grid to the packer so that a cost-benefit analysis can be performed based on the return to individual animal. A cost-benefit analysis will be performed to evaluate the economic value of different treatments.
Aim Three: Assess current use and needs of dairies incorporating BxD calves into their operations. Our objective is to survey dairies in the Northeast to quantify how many dairies are producing BxD calves, how they are managing those calves, and what support is required to improve their success.
Methods: We have partnered with the Penn State Center for Survey Research (CSR) to send out a more robust survey to dairies in the Northeast. Surveys have been sent electronically and by mail to approximately 10,000 dairy producers. To reach as broad an audience as possible with the survey, we have exhausted contact lists from Extension departments, Beef and Dairy Councils/Promotion Boards/Associations, and the Department of Agriculture in each state. The survey was made available for eight weeks. At this time, CSR is consolidating the data, and will provide a methodology report and dataset of survey responses to the research team.
Aim 1: We currently have 12 calves on the ground, with an additional 20 cows bred. We are continuing to breed to reach our target of 40 calves, and expect to reach that number in spring 2022. Of these calves, 10 have completed their milk replacer stage, and are weaned onto one of the grower diets. Muscle biopsies and growth data have been successfully collected on these calves. We have not yet statistically analyzed the data.
Aim 2: Ten calves are currently on, or transitioning to, one of the grower diets. These animals are weighed, ultrasounded, and have body measurements taken monthly. We have not yet statistically analyzed the data.
Aim 3: Working with the Penn State CSR, we distributed our survey to dairy producers across the Northeast. Paper and electronic surveys were sent to mailing lists in each state, through cooperative extension and beef and dairy producer boards. The survey was also advertised on social media. To date, we have received approximately 450 online responses and 200 paper responses. The Penn State CSR will be consolidating the data and providing a data set of responses in the upcoming months.