Presentation Title
Milk Production of Organic Dairy Cattle is Influenced by Altering Supplemental Feed Protein Content.
Abstract
As demand for organic dairy products grows, it is important that the industry focuses on feeding and management strategies that can optimize milk production. Dietary crude protein (CP) profile is variable across farms, and is a factor that impacts animal health and production during the grazing season. Over- and under-feeding of protein can be identified through milk urea nitrogen (MUN) content. This study evaluated the impact of altering the CP content of dietary supplements included in dairy rations on milk production and MUN profile from grazing cattle. Six Vermont organic dairy farms participated in a six-week trial during the 2018 summer grazing season (June to August). Farms were paired by their 2017 summer MUN profile, and farms within each pair were assigned to either 1) continuation of their regular supplements (n=3, control group, CON), or 2) a 16% CP (% of DM) supplement formulated using an organic barley and roasted soybean mix (n=3, treatment group, TRT). All farms were maintained on their regular supplements during the first two weeks of the trial (baseline), and then continued on either the CON or TRT supplements, respectively, for the last four weeks of the trial (experimental period). During the 6-week trial, milk samples were collected at two consecutive milkings every week. Individual milk yields were recorded at each sampling, and samples were collected in bronopol preservative and commercially analyzed for protein, fat, and MUN content. Data were statistically analyzed using the mixed procedure of SAS for all parameters, and effects of treatment, week, and their interaction (treatment x week) were determined. Milk weight, fat percent, protein percent, and MUN content were all affected by treatment x week (P
Primary Faculty Mentor Name
Sabrina Greenwood
Status
Graduate
Student College
College of Agriculture and Life Sciences
Program/Major
Animal Science
Primary Research Category
Biological Sciences
Milk Production of Organic Dairy Cattle is Influenced by Altering Supplemental Feed Protein Content.
As demand for organic dairy products grows, it is important that the industry focuses on feeding and management strategies that can optimize milk production. Dietary crude protein (CP) profile is variable across farms, and is a factor that impacts animal health and production during the grazing season. Over- and under-feeding of protein can be identified through milk urea nitrogen (MUN) content. This study evaluated the impact of altering the CP content of dietary supplements included in dairy rations on milk production and MUN profile from grazing cattle. Six Vermont organic dairy farms participated in a six-week trial during the 2018 summer grazing season (June to August). Farms were paired by their 2017 summer MUN profile, and farms within each pair were assigned to either 1) continuation of their regular supplements (n=3, control group, CON), or 2) a 16% CP (% of DM) supplement formulated using an organic barley and roasted soybean mix (n=3, treatment group, TRT). All farms were maintained on their regular supplements during the first two weeks of the trial (baseline), and then continued on either the CON or TRT supplements, respectively, for the last four weeks of the trial (experimental period). During the 6-week trial, milk samples were collected at two consecutive milkings every week. Individual milk yields were recorded at each sampling, and samples were collected in bronopol preservative and commercially analyzed for protein, fat, and MUN content. Data were statistically analyzed using the mixed procedure of SAS for all parameters, and effects of treatment, week, and their interaction (treatment x week) were determined. Milk weight, fat percent, protein percent, and MUN content were all affected by treatment x week (P