Effect of Metabolizable Protein Supply on Milk Performance, Ruminal Fermentation, Apparent Total-Tract Digestibility, Energy and Nitrogen Utilization, and Enteric Methane Production of Ayrshire and Holstein Cows
Author:
Benchaar Chaouki1ORCID, Hassanat Fadi2, Beauchemin Karen A.3ORCID, Ouellet Daniel R.1, Lapierre Hélène1, Côrtes Cristiano4
Affiliation:
1. Agriculture and Agri-Food Canada, Sherbrooke Research and Development Centre, Sherbrooke, QC J1M 0C8, Canada 2. Agriculture and Agri-Food Canada, Quebec Research and Development Centre, Québec, QC G1V 2J3, Canada 3. Agriculture and Agri-Food Canada, Lethbridge Research and Development Centre, Lethbridge, AB T1J 4B1, Canada 4. Agrinova, 640 rue Côté, Alma, QC G8B 7S8, Canada
Abstract
In North America, the nutrient requirements of dairy cattle are predicted using the Cornell Net Carbohydrate and Protein System (CNCPS) or the National Research Council (NRC). As Holstein is the most predominant dairy cattle breed, these models were developed based on the phenotypic, physiological, and genetic characteristics of this breed. However, these models may not be appropriate to predict the nutrient requirements of other breeds, such as Ayrshire, that are phenotypically and genetically different from Holstein. The objective of this study was to evaluate the effects of increasing the metabolizable protein (MP) supply using CNCPS on milk performance, ruminal fermentation, apparent total-tract digestibility, energy and N utilization, and enteric methane production in Ayrshire vs. Holstein lactating dairy cows. Eighteen (nine Ayrshire; nine Holstein) lactating cows were used in a replicated 3 × 3 Latin square design (35-d periods) and fed diets formulated to meet 85%, 100%, or 115% of MP daily requirement. Except for milk production, no breed × MP supply interaction was observed for the response variables. Dry matter intake (DMI) and the yields of energy-corrected milk (ECM), fat, and protein were less (p < 0.01) in Ayrshire vs. Holstein cows. However, feed efficiency and N use efficiency for milk production did not differ between the two breeds, averaging 1.75 kg ECM/kg DMI and 33.7 g milk N/100 g N intake, respectively. Methane yield and intensity and urinary N also did not differ between the two breeds, averaging 18.8 g CH4 /kg DMI, 10.8 g CH4 /kg ECM, and 27.6 g N/100 g N intake, respectively. Yields of ECM and milk protein increased (p ≤ 0.01) with increasing MP supply from 85% to 100% but no or small increases occurred when MP supply increased from 100 to 115%. Feed efficiency increased linearly with an increasing MP supply. Nitrogen use efficiency (g N milk/100g N intake) decreased linearly (by up to 5.4 percentage units, (p < 0.01) whereas urinary N excretion (g/d or g/100 g N intake) increased linearly (p < 0.01) with an increasing MP supply. Methane yield and emission intensity were not affected by MP supply. This study shows that feed efficiency, N use efficiency, CH4 (yield and intensity), and urinary N losses did not differ between Ayrshire and Holstein cows. Energy-corrected milk yield and feed efficiency increased, but N use efficiency decreased and urinary N losses increased with increasing dietary MP supply regardless of breed. Ayrshire and Holstein breeds responded similarly to increasing MP levels in the diet.
Funder
Agriculture and Agri-Food Canada
Subject
General Veterinary,Animal Science and Zoology
Reference71 articles.
1. Agriculture and Agri-Food Canada (2022, May 14). Statistics of Canada’s Animal Genetics. Available online: https://agriculture.canada.ca/en/agriculture-and-agri-food-canada/canadas-agriculture-sectors/animal-industry/canadian-dairy-information-centre/publications-and-bulletins/statistics-canadas-animal-genetics. 2. Dohner, J. (2020, November 05). Ayrshire Cattle: Heritage Livestock Breeds. Mother Earth News. Available online: https://www.motherearthnews.com/homesteading-and-livestock/ayrshire-cattle-heritage-livestock-zeylaf. 3. Lactanet (2019). L’Évolution de la Production Laitière Québécoise, Université Laval. 4. Lactanet (2019). The Evolution of Lactanet Atlantic Dairy Production, Université Laval. 5. Lactanet (2019). Ontario Progress Report, Université Laval.
Cited by
1 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献
|
|