Energy and protein gap analysis in dairy cows kept under fodder based diet with cut and carry feeding system.

Published: 8 October 2024| Version 1 | DOI: 10.17632/rysm7p5pb5.1
Contributor:
Olive Umunezero

Description

There is a gap in dry matter, water, energy and protein intake of dairy cows kept in fodder- based diet under cut and carry feeding system in Sub- Saharan countries, Rwanda included. A study was conducted in two contrasting areas of Rwanda: Eastern Savana (altitude of 1,566 m, latitude is 1o56’55’S and longitude 30o26’5’’E; rainfall average of 900 mm, with temperatures of 25oC) and Volcanic highlands (altitude of 2250 m, latitude is -1o 29’59.42’’S and longitude is 29o 38’5.89’’E; the rainfall average is 1,845 mm; the average annual temperature is 15.9oC). The objective was to determine dry matter, water, protein and energy intake in comparison to their requirements for meeting the potential milk production. Ninety households, including 60 from lowlands and 30 from highlands, were randomly selected, and a total of 96 cows were included in the data collection process. About 90 samples which corresponded to different fodder mixture fed to lactating dairy cows in surveyed household were analysed for their dry matter (DM), crude protein (CP), neutral detergent fibre (NDF), and metabolizable energy (ME). Data on NDF intake, ME and CP intake, water, DM intake, body weight and milk performance well also collected. Data on feeds characterization were computed with Farm DESIGN Manual models by Groot and Oomen, while data for the production requirement of dairy cows under lactation were computed using LIGAPS dairy models. Data were analysed using general linear model with univariate analysis of statistical package for social sciences (SPSS). Results on feed characteristics showed that the average nutritive value of offered fodder was 25% of dry matter (DM), 58.5% neutral detergent fibre, 9.8% crude protein and of 6 mega joules (MJ) per kg DM. Results on production management showed that the average daily intake was 9kg DM; 35 litres of water; 898g of crude protein (CP) and 55 MJ ME, resulting in a milk production of 8.8 litres per day in both sites. However, the average requirement for both maintenance and a target milk production of 16.5litres per day were 15kg of DM; 57 Litres of water, 1907g of CP and 137 MJ of ME. This indicated daily deficits of 6kg DM, 21.6litres of water, 1094g of crude protein and 83.7 MJ of ME, along with a 7.6litres shortfall in milk yield per day. Results of the present study demonstrate the hypothesis previously posed. Findings from this analysis will serve as instruments for researchers in developing dairy diet models to improve dairy cow productivity at household level. Demonstrating the gap of available feeds resources would trigger the uptake of new feeding technologies by farmers. For dairy feeds manufacturers, this would serve as a guide for proper rationing of high concentrates ingredients rich in energy and protein in consideration of their requirements. This would contribute to improved milk production resulting in better remuneration to farmers, increased national milk pool and per capita milk consumption.

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Dry matter intake requirement was calculated based on the body weight requirement for its maintenance and based on the current milk production. DMIR=BW x 3.5/100. DM intake of a given feed per 100 kg BW =120/NDF (%DM). Dry matter intake of feeds per body weight=120/NDF x BW/100. Gap dry matter intake was obtained by subtracting the DMI of feeds from the DMIR. Predicting equation for water intake was expressed based on their dry matter intake requirement and attainable milk; FWI =12.3+2.15 x DMIR+0.73 x PM. Where FWI=free water intake; DMIR: dry matter intake requirement and PM: Potential milk. Water intake gap was then calculated by subtracting the amount provided per day from the amount required per day. Milk production gap was obtained by subtracting the total milk performance that include assumed milk suckled by the calf from the potential milk yield. Energy intake was expressed as metabolizable energy (ME) intake. ME in feeds (MJ/kg DM) was calculated using the formula by Groot et al. (2016) where ME in feeds (MJ/kg DM) = 2.2 + 0.136 G24 + 0.057CP + 0.0029CP^2. Where GV24 = gas volume generated after 24 h of substrate incubation. Required ME for both maintenance and production was estimated according to LIGAPs-dairy model by Van der Linden et al. (2021) where 0.589 MJ per kg metabolic weight is required for maintenance, and 5.023 MJ are required per kg milk. Metabolizable energy intake=ME in feeds x DMI. Energy maintenance = BW^0.75 x 0.589. Where BW=body weight; BW^0.75= is the metabolically weight; DMI= dry matter intake. Energy for attainable milk=5.023 x attainable milk.Total energy for production=energy for maintenance + energy for attainable milk. Energy intake gaps was obtained by subtracting their daily intake from the requirements values. Therefore, Gap Energy= Energy requirement-Energy intake Protein intake was expressed as crude protein (CP) intake. The value was computed by the quantity served per day in dry matter basis. Therefore, CP in feeds (gr/kg) = % CP x 1000/100. CP intake=CP in feeds x DMI. Where DMI=dry matter intake. Required protein for both maintenance and production was estimated according to LIGAPs-dairy model by Van der Linden et al. (2021). In the model, 6.27g CP per kg metabolic weight is required for maintenance and 82g CP is required per kg milk. Therefore, CP requirement for maintenance = 6.27 x MW. Where; MW= metabolically weight. CP requirement for attainable milk= 82g x attainable milk. Total CP requirement for production=CP maintenance + CP attainable milk. Gap CP= Total CP required for attainable milk production - CP intake

Institutions

University of Nairobi Faculty of Agriculture

Categories

Dairy Cattle Nutrition

Funding

United States Agency for International Development

award number EEM-G-00-04-00013

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