Nutritional efficiency of feed restricted F1 Holstein/Zebu cows during the middle third of lactation

Abstract

The objective of this study was to evaluate the effects of different levels of quanti tative feed restriction on nutrient intake and digestibility, nitrogen balance, efficiency and feeding behavior, and productive performance in F1 Holstein/Zebu cows during the middle third of their lactation. Methods: Sixty F1 Holstein/Zebu cows with 111.5±11.75 days of lactation and an initial body weight (BW) of 499±30 kg (mean±standard error of the mean) were used. The experimental design was completely randomized with the following diet levels of feed restriction: 3.39%, 2.75%, 2.50%, 2.25%, and 2.00% of BW, with 12 replications for each level. The experiment lasted for 63 days, of which each period lasted 21 days with the first 16 days for diet adaptation followed by 5 days for collection of data and samples. Results: For each 1% of BW diet restriction, there was a decrease in dry matter intake of 5.26 kg/d (p<0.01). There was no difference in daily milk production (p = 0.09) under the restric tion levels of 3.39% to 2.0% of BW. When corrected for 3.5% fat, milk production declined (p = 0.05) 3.46 kg/d for each percentage unit of feed restriction. Conclusion: Restricting the feed supply for F1 Holstein/Zebu cows in the middle third of their lactation period altered nutrient intake, nitrogen balance and ingestive behavior but did not affect milk production or feed efficiency. However, considering the observed BW loss and decrease in milk production corrected for 3.5% fat, restriction of no less than 2.5% BW is recommended.

Feeding F1 Holstein x Zebu cows with different roughages and pseudostem hay of banana trees does not influence milk yield and chemical composition of milk and cheese

“…The higher iNDF concentration (227.4 g/kg) in the EGPS diet implies less fibrous fraction degradability, which limited the TDN intake in this diet, indicating lower energy availability for rumen fermentation (Borges et al 2019). However, Monção et al (2020 and Santana et al (2019Santana et al ( , 2020 recommended DMI for F1 Holstein/Zebu cows in the order of 2.50% BW. In this study, although lower DMI was found in cows that received the EGSP and SCPS diet, the DMI is above 2.50% BW not impairing the performance of the animals as justified by milk yield that did not change between treatments.…”

“…In the semiarid region of Brazil, sorghum silage (Sorghum bicolour (L.) Moench) It is traditionally used as a roughage (fibre source) for feedlot dairy cows due to tolerance to water restriction, mechanisable and high productivity per unit area and good nutritional value (Borges et al 2019). However, the feed cost under these conditions is high (Borges et al 2019;Santana et al 2019Santana et al , 2020. The use of traditional ingredients or byproducts and/or agribusiness wastes available in each region in the formulation of diets is a strategy to reduce feed costs and improve system efficiency.…”