Adjusting for 30-hour undigested neutral detergent fiber in substitution of wheat straw and beet pulp for alfalfa hay and corn silage in the dairy cow diet: Chewing activities, diurnal feed intake, and ruminal fermentation

Ali Kahyani; Gholam Reza Ghorbani; Masoud Alikhani; Hassan Rafiee; Omid Ramezani; Mehdi Asemi Esfahani; Farhad Ahmadi

doi:10.3168/jdsc.2022-0248

Adjusting for 30-hour undigested neutral detergent fiber in substitution of wheat straw and beet pulp for alfalfa hay and corn silage in the dairy cow diet: Chewing activities, diurnal feed intake, and ruminal fermentation

JDS Commun. 2022 Sep 3;3(6):436-440. doi: 10.3168/jdsc.2022-0248. eCollection 2022 Nov.

Authors

Ali Kahyani¹, Gholam Reza Ghorbani¹, Masoud Alikhani¹, Hassan Rafiee², Omid Ramezani³, Mehdi Asemi Esfahani⁴, Farhad Ahmadi⁵

Affiliations

¹ Department of Animal Sciences, College of Agriculture, Isfahan University of Technology, Isfahan 84156-83111, Iran.
² Animal Science Research Department; Isfahan Agriculture and Natural Resources Research and Education Center; Agriculture Research, Education and Extension Organization (AREEO), 8174835117, Isfahan, Iran.
³ Department of Animal Science, Campus of Agriculture and Natural Resources, University of Tehran, 31587-77871, Karaj, Iran.
⁴ Department of Animal Science, Agricultural Sciences and Natural Resources, University of Khuzestan, 63417-73637, Mollasani, Ahvaz, Iran.
⁵ Department of Eco-friendly Livestock Science, Institute of Green Bio Science and Technology, Seoul National University, Pyeongchang, 25354, South Korea.

Abstract

This experiment investigated the effects of replacing alfalfa hay (AH) and corn silage (CS) with wheat straw (WS) and beet pulp (BP) in diets with similar forage 30-h undigested neutral detergent fiber (uNDF₃₀) on chewing behavior and ruminal fermentation of lactating cows. Twelve multiparous Holstein cows (51 ± 3 kg/d of milk; days in milk = 97 ± 13; mean ± standard error) were housed in individual stalls and used in a replicated 3 × 3 Latin square design with 28-d periods. Experimental diets were (1) 0% forage uNDF₃₀ from WS (WS0, contained 2% BP); (2) 50% forage uNDF₃₀ from WS (WS50, contained 7.6% BP); and (3) 100% forage uNDF₃₀ from WS (WS100, contained 12.4% BP). From 0 to 2 h after the morning feeding, there was a tendency observed for a quadratic effect on dry matter intake (DMI), with cows fed WS50 consuming the greatest amount of DM (9.19 kg). Later DMI (4 to 6 h and 6 to 24 h postfeeding) decreased as dietary proportion of WS and BP increased. Increasing WS and BP decreased eating behavior, but had no detected effect on rumination time (455 min/d), which resulted in a linear reduction in chewing time (the sum of eating and rumination activities). As WS and BP inclusion increased, the number of meals decreased linearly, whereas time between meals, eating rate, and meal size per kilogram of DM increased linearly. Increased dietary inclusion of WS and BP tended to decrease total ruminal VFA and resulted in a linear decrease in propionate but an increase in acetate proportion and ammonia-N concentration in the rumen. Overall, the substitution had no effect on rumination activity, possibly suggesting that a combination of WS and BP could be used in dairy cow rations as substitutes for high-quality forages when WS was added to maintain the uNDF₃₀ level.