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Simple Summary: The global demand for mutton products has increased due to changes in consumer lifestyles, consumption concepts, and socio-economic developments. The feeding systems are widely acknowledged to significantly affect the growth, development, and body health of livestock. In this study, we evaluated the effects of different feeding methods on growth performance, serum biochemical indexes, rumen fermentation parameters, and fecal microorganisms of Huang-huai sheep. The results show that indoor feeding with restricted grazing artificial grassland can improve fattening performance, antioxidation and immune function activity, and rumen fermentation, as well as change fecal microbiota composition. This study investigated the effects of three feeding systems, indoor feeding (CONT), indoor feeding with time-restricted grazing artificial pasture (4 h/day, G4H), and indoor feeding with an eight-hour daily grazing artificial pasture (G8H), on the growth performance, serum metabolites, ruminal fermentation, and fecal microbiota composition of lambs. Average daily gain showed a tendency (p = 0.081) to be higher for the G4H group compared with the CONT group. Moreover, feeding systems did not have a significant effect on most of the serum biochemical indicators in lambs. Concentrations of serum glutathione peroxidase and immunoglobulins (IgA, gG, and IgM) were significantly lower (p < 0.01) in the CONT group. Additionally, a tendency towards higher levels of volatile fatty acids, acetate, and butyrate was found in animals of the G4H group compared to the CONT group. Furthermore, fecal microbiota composition was altered in G4H and G8H groups, resulting in the increased relative abundance of Firmicutes and Ruminococcaceae UCG-005, as well as the decreased relative abundance of Ruminobacter compared with the CONT group. Overall, these results suggest that indoor feeding with restricted grazing time does not significantly affect fattening performance or rumen fermentation but enhances antioxidation and immune function activity and also alters fecal microbiota composition. [ABSTRACT FROM AUTHOR]

The objective of this research was to study the effect on milk production and excretion of nitrogen of supplementing cows grazing clover grass for half a day with reduced protein. A low level protein supplement (11% crude protein in dry matter (DM)), which allowed for a balanced ration over 24 h, was compared to a normal level (17% crude protein in DM), which balanced the ration given while the animals were barn fed. One hundred and seventeen lactating Holstein cows in two commercial herds grazed on clover grass leys for a half day from May to June. The cows had limited access to low protein silage during the other half of the day and were fed one of the two levels of protein in the concentrate while in the barn. Average grass intake was 8.3 kg DM (19.8% crude protein in DM). Intake was estimated by calculating the difference between energy recommendations (for maintenance, growth and milk production and the energy value of feed intake in the barn). Low protein supplement significantly reduced milk yield (25.2 vs. 27.0 kg), fat (1077 vs. 1136 g) and protein (838 vs. 900 g) compared to the normal protein level. Fat and protein content were not affected. Daily milk urea concentration increased from 3.0 to 4.2 mM for low compared to normal protein levels in the concentrate. The cows fed low protein concentrate had a significantly lower milk urea content even after grazing forage with high protein content. The 33% highest yielding cows and the 33% of the cows in the earliest stage of lactation in the pre-experimental period were more sensitive to the lower level of protein in the diet than the other cows. The estimated excretion of nitrogen in manure per kg energy corrected milk (ECM) was lowest at low protein level. However, a potential for a decreasing nitrogen excretion without milk yield loss can be realized by allocation of concentrates with varied protein content, according to yield and stage of lactation. [Copyright &y& Elsevier]