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Feeding high-quality forage diets may lead to excessive weight gains and over-conditioning for dairy heifers. Restriction of energy density and dry matter intake by using low-energy forages, such as straw, is a good approach for controlling this problem. Alfalfa stems contain high fiber and moderate protein content and have the potential to be used to replace straw to reduce dietary energy. The objective of this study was to compare nutrient intakes, digestibilities, growth performance, and feeding behaviors of dairy heifers offered an alfalfa silage/corn silage high-energy diet (HE; 13.1% crude protein, 65.4% total digestible nutrients, 39.7% neutral detergent fiber) with 2 energy-diluted diets that replaced various proportions of the corn or alfalfa silages with either alfalfa stemlage (STM; 12.6% crude protein, 59.1% total digestible nutrients, 46.4% neutral detergent fiber) or chopped wheat straw (WS; 12.6% crude protein, 61.9% total digestible nutrients, 43.7% neutral detergent fiber). Seventy-two pregnant Holstein heifers (16.8 ± 1.3 mo) were stratified into 3 blocks (24 heifers/block) by initial body weight (light, 440 ± 18.0 kg; medium, 486 ± 18.6 kg; heavy, 534 ± 25.1 kg), with each block composed of 3 pens (8 heifers/pen), with diets assigned randomly to 1 pen within the block. Diets were offered in a 56-d feeding trial. Both dry matter intake and energy intake were decreased with the addition of low-energy forages to the diets, but no differences in dry matter intake were observed across diluted diets. Digestibility of dry matter, organic matter, neutral detergent fiber, and apparent N were greater for HE compared with diluted diets, and for WS compared with STM. Total body weight gain (74 vs. 56 kg) and average daily gain (1.32 vs. 1.00 kg/d) were greater for heifers offered HE compared with diluted diets. Feed efficiency tended to be less for heifers offered the diluted diets compared with HE (10.7 vs. 8.6 kg of feed/kg of gain). Heifers did not sort for or against particles when offered HE. However, increased sorting behavior was observed for diluted diets. Compared with ad libitum feeding dairy heifers a diet with high nutrient content forages (corn silage and alfalfa silage), use of diet diluted with alfalfa stemlage or wheat straw is an effective feeding management strategy to control total daily dry matter and energy intake by increasing gut fill, and maintain desirable body condition and growth rates, even though the diluted diets had greater sortability. [ABSTRACT FROM AUTHOR]

This experiment was conducted to investigate the effect of energy density (ED) in the close-up period and supplementation of extruded full-fat soybean (ESB) during the first 4 wk after parturition on intake, body weight (BW), metabolic status, and performance of dairy cows. Fifty-seven Chinese Holstein cows with similar parity, previous 305-d milk yield, and expected calving date were dried off at -60 d relative to parturition and fed the standard herd dry-cow diet until -21 d relative to parturition. Energy density at low (LED, 1.25 Mcal/kg), medium (MED, 1.41 Mcal/kg) or high (HED, 1.55 Mcal/kg) levels of the close-up diets and postpartum supplementation of ESB at 0 kg/d (control, CON) or 1.5 kg/d (TRT) were used in a 3 x 2 factorial arrangement. All cows received the same CON diet from wk 5 to wk 8. As ED increased in the close-up diet, cows had higher dry matter intake and gained more BW and body condition score, and consequently were in improved energy balance status during the prepartum period, but lost more BW and more body condition score during the first 8 wk of lactation. Compared with LED cows, HED cows had higher blood concentrations of insulin and glucose, and lower nonesterified fatty acids (NEFA) prepartum, but had lower insulin concentration, higher leptin concentration and tended to have higher NEFA concentration postpartum. Milk production was not affected by the prepartum ED, although HED cows produced approximately 2 kg/d less milk than MED and LED cows during early lactation. Postpartum ESB supplementation elevated blood glucagon concentration regardless of prepartum ED during the first 4 wk of lactation. Interactive effects between prepartum ED and postpartum ESB supplementation were observed in blood concentrations of insulin, NEFA, bilirubin, total protein, albumin, and globulin. During early lactation, TRT decreased globulin concentrations in MED cows, and reduced NEFA and bilirubin concentrations in HED cows. Compared with CON, TRT cows had higher yields of milk (34.32 vs. 36.53 kg/d), milk lactose (1.63 vs. 1.74 kg/d), and solids-nonfat (2.98 vs. 3.18 kg/d), tended to have a greater yield of milk protein (1.11 vs. 1.17 kg/d), but tended to have lower milk fat percentage (4.18 vs. 3.94%) during the first 4 wk of lactation. In conclusion, compared with feeding the HED diet, feeding the LED diet during the close-up dry period had positive carryover effects on metabolism and production during early lactation, and the MED diet showed no advantage over the LED diet. Extruded full-fat soybean supplementation during the first 4 wk of lactation had positive effects on postpartum metabolic status, especially for those receiving the MED or HED diet prepartum, and resulted in an overall improved milk production during early lactation. [ABSTRACT FROM AUTHOR]

A total of 182 beef samples were minced and divided into calibration set (n=140) and independent validation set (n=42). Calibration models of NIRS (1000-1800 nm) were built using partial least squares regression (PLSR) on the calibration set of samples. Both the coefficient of determination in calibration (R2C) and the coefficient of determination in prediction (R2P) were over 0.98 for all chemical compositions. The ratio performance deviation (RPD) was 17.37, 5.12 and 10.43 for fat, protein and moisture, respectively. The results of the present study indicate the outstanding ability of NIRS to predict chemical composition in beef. [ABSTRACT FROM AUTHOR]

The aim of the study was to evaluate the variations in the rumen ecosystem at genus level and predicted functions of rumen bacteria by using whole crop corn silage (WCS), whole crop rice silage (WRS) or rice straw (RS) as forage sources in beef cattle ration. Ruminal digesta samples from 10 bulls per treatment were collected at day 60 of experimental period. The PCoA plots based on the Bray-Curtis distance matrix (BDM) expressed separation between WRS and WCS, WRS and RS using PC1 (P<0.05, 45.56%). The PCoA plots based on BDM also expressed separation among WRS, WCS and RS group using PC2 (P<0.05, 11.95%). Microbiota composition resutls at genus level showed that the most abundant genera were Prevotella (13.37%) and Ruminococcus (4.00%). Comparison of treatments represented that Prevotella, Treponema and Anaerostipes were higher in bulls fed WCS forage. Clostridium, Anaeroplasma and RFN20 were higher in bulls fed RS forage than animals fed WCS and WRS. Butyrivibrio was higher in WRS and RS treatments than WCS treatment group. Pseudobutyrivibrio was higher in bulls fed WRS forage than animals fed RS and WCS forage. Fibrobacter was higher in RS and WCS as compared to WRS. The results of functional alteration of rumen microbiota in different experimental groups represented that the leading modified function of the microbiome was the transporter. Based on findings of current study, it is concluded that microbial community at genus level in the rumen of bulls was highly altered by forage type. [ABSTRACT FROM AUTHOR]

Objective: This study investigated the effect of dietary crude protein (CP) supplementation on nutrient intake, nitrogen (N) utilisation, blood metabolites, ruminal fermentation and growth performance of young Holstein bulls. Methods: Twenty-one young bulls weighing 277±11.2 kg were equally divided into three groups and were offered diets formulated with low CP (LCP; 10.21% CP and 4.22% rumen degradable protein [RDP]), medium CP (MCP; 12.35% CP and 5.17% RDP) and high CP (HCP; 14.24% CP and 6.03% RDP). Yellow corn silage was used as a unique forage source and was mixed with concentrate. This mixed feed was given ad libitum to the young bulls included in the study. Results: Results showed that CP intake, blood urea nitrogen, N intake, total N excretion and N balance increased linearly with an increase in dietary CP level (p<0.05). However, no significant difference was observed in nutrient digestibility among the bulls receiving the different diets. Ruminal pH (p<0.05) and ammonia nitrogen (NH3-N) concentration (p<0.01) were significantly higher in the bulls receiving the MCP and HCP diets than in those receiving the LCP diet. The bulls receiving the HCP diet showed significantly higher ruminal bacterial protein level, propionate, acetate and total volatile fatty acid (TVFA) concentrations than bulls receiving the LCP diet (p<0.05). Moreover, dietary CP level exerted a significant positive effect on the final body weight, average daily gain and gain-to-feed ratio of the bulls (p<0.05). Conclusion: High dietary CP level is optimal for achieving maximum growth and high profitability without exerting a negative effect on the physiology of growing Holstein bulls. [ABSTRACT FROM AUTHOR]

Objective: Wheat is an alternative to corn silage for ruminant feeding in northern China. This study examined the effects of harvest time and added molasses on nutritional content, ensiling characteristics and in vitro degradation of whole crop wheat (WCW). Methods: Fresh WCW at the milk-ripe stage was harvested at 0700 h (i.e., in the morning [Mo]) and 1700 h (i.e., in the afternoon [Af]), and then immediately used to prepare silage and make hay. Commercial molasses was added to Af WCW at 0%, 2%, 4%, and 6% (fresh weight) proportions. The WCW treated with molasses was mixed thoroughly prior to ensiling. Results: Dry matter (DM), neutral detergent fiber, water soluble carbohydrate (WSC) content (p<0.01), accumulative gas production in 72 h (GP72h, 77.46 mL/g vs 95.15 mL/g) and dry matter disappearance in vitro (69.15% vs 76.77%) were lower (p<0.05), while crude protein (CP) content was higher for WCW silage (WCWS) compared to WCW (p<0.01). The propionic acid and butyric acid concentrations in WCWS from Mo WCW were 1.47% and 0.26%, respectively. However, the propionic and butyric acid concentrations were negligible, while the ammonia nitrogen/total nitrogen (NH3-N/TN, p<0.01) concentration was lower and the rate of gas production at 50% of the maximum (17.05 mL/h vs 13.94 mL/h, p<0.05) was higher for Af WCWS compared to Mo WCWS. The incubation fluid's NH3-N concentration was lower in WCWS and Af WCW compared to Mo WCW (p<0.05). The CP and WSC content increased with increasing molasses levels (p<0.05). Furthermore, the pH (p<0.01) and time when gas production was 50% of the maximum (2.78 h vs 3.05 h, p<0.05) were lower in silage treated with 4% molasses than silage without molasses. Conclusion: Harvesting wheat crops in the afternoon and adding molasses at 4% level to WCW optimally improved ensiling characteristics, leading to well-preserved silage. [ABSTRACT FROM AUTHOR]