Lacticaseibacillus parahuelsenbergensis sp. nov., Lacticaseibacillus styriensis sp. nov. and Lacticaseibacillus zeae subsp. silagei subsp. nov., isolated from different grass and corn silage.

Four rod-shaped, non-motile, non-spore-forming, facultative anaerobic, Gram-stain-positive lactic acid bacteria, designated as EB0058T, SCR0080, LD0937T and SCR0063T, were isolated from different corn and grass silage samples. The isolated strains were characterized using a polyphasic approach and EB0058T and SCR0080 were identified as Lacticaseibacillus zeae by 16S rRNA gene sequence analysis. Based on whole-genome sequence-based characterization, EB0058T and SCR0080 were separated into a distinct clade from Lacticaseibacillus zeae DSM 20178T, together with CECT9104 and UD2202, whose genomic sequences are available from NCBI GenBank. The average nucleotide identity (ANI) values within the new subgroup are 99.9 % and the digital DNA-DNA hybridization (dDDH) values are 99.3-99.9 %, respectively. In contrast, comparison of the new subgroup with publicly available genomic sequences of L. zeae strains, including the type strain DSM 20178T, revealed dDDH values of 70.2-72.5 % and ANI values of 96.2-96.6 %. Based on their chemotaxonomic, phenotypic and phylogenetic characteristics, EB0058T and SCR0080 represent a new subspecies of L. zeae. The name Lacticaseibacillus zeae subsp. silagei subsp. nov. is proposed with the type strain EB0058T (=DSM 116376T=NCIMB 15474T). According to the results of 16S rRNA gene sequencing, LD0937T and SCR0063T are members of the Lacticaseibacillus group. The dDDH value between the isolates LD0937T and SCR0063T was 67.6 %, which is below the species threshold of 70 %, clearly showing that these two isolates belong to different species. For both strains, whole genome-sequencing revealed that the closest relatives within the Lacticaseibacillus group were Lacticaseibacillus huelsenbergensis DSM 115425 (dDDH 66.5 and 65.9 %) and Lacticaseibacillus casei DSM 20011T (dDDH 64.1 and 64.9 %). Based on the genomic, chemotaxonomic and morphological data obtained in this study, two novel species, Lacticaseibacillus parahuelsenbergensis sp. nov. and Lacticaseibacillus styriensis sp. nov. are proposed and the type strains are LD0937T (=DSM 116105T=NCIMB 15471T) and SCR0063T (=DSM 116297T=NCIMB 15473T), respectively.

Effects of protein and forage source on performance, and splanchnic and mammary net fluxes of nutrients in lactating dairy cows.

This study was conducted to determine if the decreased MP supply predicted by the NRC (2001) when canola meal (CM) substitutes soybean meal (SBM) was supported by direct measurement of net portal absorption of AA or energy-yielding nutrients, plus the impact of the type of forage in CM-based rations. Nine Holstein cows with indwelling catheters in splanchnic blood vessels, 8 also with a ruminal cannula were used to examine the effects of protein source in corn silage-based diets, comparing SBM versus CM, and forage source in CM-based diets, comparing corn versus grass silage. The cows were allocated to a triple 3 × 3 Latin square design with 21-d periods. The 3 experimental diets, formulated to be isoenergetic and isonitrogenous, were based on: 1) SBM and corn silage (SoyCorn); 2) CM and corn silage (CanCorn) and 3) CM and cool-season grass silage (CanGrass). Averages of intake, milk yield and milk composition of the last 3 d of each period were used for statistical analyses. On d 21 of each period, 6 sets of arterial, portal, hepatic and mammary blood samples and 2 ruminal fluid samples were collected. On d 12 of period 2, the protein sources were incubated in nylon bags to determine 16h-ruminal disappearance of DM and N and to obtain 16-h residues. Finally, 5 d after the completion of the Latin square design, the mobile bag technique was used to determine DM and N intestinal disappearance of the 16-h residues of SBM and CM. Pre-planned contrasts were used to compare the effect of the protein source in cows fed corn silage, i.e., SoyCorn versus CanCorn, and the effect of forage in cows fed CM, i.e., CanCorn versus CanGrass. Data of the cow without a rumen canula could not be used because of health problem. In corn silage-based diets, substitution of SBM by CM tended to increase milk (6%) and milk fat (7%) yields. The 8% higher ruminal N disappearance and the 19% decreased MP supply from RUP predicted by NRC (2001) were not supported by the 25% decrease in ruminal ammonia concentration, similar net portal absorption of AA (except 22% higher for Met), and the 14% decrease in urea hepatic removal when CM substituted SBM. Ruminal incubation of CM in nylon bags does not appear suitable for adequate determination of the rumen by-pass of a protein source like CM. Inclusion of grass silage rather than corn silage in CM-based diets tended to increase milk (6%) and increased milk lactose (8%) yields. Neither protein nor forage source resulted in variations of metabolism of energy-yielding nutrients that could explain observed increments in cow performance. The present study indicates no decreased AA availability when CM substitutes SBM. Therefore, substitution of SBM by CM in diets based on corn silage and CM in corn- or grass silage-diets can be used successfully in high producing dairy cows.

Effect of nicotinic acid supplementation on digestion, metabolism, microbiome, and production in late-lactation Holstein cows.

The purpose of this experiment was to determine if nicotinic acid (NA) effects on dairy cows and rumen microbial characteristics are forage-type dependent (corn silage, CS; grass silage, GS). Four late-lactation (DIM = 225 ± 12 d) Holstein cows were used in a 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. The main effects were a CS (66.10% CS) based diet or a GS (79.59%) based diet with or without 12 g/d NA. Each experimental period lasted for 28 d. Milk production and milk components, blood metabolites, apparent total-tract nutrient digestibilities, minutes rumen pH were below 5.8 as an indicator of ruminal acidosis, and body temperature changes were analyzed as indicators of heat stress. Nicotinic acid supplementation did not improve apparent total-tract nutrient digestibility. Feeding a GS-based diet improved NDF and hemicellulose digestibility. Feeding a CS-based diet increased the apparent total-tract digestibility of fat, and minutes rumen pH below 5.8 for a greater proportion of the time. The CS-based diet also improved milk yield, milk fat and protein yields, and ECM yield; however, somatic cell count and BHB were also increased. Supplementing NA tended to decrease nonesterified fatty acids, especially when combined with GS where DMI was low. There was a trend for the total protozoa population to increase when GS and NA were fed but decreased when CS and NA were fed. Nicotinic acid tended to decrease rumen protozoal populations of Dasytricha, but increased populations of Ophryoscolex and Diplodiniinae with GS diets and decreased with CS diets. Entodiniinae were increased with CS but NA had no effect. Body temperature was increased when a CS-based diet was fed when compared with a GS-based diet. More research is needed to determine how NA can affect rumen microbial protein synthesis and what kind of diets will provide the optimum effect.

Effects of dietary forage-to-concentrate ratio and forage type on milk phospholipids and fatty acid composition of polar lipids.

The effects of grass silage and red clover silage on milk fatty acid (FA) composition are extensively studied, but little is known of their effects on minor lipid constituents of milk fat globule membrane. We investigated the effects of forage:concentrate (FC) ratio in grass silage-based diets and forage type (grass silage vs. red clover silage) on selected molecular species of milk phospholipids (PL) and the FA composition of PL. Ten multiparous Nordic Red cows were offered following dietary treatments: grass silage-based diets containing 70:30 (HG) or 30:70 (LG) FC ratio or a red clover silage-based diet (RC) comprising 50:50 FC ratio on a dry matter basis. The most abundant molecular species within the phosphatidylcholines was 16:0-18:1 phosphatidylcholine that was increased by 18% in HG compared with LG milk. Dietary treatments did not affect the relative proportion of 18:1-18:1+18:0-18:2 phosphatidylethanolamine that was the most prevalent species (ca. 44%-45%) in that class. We identified the d18:1-22:0 sphingomyelin as the most abundant sphingomyelin species that tended to increase in HG milk compared with LG. The FC ratio did not affect the relative proportions of saturated FA nor monounsaturated FA in PL, but the proportion of cis-9 18:1 was elevated in HG versus LG milk, whereas the proportion of 18:2n-6 was 50% higher in LG versus HG milk. The RC diet increased monounsaturated FA and 18:3n-3 levels in PL compared with grass silage-based diets and decreased the relative proportion of saturated FA. However, the RC diet did not affect the relative proportion of polyunsaturated FA in PL, although red clover silage typically increases the proportion of polyunsaturated FA in milk fat. This study provides valuable knowledge of the minor lipid components in milk on species level in relation to common feeding strategies in high-forage systems.

Effects of prepartum concentrate feeding on reticular pH, plasma energy metabolites, acute phase proteins, and milk performance in grass silage-fed dairy cows.

We investigated how concentrate feeding during the last 21 d of pregnancy affects reticular pH, inflammatory response, dry matter (DM) intake, and production performance of dairy cows. We hypothesized that adding concentrates to dairy cows' diet before calving reduces the decrease in reticular pH postpartum and thus alleviates inflammatory response. We also hypothesized that prepartum concentrate feeding increases DM intake postpartum and consequently improves milk performance. Two feeding experiments were conducted using a randomized complete block design. In each experiment, 16 multiparous Finnish Ayrshire cows were paired based on parity, expected calving date, body weight, and milk yield of the previous lactation. Within the pairs, cows were randomly allocated on one of the 2 dietary treatments 21 d before expected calving. In experiment 1 (Exp1), diets were ad libitum feeding of grass silage as a sole feed or supplemented with increasing amounts of concentrate offered separately (increased to 4 kg/d by d -7). In experiment 2 (Exp2), diets were ad libitum feeding of a total mixed ration containing either grass silage, barley straw, and rapeseed meal (64%, 28%, and 8% on DM basis, respectively) or grass silage, barley straw, and cereal-based concentrate mixture (49%, 29%, and 30% on DM basis, respectively). Following calving, all the cows were fed similarly and observed until d 56 postpartum. Feed intake and milk yield were recorded daily, and reticular pH was monitored continuously by reticular pH bolus. Blood samples were collected at the beginning of the experiments, 7 d before the expected calving date, 1 d (in Exp1) or 5 d (in Exp2), 10 d, and 21 d postpartum. In Exp1, concentrate feeding increased metabolizable energy intake and tended to increase DM and crude protein intake prepartum. Moreover, prepartum concentrate feeding increased the concentrations of plasma ß-hydroxybutyrate and insulin, but differences in nonesterified fatty acids, glucose, or acute phase proteins were not observed. After calving, prepartum diet did not affect DM or nutrient intake, plasma energy metabolites, or milk production in Exp1. Although prepartum concentrate feeding increased reticular pH on the first day of lactation, it elevated plasma concentrations of serum amyloid-A and haptoglobin postpartum in the grass silage-based diet. In Exp2, adding concentrates to the diet based on a mixture of grass silage and straw did not affect prepartum DM intake or plasma concentrations of nonesterified fatty acids, glucose, or insulin. Adding concentrates to prepartum diet increased plasma concentration of ß-hydroxybutyrate before calving as in Exp1. After calving, prepartum concentrate feeding increased DM and nutrient intake during the second week of lactation in Exp2, but no effects were observed thereafter. In contrast to our hypothesis, prepartum concentrate feeding decreased reticular pH after calving in Exp2, but no differences in inflammatory markers were observed. Based on this study, close-up concentrate feeding in diets based on grass silage with or without straw does not alleviate the decrease in reticular pH or mitigate inflammatory response postpartum.

Effects of refused melon fruit in Canarana grass ensilage on intake, digestibility, serum biochemistry, performance, carcass characteristics and meat attributes of feedlot lambs.

Ensilage of refused fruit with forage is a viable approach to increase resource use in ruminant feed. The objective of this study was to investigate the impact of ensiling refused melon fruit (RMF) with Canarana grass on the intake, apparent digestibility, serum biochemistry, performance, carcass traits, and meat attributes of feedlot lambs. Four distinct silage treatment types were prepared by ensiling RMF at 0 g/kg (control), 70 g/kg, 140 g/kg, and 210 g/kg (as fed) with Canarana grass. Twenty-eight male Santa Inês lambs (7 lambs per treatment), initially weighing 22.3 ± 1.0 kg at 120 days of age, were distributed in a completely randomized design and confined for a total of 96 days, including a 23-day adaptation period and 73 experimental days in a feedlot. The lambs received the treatment-silage in diets as a complete mixture with a roughage: concentrate ratio of 30:70. The inclusion of RMF in Canarana grass ensilage decreased (P < 0.05) the lambs' intake of dry matter, crude protein and metabolisable energy. The inclusion of RMF in ensilage had a quadratic effect (P < 0.05) on the digestibility of non-fibrous carbohydrates. The serum total protein and cholesterol levels decreased (P < 0.05) with the inclusion of RMF in the ensilage, but we observed no effect on the final weight and average daily gain of the lambs. The feed efficiency increased (P < 0.05) by including RMF in the Canarana grass ensilage. The RMF in the ensilage did not influence cold carcass weight and yield. The fat content of the meat decreased (P < 0.05) with the inclusion of RMF in the ensilage. It is recommended the inclusion of up to 210 g/kg of RMF in Canarana grass ensilage to increase feed efficiency and avoid impacts on the performance and carcass attributes of confined lambs.

Processed fava bean as a substitute for rapeseed meal with or without rumen-protected methionine supplement in grass silage-based dairy cow diets.

Fava bean offers a sustainable home-grown protein source for dairy cows, but fava bean protein is extensively degraded in the rumen and has low Met concentration. We studied the effects of protein supplementation and source on milk production, rumen fermentation, N use, and mammary AA utilization. The treatments were unsupplemented control diet, and isonitrogenously given rapeseed meal (RSM), processed (dehulled, flaked, and heated) fava bean without (TFB) or with rumen-protected (RP) Met (TFB+). All diets consisted of 50% grass silage and 50% cereal-based concentrate including studied protein supplement. The control diet had 15% of crude protein and protein-supplemented diets 18%. Rumen-protected Met in TFB+ corresponded to 15 g/d of Met absorbed in the small intestine. Experimental design was a replicated 4 × 4 Latin square with 3-wk periods. The experiment was conducted using 12 multiparous mid-lactation Nordic Red cows, of which 4 were rumen cannulated. Protein supplementation increased dry matter intake (DMI), and milk (31.9 vs. 30.7 kg/d) and milk component yields. Substituting RSM with TFB or TFB+ decreased DMI and AA intake but increased starch intake. There were no differences in milk yield or composition between RSM diet and TFB diets. Rumen-protected Met did not affect DMI, or milk or milk component yields but increased milk protein concentration in comparison to TFB. There were no differences in rumen fermentation except for increased ammonium-N concentration with the protein-supplemented diets. Nitrogen-use efficiency for milk production was lower for the supplemented diets versus control diet but tended to be greater for TFB and TFB+ versus RSM. Protein supplementation increased plasma essential AA concentration but there were no differences between TFB diets and RSM. Rumen-protected Met clearly increased plasma Met concentration (30.8 vs. 18.2 µmol/L) but did not affect other AA. Absence of differences between RSM and TFB in milk production together with limited effects of RP Met suggest that TFB is a potential alternative protein source for dairy cattle.

Dwarf and tall elephant grass silages: intake, nutrient digestibility, nitrogen balance, ruminal fermentation, and ingestive behavior in sheep.

The objective of this study was to evaluate the exclusive supply of dwarf or tall elephant grass silages, harvested at 60 days of growth, without wilting or the use of additives, on intake, apparent digestibility, nitrogen balance, rumen parameters, and ingestive behavior of sheep. Eight castrated male crossbred sheep (57.6 ± 5.25 kg body weight), fistulated in the rumen, were distributed in two 4 × 4 Latin squares with four treatments and eight animals per treatment and four periods. The treatments consisted of four elephant grass genotype silages (Mott, Taiwan A-146 2.37, IRI-381, or Elephant B). There was no effect of silages (P > 0.05) on dry matter, neutral detergent fiber, and total digestible nutrient intake. The dwarf-sized elephant grass silages provided higher crude protein intake (P = 0.047) and N intake (P = 0.047), while the IRI-381 genotype silage provided higher non-fibrous carbohydrate intake compared to Mott (P = 0.042), without differing from Taiwan A-146 2.37 and Elephant B silages. There were no differences (P > 0.05) among the digestibility coefficients of the evaluated silages. It was observed that silages produced with Mott and IRI-381 genotypes caused a slight decrease in ruminal pH (P = 0.013), and the propionic acid concentration was higher in the rumen fluid of the animals fed with Mott silage (P = 0.021). Therefore, dwarf or tall elephant grass silages, produced with cut genotypes at 60 days of growth and without the use of additives or wilting process, can be used in sheep feeding.

Association of fibre degradation with ruminal dissolved hydrogen in growing beef bulls fed with two types of forages.

The present study investigated the association between fibre degradation and the concentration of dissolved molecular hydrogen (H2) in the rumen. Napier grass (NG) silage and corn stover (CS) silage were compared as forages with contrasting structures and degradation patterns. In the first experiment, CS silage had greater 48-h DM, neutral-detergent fibre (NDF) and acid-detergent fibre degradation, and total gas and methane (CH4) volumes, and lower 48-h H2 volume than NG silage in 48-h in vitro incubations. In the second experiment, twenty-four growing beef bulls were fed diets including 55 % (DM basis) NG or CS silages. Bulls fed the CS diet had greater DM intake (DMI), average daily gain, total-tract digestibility of OM and NDF, ruminal dissolved methane (dCH4) concentration and gene copies of protozoa, methanogens, Ruminococcus albus and R. flavefaciens, and had lower ruminal dH2 concentration, and molar proportions of valerate and isovalerate, in comparison with those fed the NG diet. There was a negative correlation between dH2 concentration and NDF digestibility in bulls fed the CS diet, and a lack of relationship between dH2 concentration and NDF digestibility with the NG diet. In summary, the fibre of CS silage was more easily degraded by rumen microorganisms than that of NG silage. Increased dCH4 concentration with the CS diet presumably led to the decreased ruminal dH2 concentration, which may be helpful for fibre degradation and growth of fibrolytic micro-organisms in the rumen.

Effect of strategy for harvesting regrowth grass silage on performance in dairy cows.

The objective of this study was to evaluate the effects of feeding lactating dairy cows with regrowth silages from different 2- and 3-cut harvesting systems on milk production, efficiency of N, and energy utilization. Thirty Nordic Red cows were offered 5 experimental diets containing regrowth silages, crimped barley, and canola meal in replicated incomplete 5 × 4 Latin squares with four 21-d periods consisting of 14 d of feed adaptation and 7 d of sampling. Four second-cut silage diets were examined in a 2 × 2 factorial arrangement, enabling evaluation of effect of harvest time of the early or late first cut on second-cut silages, short or long regrowth interval within second cut, and their interaction on dairy cow performance. The third-cut silage diet harvested from early first cut and short regrowth interval of second-cut ley was compared with the second-cut silage diets to evaluate the difference in dairy cow performance between second- and third-cut silages. Postponing the first cut and extending the regrowth interval decreased dry matter intake (DMI), energy-corrected milk (ECM) yield, nutrient digestibility, and urinary energy output, but improved N efficiency (milk N/N intake). Postponing the first cut also decreased the efficiency of metabolizable energy use for lactation, but increased CH4 yield (CH4/DMI). Extending the regrowth interval decreased feed efficiency (ECM/DMI) and increased CH4 intensity (CH4/ECM). Thus, feeding regrowth silages in 2- or 3-cut systems harvested after an early first cut and short regrowth interval promoted better dairy performance and feed intake, and higher efficiency of feed and energy utilization, but with poorer N efficiency. Feeding third-cut silage improve milk yield and feed efficiency compared with second-cut silages.

Partial replacement of corn silage with whole-plant soybean and black oat silages for dairy cows.

This study aimed to evaluate the effects of partially replacing corn silage (CS) with whole-plant soybean silage (SS) or black oat silage (OS) on nutrient intake and digestibility, in vitro neutral detergent fiber degradability of silages, feeding behavior, rumen fermentation, and performance of dairy cows. Twenty-four lactating Holstein cows (6 of which were rumen-cannulated) with 32.5 ± 4.92 kg/d milk yield, 150 ± 84.8 days in milk, and 644 ± 79.0 kg of body weight were used in a 3 × 3 Latin square design to evaluate the following treatments: (1) corn silage diet (CSD): using corn silage as the only forage source in the diet [48% dietary dry matter (DM)]; (2) whole-plant soybean silage diet (SSD): SS replacing 16% of corn silage from CSD; and (3) black oat silage diet (OSD): OS replacing 16% of corn silage from CSD. The inclusion of OS and SS decreased intakes of DM, organic matter, and crude protein. Corn silage had the greatest in vivo effective degradability of DM, and SS had the least effective degradability of neutral detergent fiber. The OSD treatment decreased milk and protein yields, whereas SSD increased rumen ammonia nitrogen concentration compared with the other diets. Cows fed OSD exhibited a greater preference for feed with small particles (<4 mm) compared with those fed SSD. Cows fed treatments containing either SS or OS at the expense of CS had increased rumination and chewing activities. Although replacing CS with OS and SS reduced feed intake, SS had no effect on productive performance of dairy cows.

The effects of gradual replacement of barley with oats on enteric methane emissions, rumen fermentation, milk production, and energy utilization in dairy cows.

This study evaluated the effects of gradual replacement of barley with oats on enteric CH4 emissions, rumen fermentation, diet digestibility, milk production, and energy utilization in dairy cows fed a grass silage-based diet. Sixteen lactating Nordic Red dairy cows received a total mixed ration [58:42 forage:concentrate on dry matter (DM) basis]. Grass silage (Phleum pratense) was the sole forage with canola meal (10% of diet DM) as a protein supplement. The effects of gradual replacement of barley with oats on DM basis were evaluated using a replicated 4 × 4 Latin square design with 21 d periods. The grain supplements (30% of diet DM) consisted of 100% barley, 67% barley and 33% oats, 33% barley and 67% oats, and 100% oats. In addition to intake, milk production, and digestibility measurements, CH4 emissions were measured by the GreenFeed system (C-Lock Inc.). The energy metabolism was estimated from the gas exchange measurements recorded by the GreenFeed unit. The last 10 d of each period were used for recordings of gas exchanges, feed intake and milk production. Dry matter intake, body weight, milk yield, and energy-corrected milk yield were not affected by gradual replacement of barley with oats in the diet. Increased inclusion of oats linearly decreased CH4 emissions from 467 to 445 g/d, and CH4 intensity from 14.7 to 14.0 g/kg energy-corrected milk. In addition, the ratio of CH4 to CO2 decreased with increasing inclusion of oats in the diet. Digestibility of organic matter, neutral detergent fiber, and potentially digestible neutral detergent fiber decreased linearly with increasing inclusion of oats. Increased inclusion of oats linearly increased fecal energy from 121 to 133 MJ/d, whereas urinary energy and heat production were not affected by dietary treatment. This resulted in a linear decrease in metabolizable energy intake. However, increased levels of oat in the diet did not significantly affect energy balance or efficiency of metabolizable energy utilization for lactation. This study concludes that barley could be replaced with oats in the diet of dairy cows fed a grass silage-based diet to mitigate CH4 emissions without having any adverse effects on productivity or energy balance. However, the effect of replacing barley with oats on CH4 emissions is dependent on the differences between barley and oats in the concentrations of indigestible neutral detergent fiber and fat.

Methionine-balanced diets improve cattle performance in fattening young bulls fed high-forage diets through changes in nitrogen metabolism.

Ruminants fed high-forage diets usually have a low feed efficiency, and their performances might be limited by methionine (Met) supply. However, the INRA feeding system for growing cattle does not give recommendation for this amino acid (AA). This study aimed to assess the effects of Met-balanced diets on animal performance and N metabolism in young bulls fed high-forage diets formulated at or above protein requirements. Four diets resulting from a factorial arrangement of two protein levels (Normal (13·5 % crude protein) v. High (16·2 % crude protein)) crossed with two Met concentrations (unbalanced (2·0 % of metabolisable protein) v. balanced (2·6 % of metabolisable protein)) were tested on thirty-four fattening Charolais bulls for 7 months before slaughter. Animal growth rate was greater in Met-balanced diets (+8 %; P = 0·02) with a trend for a greater impact in High v. Normal protein diets (P = 0·10). This trend was observed in lower plasma concentrations of branched-chain AA only when Met supplementation was applied to the Normal protein diet (P ≤ 0·06) suggesting another co-limiting AA at Normal protein level. Feed conversion efficiency and N use efficiency were unaffected by Met supplementation (P > 0·05). However, some plasma indicators suggested a better use of AA when High protein diets were balanced v. unbalanced in Met. The proportion of total adipose tissue in carcass increased (+5 percent units; P = 0·03), whereas that of muscle decreased on average 0·8 percent units (P = 0·05) in Met-balanced diets. Our results justify the integration of AA into dietary recommendations for growing cattle.

Effect of feeding hay vs. silages of various types to dairy cows on feed intake, milk composition and coagulation properties.

This research paper addresses the hypotheses (1) that milk produced from hay-fed cows differs from that of silage-fed cows and (2) that silage type has an important impact, too. Four diets differing in forage type but with equal estimated milk production potential and a forage:concentrate ratio of 0.85 : 0.15 were compared regarding their effect on feed intake, milk yield and milk properties. The forages tested were hay, grass silage, conventional short-chopped and long-chopped maize silage subjected to a novel processing technology (Shredlage®). Twenty-four dairy cows were fed two of the four diets in two consecutive runs in an incomplete (4 × 2) Latin-square design (n = 12 per diet). Each experimental period lasted 22 d, with 12 d of adaptation and 10 d of sampling. During sampling, feed intake and milk yield were recorded daily, milk composition and coagulation properties were determined four times. The composition of the diet ingredients was analysed weekly. Data were analysed with a mixed model considering feed, period and their interaction as fixed effects. Stage of lactation, milk yield and milk composition from the pre-experimental period were used as covariates in the model. Dry matter intake was lower with the long-chopped processed maize silage compared to the other three groups. There were some diet differences in intakes of net energy for lactation and absorbable protein in the duodenum, but this did not result in changes in milk yield. The milk fat content was higher with the grassland-based diets compared to the maize silage diets. No treatment effect on milk acidity and rennet coagulation properties was observed. In conclusion, there were no indications for specific physico-chemical properties of milk from a hay-based diet, and maize processing technology was not of large effect either. Future investigations should focus on sensory differentiation of the milk produced with different forages.

Influence of microbial additive on microbial populations, ensiling characteristics, and spoilage loss of delayed sealing silage of Napier grass.

OBJECTIVE: To measure whether a microbial additive could effectively improve the fermentation quality of delayed-sealing (DS) silage, we studied the effects of inoculants of lactic acid bacteria (LAB) and cellulase enzyme on microbial populations, ensiling characteristics, and spoilage loss of DS silage of Napier grass in Africa. METHODS: Quick-sealing (QS) and DS silages were prepared with and without LAB (Lactobacillus plantarum) inoculant, cellulase enzymes, and their combination. The QS material was directly chopped and packed into a bunker silo. The DS material was packed into the silo with a delay of 24 h from harvest. RESULTS: In the QS silage, LAB was dominant in the microbial population and produced large amounts of lactic acid. When the silage was treated with LAB and cellulase, the fermentation quality was improved. In the DS silage, aerobic bacteria and yeasts were the dominant microbes and all the silages were of poor quality. The yeast and mold counts in the DS silage were high, and they increased rapidly during aerobic exposure. As a result, the DS silages spoiled faster than the QS silages upon aerobic exposure. CONCLUSION: DS results in poor silage fermentation and aerobic deterioration. The microbial additive improved QS silage fermentation but was not effective for DS silage.

The effect of dietary forage to concentrate ratio and forage type on milk fatty acid composition and milk fat globule size of lactating cows.

We examined the effects of 2 grass silage-based diets differing in forage:concentrate (FC) ratio and those of a red clover silage-based diet on intake, milk production, ruminal fatty acid (FA) biohydrogenation, milk FA composition, and milk fat globule (MFG) size distribution. Ten multiparous Nordic Red cows received the following treatments: grass silage-based diets containing high (70:30, HG) or low (30:70, LG) FC ratio or a red clover silage-based diet with an FC ratio of 50:50 (RC) on a dry matter basis. Determinations of MFG were performed from fresh milk samples without addition of EDTA so the results of fat globules >1 µm in diameter are emphasized instead of the entire globule population. Lower FC ratio in grass silage-based diets increased milk production with no effect on daily fat yield, leading to 13% lower milk fat concentration. The effect of FC ratio on MFG size was moderate. It did not affect the volume-weighted diameter in grass silage-based diets, although LG lowered the volume-surface diameter of MFG in the size class >1 µm compared with HG. Compared with HG, feeding LG moderately decreased the biohydrogenation of 18:2n-6, leading to a higher level of polyunsaturated fatty acids in milk fat. Feeding RC lowered milk fat concentration and daily milk fat yield compared with grass silage-based diets. The volume-weighted diameter of MFG in the size class >1 µm was smaller in RC milk compared with grass silage-based diets. Feeding RC increased the flow of 18:3n-3 at the omasum by 2.4-fold and decreased the apparent ruminal 18:3n-3 biohydrogenation compared with grass silage-based diets despite similar intake of 18:3n-3. It also resulted in the lowest amount of saturated FA and the highest amounts of cis-9 18:1, 18:3n-3, and polyunsaturated FA in milk. In conclusion, LG decreased milk fat content and induced minor changes in MFG size distribution compared with HG, whereas RC lowered milk fat production, altered milk FA composition to nutritionally more beneficial direction, and led to smaller MFG compared with grass silage-based diets.

The effects of age and gender (bull vs steer) on the feeding behavior of young beef cattle fed grass silage.

OBJECTIVE: The objective of this study was to determine the effects of age and gender (bull vs steer) on feeding behavior parameters in young beef cattle fed grass silage. METHODS: The study was conducted on 180 young beef cattle at 7 to 18 mo of age. The experimental materials comprised 90 bulls produced by commercial crossing of Polish Holstein-Friesian cows with Charolais, Limousin and Hereford bulls (30 animals of each breed) and 90 steers of the same genotypes. The animals had ad libitum access to grass silage; the concentrate was fed separately, in feed stations. They received 28 g dry matter of concentrate per kg of metabolic body weight per day. Bunk visit data and silage intake for all experimental animals were recorded individually using the Roughage Intake Control system (5 feed bunks per 15 animals). RESULTS: Age and gender (bull vs steer) exerted significant effects on the feeding behavior of young beef cattle. The frequency of bunk visits and meal frequency decreased, whereas the feeding rate of silage, and the average duration and size of a single meal increased with age (p<0.01). Bunk attendance and meal frequency were higher (p<0.01) in steers than in bulls (49.1 vs 37.4 visits/d, and 8.63 vs 7.99 meals/d, respectively). Daily feeding time was longer in steers than in bulls (102.3 vs 100.3 min/d, respectively), but the feeding rate of silage was lower in steers, and their meals were smaller in size and shorter in duration (p<0.01). Daily silage dry matter intake was higher (p<0.01) in bulls than in steers (4.62 vs 4.47 kg/d, respectively). CONCLUSION: The results of this study indicate that age and gender (bull vs steer) exerted significant effects on the feeding behavior of young beef cattle.

Effect of grain- or by-product-based concentrate fed with early- or late-harvested first-cut grass silage on dairy cow performance.

This study compared the effects of a grain-based conventional concentrate (GC) and a concentrate based on agro-industrial by-products (BC), fed with grass silage harvested at early (ES) or late (LS) maturity stage, on dairy performance, CH4 and CO2 emissions, and metabolic status of dairy cows. Twenty lactating Nordic Red cows averaging 81 d in milk and 31.9 kg of milk/d pre-trial were assigned to a replicated 4 × 4 Latin square design. Dietary treatments were in a 2 × 2 factorial arrangement. The silages were harvested 2 wk apart from the same primary growth grass ley. The GC was made from oats, barley and wheat, and soybean meal, whereas the BC contained sugar beet pulp, wheat bran, canola meal, distillers dried grains, palm kernel expeller, and molasses. The diets were fed ad libitum as total mixed rations and were formulated from 661 g/kg of silage, 326 g/kg of concentrate, and 13 g/kg of minerals on a dry matter basis. The BC supplied the cows with less energy. Despite this, milk yield and composition were unaffected by concentrate type, except that milk protein was 0.7 g/kg lower in cows fed BC than in those fed GC. These results were accompanied by a 44 g/kg decrease in total-tract digestibility of crude protein and a 54 g/kg increase in neutral detergent fiber digestibility for cows fed BC. Cows fed ES on average consumed 2 kg/d more dry matter and yielded 3.5 kg/d more milk, 149 g/d more protein, and 141 g/d more fat than cows fed LS. There were few interaction effects between concentrate and silage sources on daily intake and dairy performance. However, edible feed conversion ratio (human-edible output in animal/potentially human-edible feed) showed greater improvements with ES than LS when replacing GC with BC. Feeding diets with late-cut silage generally reduced digestibility and energy utilization efficiency, but improved N utilization efficiency. Feeding LS also led to greater CH4 yield and CH4/CO2 ratio, and higher plasma concentration of nonesterified fatty acids. Plasma parameters reflecting energy metabolism and inflammation were all within the normal ranges, indicating that the cows were in good health during the experiment. In conclusion, a conventional concentrate can be replaced by agro-industrial by-products without compromising production in early lactation dairy cows. However, silage maturity has a stronger effect on the production traits of dairy cows than type of concentrate.

Effects of dry period energy intake on insulin resistance, metabolic adaptation, and production responses in transition dairy cows on grass silage-based diets.

High energy intake in the dry period has reportedly had adverse effects on mobilization of body reserves, dry matter intake, and productivity of dairy cows. We investigated whether grass silage (GS) fed ad libitum (high energy intake, HEI; 141% of daily metabolizable energy requirements) in an 8-wk dry period affects metabolic adaptation-specifically, peripheral insulin resistance-compared with a total mixed ration consisting of GS, wheat straw, and rapeseed meal (55/40/5%; controlled energy intake, CEI; 108% of metabolizable energy/d) fed ad libitum. Multiparous Ayrshire dairy cows (n = 16) were used in a randomized complete block design until 8 wk after parturition. Commercial concentrates were fed 1 and 2 kg/d during the last 10 to 6 and 5 to 0 d before the expected calving date, respectively. Postpartum, a similar lactation diet with ad libitum access to GS and increasing concentrate allowance (maximum of 16 kg/d) was offered to all. The HEI group gained more body weight and had higher plasma insulin, glucose, and ß-hydroxybutyrate concentrations than the CEI group prepartum. Postpartal plasma glucose tended to be higher and milk yield was greater from wk 5 onward for HEI compared with CEI cows. An intravenous glucose tolerance test (IVGTT) was performed at -13 ± 5 d and 9 ± 1 d relative to calving. The HEI cows had greater insulin response to glucose load and smaller area under the response curve for glucose than CEI cows in prepartal IVGTT. Thus, compensatory insulin secretion adapted to changes in insulin sensitivity of the peripheral tissues, preserving glucose tolerance of HEI cows. Higher insulin levels were needed in HEI cows than in CEI cows to elicit a similar decrement of nonesterified fatty acid concentration in prepartal IVGTT, suggesting reduced inhibition of lipolysis by insulin in HEI cows before parturition. In conclusion, high energy intake of moderately digestible GS with low concentrate feeding in the close-up dry period did not have adverse effects on metabolic adaptation, insulin sensitivity, and body mobilization after parturition. Instead, this feeding regimen was more beneficial to early-lactation performance than GS-based total mixed ration diluted with wheat straw.

Effect of the ionophore monensin and tannin extracts supplemented to grass silage on populations of ruminal cellulolytics and methanogens in vitro.

This study examined whether the methane-decreasing effect of monensin (∼21%) and different hydrolysable tannins (24%-65%) during in vitro fermentation of grass silage was accompanied by changes in abundances of cellulolytics and methanogens. Samples of liquid (LAM) and solid (SAM) associated microbes were obtained from two rumen simulation technique experiments in which grass silage was either tested in combination with monensin (0, 2 or 4 mg d-1) or with different tannin extracts from chestnut, valonea, sumac and grape seed (0 or 1.5 g d-1). Total prokaryotes were quantified by 4',6-diamidino-2-phenylindol (DAPI) staining of paraformaldehyde-ethanol-fixed cells and relative abundances of ruminal cellulolytic and methanogenic species were assessed by real time quantitative PCR. Results revealed no change in absolute numbers of prokaryotic cells with monensin treatment, neither in LAM nor in SAM. By contrast, supplementation of chestnut and grape seed tannins decreased total prokaryotic counts compared to control. However, relative abundances of total methanogens did not differ between tannin treatments. Thus, the decreased methane production by 65% and 24% observed for chestnut and grape seed tannins, respectively, may have been caused by a lower total number of methanogens, but methane production seemed to be also dependent on changes in the microbial community composition. While the relative abundance of F. succinogenes decreased with monensin addition, chestnut and valonea tannins inhibited R. albus. Moreover, a decline in relative abundances of Methanobrevibacter sp., especially M. ruminantium, and Methanosphaera stadtmanae was shown with supplementation of monensin or chestnut tannins. Proportions of Methanomicrobium mobile were decreased by monensin in LAM while chestnut and valonea had an increasing effect on this methanogenic species. Our results demonstrate a different impact of monensin and tannins on ruminal cellulolytics and gave indication that methane decrease by monensin and chestnut tannins was associated with decreased abundances of M. ruminantium and M. stadtmanae.