Levels and degradability of crude protein in digestive metabolism and performance of dairy cows

Two experiments were conducted to evaluate the effect of the level and degradability of crude protein (CP) on the digestive metabolism and productive performance of dairy cows. In both experiments, 15 Holstein cows with 585 ± 40 kg of body weight were distributed in a Latin square design with five contemporary squares, three periods of 21 days and three treatments. In experiment 1, treatments consisted of three CP levels (130, 160 or 180 g CP/kg DM), while in experiment 2, the treatments consisted of three levels of rumen degradable protein (RDP; 80, 100 or 120 g RDP/kg DM) in diets with average of 163 g CP/kg DM. Variables evaluated in both experiments were dry matter intake (DMI), total apparent digestibility, milk yield (MY) and composition, ruminal fermentation and N balance. In experiment 1, the increase of CP from 130 to 180 linearly increased the organic matter, CP, neutral detergent fiber (NDF) and acid detergent fiber (ADF) intake (kg) and the apparent total digestibility coefficient of DM and CP. In addition, a linear increase of MY, fat corrected milk (FCM) and daily production of fat, protein, lactose, casein and total solids was observed. A linear increase in ruminal ammoniacal nitrogen (NH 3 -N) concentration and nitrogen excretion in milk, feces and urine was also observed. However, there was no observed effect on SCFA concentration. In experiment 2, the increase of the RDP from 80 to 120 increased the DMI, MY, FCM, milk protein content and digestibility coefficient of the NDF, ADF and ethereal extract. Additionally, there was an increase in NH 3 -N concentration and milk nitrogen excretion. The studies indicated that the increase of CP content up to 100 g RDP/kg DM increased the DMI and the productive performance of the cows, but also increased urine N. Thus, it is desirable that the increase of the CP through the increase of the RDP is carried out up to 100 g of RDP/kg DM, since there is elimination of nitrogen, decrease of milk yield and decrease of propionic acid in values above that level

Proportions of concentrate and rehydrated ground grain corn silage at different storage times for better use of starch by lambs.

This study aimed to evaluate the nutritional and bioeconomic potential of rehydrated ground grain corn silage (RGGCS), at different storage times associated with proportions of concentrates for better starch utilization by lambs. Forty Dorper- Santa Inês crossbred lambs were used, with an average body weight of 24 ± 3.9 kg, and an average age of 90 days. The lambs were feedlot for 63 days in experiment design completely randomized, with eight repetitions and five experimental diets: Diet 1: 850 g/kg concentrate including dry ground corn; diet 2: 850 g/kg concentrate including RGGCS ensiled for 45 days; diet 3: 650 g/kg concentrate including RGGCS ensiled for 90 days; diet 4: 650 g/kg concentrate including RGGCS ensiled for 45 days; diet 5: 850 g/kg concentrate including RGGCS ensiled for 45 days. As roughage, silage corn whole plant. Starch intake was higher (P < 0.05) with the dry ground corn diet; however, digestibility was lower (P < 0.05) for most nutrients compared to the RGGCS diet. A smaller amount of starch in the feces of animals that received the RGGCS diet was found. A diet with 850 g/kg of concentrate, including RGGCS ensiled for 45 days, generates higher net income, increases nutrient intake, and could be an alternative during the fluctuation of corn prices

Impacto da granulometria do grão de milho no desempenho produtivo de vacas leiteiras

Orientador: Prof. Dr. Rodrigo de AlmeidaCoorientador: Prof. Ph.D. Luiz Felipe FerrarettoDissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências Agrárias, Programa de Pós-Graduação em Zootecnia. Defesa : Curitiba, 19/02/2020Inclui referênciasResumo: O milho é a mais importante fonte de energia na dieta de rebanhos leiteiros, devido as altas concentrações de amido. Entretanto, a utilização desse grão de cereal nem sempre é eficiente, pois muitos produtores fornecem milho com reduzida digestibilidade do amido, já que muitas vezes o processamento de moagem do milho é insuficiente para permitir que esse nutriente seja utilizado de forma satisfatória pelos animais, e com isso há uma perda em produção de leite. Este projeto objetivou avaliar o desempenho produtivo de vacas em lactação recebendo dietas com duas granulometrias do grão de milho. Foram utilizadas 50 vacas em lactação divididas em dois grupos, cada um recebendo o milho moído com granulometria grossa ou fina (915 ?m e 660 ?m, respectivamente), com concentrados atingindo o tamanho de partícula médio de 772 ?m e 596 ?m. Os resultados indicam que vacas recebendo ração mais grossa, com maior granulometria, apresentaram maior amido fecal que vacas recebendo ração mais fina, de menor granulometria (6,96 vs. 4,84%; P0,05). As produções em kg destes mesmos sólidos também não foram afetadas (P>0,05). Palavras-chave: Amido. Consumo de matéria seca. Tamanho de partícula.Abstract: Corn is the most important source of energy in the diet of dairy herds due to the high concentrations of starch. However, the use of this grain is not always efficient, since many properties have low starch digestibility, since corn ground processing is often insufficient to allow this energy to be used by the cows, not being converted into milk production. It is recommended that grind of the grain reaches a mean particle size of 600 ?m with a GSD < 2.0, so that fecal starch be less than 3%. It is expected that the ideal total tract starch digestibility be 97%, considering up to 95% as adequate. Values below 95% show that efficiency in the use of starch is low, and improvement measures must be taken. This project aimed to evaluate the productive performance of lactating dairy cows receiving diets with two corn grain particle sizes. Fifty dairy cows were divided into large and small corn grain particle size groups (915 ?m and 660 ?m, respectively), with concentrates reaching the mean particle size of 772 ?m and 596 ?m. The results indicate that cows fed small particle size diet had lower fecal starch than cows fed large particle size diet (6.96 vs. 4.84%; P<0.01), as well as a greater total tract starch digestibility (93.95 vs. 91.29%; P<0.01). D-lactate level was greater for cows fed smaller particle sizes diet (98.5 vs. 79.7 ?M; P<0.05). Individual dry matter intake is also lower for cows fed small particle size concentrate (22.05 vs. 21.22 kg; P<0.01). Milk yield tended to be greater for cows fed diet with smaller particle sizes (36.85 vs. 37.90 kg; P = 0.12). With that, milk efficiency tended to be greater for cows fed corn grain small particle size (1.78 vs. 1.69; P<0.05). However, milk protein (3.34 vs. 3.31; P=0.52) and milk fat concentration (3,73 vs. 3,63; P=0,29) were not affected by treatments, as well as lactose, casein and total solids concentrations. Keywords: Dry matter intake. Particle size. Starch

Influence of dietary factors on the macro and micro-composition of bovine milk for use in protein ingredient powder manufacture

The increasing frequency of “grass-fed” labelling claims in dairy product marketing, predicated in part on improved product quality and nutritional benefits associated therewith, has necessitated both rigorous experimental data to determine the relative differences in the composition of milk from grass-fed and non-grass-fed cows and robust methods for verifying these labelling claims. The “Grass-fed Standard” established by Bord Bia in 2020 is the first scientifically-backed standard in use internationally, which is founded on the somewhat unique pasture-based dairy production system practiced in Ireland. The compositional and functional benefits associated with products derived from pasture-fed cows have thus far been focused on business-to-consumer products. The effect of pasture-based production relative to the conventional indoor production system utilised most widely throughout the world on the composition and functional properties of “business-to-business” milk powder products, which represent a major aspect of Irish dairy production, remained to be established. Variation in the composition and functional properties of dairy products arises due to numerous factors, including feed composition, which can differ depending on the type of production system practiced. Therefore, the objective of this research was to investigate the effect of perennial ryegrass only (GRS), perennial ryegrass/white clover pasture (CLV) and indoor total mixed ration (TMR) feeding systems on the composition and functional properties of bovine milk-based protein ingredients. There was a significant effect of feeding system on the concentration of metabolite compounds and B vitamins in skim milk powder (SMP) and whey ingredients, which were distinguishable by liquid chromatography-mass spectrometry. Concentrations of vitamins B1, B2 and B7 were significantly higher in GRS and CLV samples than TMR samples, for which concentrations of vitamin B3 and B3-amide were higher than in CLV and GRS samples, respectively. Gross compositional parameters were similar between the feeding systems; however, the CLV and TMR systems were associated with high concentrations of non-protein nitrogen and high heat stability in whole milk powder and SMP samples. Some differences in total amino acid (AA) composition were also exhibited between WMP and SMP samples from each diet, which suggests that AA profile may be responsive to dietary variation. Yoghurts produced from GRS and CLV-derived WMP were typified by significantly higher gel strength and textural firmness than those derived from TMR, despite significantly higher concentrations of palmitic acid in TMR samples. Fatty acid (FA) profiles of WMP samples from each diet were similar to those in the literature produced from pasture or concentrate-based systems. The level of FA unsaturation and carotenoid content could also distinguish between pasture and TMR samples using Raman spectroscopy. The mineral composition of WMP, SMP and whey protein concentrate (WPC) samples from each diet did not vary significantly, with the exception of selenium and iodine, which were consistently, and significantly, higher in TMR samples than GRS and CLV samples. The viscosity of GRS-derived skim milk concentrate was significantly higher than that for TMR, but the effect of diet on the heat-dependent viscosity of dispersions of skim milk with WPC was not as substantial as the differences between WPC types, with micellar casein whey being most stable on heating, and acid WPC the least stable. Proteomic and peptidomic analysis of WMP and digested WMP samples determined qualitative and quantitative differences in proteins and peptides arising from each diet. In conclusion, this research demonstrated that the influence of bovine diet on milk components is not limited to gross compositional factors, but the micro-composition and functional properties, such as heat stability and acid-induced gelation, of value-added dairy products can also be influenced by feeding practices. This research will be of most interest to the manufacturers of dairy powder ingredients, such as SMP and WPC and premium WMP products in establishing the commercial point-of-difference for pasture or concentrate-derived products along with the unique compositional elements and functional behaviour associated with products from the three feeding systems investigated herein. Furthermore, this research will aid in ingredient selection for manufacturers of value-added dairy commodities, such as infant milk formula. Finally, this research contributes to the list of compositional variables which demonstrate potential for differentiation between feeding systems, providing preliminary information, relating to the establishment of robust analytical methods for verification of “Grass-fed” labelling claims for milk powder products to international entities responsible for policy implementation, such as Bord Bia

Effects of bacteria and enzyme mixture inoculants on quality of high-moisture maize grain silage

The objective of this study was to evaluate the effect of applying lactic acid bacteria (LAB) and enzymes mixture inoculants (Sil-All and Silaprilis) on the chemical composition and fermentation of high-moisture grain silage of two maize hybrids Zenit and ZP 735. Maize hybrids were harvested at 68-72% of dry matter. Commercial inoculants were prepared and sprayed following the manufacturer's specifications. Silages were stored in glass jars with a special valve filled with water in the middle of the lid. Significant differences between hybrids were found for ash, crude protein, pH, and acetic acid. The hybrid Zenit had significantly higher ash (14.9 g kg-1 dry matter (DM)), pH (4.03), and acetic acid (6.3 g kg-1 DM), and significantly lower crude protein (89.0 g kg-1 DM) than hybrid ZP 735 (12.5 g kg-1 DM, 3.98, 5.1 g kg-1 DM and 101.2 g kg-1 DM, respectively). Compared to control, LAB+enzymes mixture inoculants stimulated ensiling of high-moisture maize grain. Inoculants decreased the contents of ammonia nitrogen and acetic acid, and pH value, and increased the contents of dry matter, ash, crude protein, crude fat, and lactic acid during silage fermentation than control. Accordingly, the application of LAB+enzymes mixture inoculants is justified and they can be recommended for high-quality silage production in feeding livestock

Effects of Wilting Extent on the Phytoestrogen Levels, Nutritional Value, Microbial Populations, and In Vitro Ruminal Methane Emissions of Red Clover Hay and Silage Across Stages

The main objective of this thesis is to improve the understanding and awareness of methodologies to decrease phytoestrogens in conserved legumes without sacrificing forage nutritive value. In chapter 1, we discussed the main factors influencing each stage of hay production and our current understanding of the hay microbiome dynamics. The primary objective of haymaking is to dry forage enough (80-85% DM) to inhibit the growth of undesirable microbes and halt residual plant enzymatic activity that causes nutrient losses. During the field and storage phases of haymaking, the environment, management practices, and other factors influence the extent of DM losses. This chapter discusses these factors and the strategies that have been developed to mitigate these nutrient losses. A major emphasis was placed on hay microbiota dynamics, as it has been scarcely studied despite its importance on nutrient losses during storage and harvest, especially in high moisture conditions. Since soil particles are a significant source of undesirable microbes and ash contamination, the effects of cutting height, mower type, and swath manipulation on soil contamination were discussed. Also, the impact of environmental conditions and swath manipulation on wilting time was analyzed for both humid and arid conditions. Special attention was given to design improvements in harvesting equipment to reduce curing time and field losses. Furthermore, we assessed the nutrient losses during storage caused by undesirable microbial and residual plant enzymatic activity resulting from excessive moisture at baling or re-introduced moisture during storage. The extent of spoilage during storage depends not only on bale moisture but also on bale size, density, shape, wrapping, forage type, and storage facilities. A Venn diagram analysis condensed all relevant hay microbiology research and showed that each phase of the haymaking process has a unique microbiome. It also showed that certain fungal and bacterial genera could be shared across more than one hay production phase. For instance, Aspergillus, Cladosporium, and Alternaria are fungal genera that tend to be present throughout the haymaking process. In order to take corrective actions, hay producers need to be aware of the increased susceptibility to nutrient losses associated with particular field and storage practices, environmental conditions, and forage types. In Chapter 2, we evaluated the effects of insufficient (WET) or ample (CUR) wilting on the phytoestrogen levels, nutritional value, microbial populations, in vitro ruminal methane emissions, and in situ degradability of red clover silage (29.4 and 45.3% DM) and hay (65.1 and 89.1, respectively) across the storage stages. Measurements were taken at the start of storage (STRT), after 14 d (MicA), and once storage processes had stabilized for hay and silage (50 and 78 d, respectively; LATE). Only LATE samples of hay and silage were tested for the in situ procedure. Data were analyzed as a RCBD (5 blocks) with a 2 (wilting extents) x 2 (conservation methods) x 3 (storage stages) factorial. Results showed that storage DM losses were higher for WET hay than CUR but no differences were observed between WET and CUR silage. Ample wilting of hay and silage preserved better water-soluble carbohydrates during storage relative to insufficient wilting. Due to microbial spoilage, the NH3-N of WET hay was higher than CUR hay after 14 d of storage, but the opposite was observed after 50 d. For the WET and CUR silage, NH3-N increased across the ensiling period. The neutral detergent fiber of WET hay increased across storage stages while it remained stable for CUR hay. In contrast, the neutral detergent fiber of WET and CUR silage decreased during the ensiling period. The WET hay favored the growth of molds during storage, while CUR hay reduced their counts after 50 d of storage. For silage, mold counts were lower in WET compared to CUR after 14 d of storage but no differences were observed after 78 d. When the ensiling period is limited to 14 d, CUR silage that was aerobically exposed for 7 d was more susceptible to storage DM losses and subsequent heating relative to WET. However, if the ensiling period is extended to 78 d, no differences were observed between WET and CUR silage in terms of HDD and storage DM losses after being aerobically challenged. Ample wilting preserved the optimal ruminal fermentation kinetics of hay compared to insufficient wilting, while the ruminal fermentation kinetics of silage was not affected by the wilting extent. In vitro ruminal fermentation of WET silage resulted in higher methane yield than CUR, whereas methane yield of WET and CUR hay were not different. For both conservation methods, insufficient wilting reduced methane yield only at the end of storage. The in situ rumen degradability kinetics showed that ensiling increased the soluble DM fraction relative to haymaking. Ensiling reduced the potentially degradable DM fraction compared to haymaking but increased the rate of degradation of DM. Within insufficient wilting, silage had a higher degradation rate of NDF than hay. Ample wilting was more beneficial for silage than hay in terms of decreasing the levels of phytoestrogens. Across storage stages, hay had lower formononetin and biochanin A than silage. Formononetin and biochanin A of red clover hay decreased after 14 d of storage due to microbial degradation. Overall, ample wilting helped conserve the nutritional quality of hay and silage and decreased the phytoestrogens, especially in silage