The use of maize for livestock feeding in the United Kingdom

Maize and grass silages are commonly used as major feed materials for dairy cows in Europe and are becoming common parts of dairy cow rations in other parts of the world. Thenutritive value of maize and grass silages varies greatly due to variation in chemical composition. A combination of different factors such as the use of various cultivars, fertilization practices, growing conditions, harvesting technology, maturity at harvest and ensiling conditions cause this variation in chemical composition. The first aim of this thesis was to investigate relationships between the chemical composition and the in situ rumen degradation characteristics and in situ mobile nylon bag digestibility of dietary nutrients of maize and grass silages. Maize and grass silages with a broad range in chemical composition and quality parameters were selected from different Dutch commercial farms. The broad range in the chemical composition of the maize and grass silages resulted in a large variation in rumen degradable fractions of dry matter (DM), organic matter (OM), crude protein (CP), neutral detergent fibre (NDF) and starch. The intestinal digestibility of CP, NDF and/or starch was affected by the concentration of these components in the maize and grass silages, by the rumen incubation time and the rumen escape content. Regression equations were developed describing relationships between the chemical composition and the in situ ruminal and postruminal degradation characteristics of dietary nutrients of maize and grass silages. A number of the developed regression equations presented in this thesis can be used for accurate and rapid estimation of the ruminal and postruminal degradation characteristics of dietary nutrients of maize and grass silages, without conducting time consuming and expensive in situ experiments. The second aim of this thesis was to determine whether three cows are sufficient to cover the variation between individual cows in in situ rumen degradation characteristics of dietary nutrients of maize and grass silages. Significant differences (P<0.05) were found between individual cows for a number of parameters of DM, OM and CP of maize silages, indicating that four or more cows should be used for nylon bag incubations of maize silages. For grass silages, no significant differences (P>0.05) between individual cows were found for all the parameters of DM, OM, CP and NDF. The results suggest that using three cows are sufficient for nylon bag incubations of grass silages and pooling of rumen incubated residues is allowed to obtain a representative sample. The third aim of this thesis was to compare two fractionation methods; the washing machine method and a modified method, for nitrogen (N) and starch fractions of maize silages and N fractions of grass silages. The N and/or starch fractions of maize and grass silages determined, using the washing machine method (washing with water for 40 min) and the modified method (shaking with buffer solution for 60 min) were compared. The different methodological approaches of both methods resulted in different values for the washout (W), the soluble (S) and the non-washout (D+U) fractions of N of maize and grass silages and for the W, the insoluble washout (W-S) and the D+U fractions of starch of maize silages. The loss of insoluble small particles of starch was less during shaking of nylon bags in buffer solution, compared to washing nylon bags in the washing machine. Therefore, large differences were found between the D+U fractions of starch determined by both methods compared to the D+U fractions of N of maize silages. The developed regression equations for W, S and D+U fractions of N in grass silages and for D+U fractions of starch in maize silages determined by both methods can be used for rapid estimation of these fractions from chemical characteristics of maize and grass silages. The information on nutrient bioavailability of maize and grass silages presented in this thesis can be used to more accurately formulate dairy ration in terms of maintenance, health and production of dairy cows.

Understanding Regional Variations in Equity and Growth Finance: An Analysis of the Demand and Supply of Equity Finance in the UK Regions

To counteract a decrease in the availability of grazing for feeding dairy cows in France, a simulation model is proposed in the paper, which combines decision and agronomic submodels to study forage system management strategies compatible with spring grazing use. Nine strategies were tested with the model using a sequence of 16 climatic years. Three of these strategies come from a survey in south‐west France and six others were designed with research scientists or farm advisors. The strategies differ in the duration of maize silage feeding, the area dedicated to maize silage and the area dedicated to grass silage. Results from simulation models show that the consequence of a large and constant maize silage area is a high maize silage overstock if there is an early turnout or a high grass silage overstock if turnout is late. The consequence of a low maize area is a high grazing duration combined in some years with feeding shortages. Strategies that have no feeding shortage and a low level of maize and grass silage overstock have a high grazing duration and have no constant maize or grass silage areas. The solution proposed to avoid climatic risk, and its consequences on feeding, is based on two procedures: use of reserve areas for production and allowing the production programme to be modified to take into account fresh information, especially weather records.

Causes of variation in fatty acid content and composition in grass and maize silages

Apparent digestibility and nitrogen utilisation of diets based on maize and grass silage fed to beef steers

ABSTRACT: Olive cake (OC) is a wet by-product of olive processing that may be used as animal feedstuff. Our objective was to investigate the impact of adding OC on fermentation and aerobic stability of maize and grass silages. Whole-crop maize (326 g dry matter (DM)/kg as fed) and 4 h-wilted elephant grass (229 g DM/kg as fed) were ensiled without (untreated) or with fresh OC (5% as fed basis). Ensiling was performed in experimental silos (n = 3), which remained stored for 99 d. As results, fermentative losses were unaffected by OC (P = 0.17), while the lactic acid concentration decreased (P = 0.02) by 33.7% in silages with OC. The pH of grass silage increased (P &lt; 0.001) by adding OC (4.43 vs. 4.01 in the control), but it did not change the pH in maize silage. The concentration of acetic acid (P = 0.01) decreased by 15.2% in maize silage with OC and increased by 19.4% in grass silage with OC. The ether extract concentration increased (P = 0.02) in maize silage with OC compared to the control, and it was similar between grass silage without and with OC. After feedout, silage aerobic stability was not altered (P ≥ 0.18) by the addition of OC in maize and grass silages. Therefore, a possible fate for OC is to ensile it together maize forage, because there is no impairment of fermentation and aerobic stability of silages. Ensiling OC with grass is not recommended as it worsened the fermentation pattern.

Intake, digestibility, milk production and kinetics of digestion and passage for diets based on maize or grass silage fed to late lactation dairy cows

Recent developments in maize breeding and in agronomic practices, particularly the development of degradable full cover plastic mulch, have resulted in the possibility of consistently producing high yields of high starch maize silage in Northern Ireland. However, there is considerable variability in the quality of maize and grass silages produced. In a recent study Keady et al. (2002) concluded that the highest yield of fat and protein from dairy cows was obtained from maize silage ensiled at approximately 30% dry matter (DM) when offered as 40% of the forage component of the diets consisting of either medium or high feed value grass silages supplemented with concentrates. Also Keady et al. (2002) concluded that replacing 40% of the grass silage component of the diet with maize silage had a concentrate sparing effect, as determined for milk yield, of up to 1.9 kg/cow/d. The objective of the current study was to examine further the effect of maturity of maize silage at harvest on the performance of dairy cattle offered grass silages differing in feed value. The potential concentrate sparing effect of contrasting maize silages was also examined.

In insitu nylon bag technique, many feed evaluation systems use a washing machine method (WMM) to determine the washout (W) fraction and to wash the rumen incubated nylon bags. As this method has some disadvantages, an alternate modified method (MM) was recently introduced. The aim of this study was to determine and compare the W and non-washout (D+U) fractions of nitrogen (N) and/or starch of maize and grass silages, using the WMM and the MM. Ninety-nine maize silage and 99 grass silage samples were selected with a broad range in chemical composition. The results showed a large range in the W, soluble (S) and D+U fractions of N of maize and grass silages and the W, insoluble washout (W-S) and D+U fractions of starch of maize silages, determined by both methods, due to variation in their chemical composition. The values for N fractions of maize and grass silages obtained with both methods were found different (p<0.001). Large differences (p<0.001) were found in the D+U fraction of starch of maize silages which might be due to different methodological approaches, such as different rinsing procedures (washing vs. shaking), duration of rinsing (40min vs. 60min) and different solvents (water vs. buffer solution). The large differences (p<0.001) in the W-S and D+U fractions of starch determined with both methods can led to different predicted values for the effective rumen starch degradability. In conclusion, the MM with one recommended shaking procedure, performed under identical and controlled experimental conditions, can give more reliable results compared to the WMM, using different washing programs and procedures.

Implications of silage hygienic quality for animal production were investigated on forty‐five dairy farms in South West England. Samples of grass and maize silages and of total mixed rations (TMR) were obtained together with information on silage technology, herd size and animal production. Samples were analysed for mycotoxins, bacteria, yeasts, moulds and chemical composition. Thirteen mycotoxins were assayed, but none were detected in the samples of grass silage. However, mycotoxins were found in 0·9 of all maize and other silage samples, with deoxynivalenol and zearalenone predominating. There was no relationship between total mycotoxin concentration and mean lactation milk yield per cow. Enterobacteria counts tended to be higher in maize silage than in grass silage and higher still in TMR – a cause for concern. There were no relationships between mould counts and mycotoxin concentrations in silages, implying that mycotoxins may have been produced in the field pre‐ensiling.

The aim of the present study was to determine the effects of the potential methane reducer fumaric acid on the fattening performance and acid–base balance of growing bulls fed two different silage types as roughage (maize and grass silage). A total of 62 fattening bulls (German Holstein breed, initial body weight: 266 ± 42 kg), randomly assigned to eight feeding groups, received four levels of fumaric acid (0, 100, 200 or 300 g/d) at each silage type. The daily feed and water intake and the live weight were measured over the whole testing period of 280 days. In blood samples, blood cells and blood gases as a parameter of acid–base status were analysed. Feed and faeces were collected to determine the apparent nutrient digestibility. Five animals from each group fed maize or grass silage, supplemented with 0 g or 300 g fumaric acid, were slaughtered at 580 kg body weight. After slaughter, rumen fluid pH was measured and dressing percentage was calculated. Neither the total feed intake (8.81 ± 0.07 kg/d) nor the daily weight gain (1277±24 g/d) was influenced significantly by treatments. Fumaric acid supplementation did not influence the erythrocyte count or the blood gas concentration. The silage type significantly influenced the apparent digestibility of the whole diet. The dressing percentage was slightly higher (p < 0.1) after fumaric acid supplementation. No signs of an incompatibility to fumaric acid on the animals were observed over the whole experimental period. However, it seems to be necessary to conduct more long-term studies with different silage types and addition of organic acids combined with direct measurements of methane.

The objective of this experiment was to study the effects of interactions between grass silage (GS) dominated by orchardgrass (Dactylis glomerata L.) and maize silage (MS) (Zea mays L.) on ad libitum intake, digestibility and nitrogen retention in wether sheep. The GS in this experiment reflected the quality of GS produced on family farms in Croatia, while the MS used is frequently produced in seasons unfavourable for high quality MS production. The study consisted of four feeding treatments involving GS and MS alone, and GS and MS mixtures in ratios of 67 : 33 or 33 : 67 (DM basis), fed twice daily. Mean DM contents of GS and MS were 396 and 264 g/kg fresh weight, respectively. MS was much lower (P &lt; 0.001) in crude protein (CP) (62 g/kg DM) than the GS (120 g/kg DM). GS contained larger (P &lt; 0.001) quantities of neutral detergent fibre (NDF) and acid detergent fibre (ADF) than MS. In contrast, MS contained more (P &lt; 0.001) non-structural carbohydrate than GS, as starch, which comprised 211 g/kg DM. Inclusion of MS in the diet (33% v. 67%) had positive linear effects on fresh matter voluntary intake (P &lt; 0.05), CP and starch digestibility (P &lt; 0.05), and N balance (P &lt; 0.05). A positive associative effect of GS and MS was observed for DM, organic matter intake (quadratic, P &lt; 0.05), N intake and N balance (quadratic, P &lt; 0.01), while it was negative for ADF digestibility (quadratic, P &lt; 0.05). It was concluded that positive interactions of GS and MS were due to a better balance of available energy and protein when the two forages were fed together. No positive associative responses were recorded for digestibility, probably due to higher passage rates of digesta with MS supplementation i.e. lower MS quality in terms of maize plant maturity at harvest.

Effects of supplementing maize and grass silages with barley, and maize silage with urea or ammonia, on the intake and performance of fattening bulls

The effect of crop maturity on the nutritional value of maize silage for lactating dairy cows. 3. Food intake and milk production

A gas production technique as a tool to predict organic matter digestibility of grass and maize silage