Eva Spörndly

Enteric methane emissions from dairy cows fed different proportions of highly digestible grass silage

Abstract Enteric methane (CH4) emissions were measured from six lactating dairy cows using the sulfur hexafluoride tracer technique. Three diets with different proportions of highly digestible grass silage/concentrates were fed: 500/500, 700/300, or 900/100 g kg–1 dry matter (DM). The average daily CH4 emissions were 282, 300, and 321 g animal–1, respectively and the methane conversion factor (Y m ) from gross energy (GE) ranged from 0.051 to 0.056. However, the statistical power of the study was weak and the differences between diets were not significant (p=0.149 and p=0.293, respectively). A linear regression analysis showed a trend (p=0.08) toward higher enteric CH4 emissions with higher proportion of high quality grass silage in the diet. A definite conclusion is not possible and further studies are needed as a base for concrete advice on how to mitigate enteric CH4 emissions from high yielding dairy cows in Scandinavia.

The Effect of Fouling on Herbage Intake of Dairy Cows on Late Season Pasture

Abstract During three years (experiments 1-3) short-term grazing experiments were performed to study late season herbage intake by dairy cows. Change-over designs were used during experiments 1 and 2 while a continuous design with a covariate period was used in experiment 3. The effect of fouling on intake at a herbage allowance of 30 kg dry matter (DM) per cow and day was studied by comparing herbage intake on clean, grass-dominated pastures (treatment CG), with herbage intake on fouled grass-dominated pastures (treatment FG), in experiments 1-3. In experiment 2, a third treatment was included, consisting of grazing a clean clover-grass ley (treatment CC). Pastures on treatment CG were cut and those on FG were grazed and then immediately topped at the same times throughout the grazing season until the start of the experiment. In experiment 2, the grazing area of treatment CC was the regrowth after an early season harvest. The herbage intake on treatment FG was 13.0, 13.8 and 14.2 kg organic matter (OM) p...

Grazing by steers at different sward surface heights on extensive pastures: a study of weight gain and fat deposition.

Live weight gain of steers grazing at three different target sward heights, Low (3-6 cm), Medium (6-10 cm) and High (>10 cm), together with carcass fat deposition, were studied during two grazing seasons. Sward height was measured with a sward stick. The grassland consisted of seminatural grazing areas mixed with previously cultivated areas. Animals grazed continuously with small adjustments in animal numbers (year 1) or pasture area (year 2) to maintain sward height within the target for each treatment. The recorded average sward heights were 4.7, 6.8 and 11.1 cm for pastures on treatments Low, Medium and High, respectively. The animals weighed approximately 440 kg at the start of the grazing season and went directly from pasture to slaughter at the end of the experiment. No differences between years were found and data from both years were thus pooled, giving a total of 50 steers of the Swedish Red and White breed in the data set. Over the whole grazing season, the average daily live weight gain of animals on treatment Low (0.43 kg day

Effect of Harvesting Frequency, Variety and Leaf Maturity on Nutrient Composition, Hydrogen Cyanide Content and Cassava Foliage Yield

The experiment studied the effect of harvesting frequencies and varieties on yield, chemical composition and hydrogen cyanide content in cassava foliage. Foliage from three cassava varieties, K94 (very bitter), K98-7 (medium bitter) and a local (sweet), were harvested in three different cutting cycles, at 3, 6 and 9 months; 6 and 9 months and 9 months after planting, in a 2-yr experiment carried out in Hanoi, Vietnam. Increasing the harvesting frequency increased dry matter (DM) and crude protein (CP) production in cassava foliage. The K94 variety produced higher foliage yields than the other two varieties. Dry matter, neutral detergent fibre (NDF), acid detergent fibre (ADF) and total tannin content increased with months to the first harvest, whereas CP content decreased. Hydrogen cyanide (HCN) content was lower at the first harvest than at later harvests for all cutting cycles. At subsequent harvests the content of total tannins tended to decline, while HCN content increased (p<0.05). Chemical composition differed somewhat across varieties except for total tannins and ash. Dry matter, NDF, ADF and total tannins were higher in fully matured leaves, while CP and HCN were lower in developing leaves.

Effects of Sward Height and Season on Herbage Intake of Strip-grazed Dairy Cows

Abstract Herbage intake by strip-grazed dairy cows was estimated, using chromic oxide as marker, during experimental periods covering different parts of the grazing season, different sward heights and different years. Herbage mass, herbage composition and the milk yield, live weight, lactation week and age of experimental animals were also registered with the objective of including those variables that were significant in a model for studying the influence of sward height and season on herbage intake. Pastures were grazed when planned target sward height was obtained. Average sward height over all experimental periods was 15.0 cm (range 7.4-21.2). The grazing season was divided into early season (May 17 to June 19), mid-season (June 20 to July 31) and late season (August 1 to August 20). The data comprise herbage intake measurements on 69 dairy cows with an average milk yield and live weight of 15.6 kg/day and 546 kg, respectively. Pasture allowance was 30 kg dry matter/cow and day. The content of metabol...

Grazing semi-natural pastures late in the season or every second year – effects on the weight gain of steers and composition of selected vegetation

Abstract In a five year experiment the weight gain of a total of 106 steers on three grazing treatments was studied: Partial–Delay (delayed onset of grazing in part of the grazing area), Intermittent (grazing every second year) and Continuous (continuous yearly grazing). Daily weight gain of steers was similar between treatments during the first three years but lower (P<0.05) on the Partial–Delay (0.6 kg) compared with the Intermittent and Continuous treatments (0.8–0.9 kg) during the last 2 experimental years. The mean proportions of grass, forbs and senescent plant material were similar between treatments: 59–61, 23–24, 15–17% of dry matter (DM), respectively.

Effect of feeding varying levels of banana peelings supplemented with maize bran, cotton seed cake and Gliricidia sepium on the performance of lactating dairy cows

Potential of banana peelings (BP) as animal feed for lactating dairy cows was evaluated. The cows were fed BP at 0, 20, 40 and 60% levels of their daily ration. The diets were supplemented with maize bran, cottonseed cake and Gliricidia Sepium to make them iso-nitrogenous. Four multi-parous cows were allotted to each of the four dietary treatments in a 4×4 Latin square design. Dry matter intake on diets with 40 and 60% BP were similar and higher (P < 0.05) than those on diets with 0 and 20% BP. Daily live weight changes did not differ between treatments. Daily milk yields ranged from 10.2 to 11.4 kg, with no significant differences between diets. Milk fat yields were 4.80, 5.54, 3.63 and 3.58% on diets with 0, 20, 40 and 60% BP, respectively; being lower on diets with higher BP levels (P < 0.05) while the other milk components were not affected by the treatments. Blood potassium reduced at the 60% BP level while phosphorus was higher and similar at the 20, 40 and 60% BP levels. Non-esterified fatty acids were lower at the 40 and 60% BP feeding levels. It is concluded that banana peelings can support moderate milk yields when accompanied with strategic supplementation.

Whole lactation production responses in high‐yielding dairy cows using high‐quality grass/clover silage

BACKGROUND Limiting the use of purchased concentrate for livestock and replacing it with home-grown forage without compromising milk production can offer benefits in both organic and conventional dairy systems. A full lactation trial was conducted with 92 cows over two years comparing three diets, each differing in the mean forage proportion over the lactation, 500 (500F), 600 (600F) and 700 (700F) g kg-1 dry matter (DM) respectively. The diets were designed to represent common conventional feeding, current regulations for organic production and more extreme high-forage-based production respectively. The aims were to determine the effects of forage proportion in the diet on milk production and feed utilisation. RESULTS Compared with 500F, daily milk yield did not differ in 600F but was lower in 700F (31.3, 31.1 and 29.2 kg energy-corrected milk respectively). Daily dry matter intake (DMI) was similar between treatments (20.3, 20.4 and 19.9 kg in 500F, 600F and 700F respectively). CONCLUSION Increasing the forage proportion from 500 to 600 g kg-1 DM did not have any adverse effects on milk production or DMI. Thus it is possible to produce the same quantity of milk with less concentrate and reduce the use of potential human feeds in dairy production.