Kjell Martinsson

Effects of feeding dairy cows different legume-grass silages on milk phytoestrogen concentration

Phytoestrogens are hormone-like substances in plants that can substantially influence human health (positively or negatively), and when fed to dairy cows are partly transferred to their milk. The aim of this study was to investigate the effects of varying the botanical composition and regrowth interval of legume-grass silage on phytoestrogen intake and milk phytoestrogen concentrations. In one experiment, 15 Swedish Red dairy cows were fed 2- or 3-cut red clover-grass silage, or 2-cut birdsfoot trefoil-grass silage. In a second experiment, 16 Norwegian Red dairy cows were fed short-term ley silage with red clover or long-term ley silage with white clover, and the effects of supplementation with α-tocopherol were also tested. High concentrations of formononetin and biochanin A were found in all silage mixtures with red clover. The milk concentration of equol was highest for cows on the 2-cut red clover-grass silage diet (1,494 μg/kg of milk). Because of the metabolism of biochanin A, genistein, and prunetin, their concentrations in milk and the apparent recovery were low. Coumestrol was detected in only short-term and long-term ley silage mixtures, and its milk concentration was low. Concentrations of secoisolariciresinol and matairesinol were higher in 2-cut birdsfoot trefoil-grass and long-term ley silage mixtures, those with legume species other than red clover, and the highest grass proportions. The 2-cut birdsfoot trefoil-grass silage diet also resulted in higher enterolactone concentration than the other diets (226 μg/kg of milk). Lengthening the regrowth interval increased the intake of secoisolariciresinol and decreased the recovery of lignans. Feeding long-term ley silage resulted in higher milk lignan concentrations but lower milk isoflavone concentrations than feeding short-term ley silage. The apparent recovery of all phytoestrogens except prunetin was highest on the 2-cut birdsfoot trefoil-grass silage diet. No effect of α-tocopherol supplementation was observed on milk concentrations of any of the measured phytoestrogens. Variations were observed in milk concentrations of phytoestrogens, especially of equol, among cows, which could not be explained by variations in diet composition or phytoestrogen intake. The results show that milk phytoestrogen concentration is strongly influenced by silage botanical composition, but questions regarding phytoestrogen metabolism remain to be answered.

Seasonal variation in biochemical composition of cell walls, digestibility, morphology, growth and phenology in timothy

The dynamics of the evolution of the cell wall concentration and the changes in biochemical composition (lignin, carbohydrate and protein fractions) and digestibility of the cell walls of timothy (Phleum pratense L.) were studied during spring growth and summer growth in Sweden during 2 years. The influences of plant development, leaf proportion, dry matter (DM) production, time and environmental factors were investigated. It was found that both concentration and digestibility of the cell walls were strongly related to DM growth, much stronger than to plant development or leaf proportion. It was also found that indigestible fibre (IF) (the amount that was not digested during the IVDOM analysis) increased exponentially when neutral detergent fibre (NDF) concentration increased indicating that the cell wall concentration and thus the thickness of the cell wall was important for the IF concentration. Metabolisable energy (ME) is often calculated from the in vitro digestible organic matter (IVDOM), and the ash concentration. However, IVDOM and ash concentration are affected by different environmental factors and should be handled as separate parameters and not confounded with the ME concept. The lignin concentration was not a good criterion for optimal harvest quality, because the change in lignin over time did not follow a smooth curve, and the analytical errors were great compared with the total variation. At harvest time, the growth of stems and the change in stem properties was important, because leaf growth rates were very small of that time.

In vitro degradation characteristics of Timothy and Red Clover at different harvest times

The nutritional value of red clover (Trifolium pratense L.) and timothy (Phleum pratense L.) were studied over two consecutive growing seasons (1995 and 1996) with an in vitro gas production technique and chemical analysis. The decline in degradability was more pronounced with increasing maturity in timothy than in red clover during spring growth, but similar during summer growth. Red clover contained more components soluble in neutral detergent solution (NDS) at all harvest occasions. The fractional degradation rate for the NDS fraction was lower in red clover compared to timothy. Red clover had slightly higher fractional degradation rate for the whole forage, but the total kinetic release of energy was similar for the two species at the same harvest time. The results indicate that timothy and red clover have different intrinsic characteristics limiting degradation. Effects of the treatments with NDS on the allocation of pectins could partially explain the differences in degradation characteristics.

Intake and digestion of whole-crop barley and wheat silages by dairy heifers.

The effect of maturity at harvest on the digestibility and intake of large bale silage made from whole-crop barley and wheat when fed to growing heifers was evaluated. Two crops of spring barley (Hordeum distichum cv. Filippa and Kinnan) and 1 of winter wheat (Triticum aestivum cv. Olevin) were harvested at the heading, milk, and dough stages of maturity. The silage was fed to 36 dairy heifers in a balanced crossover experiment with 3 periods and 9 treatments (diets based on 3 crops and 3 stages of maturity), organized into 6 pairs of 3 × 3 Latin squares. No clear relationship was observed between intake and stage of maturity of whole-crop cereal silage, but intake was positively correlated to silage DM content (P < 0.001, r = 0.46) and negatively correlated to NDF content (P < 0.001, r = -0.42). Organic matter digestibility decreased between the heading and milk stages of maturity in all crops (P < 0.001), did not differ between the milk and the dough stages in the 2 barley crops, but increased in the wheat silage (P = 0.034). The NDF digestibility decreased between the heading and milk stages in all crops (P < 0.001), whereas it decreased in 1 barley crop (P < 0.001), increased in the other barley (P = 0.025), and was unchanged in the wheat between the milk and dough stages of maturity. Starch digestibility was less in the 2 barley crops compared with the wheat at the dough stage of maturity (P < 0.001). The feeding value of the whole-crop barley and wheat declined between the heading and milk stages of maturity, but thereafter the effect of maturity on the feeding value was minor.

Digestibility of whole-crop barley and oat silages in dairy heifers

This study evaluated the digestibility of whole-crop cereal silage (WCCS) made from oats and six-rowed barley harvested at the heading, early milk and early dough stages, and two-rowed barley harvested at the early milk and early dough stages of maturity. The eight WCCSs were fed to 32 Swedish Red heifers in a changeover design over three periods of 28 days each. The heifers were first fed ad libitum for 17 days and then at 0.95 of ad libitum for 11 days of each period. During the last 5 days all faeces and orts were collected to determine the digestibility of the silages. Only the maturity stage effect was significant for the WCCS organic matter (OM) digestibility and the average OM digestibility was higher at the heading stage (698 g/kg) than at early milk (647 g/kg) and early dough (652 g/kg) stages of maturity. For neutral detergent fibre (NDF) digestibility the crop × maturity stage effect was significant. The NDF digestibility decreased from the heading to the early milk stage for both six-rowed barley (746 to 607 g/kg) and oats (698 to 596 g/kg). There was no further significant decrease in NDF digestibility for six-rowed barley at the early dough stage (577 g/kg), but for two-rowed barley it decreased from the early milk (682 g/kg) to the early dough (573 g/kg) stage, and also for oats the NDF digestibility was lowest at the early dough stage (507 g/kg). The decrease in NDF digestibility during maturation was to a large extent compensated by an increase in starch concentration in the crops. The starch digestibility was lower for six-rowed barley at early dough stage (948 g/kg) than at early milk stage (977 g/kg), and was also lower compared with oats (979 g/kg) at early dough stage. The average crude protein (CP) digestibility was higher at the heading (646 g/kg) and the early milk (642 g/kg) stages than at the early dough stage (599 g/kg), and oats had higher average CP digestibility (650 g/kg) than six-rowed (613 g/kg) and two-rowed (624 g/kg) barley. Delaying the harvest of WCCS from the heading to the early milk and dough stage of maturity will decrease the OM digestibility; as a result there is a decreased NDF digestibility.

Effects of stage of maturity and conservation strategy on fermentation, feed intake and digestibility of whole-crop pea-oat silage used in dairy production

Abstract In two repeated 3×3 Latin Square design trials, dairy cows have been fed bi-crop pea-oat silage to investigate the effect of maturity stage and harvest strategy on feed intake and milk production. In experiment 1 the crop was harvested when the peas were at the flat pod (cut 1) or full pod (cut 2) stage. At the first cut half of the forage was wilted and half was acid-treated with a 2:1 mixture of formic and propionic acid. At the second cut all of the forage was acid-treated. Voluntary intake was highest for the cut 2 silage. In experiment 2 the crop was harvested when the peas were at the flat pod (cut 1), pod fill (cut 2) or full pod (cut 3) stage. The crop was pre-wilted overnight and then acid-treated. Voluntary intake was highest for the cut 3 silage, although the in vivo apparent digestibility was lowest. Milk and protein yield increased with crop maturity. It was concluded that pre-wilting and acid treatment produces good quality, palatable pea-oat bi-crop silage. In terms of feed intake and milk production, the optimal time of harvest was when peas were at the pod fill stage and the oats were in the late milk to early dough stage.

The influence of level of feeding and live weight on feed conversion and carcass composition in Friesian bulls

Abstract Feed conversion and carcass quality in relation to feeding level were investigated using 75 bulls of the Swedish Friesian breed. The experiment was carried out using a factorial design with three feeding levels (H, L and F) and three slaughter stages. The bulls were fed concentrate and hay to gain 1100 g/day (H) or 850 g/day (L). The third group (F) was fed to gain 850 g/day until 18 months of age and 1100 g/day thereafter. On each feeding level the bulls were slaughtered at three different ages (H: 13, 18 and 23 months; L and F: 18, 23 and 28 months) and when reaching treatment mean carcass weights of 240, 325, 418, 277, 363, 422, 275, 372 and 454 kg, respectively. The relative amounts of fat, lean and bone were strongly affected by both feeding level and age or weight. The carcasses became fatter and the relative weight of the bone decreased as the carcasses grew heavier and as feeding level increased. The feed conversion ratio to the same degree of fatness, expressed as metabolizable energy consumed per kg carcass weight gain, was similar irrespective of feeding level. The conversion of feed into live weight and carcass weight gains increased sharply with increasing live weight.

A Study on the Value of Ultrasonic Scanning as a Method to Estimate Carcass Traits on Live Cattle

Abstract A total of 460 bulls of different breeds from the Swedish performance testing stations and 90 bulls from an experimental station were scanned monthly from 9 to 12 months of age and from 9 months to slaughter, respectively. Scanning was performed at the 2nd lumbar vertebra and on certain occasions also at the 13th and 10th thoracic vertebrae. When the bulls from the experimental station were slaughtered, the composition of each carcass was inspected closely. The scanning pictures of the cross-sectional area of M. longissimus dorsi and average subcutaneous fat thickness were interpreted. Significant differences in the scanning measurements were found between beef breeds and between year-batches. Repeatabilities, expressed as intraclass correlation for muscle area when interpreted by different persons, varied between 0.35 and 0.58. The corresponding values for fat thickness were 0.35 and 0.42. The higher values were obtained by persons who had earlier trained interpretation together. It was conclude...

Effects of increasing amounts of hempseed cake in the diet of dairy cows on the production and composition of milk.

This study explored the potential for using seed cake from hemp (Cannabis sativa L.) as a protein feed for dairy cows. The aim was to evaluate the effects of increasing the proportion of hempseed cake (HC) in the diet on milk production and milk composition. Forty Swedish Red dairy cows were involved in a 5-week dose-response feeding trial. The cows were allocated randomly to one of four experimental diets containing on average 494 g/kg of grass silage and 506 g/kg of concentrate on a dry matter (DM) basis. Diets containing 0 g (HC0), 143 g (HC14), 233 g (HC23) or 318 g (HC32) HC/kg DM were achieved by replacing an increasing proportion of compound pellets with cold-pressed HC. Increasing the proportion of HC resulted in dietary crude protein (CP) concentrations ranging from 126 for HC0 to 195 g CP/kg DM for HC32. Further effects on the composition of the diet with increasing proportions of HC were higher fat and NDF and lower starch concentrations. There were no linear or quadratic effects on DM intake, but increasing the proportion of HC in the diet resulted in linear increases in fat and NDF intake, as well as CP intake (P < 0.001), and a linear decrease in starch intake (P < 0.001). The proportion of HC had significant quadratic effects on the yields of milk, energy-corrected milk (ECM) and milk protein, fat and lactose. The curvilinear response of all yield parameters indicated maximum production from cows fed diet HC14. Increasing the proportion of HC resulted in linear decreases in both milk protein and milk fat concentration (P = 0.005 and P = 0.017, respectively), a linear increase in milk urea (P < 0.001), and a linear decrease in CP efficiency (milk protein/CP intake; P < 0.001). In conclusion, the HC14 diet, corresponding to a dietary CP concentration of 157 g/kg DM, resulted in the maximum yields of milk and ECM by dairy cows in this study.

Effects of Temperature during Moist Heat Treatment on Ruminal Degradability and Intestinal Digestibility of Protein and Amino Acids in Hempseed Cake

The objective of this study was to evaluate ruminal degradability and intestinal digestibility of crude protein (CP) and amino acids (AA) in hempseed cake (HC) that were moist heat treated at different temperatures. Samples of cold-pressed HC were autoclaved for 30 min at 110, 120 or 130°C, and a sample of untreated HC was used as the control. Ruminal degradability of CP was estimated, using the in situ Dacron bag technique; intestinal CP digestibility was estimated for the 16 h in situ residue using a three-step in vitro procedure. AA content was determined for the HC samples (heat treated and untreated) of the intact feed, the 16 h in situ residue and the residue after the three-step procedure. There was a linear increase in RUP (p = 0.001) and intestinal digestibility of RUP (p = 0.003) with increasing temperature during heat treatment. The 130°C treatment increased RUP from 259 to 629 g/kg CP, while intestinal digestibility increased from 176 to 730 g/kg RUP, compared to the control. Hence, the intestinal available dietary CP increased more than eight times. Increasing temperatures during heat treatment resulted in linear decreases in ruminal degradability of total AA (p = 0.006) and individual AA (p<0.05) and an increase in intestinal digestibility that could be explained both by a linear and a quadratic model for total AA and most individual AA (p<0.05). The 130°C treatment decreased ruminal degradability of total AA from 837 to 471 g/kg, while intestinal digestibility increased from 267 to 813 g/kg of rumen undegradable AA, compared with the control. There were differences between ruminal AA degradability and between intestinal AA digestibility within all individual HC treatments (p<0.001). It is concluded that moist heat treatment at 130°C did not overprotect the CP of HC and could be used to shift the site of CP and AA digestion from the rumen to the small intestine. This may increase the value of HC as a protein supplement for ruminants.