Metabolic changes during he transition period

We used four ruminally fistulated, multiparous, pregnant Holstein cows to measure changes in concentrations of plasma metabolite as the dairy cow transitions from one lactation to the next. Diets consisted of typical far-off and close-up diets, a late lactation diet containing wet corn gluten feed (20% DM), and an alfalfa hay-corn silage based early lactation diet. Calculated NEL (Mcal/lb), measured crude protein (%), and diet digestibilities (%; based on steers fed at 2% of BW) were 0.78, 18.7, 74.1; 0.70, 11.5, 66.2; 0.74, 15.6, 71.0; 0.73, 18.4, 70.7 for late lactation, far-off dry, close-up dry, and early lactation diets, respectively. Blood samples were obtained on day 79 prior to calving and weekly thereafter until calving and on days 1, 3, 5, 7, 15, 20, 25, 30, 60, and 90 after calving. Cows gained body weight and condition during the dry period, peaked just prior to calving, and lost weight and condition steadily through the first 11 weeks of lactation. Calculated energy balance was negative during the first 3 weeks of lactation. Plasma concentrations of non-esterified fatty acids (NEFA), glucose, and insulin to glucagon ratio remained fairly stable during the dry period. Plasma glucose increased just before calving, decreased markedly during early lactation, then increased and stabilized by day 30 of lactation. Plasma NEFA concentrations increased at calving and were elevated during early lactation, then returned to prepartum concentrations by day 30 of lactation. The insulin to glucagon ratio decreased just prior to calving, continued to decrease until day 7 of lactation, and then remained stable until the end of the trial. Changes in diet and intake affected plasma urea nitrogen, which decreased as dietary protein decreased during the far-off period, decreased with intake during the close-up period, and increased after calving consistent with the higher dietary protein and increase in dry matter intake. Most of the observed metabolic adaptations reflected the energy status of the cow with large shifts occurring around parturition. Certainly, some of the hormones associated with calving can initiate metabolic events favorable to lactation, but the changes in energy balance and nutrient supply support the continued diversion of nutrients to the mammary gland. These data support the concept that dairy cows experience a period of increased tissue mobilization from approximately 2 days prior to calving until 30 days after calving. In conclusion, a number of metabolic adaptations occur in transition dairy cows that provide clues to improve feeding and management guidelines.; Dairy Day, 2002, Kansas State University, Manhattan, KS, 2002

Comlete lactational performance of cows fed wet corn gluten feed and pellet consisting of raw soybean hulls and corn steep liquor

We evaluated the effect of wet corn gluten feed and a novel product containing raw soybean hulls and corn steep liquor on performance in lactating dairy cows. Forty-six multiparous Holstein cows were used in a randomized incomplete block design. Cows were housed in tie stalls for the first 13 weeks of lactation and moved to group pens for the remainder of the study. Cows were blocked by calving date and assigned to control, wet corn gluten feed (20% of diet DM), or the novel product (20% of diet DM). Diets were administered as total mixed rations at the first feeding postpartum. Control contained (DM basis) 30% alfalfa hay, 15% corn silage, 32% corn, 9.3% whole cottonseed, 4.4% solvent soybean meal (SBM), 3.3% expeller SBM, 1.3% fish meal, 1% wet molasses, and 3.7% vitamins/minerals. Wet corn gluten feed replaced 10% alfalfa hay, 5% corn silage, 5% corn grain, and expeller SBM replaced solvent SBM to maintain diet rumen undegradable protein. The novel product replaced 10% alfalfa hay, 5% corn silage, 3% solvent SBM, and 2% corn. Diet crude protein % and energy density (Mcal/lb, NEL) for control, wet corn gluen feed, and the novel product were 18.4, 0.73; 18.2, 0.75; 18.5, 0.73; respectively. Milk, energy corrected milk, dry matter intake, and production efficiency (ratio of milk to DM intake) did not differ among diets during the first 91 days of lactation, but there was a diet by week interaction for production efficiency. Cows fed control were more efficient during the first 2 weeks postpartum than cows fed wet corn gluten feed and the novel product, likely due to increased fat mobilization from adipose tissue because intake as a percent of body weight was less for cows fed control. During weeks 3 through 14 postpartum, wet corn gluten feed and the novel product improved milk, energy corrected milk, and milk component yield, and production efficiency. Inclusion of wet corn gluten feed and the novel product at 20% of dietary DM as a partial replacement for alfalfa hay, corn silage, corn grain, and SBM in diets fed to lactating dairy cattle supported performance during early lactation and improved performance during mid and late lactation. In addition, combining wet corn gluten feed or the novel product with corn silage and alfalfa hay maintained milk fat yields, thereby demonstrating that they can serve as effective sources of fiber when fed at 20% of dietary DM. Improved performance attributed to wet corn gluten feed and the novel product is due to factors other than improved digestibility of the diets. These results indicate that wet corn gluten feed and the novel product can serve as alternative feedstuffs in diets fed to lactating dairy cattle.; Dairy Day, 2002, Kansas State University, Manhattan, KS, 2002

Characteristic changes of ruminal fermentation in transition dairy cows

Four-ruminally fistulated, multiparous, pregnant Holstein cows were used to delineate changes in ruminal fermentation in dairy cows as they experienced the transition from one lactation to the next. Diets consisted of typical far-off and close-up diets, a late lactation diet containing wet corn gluten feed (20% DM) and an alfalfa hay-corn silage based early lactation diet. Calculated NEL (Mcal/lb), measured crude protein (%), and diet digestibilities (%; based on steers fed at 2% of BW) were: 0.78, 18.7, 74.1; 0.70, 11.5, 66.2; 0.74, 15.6, 71.0; 0.73, 18.4, 70.7 for late lactation, far-off dry, close-up dry, and early lactation diets, respectively. Ruminal measurements were taken on days 72 (late lactation), 51 (faroff), 23, and 9 (close-up dry) before calving and on days 6, 20, 34, 48, 62, 76, and 90 days after calving. Ruminal samples were collected at hours 0, 3, 6, 9, and 12 after feeding on each sampling date. Major shifts in ruminal fermentations occurred when the close-up diet was consumed before calving and in concert with an increase in DM intake during the first 48 days of lactation. Dry matter digestibility increased after cows were switched to the close-up diet and continued this trend through day 6 postpartum. Ruminal pH decreased and total volatile fatty acids, peptides, and free amino acids increased after cows were switched to the early lactation diet. These data support the concept that alterations in ruminal fermentation reflect changes in both diet and intake.; Dairy Day, 2002, Kansas State University, Manhattan, KS, 2002

Changes in rumen capacity of dairy cows during the periparturient period

Four-ruminally fistulated, multiparous, pregnant Holstein cows were studied to characterize ruminal adaptations during the transition from gestation to lactation. Cows were fed typical far-off and close-up diets, a late lactation diet containing wet corn gluten feed (20% DM), and an alfalfa hay, corn silage based early lactation diet. Ruminal measurements were obtained 72 (late lactation), 51 (far-off dry), 23 and 9 (close-up dry) days before expected parturition and 6, 20, and 34 days postpartum. Measurements included total fill, dry matter fill, fluid fill, and water-holding capacity of the rumen. Dry matter intake and milk production data were collected daily and body weight and body condition were determined weekly. Body weights and condition increased during the dry period, whereas intake as a percentage of body weight decreased. Ruminal water holding capacity, an indicator of rumen capacity, increased linearly from late lactation to 34 days postpartum. These data suggest rumen capacity is not the causative factor of intake depression in dairy cows during the final 3 wk of gestation.; Dairy Day, 2001, Kansas State University, Manhattan, KS, 2001

Changes in ruminal microbial populations in transition dairy cows

We used four ruminally fistulated, multiparous, pregnant Holstein cows to delineate microbial adaptations in dairy cows as they experienced the transition from one lactation to the next. Diets consisted of typical far-off and close-up diets, a late lactation diet containing wet corn gluten feed (20% DM) and an alfalfa hay-corn silage based early lactation diet. Calculated NEL (Mcal/lb), measured crude protein (%), and diet digestibilities (%; based on steers fed at 2% of BW) were: 0.78, 18.7, 74.1; 0.70, 11.5, 66.2; 0.74, 15.6, 71.0; 0.73, 18.4, 70.7 for late lactation, far-off dry, close-up dry, and early lactation, respectively. Microbial samples were obtained on days 72 (late lactation), 51 (far-off dry), 23, and 9 (close-up dry) prepartum and days 6, 20, 34, 48, 62, 76, and 90 postpartum. We analyzed ruminal samples for ciliated protozoa and viable counts of bacteria and fungi. Changing from a high forage to a high concentrate diet impacted bacterial counts less than ciliated protozoal and fungal counts. Switching diets from high concentrate to high forage increased ciliated protozoa and fungal counts, and counts decreased when diets were switched from high forage to high concentrate. Bacterial and ciliated protozoa counts increased in early lactation and decreased as cows approached peak dry matter intake. Dietary changes with the onset of lactation led to virtual disappearance of fungi from the rumen. In general, ruminal microbial populations of dairy cows respond to changes in diet and intake. Changes in diet affected populations of protozoa and fungi, whereas changes in intake affected populations of bacteria, protozoa, and fungi.; Dairy Day, 2002, Kansas State University, Manhattan, KS, 2002

Diet digestibility and rumen traits in response to feeding wed corn gluten feed and a pellet consisting of raw soybean hulls and corn steep liquor

Four ruminally cannulated and two intact multiparous Holstein cows were used in a 3 x 3 replicated Latin square design to evaluate digestibility and rumen traits in lactating dairy cows in response to feeding wet corn gluten feed and a novel product containing raw soybean hulls and corn steep liquor. Three dietary treatments were fed in the experiment. The control contained (DM basis) 30% alfalfa hay, 15% corn silage, 32% corn, 9.3% whole cottonseed, 4.4% solvent soybean meal (SBM), 3.3% expeller SBM, 1.3% fish meal, 1% wet molasses, and 3.7% vitamins/ minerals. Wet corn gluten feed replaced 10% alfalfa hay, 5% corn silage, 5% corn grain, and expeller SBM replaced solvent SBM to maintain diet rumen undegradable protein. The novel product replaced 10% alfalfa hay, 5% corn silage, 3% solvent SBM, and 2% corn. Diets were analyzed to have dietary crude protein percentage and energy density values (Mcal/lb, NEL) of 18.7, 0.75; 18.7, 0.77; 18.7, 0.74; for control, wet corn gluten feed, and the novel product, respectively. Experimental periods were 14 days (10 days adaptation and 4 days collection). Acid insoluble ash was used to estimate fecal output. Dry matter intake averaged 37.9 lb/day and total tract digestibilities of dry matter (DM), organic matter, neutral detergent fiber (NDF), acid detergent fiber (ADF), and crude protein did not differ among diets: 71.7%, 73.2%, 63.1%, 58.5% and 73.0%, respectively. Diets affected liquid dilution rate, ruminal pH, and ruminal concentrations of total volatile fatty acids and ammonia similarly. The molar ratio of acetate to propionate was greater (P\u3c0.05) for control (3.38) than for wet corn gluten feed (2.79) and the novel product (2.89). Inclusion of wet corn gluten feed and the novel product at 20% of dietary DM as a partial replacement for alfalfa hay, corn silage, corn grain, and SBM in diets fed to lactating dairy cattle supported lactational performance similar to the control diet. Additionally, combining wet corn gluten feed or the novel product with corn silage and alfalfa hay maintained milk fat yields and ruminal pH, thereby demonstrating that wet corn gluten feed and the novel product can serve as an effective source of fiber when fed at 20% of dietary DM. These results indicate that wet corn gluten feed and the novel product tested can serve as alternative feedstuffs in lactating dairy cattle diets.; Dairy Day, 2002, Kansas State University, Manhattan, KS, 2002

Intake and performance of dairy cows fed wet corn gluten feed during the periparturient period

Eight primiparous and nine multiparous Holstein cows were used in a randomized block design to determine the effect of wet corn gluten feed in the diet during the last 21 days of gestation on dry matter intake and early postpartum performance. Multilactation cows fed wet corn gluten feed maintained a higher dry matter intake and intake as a percentage of body weight during the last week before calving than cows fed the control diet. First-lactation cows fed wet corn gluten feed consumed less dry matter, both total and as a percentage of body weight, across calving than first-lactation cows fed the control diet. Milk, milk components, and blood metabolites were not influenced by diet. Wet corn gluten feed may help alleviate the depression in intake typically observed during late gestation for multiparous but not primiparous cows.; Dairy Day, 2000, Kansas State University, Manhattan, KS, 2000

Effect of the ratio of zinc amino acid complex to zinc sulfate on the performance of Holstein cows

Multiparous (n = 70) and primiparous (n = 66) Holstein cows were balanced by 305-d previous mature-equivalent milk yield and parity and assigned to 1 of 3 dietary treatments to evaluate the ratio of zinc sulfate to zinc amino acid complex (CZ) in pre- and postpartum Holstein cows fed diets containing 75 mg of added zinc/kg. Treatments were (1) 75 mg of supplemental zinc/kg of dry matter (DM) provided entirely as zinc sulfate (0-CZ); (2) 0-CZ diet, except 33.3 mg of zinc sulfate/kg of DM in the prepartum and 15.5 mg of zinc sulfate/kg of DM in the postpartum diet were replaced by CZ from Availa-Zn (16-CZ; Zinpro Corp., Eden Prairie MN); and (3) 0-CZ diet, except 66.6 mg of zinc sulfate/kg of DM in the prepartum and 40.0 mg of zinc sulfate/kg of DM in the postpartum diet was replaced by Availa-Zn (40-CZ). Cows were housed at the Iowa State University Dairy Farm and were individually offered a total mixed ration containing dietary treatments beginning at 28 +/- 15 d before expected calving date until 250 d in milk. Relative to 0-CZ, multiparous cows (but not primiparous) fed CZ (16-CZ or 40-CZ) had increased (20%) colostrum IgG concentrations. Prepartum DM intake (DMI) was decreased with CZ supplementation. Postpartum DMI was decreased in cows fed CZ, whereas milk yield (MY) was increased in the 40-CZ-fed cows relative to those fed both 0-CZ and 16-CZ. Feed efficiency increased linearly when measured as MY/DMI, 3.5% fat-corrected MY/DMI, and solids-corrected MY/DMI. Regardless of level, feeding CZ decreased services per conception. Feeding 16-CZ decreased milk fat concentration and feeding CZ linearly increased milk urea nitrogen concentration. In summary, supplementing zinc as a mixture of CZ and zinc sulfate, as opposed to supplementing only zinc sulfate, has beneficial effects on production parameters in dairy cows, with those benefits becoming more apparent as the ratio of CZ to zinc sulfate increases

Monensin: an overview of its application in lactating dairy cow diets

The efficiency of feedstuff utilization by ruminal microorganisms and the cow’s genetic ability to convert feed nutrients into milk and milk components are major factors that influence the profitability of a dairy herd. Monensin’s ability to modify the movement of ions across biological membranes leads to alterations in bacterial populations and subsequent changes in the proportion of volatile fatty acids produced during ruminal fermentation. Manipulating ruminal microbial populations with ionophores has the potential to improve performance by reducing ketosis, acidosis, and bloat and increasing digestive efficiency. Monensin improves fiber digestion by preventing suboptimal ruminal pH, enhances amino acid use by reducing the degradation of dietary protein, and improves the energy status of periparturient animals. Monensin is not approved for use in diets for lactating dairy cows at this time, but its status is currently under review by the U.S. Food and Drug Administration. If approved, monensin will provide another management tool to the dairy industry