Type of cottonseed and level of gossypol in diets of lactating dairy cows: plasma gossypol,health, and reproductive performance

Objectives were to determine effects of altering gossypol intake by feeding whole linted Upland (WUP) or a 1:2 blend of WUP and cracked Pima (BUPCP) cottonseed on plasma gossypol (PG) concentrations, reproduction, and health of Holstein cows. Cows, 813, on three dairy farms were assigned to one of two diets starting at 13 +/- 11 d in milk for a 170-d experiment. Diets contained 717 and 951 mg of free gossypol/kg of dry matter from WUP and BUPCP, respectively. Concentrations of PG, as well as the proportion of total gossypol (TG) as the minus isomer were higher for cows fed BUPCP vs cows fed WUP. Conception rate at the first postpartum artificial insemination did not differ between treatments. However, cows consuming the higher gossypol diet had reduced subsequent conception rates and a lower pregnancy rate. Incidence of abortions increased in the higher gossypol diet, and cows that aborted or remained open had higher PG concentrations. Increasing PG concentrations resulted in reduced conception rates and extended days open. The probability of conception after the first artificial insemination declined at a decreasing rate as the plasma TG increased. Incidence of health disorders were unaffected by gossypol intake and PG concentrations. Similarly, gossypol intake and PG concentrations had no effect on culling or mortality. Six cows died in each diet, and none had postmortem signs compatible with gossypol toxicity. Consumption of a high gossypol diet for 170 d had no effect on health of lactating dairy cows, but it increased PG concentrations and impaired reproductive performance.     

Effect of whole and expanded-expelled cottonseed on milk yield and blood gossypol

Thirty-two primiparous and 12 multiparous Holstein cows were randomly assigned at calving to treatments to determine the effects of type and amount of cottonseed product on plasma gossypol, milk production, and composition, and conjugated linoleic acid concentration in milk fat. Rations consisted of corn silage, corn grain, soybean meal, and cottonseed hulls, and contained on average 16.8% crude protein and 25.3% acid detergent fiber on a dry matter basis. On a dry matter basis, diets contained one of the following: 1) 14% whole cottonseed; 2) 14% expanded-expelled cottonseed; 3) 21% expanded-expelled cottonseed; or 4) 28% expanded-expelled cottonseed. Cows remained on treatment from 30 through 120 d in milk. Dry matter intakes were not significantly different, but intakes of crude protein, acid detergent fiber, and fat were higher for multiparous cows fed whole cottonseed. Multiparous cows fed whole cottonseed had higher yields of milk, fat-corrected milk, crude protein, fat and solids-not-fat than those fed any level of expanded-expelled cottonseed. Concentrations of milk fat, protein, and SNF were not affected by treatment. Although there were treatment differences in fat intake, there were no production differences in primiparous cows. Milk production efficiency (fat-corrected milk/dry matter intake) was not affected by treatment for either multiparous or primiparous cows. Cows fed 14% whole or 14% expanded-expelled cottonseed had similar levels of total plasma gossypol and plasma levels of the negative isomer of gossypol. Increasing the level of expanded-expelled cottonseed in the diet increased both total plasma gossypol and the negative isomer. In this experiment, multiparous but not primiparous cows fed whole cottonseed produced more milk than those fed expanded-expelled cottonseed at 14 to 28% of the diet dry matter, however, feed efficiencies were similar for all treatments.     

Effects of different sources and levels of dietary gossypol on gossypol residues in plasma and milk of lactating cows

Free gossypol residues in tissues or milk from feeding whole cottonseed and cottonseed meal were measured for their effect on health of dairy cows and humans. Forty lactating cows were randomly assigned to 5 treatments in a 60-d experiment to investigate the effects of sources and dietary level of gossypol on plasma and milk gossypol concentrations in lactating cows. Five experimental diets had identical net energy for lactation and crude protein content on a dry matter (DM) basis. Soybean meal was the main protein ingredient used in the control diet. Cottonseed meal (CSM) or whole cottonseed (WCS) substituted for part of the soybean meal in the other 4 diets. Gossypol levels in the 5 diets were 0 (control), 91.15mg/kg of DM in CSM1, 117.31mg/kg of DM in CSM2, 385.43mg/kg of DM in WCS1, and 611.13mg/kg in WCS2. Yields of 3.5% fat-corrected milk were significantly higher for cows in the WCS2 group; cows in the CSM1 and WCS1 groups showed no differences but both were numerically higher than the control and CSM2 groups. Milk protein concentration was lower for cows consuming WCS1 compared with the control group. Lactose concentration was lower for cows in the CSM2 group compared with the WCS2 group, but no differences were observed among other diets. Aspartate aminotransferase in serum was significantly higher for the WCS2 group compared with the control and WCS1 groups, but no difference was observed with the CSM1 and CSM2 groups. Concentrations of gossypol in plasma and milk of cows in the WCS1 and WCS2 groups were both higher than those of the other groups. No adverse effects were observed on cows fed diets containing 12.0% CSM, and no gossypol was found in plasma and milk. When WCS comprised 15% of the diet DM, yields of 3.5% fat-corrected milk were increased in cows and gossypol was detected in plasma and milk but not at harmful levels.     

The effects of varying gossypol intake from whole cottonseed and cottonseed meal on lactation and blood parameters in lactating dairy cows

Effects of varying amounts of gossypol from whole Upland cottonseed (WCS) and cottonseed meal (CSM) were evaluated in 40 midlactation Holstein cows. After 14 d of pretreatment, cows were assigned to 1 of the 5 treatments for 84 d: control (no gossypol), 931 mg/kg total gossypol (TG) and 850 mg/kg free gossypol (FG) from WCS (moderate TG and high FG); 924 mg/kg TG and 91 mg/kg FG from CSM (moderate TG and low FG), 945 mg/kg TG and 479 mg/kg FG with equal amounts of TG from WCS and CSM (moderate TG and FG), or 1894 mg/kg TG and 960 mg/kg FG with equal amounts of TG from WCS and CSM (high TG and FG). Concentrations of plasma gossypol (PG) and its isomers were directly proportional to FG intake. Concentrations of PG reached a plateau after 28 d on treatment, and they were highest in cows receiving a diet with high TG and FG. Erythrocyte fragility differed among treatments and increased with increasing FG intake. Plasma gossypol returned to negligible concentrations 28 d after withdrawal of cottonseed products from the high TG and FG diet. Serum vitamin A was similar among treatments, but vitamin E increased with increasing FG intake. Serum enzymes were generally unaffected by treatments, but urea N increased in diets higher in TG and FG. Intake of dry matter was higher for the diet high in TG and FG than for the control diet, but was similar for other treatments. Cows receiving the high TG and FG diet produced more milk and 3.5% fat-corrected milk, with no changes in milk composition. Feeding a diet containing 1894 mg/kg TG and 960 mg/kg FG for 84 d increased PG concentrations and erythrocyte fragility and resulted in minor changes in blood metabolites and enzymes, but no detrimental effect on lactation performance was observed. Indicators of liver, kidney, and muscle cell viability suggest that the higher amounts of gossypol consumed in this study had only minor effects on those tissues in lactating dairy cows.     

Effects of source of gossypol and supplemental iron on plasma gossypol in Holstein steers

Four experiments were conducted to evaluate factors influencing concentrations of plasma total gossypol (TG) in 30 Holstein steers fed cottonseed products. At the end of each 28-d experiment, steers were weighed and blood samples were collected and analyzed for plasma TG concentrations. During the entire study, steers did not show any overt signs of gossypol toxicity. In the 28 d before experiment 1, 30 steers with a body weight (BW) of 273 kg were fed a standardization diet with 15.0% Upland whole cottonseed (WCS) that resulted in a mean intake of 9.08 g/d of TG per steer/d and a plasma TG of 1.66 μg/mL. In experiment 1, 30 steers were fed 1 of 5 diets with 15.0% Upland WCS, but different levels of supplemental Fe [0, 150, 300, 450, and 600 mg/kg of diet dry matter (DM)]. Average daily gain was not affected by level of Fe in the diet, but DM intake, plasma TG, and plasma TG response decreased linearly as Fe in diets increased. In experiment 2, steers were fed diets with 15.0% Upland cottonseed as whole, cracked, roasted, cracked-roasted, or extruded. Analysis of the seed revealed that roasting or extrusion markedly reduced free gossypol (FG) content. Minor effects on animal performance were observed, but plasma TG decreased with roasting or extrusion of seeds, with the greatest reduction when the seed was cracked and then roasted. In experiment 3, steers were fed 2 levels of WCS (7.0 or 14.0% of DM) with 3 levels of cottonseed meal (2.8, 5.5, or 8.5% of DM) in the diet. Animal performance was not altered by diet, but plasma gossypol concentrations and responses were greater in steers fed diets with more WCS, because of the greater FG intake. In experiment 4, 24 steers were fed diets with 15.0% cottonseed (Upland or Pima) either as whole or cracked. Pima cottonseed increased TG and FG intakes, which resulted in greater plasma TG concentration and response. Animal response to processing of cottonseed tended to differ according to type of cottonseed. However, feeding Pima and cracking of cottonseed increased gossypol availability and plasma TG concentrations.     

Increasing dietary levels of cracked pima cottonseed increase plasma gossypol but do not influence productive performance of lactating Holstein cows

Lactating Holstein cows were fed diets with increasing levels of cracked Pima cottonseed to determine its effects on plasma gossypol concentrations as well as milk yield and composition and dry matter (DM) intake in a short-term study. All diets contained 12.8% cottonseed, 43.5% concentrate, and 43.7% chopped alfalfa hay on a DM basis. The proportion of whole Upland cottonseed to cracked Pima cottonseed in the four dietswas 100:0, 67:33, 33:67, and 0:100. Four primiparous cows were fed the diets in a 4 x 4 Latin square design, and three multiparous cows were fed the diets in a Youden square design with five periods. All periods were 35 d. Upland and cracked Pima cottonseed contained 0.64 and 1.00% total gossypol (DM) with 41 and 52% of gossypol as the (-) isomer, respectively. Gossypol is a natural defense compound in the plant that protects it against pests and diseases, but can have antinutritional quality effects when consumed by dairy cattle. Total plasma gossypol concentrations increased linearly with increasing proportions (100:0, 67:33, 33:67, and 0:100) of cracked Pima cottonseed in the diet for primiparous (4.4, 6.0, 7.7, and 8.9 microg/ml) and multiparous (4.3, 7.3, 9.7, and 11.4 microg/ml) cows, respectively. While primiparous cows responded similarly to gossypol intake, the response of plasma gossypol intake in multiparous cows differed among cows. This indicates the importance of animal variation when relating plasma gossypol levels with gossypol intake. Milk yield, as well as its components and DM intake, were not affected by increasing dietary inclusion levels of cracked Pima cottonseedup to 8.6% of DM intake for either primiparous or multiparous cows, even though plasma gossypol concentrations increased sharply over this dietary inclusion range. Although the highest dietary inclusion level of Pima cottonseed (i.e., 12.8%) numerically depressed performance of cows of both parities, these differences failed to reach statistical significance in these short-term trials with few cows.     

Physiological effects of whole cottonseed in the diet of lactating dairy cows

With 32 lactating Holstein cows we evaluated physiological effects of gossypol and cyclopropenoid fatty acids in diets containing 18.5% whole cottonseed (dry matter) based on corn, corn silage, and soybean meal. All cows consumed a control diet for the first 2 wk of lactation and then were assigned to either control or whole cottonseed diet for the remainder of their lactation. Milk production, milk fat and protein percentages, and daily dry matter intake were measured. Dry matter intakes were less for cows consuming the whole cottonseed diet, but net energy intake was similar for all diets. Milk fat from cows consuming whole cottonseed contained detectable concentrations of cyclopropene fatty acids. Total lipid in plasma, total serum cholesterol, serum gossypol, and apparent liver gossypol concentrations were greater in cows fed whole cottonseed. Gossypol and cyclopropenoid fatty acids appeared to be absorbed from the gut of cows fed whole cottonseed. Small amounts of gossypol in serum and liver tissue and small amounts of cyclopropene fatty acids in adipose tissue lipids and milk fat indicate a need to elucidate the significance of these physiologically active compounds in the human diet and their biological effects on lactating dairy cows.     

The effects of feeding varying amounts of gossypol from whole cottonseed and cottonseed meal in lactating dairy cows.

Effects of feeding varying amounts of total gossypol from whole cottonseed and cottonseed meal were evaluated in 30 lactating Holstein cows. After a 14-d pretreatment period, cows were assigned for 42 d to one of five treatments: control (diet A); 1040 mg/kg of total gossypol, and 989 mg/kg of free gossypol from whole cottonseed (diet B); 900 mg/kg of total gossypol and 64 mg/kg of free gossypol from cottonseed meal (diet C); 960 mg/kg of total gossypol and 531 mg/kg of free gossypol with equal amounts of total gossypol from whole cottonseed and cottonseed meal (diet D); or 1922 mg/kg of total gossypol and 1050 mg/kg of free gossypol with equal amounts of total gossypol from whole cottonseed and cottonseed meal (diet E). Concentrations of plasma gossypol and its isomers were directly proportional to free gossypol intake. Plasma gossypol concentrations plateaued after 35 d on treatment, and they were highest in cows receiving diet E. At 42 d on treatment, erythrocyte fragility was higher in the cows receiving the diet E, but it did not differ among other treatments. Dry matter intakes were similar for all groups. Cows receiving diet E produced more milk and 3.5% fat-corrected milk, but milk protein content decreased. Feeding diets containing 1900 mg/kg of total gossypol and 1050 mg/kg of free gossypol for 42 d resulted in increased plasma gossypol concentrations and erythrocyte fragility, but no detrimental impact on lactation performance were observed.     

Iron sulfate and feed pelleting to detoxify free gossypol in cottonseed diets for dairy cattle.

Thirty-two lactating cows were fed ad libitum diets with 1) 18.7% soybean meal, 2) diet 1 plus 500 ppm supplemental Fe from FeSO4.H2O, 3) 15% whole cottonseed, or 4) diet 3 plus 500 ppm Fe from FeSO4.H2O. Dry matter intakes were similar except for cows fed diet 2, which was lower. Cows fed whole cottonseed diets ingested 23 g/d of free gossypol per cow. Free gossypol apparently excreted was lower than its intake. Iron excretion was similar to Fe intake. Blood metabolites and productive performance did not differ among the diet groups. No signs of gossypol toxicity were observed. Twelve neonatal Holstein male calves were fed a commercial milk replacer for 4 wk, then were allowed ad libitum access to diets with 1) 27% soybean meal, 2) 50% whole cottonseed, or 3) diet 2 plus 500 ppm Fe from FeSO4.H2O. Dry matter intakes were similar but slightly lower for calves fed diet 3. Daily individual intakes of free gossypol from diets 2 and 3 were 2 g, which was lower than the expected 4 g due to an apparent effect of pelleting. Blood metabolites did not differ among the groups, and calves averaged about .6 kg of daily gain on these diets. A follow-up study showed that pelleting reduced free gossypol by as much as 70% in whole cottonseed and by 48% in cottonseed meal. Pelleting represents a mechanism to decrease the toxicity of gossypol in cottonseed products.     

The effect of roasting nonlinted whole cottonseed on milk production by dairy cows

This study was conducted to examine the effect of roasting nonlinted whole cottonseed on ruminal crude protein (CP) degradability and performance in high-yielding dairy cows. Multiparous Israeli Holstein-Friesian cows (parity average 2.5+/-1.5; n = 132) with 571+/-65 kg of body weight (BW), 107+/-48 d in milk (DIM), and 37+/-5.8 kg of milk yield/d were used in the study. Cows were divided into two dietary treatment groups according to their BW, DIM, and milk production. The two diets were similar in CP, net energy for lactation, and neutral detergent fiber content [17%, 1.74 Mcal/kg, and 30% on a dry matter (DM) basis] and included either 15% (on a DM basis) whole cottonseed or roasted whole cottonseed. Ruminal effective degradability of CP, organic matter (OM), and ether extract (EE) decreased 14, 11, and 10%, respectively, compared to whole cottonseed. Total tract digestibilities of CP and EE were similar for both treatments and averaged 57 and 59%, respectively. However, DM and OM digestibilities were 6 and 5% higher in cows offered roasted whole cottonseed relative to those fed whole cottonseed diet. The inclusion of roasted whole cottonseed in the ration decreased ruminal ammonia and blood urea N concentration by 12% compared with diet with the raw whole cottonseed. Milk production, milk fat content, and production, and milk protein yield increased when roasted, nonlinted whole cottonseed was included in the diet. Milk protein content was similar for both treatments, averaging 2.92%.     

Effect of feeding a corn hybrid selected for leafiness as silage or grain to lactating dairy cattle

A leafy corn hybrid was compared to a grain corn hybrid as silage and high moisture grain to evaluate dry matter intake, milk yield, and milk composition. Sixteen multiparous Holstein cows averaging 97 DIM were used in a feeding trial based on 4 x 4 Latin squares with 21-d periods. Each of four diets contained (dry basis) 8% chopped hay, 42% corn silage, 11% high moisture corn grain, 10% whole, fuzzy cottonseed, and 29% protein concentrate. One diet used leafy corn as both high moisture grain and silage. A second diet contained grain corn hybrid (control) as both high moisture grain and silage. A third diet contained leafy corn for high moisture grain and control corn for silage and the fourth diet used control corn for high moisture grain and leafy corn for silage. Cows fed diets containing leafy silage produced more milk and milk protein and ate more DM than cows fed control silage. The corn hybrid used for high moisture grain did not influence milk yield or composition. Dry matter intake was greater for cows fed the diet containing both leafy high moisture grain and leafy silage than for cows fed both control high moisture grain and control silage, but milk yield and composition were not different. When fed as silage, the leafy corn hybrid used in this experiment supported greater DMI as well as higher milk and protein yields when compared to the grain corn hybrid.     

Effects of amount of whole cottonseed on intake, digestibility, and physiological responses of dairy cows

In Experiment 1, 27 lactating cows were fed complete rations ad libitum of 0, 15, and 30% whole cottonseed to examine the effects on intake, digestibility, blood gases, and blood metabolites. Dry matter intake declined linearly with increased cottonseed, but because of greater energy density, calculated net energy for lactation intake was not depressed significantly. Ether extract, crude protein, and calcium digestibility increased with cottonseed in the diet. Respiration rates declined with dry matter intake and increased cottonseed feeding; some blood gases were influenced by cottonseed feeding but not in a detrimental way. No data among 13 blood metabolites indicated effects of gossypol toxicity with 30% whole cottonseed in the diet. In Experiment 2, 24 dry, nonpregnant Holstein cows were offered complete rations ad libitum of 15, 35, and 55% whole cottonseed to measure responses in intake, respiration rates, and blood metabolites. The highest cottonseed diet significantly depressed intake of both dry matter and calculated net energy for lactation. Maximum dry matter from cottonseed eaten by an individual was 8.4 kg/d (average for 1 wk). Respiration rates declined parallel to intake. No evidence for gossypol toxicity was seen among data of 11 metabolites in blood.     

Feeding glycerol to transition dairy cows: effects on blood metabolites and lactation performance

Glycerol can alleviate the symptoms of ketosis when delivered as an oral drench. The addition of glycerol to the diet would eliminate the need for restraining cows for drenching yet deliver a glucogenic substrate, alleviate the fatty liver-ketosis complex, and improve lactational performance. For this study, 21 multiparous and 9 primiparous Holstein cows blocked by parity and expected calving date were used in a randomized block design to evaluate the effects of feeding glycerol from 14 d prepartum to 21 d in milk (DIM). Treatments (kg/d dry matter basis) were 0.86 of cornstarch (control), 0.43 cornstarch + 0.43 glycerol (LG), or 0.86 glycerol (HG), topdressed and hand-mixed into the upper one-third of the daily ration. All cows were fed a common diet from 22 to 70 DIM. Prepartum dry matter intake (DMI) was greater for cows fed the control diet compared with LG or HG (13.3, 10.8, and 11.3 +/- 0.50 kg/d, respectively). Prepartum plasma glucose, insulin, beta-hydroxybutyrate, nonesterified fatty acids, and ruminal profiles were not affected by treatments. Rumen fluid collected postpartum from cows fed LG and HG had greater total volatile fatty acids, greater molar proportions of propionate, and a decreased ratio of acetate to propionate. Furthermore, concentrations of butyrate tended to be greater in rumens of cows fed LG and HG. Postpartum concentrations of glucose in plasma were greatest for cows fed the control diet relative to LG and HG (66.0 vs. 63.1 and 58.4 mg/dL, respectively) and decreased sharply at 21 DIM, after treatments ended, for cows fed HG (diet x day interaction). Body weight and condition loss, plasma nonesterified fatty acids, and liver lipids during the first 21 DIM were similar among treatments. Postpartum DMI was not affected by treatments; however, a tendency was observed for a diet x day interaction for body weight, as cows fed LG gained more body weight from 21 to 70 DIM relative to cows fed HG. Yield of energy-corrected milk during the first 70 DIM tended to be greatest for cows fed the control diet. The LG and HG diets decreased urea nitrogen concentrations in milk relative to controls. Based upon prepartum DMI and concentrations of glucose and beta-hydroxybutyrate in blood postpartum, feeding glycerol to dairy cows at the levels used in this experiment increased indicators used to gauge the degree of ketosis in dairy cattle.     

Impact of dietary protein amount and rumen undegradability on intake, peripartum liver triglyceride, plasma metabolites, and milk production in transition dairy cattle

Feeding strategies of transition dairy cows contribute to the risk factors associated with metabolic disorders that limit production in the ensuing lactation. To investigate the effects of prepartum dietary crude protein (CP) concentration and amount of rumen-undegradable protein (RUP) on postpartum health and production, 44 multiparous Holstein cows were blocked by expected calving date and assigned to one of four isoenergetic prepartum rations beginning 28 d prior to expected calving date. Prepartum rations were: 12% CP and 26% RUP, 16% CP and 26% RUP, 16% CP and 33% RUP, or 16% CP and 40% RUP on a dry matter basis. All cows were fed the same postpartum diet (18% CP, 40% RUP) from 1 to 56 d in milk (DIM). Prepartum dry matter intake (DMI) was not different among dietary treatments. Mean postpartum intakes (kg/d) were higher through 56 DIM (P<0.05) for cows fed the 12% CP:26% RUP diet prepartum compared with any of the 16% CP diets (21.8 vs. 19.8, 18.6 and 18.6; 12% CP:26% RUP vs. 16% CP:26% RUP, 16% CP:33% RUP and 16% CP:40% RUP). There was a DIM x prepartum diet interaction (P<0.05) with the greatest effect of the 12% CP:26% RUP diet evident during the first 35 DIM. Cows fed the 12% CP:26% diet during the transition period tended to produce more milk (kg/d) (P = 0.08) than did cows fed any of the 16% CP diets (40.8 versus 37.8, 38.7, and 37.4; 12% CP:26% RUP vs. 16% CP:26% RUP, 16% CP:33% RUP, and 16% CP:40% RUP). Additional protein (12 vs. 16% CP) in the prepartum diet tended to decrease milk protein (P = 0.10) and milk fat yield (P = 0.08) but did not alter percent milk fat, percent milk protein, or MUN. Liver triglyceride (TG) expressed as milligrams of TG per microgram of DNA or percentage of dry matter (DM) on d -28, -14, +1, +28, and +56 relative to calving were not significantly different among treatments. Maximal (P<0.05) infiltration of TG in liver was observed on +1 d when expressed as a percentage of DM and on +28 d when expressed as milligrams of TG per microgram of DNA. Plasma glucose, calcium, urea nitrogen, beta-hydroxybutyrate, and nonesterified fatty acids were not different (P<0.05) among treatments. The data indicate carryover effects of prepartum dietary protein on postpartum intake and milk production, pointing to beneficial effects of maintaining dietary protein for dairy cows in late gestation at 12% CP.     

Digestibility in lactating cows of diets containing whole Pima treated with sodium hydroxide versus Akala or Pima cottonseed

This study examines the effect of NaOH treatment on the nutritive value of Pima cottonseed for lactating cows. Treatment of Pima cottonseed with NaOH increased the extent of dry matter (DM) and neutral detergent fiber in vitro digestibility. Three groups of cows were fed 3 similar total mixed rations (TMR) differing only in the type of cottonseed fed, either whole linted Akala, whole unlinted Pima, or whole Pima treated with 4% NaOH (T-Pima). Dry matter and organic matter (OM) intakes of Akala and Pima TMR were similar and tended to be lower compared with cows fed T-Pima. This was reflected in similar intake of crude protein and lipids by cows fed the 3 TMR. Digestibility of DM, OM, and crude protein were similar in cows fed Pima and T-Pima diets, and slightly higher in cows fed the Akala TMR. Lipid digestibility was highest in cows fed Akala TMR, whereas cellulose and NDF digestibility were lowest in Pima TMR. In the 3 TMR, there was a large gap between the high values of "digestibility of intact seeds" and actual in vivo digestion of DM and OM. Similar yields of milk and milk protein were obtained in cows fed the Akala and Pima TMR, whereas higher yields of milk, milk protein, milk fat, and 4% fat-corrected milk were found in the T-Pima cows. Similar efficiency of DM intake for fat-corrected milk production was achieved by cows fed the 3 TMR.     

Effects of forage neutral detergent fiber and yeast culture on performance of cows during early lactation

Sixty Holstein cows were assigned to two treatments at 21 d before calving and were group-fed a prepartum diet with or without yeast culture. After parturition, cows were individually fed one of five treatments for 140 d: 1) 21% forage neutral detergent fiber (NDF) without yeast culture, 2) 21% forage NDF with yeast culture, 3) 17% forage NDF without yeast culture, 4) 17% forage NDF with yeast culture, and 5) 25% forage NDF with yeast culture for 30 d and then switched to diet 4 for 110 d. Cows fed yeast culture prepartum were also fed yeast culture postpartum (60 g/d). A quadratic increase to 25, 21, and 17% forage NDF occurred during the first 30 d in milk (DIM) for dry matter intake, milk yield, and milk protein yield. No differences were observed for yeast culture or interaction of yeast culture and forage NDF for the first 30 DIM. Feeding 17 versus 21% forage NDF increased milk protein percentage and tended to increase dry matter intake as a percentage of body weight from 31 to 140 DIM. During this period, yeast culture tended to increase milk fat percentage and appeared to have positive effects on dry matter intake, milk yield, and milk fat yield when supplemented to diets with 21% forage NDF but not with 17% forage NDF. Feeding 17% forage NDF may be too low for the first 30 DIM but may improve animal performance after 30 DIM compared to 21% forage NDF.     

Effect of coating whole cottonseed on performance of lactating dairy cows.

Thirty-six lactating Jersey cows were used in a randomized block design to determine the effect of coating whole fuzzy cottonseed to improve handling characteristics on intake, milk yield, apparent digestibility of nutrients, and blood gossypol concentrations. Treatments included whole cottonseed at 15% of dietary dry matter either as whole cottonseed, whole cottonseed coated with 5% gelatinized corn starch, or whole cottonseed coated with 5% corn starch plus 10% maltodextrin sugar. Dry matter intake, milk yield, percentage of milk protein and lactose, and yield of milk components were not different among treatments; however, the percentage of milk fat was depressed when maltodextrin sugar was included in the coating. When in vitro fermentations of mixed ruminal microorganism were conducted, final pH was lower and concentrations of total fatty acids, propionate, and L-lactate were higher for whole cottonseed coated with starch and sugar compared with uncoated cottonseed. Nutrient intake was similar among treatments, but the apparent digestibility of acid and neutral detergent fiber was reduced when coated cottonseed were fed. Total plasma gossypol concentration was higher for the cottonseed coated with starch compared with cottonseed coated with starch and sugar, but the difference was not of biological significance. Results of this study indicate that coating whole cottonseed with starch does not alter its palatability or nutrient value for supporting milk yield, but a reduction in fiber digestibility was observed. Inclusion of 10% maltodextrin sugar in the coating altered ruminal fermentation and resulted in a depressed percentage of milk fat.     

Postpartum supplementation of fermented ammoniated condensed whey improved feed efficiency and plasma metabolite profile

Postpartum dietary supplementation of gluconeogenic precursors may improve the plasma metabolite profile of dairy cows, reducing metabolic disorders and improving lactation performance. The objective of this trial was to examine the effects of supplementation with fermented ammoniated condensed whey (FACW) postpartum on lactation performance and on profile of plasma metabolites and hormones in transition dairy cows. Individually fed multiparous Holstein cows were blocked by calving date and randomly assigned to control (2.9% dry matter of diet as soybean meal; n = 20) or FACW (2.9% dry matter of diet as liquid GlucoBoost, Fermented Nutrition, Luxemburg, WI; n = 19) dietary treatments. Treatments were offered from 1 to 45 d in milk (DIM). Cows were milked twice a day. Dry matter intake and milk yield were recorded daily and averaged weekly. Individual milk samples from 2 consecutive milkings were obtained once a week for component analysis. Rumen fluid was collected (n = 3 cows/treatment) at 4 time points per day at 7 and 21 DIM. Blood samples were collected within 1 h before feeding time for metabolite analysis and hyperketonemia diagnosis. Supplementation of FACW improved feed efficiency relative to control; this effect may be partially explained by a marginally significant reduction in dry matter intake from wk 3 to 7 for FACW-supplemented cows with no detected FACW-driven changes in milk yield, milk protein yield, and milk energy output compared with control. Also, there was no evidence for differences in intake of net energy for lactation, efficiency of energy use, energy balance, or body weight or body condition score change from calving to 45 DIM between treatments. Supplementation of FACW shifted rumen measures toward greater molar proportions of propionate and butyrate, and lesser molar proportions of acetate and valerate. Cows supplemented with FACW had greater plasma glucose concentrations in the period from 3 to 7 DIM and greater plasma insulin concentrations compared with control. Plasma nonesterified fatty acid and β-hydroxybutyrate concentrations were decreased in cows supplemented with FACW compared with control cows in the period from 3 to 7 DIM. These findings indicate that FACW may have improved the plasma metabolite profile immediately postpartum in dairy cows. Additionally, supplementation of FACW resulted in improved feed efficiency as accessed by measures of milk output relative to feed intake.     

Effect of varying prepartum dietary cation-anion difference and calcium concentration on postpartum mineral and metabolite status and milk production of multiparous cows

Eighty-two multiparous Holstein cows were enrolled 28 d before expected calving and assigned to 1 of 4 dietary treatments in a randomized block design experiment with a 2 × 2 factorial arrangement of treatments to determine the effect of feeding a neutral or acidogenic diet varying in Ca concentration on prepartum and postpartum intake, blood mineral and metabolite concentrations, and postpartum milk production. Prepartum diets were formulated to provide a dietary cation-anion difference (DCAD) of ?21 (negative, NEG) or ?2 (neutral, NEU) mEq/100 g of dry matter with either 1.3% or 1.8% Ca. After calving, cows remained on trial through 63 d in milk (DIM) and were fed a common lactation diet. Urine pH was lower for NEG compared with NEU and tended to be lower for 1.8% Ca compared with 1.3% Ca. Fractional excretion of Ca and Mg in urine was greater for NEG than for NEU. Prepartum plasma bicarbonate was lower and P was higher for NEG compared with NEU. Prepartum plasma P and blood urea nitrogen to creatinine ratio was higher for 1.3% compared with 1.8% Ca. Postpartum, concentrations of plasma total protein, albumin, blood urea nitrogen, Mg, and ionized Mg (iMg) were higher and Na was lower for NEU compared with NEG. An interaction of DCAD and Ca was observed for plasma creatinine, which was highest for cows fed NEU and 1.3% Ca compared with all other treatments. Interactions of DCAD and DIM were observed for plasma bicarbonate and iMg. Bicarbonate was higher at 3 DIM and lower at 14 DIM for NEU compared with NEG. Concentrations of iMg were higher at 1, 2, and 14 DIM for NEU compared with NEG. Interactions of Ca and DIM were observed for plasma Ca, Cl, and anion gap. Compared with cows fed 1.5% Ca, those fed 1.3% Ca had lower Ca and anion gap and higher Cl at 1 DIM and lower Cl and higher anion gap at 14 DIM. No differences were observed in body weight or body condition score due to DCAD or Ca. Prepartum dry matter intake (DMI) was lower for NEG compared with NEU and lower for 1.8% compared with 1.3% Ca. Postpartum DMI was not different among treatments. An interaction was observed for DCAD and DIM due to higher milk yield after 45 DIM for NEG compared with NEU. No differences were observed in milk component percentage or yield among treatments. There was an interaction of DIM and Ca for milk urea concentrations, which were higher at 5 wk and lower at 6 wk for 1.3% Ca compared with 1.8% Ca. These results suggest that feeding NEG prepartum alters plasma and urine mineral concentrations compared with feeding NEU and supports increased milk yield after 45 DIM. Feeding 1.8% Ca prepartum only improved plasma Ca at 1 DIM. Feeding either NEG or 1.8% Ca reduced DMI prepartum compared with NEU or 1.3% Ca.     

Effect of fat source differing in fatty acid profile on metabolic parameters, fertilization, and embryo quality in high-producing dairy cows

The objectives were to evaluate the effects of source of fatty acids (FA) on embryo quality of dairy cows. A total of 154 Holstein cows were assigned randomly to 1 of 2 sources of FA supplemented at 2% of the dietary dry matter as calcium salts of either palm oil (PO) or linoleic and trans-octadecenoic acids (LTFA) from 25 d prepartum to 80 d in milk (DIM). Cows were presynchronized beginning at 30 ± 3 DIM and then subjected to the Ovsynch protocol beginning on d 39 ± 3 postpartum. Timed artificial insemination was performed 12 h after the final GnRH of the Ovsynch protocol with semen from a single sire of proven fertility. The uteri of cows were nonsurgically flushed at 5 d after artificial insemination for collection of embryos-oocytes. Ovaries were examined by ultrasonography throughout the synchronization protocol. Blood was sampled and plasma was analyzed for concentrations of metabolites and hormones. The body condition score and yields of milk and milk components were measured throughout the first 90 DIM. Treatment did not affect concentrations of nonesterified FA, β-hydroxybutyrate, glucose, and progesterone in plasma. Body condition was similar between treatments. Milk production was similar between treatments, but concentrations of fat in milk and yields of fat and 3.5% fat-corrected milk decreased in cows fed LTFA, whereas concentration of true protein increased. Source of dietary FA did not influence ovulatory responses, diameter of the ovulatory follicle, and diameter of the corpus luteum during synchronization. Embryo-oocyte recovery relative to the number of corpora lutea did not differ between treatments. Fertilization tended to increase in cows fed LTFA compared with cows fed PO. Feeding LTFA improved the proportion of excellent-, good-, and fair-quality embryos, and embryos from cows fed LTFA had a greater number of blastomeres than embryos from cows fed PO. Feeding a more unsaturated source of FA improved fertilization and embryo development in lactating dairy cows, despite similar indicators of metabolic status.