Effect of prepartum dietary protein level on performance of primigravid and multiparous Holstein dairy cows

This study compared the effects of two levels of crude protein (CP) fed during late gestation on the performance, blood metabolites, and ovarian activity of Holstein cows. One-hundred and six cows (42 primigravid and 64 multiparous) 32 d before calving were divided into two groups and fed diets containing moderate (12.7% CP, 36% rumen undegradable protein, (RUP) or high (14.7% CP, 40% RUP) protein. Higher prepartum CP diet increased milk production during the first 120 d in milk (DIM), but most of that effect was detected for the primigravid cows. Primigravid cows fed the prepartum diet higher in protein produced 2.0 kg/d more milk and 3.1 kg/d more 3.5% fat-corrected milk (FCM) during early lactation. Yields of milk fat and protein in early lactation were also increased by the high prepartum CP diet fed to primigravid cows. During the complete lactation, the response to prepartum dietary protein differed between primigravid and multiparous cows. Yields of milk, 3.5% FCM, and milk fat and protein were not affected by the prepartum diet for primigravid cows, but decreased for multiparous cows fed the high protein diet. However, primigravid cows fed the high prepartum protein diet had a higher 305-d mature equivalent milk yield. Colostrum composition, blood metabolites, ovarian activity, and disease incidence were not influenced by prepartum protein. Data from this study suggest that the current prepartum protein recommendation seems to be adequate for multiparous cows, but late-gestation primigravid cows might benefit from diets with a CP content above 12.7%.     

Peripartum performance and metabolism of dairy cows in response to prepartum energy and protein intake

Twenty-six multiparous Holstein cows were used to examine the effects of prepartum energy and protein intake on periparturient metabolism and lactation performance. Two levels of energy, 1.65 Mcal/kg of net energy for lactation (NEL) and 1.30 Mcal/kg of NEL, and two levels of protein, 17.0% CP and 12.5% CP, were tested according to a factorial arrangement in a randomized block design. Dietary treatments were fed ad libitum from 21 d before expected calving date to the day of calving. After calving, all cows were fed the same diet. Increased nutrient density did not affect prepartum feed intake, but postpartum intake was higher for cows fed the high-energy diets. Treatment had no effect on cow body weight and body condition score, however, cows fed the high-energy diets were in greater energy balance throughout the study. Milk and milk component yields were unaffected by treatment. Cows fed the high-energy diets had lower plasma nonesterified fatty acid concentrations than cows fed the low energy diets (354.3 vs. 439.9 mumol/L). Hepatic triglyceride concentrations were lower for cows on the high-energy diets than for those on the low-energy diets. Liver glycogen was unaffected by treatment. Acetyl-CoA carboxylase and fatty acid synthase abundance was significantly lower at calving than pretreatment, and higher for cows on the high-energy diets relative to those on the low-energy diets. The activity of acetyl-CoA carboxylase and lipoprotein lipase was greatly decreased with the onset of lactation. Increased protein intake prepartum resulted in elevated plasma beta-hydroxybutyrate concentrations postpartum. Prepartum plasma urea nitrogen was increased and 3-methylhistidine decreased by the high protein treatments. Overall, increased energy density of prepartum diets had beneficial effects on feed intake and lipid metabolism but did not improve lactation performance. Increasing the protein content of the prepartum diet did not appear to confer any advantages to cow productivity.     

Effect of energy and protein density of prepartum diets on fat and protein metabolism of dairy cattle in the periparturient period.

To determine if increased nutrient density in prepartum diets improves nutrient balance of peripartum cows, we blocked 40 Holstein cows and 40 heifers by expected date of parturition and assigned them randomly within blocks to one of four treatment diets varying in density of net energy for lactation (NEL) and crude protein (CP). Diets were 1.30 Mcal of NEL/kg and 12.2% CP, 1.49 Mcal of NEL/kg and 14.2% CP, 1.61 Mcal of NEL/kg and 15.9% CP, and 1.48 Mcal of NEL/kg and 16.2% CP. These diets were fed ad libitum from 25 d prepartum until parturition, and all cows were fed the same diet after calving. Increased nutrient-density of prepartum diets did not decrease feed intake. Compared to animals fed the lowest density, those fed the highest density consumed more NEL (20 vs. 14 Mcal/d) and gained more body condition, backfat, and body weight. They also had less nonesterified fatty acids in plasma (176 vs. 233 microM) and more insulin-like growth factor-I in plasma (472 vs. 390 ng/ml) during the last 2 wk prepartum and less triglyceride in liver at parturition (0.9 vs. 1.5%, wet tissue basis). Quadratic effects of energy density were not observed, and the addition of protein in the medium energy diet had no effect. Prepartum diets did not alter any variables during lactation. In conclusion, increasing the energy and protein density up to 1.6 Mcal of NEL/kg and 16% CP in diets during the last month before parturition improves nutrient balance of cattle prepartum and decreases hepatic lipid content at parturition.     

Effects of prepartum metabolizable protein supply and management strategy on lactational performance and blood biomarkers in dairy cows during early lactation

Our objective was to investigate the effects of prepartum metabolizable protein (MP) supply and management strategy on milk production and blood biomarkers in early lactation dairy cows. Ninety-six multigravida Holstein cows were used in a randomized complete block design study, blocked by calving date, and then assigned randomly to 1 of 3 treatments within block. Cows on the first treatment were fed a far-off lower MP diet [MP = 83 g/kg of dry matter (DM)] between ?55 and ?22 d before expected calving and then a close-up lower MP diet (MP = 83 g/kg of DM) until parturition (LPLP). Cows on the second treatment were fed the far-off lower MP diet between ?55 to ?22 d before expected parturition and then a prepartum higher MP diet (MP = 107 g/kg of DM) until calving (LPHP). Cows on the third treatment had a shortened 43-d dry period and were fed the prepartum higher MP diet from dry-off to parturition (SDHP). After calving, cows received the same fresh diet from d 0 to 14 and the same high diet from d 15 to 84. Data were analyzed separately for wk ?6 to ?1 and wk 1 to 12, relative to parturition. Dry matter intake from wk ?6 to ?1 was not different between LPHP and LPLP and increased for SDHP compared with LPLP. In contrast, dry matter intake for wk 1 to 12 postpartum did not change for LPHP versus LPLP or for SDHP versus LPLP. Compared with LPLP cows, LPHP cows had lower energy-corrected milk yield and tended to have decreased milk fat yield during wk 1 to 12 of lactation. Conversely, yields of energy-corrected milk and milk fat and protein were similar for SDHP compared with LPLP. Plasma urea N during wk ?3 to ?1 increased for LPHP versus LPLP and for SDHP versus LPLP; however, no differences in plasma urea N were observed postpartum. Elevated prepartum MP supply did not modify circulating total fatty acids, β-hydroxybutyrate, total protein, albumin, or aspartate aminotransferase during the prepartum and postpartum periods. Increased MP supply prepartum combined with a shorter dry period (SDHP vs. LPLP) tended to increase whole-blood β-hydroxybutyrate postpartum; however, other blood metabolites were not affected. Taken together, under the conditions of this study, elevated MP supply in close-up diets reduced milk production without affecting blood metabolites in multiparous dairy cows during early lactation. A combination of a shorter dry period and increased prepartum MP supply (i.e., SDHP vs. LPLP) improved prepartum dry matter intake without modifying energy-corrected milk yield and blood biomarkers in early lactation cows.     

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.     

Production,metabolism, and follicular dynamics in multiparous dairy cows fed diets providing different amounts of metabolizable protein prepartum and postpartum

Our objectives were (1) to determine whether increasing metabolizable protein (MP) supply above requirements in late-gestation cows would benefit health, milk production, and reproduction; (2) to determine whether an increased supply of MP postpartum affects production; and (3) to determine whether supply of MP prepartum interacts with MP supply postpartum. Pregnant nonlactating cows (n = 60) blocked by expected parturition date were assigned to 1 of 3 prepartum diets from 21 d prepartum to parturition: 12% crude protein (CP) soybean meal (SBM) supplement (LSB); 15% CP SBM supplement (HSB); and 15% CP SBM plus animal-marine protein supplement (HMP). Diets were formulated to supply an estimated 924, 988, and 1,111 g/d of MP, respectively, at 11.5 kg of dry matter intake (DMI). After parturition, cows received diets containing 18% CP, either from SBM (SB) or SBM plus animal-marine protein (AMP) supplements, that provided 2,056 (SB) or 2,293 g/d (AMP) of MP at 21 kg of DMI; thus, treatments were in a 3 × 2 factorial arrangement. Milk production and DMI were recorded for 63 d postpartum. Prepartum DMI was lower at wk ?3 for cows fed LSB compared with those fed HSB or HMP. Postpartum DMI did not differ significantly between cows fed SB and those fed AMP (20.8 vs. 19.6 kg/d). Milk production did not differ due to prepartum diets or postpartum diets. Milk fat and protein percentages were not affected by prepartum or postpartum diets. Cows fed AMP postpartum tended to produce more milk fat, but 4% fat-corrected milk (FCM) did not differ from SB-supplemented cows (33.6 kg/d vs. 32.2 kg/d). Gross feed efficiency (FCM/DMI) was greater for cows fed AMP postpartum (1.82 vs. 1.68). Prepartum concentrations of urea N in plasma were lower for LSB than for HSB and HMP, and HSB was greater than HMP. Postpartum concentrations of nonesterified fatty acids and β-hydroxybutyrate were greater for cows fed AMP postpartum than for those fed SB. Postpartum urea N was higher for SB than for AMP (14.4 vs. 12.5 mg/dL). Concentration of total protein in plasma was greater postpartum for cows fed HSB or HMP prepartum than for those fed LSB, and was greater postpartum for cows fed AMP than for those fed SB. Hepatic concentrations of total lipids and triglyceride did not differ among treatments. Hepatic glycogen was greater postpartum for cows fed SB postpartum. Feeding HSB or HMP increased the number of follicles 6 to 9 mm in diameter compared with LSB. The size of the largest follicle was increased by HMP compared with HSB. In conclusion, increasing the amount of MP fed to cows during the last 21 d prepartum did not affect milk production or BCS but increased plasma total protein concentration. Follicular dynamics were improved by increasing the amount of MP prepartum. Feeding HMP prepartum improved follicular dynamics prepartum and increased milk fat yield in wk 1. Feeding AMP postpartum increased efficiency of FCM production and plasma total protein. We found few interactions between prepartum and postpartum MP supply.     

Prepartum plane of energy intake affects serum biomarkers for inflammation and liver function during the periparturient period

Serum collected from multiparous Holsteins (n = 73) in a previous experiment was used to determine the effect of prepartum plane of energy intake on metabolites related to inflammation and liver function in periparturient cows. Prepartum diets were in a 3 × 2 factorial arrangement over the far-off (d ?65 to ?26 before expected parturition) and close-up (d ?25 relative to parturition until parturition) dry periods. During the far-off period, 2 diets were fed for ad libitum intake (ADLIB) to supply either 100% (100E) or 150% (150E) of National Research Council recommendations for net energy for lactation for mature cows in late gestation. For the third dietary far-off treatment, the 150E diet was fed at restricted intake (REST) to supply 80% (80E) of recommendations. During the close-up period, cows were fed a diet either at ADLIB or REST to supply 150% of net energy for lactation or 80% of net energy for lactation requirements, respectively. Beginning at parturition, all cows were fed a lactation diet through 56 d in milk. Cows fed 150E tended to accumulate more liver lipid postpartum; peak lipid accumulation occurred in all groups on d 14 postpartum. Cows fed 150E tended to have lower serum Ca on d 1 after calving, and cows fed REST had higher Ca than those fed ADLIB. Cows fed 150E tended to have higher serum bilirubin prepartum compared with other groups. Feeding REST in the close-up period resulted in higher bilirubin prepartum compared with ADLIB; bilirubin was positively associated (r = 0.34) with lipid accumulation postpartum. Feeding REST resulted in lower serum vitamin A (an indirect measure of retinol binding protein) prepartum compared with ADLIB, especially when coupled with 80E. Postpartum paraoxonase was negatively associated (r = ?0.27) and ceruloplasmin was positively associated (r = 0.21) with liver lipid accumulation postpartum. A larger spike in haptoglobin was observed on d 1 and 7 postpartum for cows fed 100E and 150E during the far-off period followed by REST during the close-up period. The ratio of albumin to globulin in serum was higher for cows fed 100E than for those fed 150E both prepartum and postpartum. Liver activity index indicated poorer liver function for cows fed 150E in the far-off period regardless of close-up diet. Negative liver function was also noted for cows fed 80E and REST. Cows in the 100E group fed ADLIB or REST had positive liver activity index postpartum. Avoidance of gross overconsumption of energy prepartum, particularly during the far-off period, appears best to reduce systemic inflammatory signals and improve liver function.     

Interactions of protein levels fed to Holstein cows pre- and postpartum on productive and metabolic responses

The objective of this study was to examine the interaction between levels of dietary crude protein (CP) pre- and postpartum on feed intake, performance, and metabolic status of dairy cows with a 14-d close-up experimental period. Forty multiparous Holstein cows were blocked by expected calving date and previous lactation milk yield at ?14 d relative to expected calving and randomly allocated to receive either a 12.5% CP diet with 3.3% rumen undegraded protein (RUP; 12pre) or a 15.2% CP diet with 5% RUP (15pre) based on dry matter (DM). From d 1 to 21 postpartum, cows within each prepartum group were randomly assigned to receive either a 16.1% CP diet with 4.9% RUP (16post) or a 18.6% CP diet with 6.8% RUP (19post) based on DM. The experiment was conducted as a split-plot design, with CP prepartum being the whole-plot factor and CP postpartum as the subplot factor. Diets were similar in net energy for lactation, and CP levels were increased by replacing grain with a combination of corn gluten meal and fish meal. In prepartum, cows fed the 15pre diet tended to consume more DM than cows fed the 12pre diet (9.65 vs. 9.30 kg/d). Except for blood urea nitrogen (BUN) concentration, no other blood metabolite in prepartum was affected by diets. The interaction between pre- and postpartum CP levels showed that elevating dietary CP from 16post to 19post increased DM intake (15.20 vs. 17.67 kg/d) and milk yield (35.16 vs. 40.26 kg/d) in 12pre cows but not in 15pre cows. Milk fat, protein, and lactose contents were not affected by the interaction between pre- and postpartum CP levels. Feeding 19post compared with 16post increased milk protein (1.28 vs. 1.08 kg/d) and lactose (1.86 vs. 1.61 kg/d) yields in 12pre cows, whereas this effect was not observed in 15pre cows. Milk urea nitrogen was elevated when dietary CP increased from 16post to 19post in 15pre cows (12.98 vs. 14.84 mg/dL) but not in 12pre cows. The concentrations of BUN were greater in 19post cows than in 16post cows for both 12pre (16.31 vs. 13.81 mg/dL) and 15pre (18.44 vs. 14.71 mg/dL) cows. The 19post cows had lower serum fatty acids than 16post cows (0.65 vs. 0.96 mmol/L) in 12pre but not in 15pre. However, a reduction in serum aspartate aminotransferase (AST) concentration was observed in 19post cows compared with 16post cows (68.30 vs. 98.24 U/L) when cows were fed 12pre. For cows fed 15pre, those fed 19post had higher serum AST levels than those fed 16post (86.61 vs. 67.74 U/L) during 21 d of lactation. Body weight and body condition score changes were not affected by interactive effects between pre- and postpartum CP levels, but 19post cows tended (?0.30 vs. ?0.45) to have smaller body condition score losses than 16post cows when fed the 12pre diet. Overall, increasing dietary CP postpartum from 16 to 19% DM improved performance and metabolic status of cows fed 12% CP prepartum. The lack of responses to increased dietary CP postpartum in cows fed 15% CP prepartum suggests that dietary CP postpartum could decrease to 16% DM when cows are fed higher dietary CP prepartum.     

Effects of pre- and postpartum dietary starch content on productivity,plasma energy metabolites,and serum inflammation indicators of dairy cows

The objective of this study was to evaluate the effects of the starch content of pre- and postpartum diets on productivity, plasma energy metabolites, and serum markers of inflammation of dairy cows during the calving transition period. Eighty-eight primiparous and multiparous cows were randomly assigned to pre- and postpartum dietary treatments balanced for parity and pretrial body condition score at d 28 ± 3 before expected calving date. Cows were fed either a control [Control; 14.0% starch, dry matter (DM) basis] or high-starch (High; 26.1% starch, DM basis) prepartum diet commencing 28 ± 3 d before expected calving date. Following calving, cows were fed either a high-fiber (HF; 33.8% neutral detergent fiber, 25.1% starch, DM basis) or high-starch (HS; 27.2% neutral detergent fiber, 32.8% starch, DM basis) postpartum diet for the first 20 ± 2 d following calving. Cows fed the High prepartum diet had greater DM intake (12.4 vs. 10.2 kg/d), plasma concentrations of insulin (1.72 vs. 14.2 ng/mL), glucose (68.1 vs. 65.0 mg/dL), and glucagon-like peptide-2 (0.41 vs. 0.32 ng/mL) before parturition, but increased plasma free fatty acid concentration (452 vs. 363 µEq/L) and milk fat yield (1.64 vs. 1.48 kg/d) after parturition. Cows fed the HS postpartum diet had lower plasma free fatty acid (372 vs. 442 µEq/L) and serum haptoglobin (0.46 vs. 0.70 mg/mL) concentrations over a 3-wk period after calving. In addition, there was a tendency for interaction between prepartum and postpartum diets for milk yield, where feeding the HS postpartum diet increased milk yield compared with the HF diet for cows fed the Control prepartum diet (40.8 vs. 37.9 kg/d) but not for cows fed the High prepartum diet. These results suggest that management efforts to minimize the change in diet fermentability during the calving transition by feeding the High prepartum diet, the HF postpartum diet, or both did not increase productivity of dairy cows but increased fat mobilization after calving. Our findings also suggest that feeding high-starch postpartum diets can decrease fat mobilization and serum indicators of systemic inflammation and increase milk production even with the transition from a low-starch prepartum diet.     

Performance of dairy cows as affected by prepartum dietary carbohydrate source and supplementation with chromium throughout the transition period

Holstein cows (n = 72) entering second or later lactation were used to determine whether productive performance and dry matter intake (DMI) are affected by carbohydrate source in the prepartum diet and chromium-L-methionine (Cr-Met) supplementation throughout the periparturient period. Cows were fed either a TMR with the concentrate portion based on starch-based cereals [high nonfiber carbohydrate (NFC); 1.59 Mcal/kg of net energy for lactation (NEL), 14.4% crude protein (CP), 40.3% NFC] or a TMR with the concentrate portion based on nonforage fiber sources (low NFC; 1.54 Mcal/kg NEL, 14.5% CP, 33.6% NFC) from 21 d before expected parturition until parturition. After parturition all cows were fed a lactation TMR (1.74 Mcal/kg NEL, 16.5% CP, 40.0% NFC). The Cr-Met was supplemented once daily via gelatin capsule at dosages of 0, 0.03, or 0.06 mg of Cr/kg of metabolic body weight. Thus, treatments were in a 2 (carbohydrate source) x 3 (Cr-Met) factorial arrangement. Neither prepartum nor postpartum DMI was affected by prepartum dietary carbohydrate source. Administering increasing amounts of Cr-Met linearly increased milk yield and, subsequently, postpartum DMI. Prepartum carbohydrate source did not affect postpartum milk yield; however, cows fed the low NFC diet tended to yield milk with a lower content of total solids. These data indicate that prepartum carbohydrate source has little influence on performance during the immediate peripartal period, and that increases in milk yield for cows supplemented with Cr-Met are independent of prepartum dietary carbohydrate source.     

Metabolic and yield responses of multiparous Holstein cows to prepartum rumen-undegradable protein

The effects of concentration of rumen-undegradable protein (RUP) in prepartum diets on performance and metabolic measures were determined. Pregnant, nonlactating cows were assigned to one of three dietary treatments that differed in concentrations of crude protein and RUP. The crude protein and RUP percentages (dry matter basis) in the diets were 11.7 and 3.1%, 15.6 and 6.8%, and 20.6 and 10.6%, which were identified as low, medium, and high protein diets, respectively. Dietary treatments were initiated 6 wk prior to expected calving date and were fed until parturition. All cows were fed similar postpartum diets through wk 10 of lactation. Prepartum intakes of dry matter and rumen-degradable protein were similar among treatments. Yields of milk, protein, and fat were not affected by prepartum RUP. Concentrations of plasma urea N in cows fed the medium and high protein diets were elevated during the prepartum period even though intakes of rumen-degradable protein were similar for cows on all treatments. Cows fed the medium and high protein diets had greater prepartum concentrations of Val, Ile, and Leu but not other essential amino acids in plasma. Dietary treatments did not affect prepartum or postpartum contents of triglycerides in liver or plasma nonesterified fatty acid concentrations. Thus, supplemental RUP fed to cows for 6 wk prepartum affected protein metabolism but not measures of energy metabolism.     

Limit-feeding a high-energy diet to meet energy requirements in the dry period alters plasma metabolite concentrations but does not affect intake or milk production in early lactation

Limit-feeding dry cows a high-energy diet may enable adequate energy intake to be sustained as parturition approaches, thus reducing the extent of negative energy balance after parturition. Our objective was to evaluate the effect of dry period feeding strategy on plasma concentrations of hormones and metabolites that reflect energy status. Multiparous Holstein cows (n = 18) were dried off 45 d before expected parturition, paired by expected calving date, parity, and previous lactation milk yield, and randomly assigned to 1 of 2 dry-period diets formulated to meet nutrient requirements at ad libitum or limited intakes. All cows were fed the same diet for ad libitum intake after parturition. Prepartum dry matter intake (DMI) for limit-fed cows was 9.4 kg/d vs. 13.7 kg/d for cows fed ad libitum. During the dry period, limit-fed cows consumed enough feed to meet calculated energy requirements, and ad libitum-fed cows were in positive calculated net energy for lactation (NE_L) balance (0.02 vs. 6.37 Mcal/d, respectively). After parturition, milk yield, milk protein concentration, DMI, body condition score, and body weight were not affected by the prepartum treatments. Cows limit fed during the dry period had a less-negative calculated energy balance during wk 1 postpartum. Milk fat concentration and yield were greater for the ad libitum treatment during wk 1 but were lower in wk 2 and 3 postpartum. Plasma insulin and glucose concentrations decreased after calving. Plasma insulin concentration was greater in ad libitum-fed cows on d −2 relative to calving, but did not differ by dietary treatment at other times. Plasma glucose concentrations were lower before and after parturition for cows limit-fed during the dry period. Plasma nonesterified fatty acid concentrations peaked after parturition on d 1 and 4 for the limit-fed and ad libitum treatments, respectively, and were greater for limit-fed cows on d −18, −9, −5, and −2. Plasma tumor necrosis factor-α concentrations did not differ by treatment in either the pre- or postpartum period, but tended to decrease after parturition. Apart from a reduction in body energy loss in the first week after calving, limit feeding a higher NE_L diet during the dry period had little effect on intake and milk production during the first month of lactation.     

Effects of prepartum diets varying in dietary energy density and monensin on early-lactation performance in dairy cows

Our objectives were to evaluate the effects of prepartum monensin supplementation and dry-period nutritional strategy on the postpartum productive performance of cows fed monensin during lactation. A total of 102 Holstein cows were enrolled in the experiment (32 primiparous and 70 multiparous). The study was a completely randomized design, with randomization restricted to balance for parity, body condition score, and expected calving date. A 2 × 2 factorial arrangement of prepartum treatments was used; the variables of interest were prepartum feeding strategy [controlled-energy diet throughout the dry period (CE) vs. controlled-energy diet from dry-off to 22 d before expected parturition, followed by a moderate-energy close-up diet from d 21 before expected parturition through parturition (CU)] and prepartum monensin supplementation [0 g/t (control, CON) or 24.2 g/t (MON); Rumensin; Elanco Animal Health, Greenfield, IN]. Lactation diets before and after the dry period contained monensin at 15.4 g/t. During the close-up period, cows fed CU had greater DM and NE_L intakes than cows fed CE. Calf BW at birth tended to be greater for cows fed CU than for those fed CE but was not affected by MON supplementation. Diet did not affect calving difficulty score, but cows supplemented with MON had an increased calving difficulty score. We found a tendency for a MON × parity interaction for colostral IgG concentration, such that multiparous MON cows tended to have lower IgG concentration than CON cows, but colostral IgG concentration for primiparous MON and CON cows did not differ. Postpartum milk yield did not differ between diets but tended to be greater for cows supplemented with MON. Milk fat and lactose content were greater for cows fed CU than for those fed CE, and lactose content and yield were increased for cows supplemented with MON. Solids-corrected and fat-corrected milk yields were increased by MON supplementation, but were not affected by diet. Overall means for postpartum DMI did not differ by diet or MON supplementation. The CU diet decreased the concentration of nonesterified fatty acids during the close-up period but increased it postpartum. Neither diet nor monensin affected β-hydroxybutyrate or liver composition. Overall, postpartum productive performance differed little between prepartum dietary strategies, but cows fed MON had greater energy-corrected milk production. In herds fed monensin during lactation, monensin should also be fed during the dry period.     

Determination of when during the lactation cycle to start feeding a cellulase and xylanase enzyme mixture to dairy cows

We used 48 multiparous Holstein cows to compare the response of dairy cows to a direct-fed mixture of cellulase and xylanase enzymes (1.25 L of enzyme concentrate/tonne of forage dry matter) applied to the forage portion (60% corn silage and 40% alfalfa hay) of a total mixed diet starting either in the close-up dry period, at calving, or at peak milk production. Cows were blocked by calving date and, within blocks, randomly assigned to one of four treatment diets. Treatments were: 1) an untreated control diet, 2) enzyme addition to the forage from wk 6 to 18 postpartum, 3) enzyme addition to the forage from calving to wk 18 postpartum, and 4) enzyme addition to the forage from wk 4 prepartum to wk 18 postpartum. Total mixed diets were 65% forage and 35% concentrate prepartum, and 50:50 forage:concentrate postpartum. The production of milk, solids-corrected milk, fat-corrected milk, and energy-corrected milk was higher for cows fed enzyme-treated diets than for cows fed control diet. Production was similar for cows in all enzyme-treated groups, although numerically highest for cows that started receiving enzyme-treated forages right after parturition and numerically lowest when started prepartum. Concentrations of fat, protein, and lactose in milk were similar for all treatments; yields of protein and fat were higher for cows fed enzyme-treated forages. Dry matter intake and body condition scores, both prepartum and postpartum, were similar for all diets. Eating rates, as determined in two 24-h studies, were similar for control and enzyme-treated diets. The feeding of enzyme-treated forages increased milk production. While the effect of when the feeding of enzyme-treated forages started was not statistically significant, we recommend starting soon after parturition because of the greatest total milk production when starting at that time.     

Effect of peripartum energy concentration on production performance of Holstein cows

Ninety multiparous Holstein cows were used to measure the effect of energy during the prepartum and postpartum periods. During the prepartum period (63 d) half of the cows were fed grass silage ad libitum and a concentrate (16% protein) was offered daily at .25% of BW. The other half of the cows were offered the silage ad libitum but concentrate at .75% of BW. At calving each of the two prepartum groups was subdivided into three subgroups and fed corn silage for ad libitum consumption, 4.5 kg of hay/d and concentrate (20% protein) at .25 or .75% of BW daily, or ad libitum. After 112 d of lactation, all cows were switched to a diet consisting of corn silage fed ad libitum and 1 kg of concentrate (20% protein)/4 kg of milk. Roughage intake was reduced with an increase of concentrate consumption. Body measurements, calf weight, milk yield, feed efficiency, services per conception, and incidence of diseases were not influenced by the prepartum regimen. However, the interval from parturition to conception was 24 d longer for cows on the higher prepartum energy concentration (.75% of BW). None of the cows was able to meet its nutrient requirement in early lactation. Milk yield increased with each increment of concentrate in the postpartum diet. Reproduction and health were not affected by the postpartum regimen.     

Effects of prepartum milking on milk production and health performance

A field study using seven Holstein herds was conducted to determine effects of prepartum milking on milk production, health disorders, and reproductive performance. In each herd, 80 cows (30% first lactation cows) were assigned 1 mo prior to expected calving date to one of two treatments: postpartum or prepartum milking. The group milked prepartum was machine-milked twice daily at regular milking intervals beginning 14 d prior to date of expected calving. The group milked postpartum was milked for the first time after calving. The day prior to calving, 36, 33, and 31% of the cows milked prepartum produced less than 4.5 kg, 4.5 to 9 kg, and greater than 9 kg of milk, respectively. No relationship existed between days milked prepartum and prepartum milk yield. Lactation milk yield and persistency were not affected by prepartum milking. Prepartum milking reduced incidence of milk fever and mastitis during the 1st mo after parturition. Treatment was not a significant source of variation for reproductive performance or body condition; however, culling was higher for cows milked postpartum. Results indicate no adverse effects on cow performance due to prepartum milking nor increase in lactation milk yield.     

Effects of prepartum dietary protein level and feed intake on postpartum lactation performance and feeding behavior of multiparous Holstein dairy cows

An experiment was conducted to determine the effects of low and high metabolizable protein (MP) diets when fed for ad libitum and controlled intake during the prepartum period on postpartum lactation performance and feeding behavior of dairy cows. Thirty-six multiparous Holstein cows were blocked by parity, expected calving date, and previous lactation milk yield at −21 d relative to expected calving and were randomly assigned to 1 of 4 close-up period dietary treatments providing low MP (LMP) or high MP (HMP) diets with controlled intake (CNI) or ad libitum intake (ALI). The concentrations of MP were 65 and 90 g/kg dry matter for LMP and HMP diets, respectively, whereas intake was controlled to supply 100 and 160% of the NRC (2001) energy requirements for CNI and ALI groups, respectively. The concentration of net energy for lactation (NE_L) in the treatment diets was 1.50 Mcal/kg. All cows were fed a similar lactation diet after calving (1.50 Mcal/kg of NE_L and 83.3 g/kg of MP). The HMP diet increased dry matter intake during the first 3 wk and tended to increase dry matter intake over the 9 wk of lactation. Meal size and eating rate increased in the ALI cows during the prepartum period. Meal frequency increased with the HMP diet during the postpartum period. Milk yield increased by 15.2% with the HMP diet over the 9 wk of lactation. The HMP diet increased energy-corrected milk (ECM) yield in CNI versus ALI cows, whereas the LMP diet increased ECM yield in ALI versus CNI cows over the 9 wk of lactation. The increase in ECM yield of LMP-ALI versus LMP-CNI cows was supported by greater body condition loss and serum β-hydroxybutyrate over the 9 wk of lactation. Taken together, these data indicate that prepartum controlled intake of a high protein diet can provide the benefits of both strategies.     

Periparturient responses of multiparous Holstein cows fed different dietary phosphorus concentrations prepartum

Our objective was to compare the effects of different prepartum dietary phosphorus concentrations on periparturient metabolism and performance. Forty-two late pregnant multiparous Holstein cows were fed 0.21, 0.31, or 0.44% P (dry basis) for 4 wk before expected calving. After parturition, all cows were fed a common lactation diet (0.40% P). In the prepartum period, cows fed 0.21% P had lower blood serum P concentrations compared with cows fed 0.31 or 0.44% P. However, serum P concentrations of all cows were within the normal range (4 to 8 mg/dL) until the day of calving when average concentrations dropped below 4 mg/dL. From 3 to 14 d postpartum, serum P of cows fed 0.21% P was greater than that of cows fed 0.31 or 0.44% P. No cows presented with or were treated for clinical hypophosphatemia in the periparturient period. Total serum Ca was lower before calving through 2 d postpartum for cows fed 0.44% P compared with those fed 0.21 or 0.31%. Prepartum dietary P treatments did not alter blood osteocalcin, hydroxyproline, and deoxypyridinoline, indicators of bone metabolism, or concentrations of parathyroid hormone or 1,25-dihydroxyvitamin D₃. Energy-corrected milk yield and milk composition (first 28 d of lactation) were not affected by prepartum dietary P concentrations. It is concluded that feeding 0.21% P (34 g of P/cow daily) prepartum is adequate for periparturient multiparous Holstein cows with high metabolic demands and genetic potential for milk production. No adverse effects on periparturient health, dry matter intake, or 28-d lactation performance resulted.     

Effects of rumen undegradable protein supplementation on productive performance and indicators of protein and energy metabolism in Holstein fresh cows

The objective of this study was to determine the effects of feeding increased dietary crude protein (CP) on productive performance and indicators of protein and energy metabolism during 21 d postpartum. Thirty multiparous Holstein dairy cows were balanced by previous lactation milk yield, body condition score (BCS) at calving, and parity and randomly allocated to 1 of 3 dietary treatments from calving until 21 d postpartum. Dietary treatments were 16.0% CP with 5.0% rumen undegradable protein (RUP) based on dry matter (DM) (16CP), 18.7% CP with 7.0% RUP based on DM (19CP), and 21.4% CP with 9.0% RUP based on DM (21CP). Diets were similar in net energy for lactation (approximately 1.7 Mcal/kg of DM) and CP levels were increased with corn gluten meal and fish meal. Dry matter intake (DMI) was increased by increasing dietary CP levels from 16.0 to 19.0% of DM, but dietary CP beyond 19.0% had no effect on DMI. Milk yields were 4.7 and 6.5 kg/d greater in cows fed the 19CP and 21CP diets versus those fed the 16CP diet, whereas 4% fat-corrected milk was greater for cows fed the 21CP than the 16CP diet (36.0 vs. 31.4 kg/d). Milk protein content and yield, lactose yield, and milk urea nitrogen were elevated by increased dietary CP. Milk lactose content and fat yield were not different among dietary treatments, but milk fat content tended to decline with increasing content of CP in diets. High CP levels increased milk N secretion but decreased milk N efficiency. Apparent digestibility of DM, CP, and neutral detergent fiber was greater on the 19CP and 21CP diets compared with the 16CP diet. Cows fed the 19CP and 21CP diets lost less body condition relative to those fed the 16CP diet over 21 d postpartum. Feeding higher CP levels increased the concentrations of serum albumin, albumin to globulin ratio, and urea nitrogen and decreased aspartate aminotransferase, nonesterified fatty acids, and β-hydroxybutyrate, but had no effect on globulin, glucose, cholesterol, or triacylglycerol. These findings indicated that elevating dietary CP up to 19.0% of DM using RUP supplements improved DMI, productive performance and the indicators of protein and energy metabolism from calving to 21 d postpartum.     

Effects of feeding synthetic zeolite A during the prepartum period on serum mineral concentration,oxidant status,and performance of multiparous Holstein cows

The objective of this study was to determine the effects of feeding synthetic zeolite A for 3 wk before expected calving on peripartal serum mineral concentrations, hypocalcemia, oxidant status, and performance. Holstein cows (n = 55) entering their second or greater lactations were assigned randomly to 1 of 2 dietary treatments starting 21 d before expected calving: control (CON: 40% corn silage, 33% wheat straw, and 27% concentrate; n = 29) or experimental [EXP: CON plus zeolite A (X-Zelit, Protekta Inc., Lucknow, ON, Canada/Vilofoss, Graasten, Denmark; n = 26) at an inclusion rate of 3.3% of dry matter, targeting 500 g/d as-fed]. Cows were fed the same postpartum diet and housed in individual tiestalls through 28 d in milk. Cows fed EXP had higher serum Ca concentrations as parturition approached and during the immediate postpartum period. Serum P concentrations were lower for the EXP-fed cows during the prepartum period and the first 2 d of lactation, whereas serum Mg concentrations were lower than those of the CON-fed cows only during the immediate periparturient period. Cows fed EXP had decreased prevalence of subclinical hypocalcemia (SCH) from d −1 through 3 relative to day of parturition, with the largest difference occurring within the first day postpartum. Prepartum dry matter intake tended to be decreased and rumination was decreased in cows fed EXP; however; postpartum dry matter intake, rumination, milk yield, milk component yield, and colostrum measurements did not differ between treatments. Cows fed EXP tended to have increased hazard of pregnancy by 150 d in milk when controlling for parity compared with CON-fed cows; potential reproductive benefits merit further study. This study demonstrated that zeolite A supplementation during the prepartum period results in markedly improved serum Ca concentrations around parturition and similar postpartum performance compared with controls and is effective at decreasing hypocalcemia in multiparous Holstein cows.