Post-ruminal or intravenous infusions of carbohydrates or amino acids to dairy cows 1. Early lactation

Schei, I.; Danfær, A.; Boman, Inger Anne; Volden, H.

doi:10.1017/s175173110768505x

Cited by 16 publications

(25 citation statements)

References 51 publications

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“…However, the increased activity of membrane transporters may not be cell specific, and thus competition between organs may be detrimental for the intracellular AA supply of mammary epithelial cells. By improving the extraction rate, Schei et al (2007a) also observed a higher extraction rate of essential AA during intravenous infusion of a mixture of AA, but the effects were larger after glucose infusion. These effects were observed in early lactation, but were inconsistent in late lactation (Schei et al, 2007b).…”

Section: Factors Affecting the Efficiency Of N Utilization In The Mammentioning

confidence: 90%

Strategies for optimizing nitrogen use by ruminants

Calsamiglia

Ferret

Reynolds

et al. 2010

Animal

249

165

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The efficiency of N utilization in ruminants is typically low (around 25%) and highly variable (10% to 40%) compared with the higher efficiency of other production animals. The low efficiency has implications for the production performance and environment. Many efforts have been devoted to improving the efficiency of N utilization in ruminants, and while major improvements in our understanding of N requirements and metabolism have been achieved, the overall efficiency remains low. In general, maximal efficiency of N utilization will only occur at the expense of some losses in production performance. However, optimal production and N utilization may be achieved through the understanding of the key mechanisms involved in the control of N metabolism. Key factors in the rumen include the efficiency of N capture in the rumen (grams of bacterial N per grams of rumen available N) and the modification of protein degradation. Traditionally, protein degradation has been modulated by modifying the feed (physical and chemical treatments). Modifying the rumen microflora involved in peptide degradation and amino acid deamination offers an alternative approach that needs to be addressed. Current evidence indicates that in typical feeding conditions there is limited net recycling of N into the rumen (blood urea-N uptake minus ammonia-N absorption), but understanding the factors controlling urea transport across the rumen wall may reverse the balance to take advantage of the recycling capabilities of ruminants. Finally, there is considerable metabolism of amino acids (AA) in the portal-drained viscera (PDV) and liver. However, most of this process occurs through the uptake of AA from the arterial blood and not during the 'absorptive' process. Therefore, AA are available to the peripheral circulation and to the mammary gland before being used by PDV and the liver. In these conditions, the mammary gland plays a key role in determining the efficiency of N utilization because the PDV and liver will use AA in excess of those required by the mammary gland. Protein synthesis in the mammary gland appears to be tightly regulated by local and systemic signals. The understanding of factors regulating AA supply and absorption in the mammary gland, and the synthesis of milk protein should allow the formulation of diets that increase total AA uptake by the mammary gland and thus reduce AA utilization by PDV and the liver. A better understanding of these key processes should allow the development of strategies to improve the efficiency of N utilization in ruminants. Keywords: ruminant, nitrogen efficiency ImplicationsRuminants have a low efficiency of N utilization compared with non-ruminants. This low efficiency has implications not only for production performance and economic efficiency but also for the emission of contaminants to the environment. The efficiency of N utilization can be improved through the understanding and modification of factors regulating the efficiency of N utilization in key processes, including N capture in the rumen, ...

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Section: Factors Affecting the Efficiency Of N Utilization In The Mammentioning

confidence: 90%

Strategies for optimizing nitrogen use by ruminants

Calsamiglia

Ferret

Reynolds

et al. 2010

Animal

249

165

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“…The cows were the same as used in the early lactation experiment presented in our accompanying paper (Schei et al, 2007). The experiment was conducted in late lactation starting 165^4 (mean^s.e.)…”

Section: Methodsmentioning

confidence: 99%

“…days post partum (milk yield 22.5^1.1 kg). The cows were fed the same basal ration consisting of concentrate and grass silage in the same ratio 55 : 45 and using the same feeding management as in the early lactation experiment (Schei et al, 2007). Silage was stored in tower silos until start of the early lactation experiment, then packed in plastic bags and frozen until use also for the late lactation trial, to ensure that the same feed was used in both lactation stages.…”

Section: Methodsmentioning

confidence: 99%

“…For all cows, daily DM intake (DMI) was set to 7 kg concentrate DM and 6.3 kg silage DM. Ingredients and chemical composition of the basal diet are presented by Schei et al (2007).…”

Section: Methodsmentioning

confidence: 99%

“…Therefore, we wanted to compare directly, within the same animals and similar energy balance at two lactation stages, the effect of abomasal or intravenous carbohydrate (CHO) or AA delivery on milk production response, nitrogen (N) utilisation and plasma metabolites. In our accompanying paper (Schei et al, 2007), we presented the responses obtained in early lactation starting 54 (^4) days post partum. In this paper we will present a replicate of the experiment using the same animals and the same basal diet in late lactation, starting 165 (^4) days post partum.…”

Section: Introductionmentioning

confidence: 99%

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Post-ruminal or intravenous infusions of carbohydrates or amino acids to dairy cows 2. Late lactation

Schei

Danfær²,

Mydland

et al. 2007

Animal

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The objectives of this study were to compare the effects of post-ruminal and intravenous infusions of wheat starch or glucose (CHO) or a mixture of amino acids (AA) on milk protein yield, nitrogen (N) utilisation, plasma metabolites and mammary extraction rate of dairy cows in late lactation. Eight cow, ruminally fistulated, was assigned to two 4 £ 4 Latin squares during 14-day periods, where the last 7 days were for infusions. Infusions were: (1) starch in the abomasum (SP), (2) glucose in the blood (GB), (3) AA in the abomasum (AP), and (4) AA in the blood (AB). The experiment started 165^4 days (mean^s.e.) post partum (milk yield 22.5^1.1 kg) Daily amounts of nutrients infused were 257, 283, 233, and 260 g for SP, GB, AP and AB, respectively. The cows were fed a basal diet consisting of a concentrate mixture and grass silage (55:45 on a dry-matter (DM) basis), where total dry-matter intake (DMI) was 13.3 kg/day. Milk production was affected by site of infusion within substrate, whereas infusion substrates within infusion site (CHO or AA) were of minor importance. Responses to intravenous infusions (GB or AB) were similar to those in early lactation, but more pronounced. Compared with SP infusion, GB infusion increased ( P , 0.05) milk yield, energy-corrected milk (ECM), protein and lactose yield by 1.4 and 0.9 kg, 38 and 59 g, respectively. The AB infusion had 1.4 and 1.3 kg, 51, 52 and 50 g higher ( P , 0.05) milk yield, ECM, protein, fat and lactose yields than the AP infusion, respectively. N balance data indicated higher losses of metabolic faecal nitrogen (MFN) by abomasal than by intravenous infusions, but the catabolism of AA was lower than in early lactation indicated by no difference ( P , 0.05) in urinary N excretion between treatments. Intravenous AA infusion increased plasma glucose and insulin above that of intravenous glucose infusion. The treatment effects on plasma insulin concentrations were higher in late than in early lactation, suggesting a higher sensitivity in late lactation even at similar negative energy balance. Compared with the SP infusion, GB infusion showed lower ( P , 0.05) concentrations of essential AA (EAA) and branched-chain AA (BCAA) resulting in a higher AA utilisation because of a higher milk protein production. AP infusion increased ( P , 0.05) plasma non-essential AA concentration compared with AB infusion, but infusion site of AA had no effect ( P . 0.05) on plasma EAA or BCAA. It is concluded that it is the nutrient supply and not the lactation stage per se that is important for the response in milk production. Nevertheless, stage of lactation affects the N metabolism and the response in plasma hormone concentrations even when cows are in negative energy balance in both lactation stages.

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Responses of milk production of dairy cows to jugular infusions of a mixture of essential amino acids with or without exclusion leucine or arginine

Tian

Zhao

et al. 2017

Animal Nutrition

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The purpose of this study was to determine effects of jugular infusion of either balanced or imbalanced amino acid mixture on milk production and composition in dairy cows. Eight mid-lactation Holstein cows were randomly assigned to 5-d continuous jugular infusions of saline (CTL), essential amino acid (EAA) mixture prepared on the profile of casein (CSN, 160 g/d), EAA mixture excluding leucine (Leu) (−Leu, 163 g/d) or EAA mixture excluding arginine (Arg) (−Arg, 158 g/d) in a duplicated 4 × 4 Latin square design with 4 infusion periods separated by a 7-d interval period. The basal diet was formulated with corn grain, soybean meal, cottonseed meal, corn silage, alfalfa hay and Chinese wildrye grass hay according to NRC (2001) and supplied 1.6 Mcal net energy for lactation (NEL) and 94.4 g metabolizable protein (MP) per kg dry matter (DM) to meet requirements for lactation. The results showed that the dry matter intake (DMI) and normal physiological status were not affected by amino acid mixture infusions. Compared with CTL treatment, the CSN treatment increased milk yield (14.9%, P < 0.001), milk lactose yield (14.5%, P = 0.001), milk fat yield (16.6%, P = 0.01), milk protein yield (18.2%, P < 0.001) and the contents of αS1-casein (αS1-CN, 11.8%, P = 0.007), β-casein (β-CN, 4.2%, P = 0.035) and κ-casein (κ-CN, 8.5%, P = 0.003). However, the −Leu and −Arg treatments had lower milk yield (6.3%, P = 0.058 and 5.7%, P = 0.073, respectively), milk protein yield (8.8%, P = 0.010 and 8.2%, P = 0.011, respectively) and the contents of αS1-CN (7.3%, P = 0.057 and 8.4%, P = 0.026, respectively), β-CN (4.2%, P = 0.033 and 3.8%, P = 0.048, respectively) and κ-CN (5.8%, P = 0.023 and 7.6%, P = 0.003, respectively) than those of the CSN treatment. Milk lactose yield (5.9%, P = 0.076) tended to decrease when Leu was removed from amino acid mixture infusate. In conclusion, the supply of casein profile can increase milk production in dairy cows, but a deficiency of Leu or Arg had negative effects on milk yield and milk protein yield.

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Post-ruminal or intravenous infusions of carbohydrates or amino acids to dairy cows 1. Early lactation

Cited by 16 publications

References 51 publications

Strategies for optimizing nitrogen use by ruminants

Strategies for optimizing nitrogen use by ruminants

Post-ruminal or intravenous infusions of carbohydrates or amino acids to dairy cows 2. Late lactation

Responses of milk production of dairy cows to jugular infusions of a mixture of essential amino acids with or without exclusion leucine or arginine

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