Limits to Milk Production Efficiency by the Dairy Cow

Tyrell, H. F.

doi:10.2527/jas1981.5161441x

Cited by 17 publications

(5 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Second, from an energetic standpoint, cows fed HF were more efficient in producing milk energy (kilograms of SCM) per megacalorie of NE L intake than were cows fed HC. Lower apparent efficiency of milk energy secretion for cows fed HC likely arose from the depression of milk fat synthesis and consequent diversion of feed energy to fat deposition in adipose tissue (Tyrrell, 1980). However, differences in BW or BCS (Table 4) did not achieve statistical significance.…”

Section: Resultsmentioning

confidence: 96%

Responses of Primiparous and Multiparous Holstein Cows to Additional Energy from Fat or Concentrate During Summer

Drackley

Cicela²,

LaCount³

2003

Journal of Dairy Science

View full text Add to dashboard Cite

Supplemental fat has been advocated for use during hot weather and often increases milk yield of cows past peak production when energy intake should not be limiting. Relative responses of primiparous and multiparous cows to supplemental fat or isocaloric addition of concentrates under hot weather conditions have not been determined. Nine multiparous and nine primiparous Holstein cows (154 and 167 d in milk, respectively) were used in a replicated 3 x 3 Latin square design with 28-d periods. Diets were 1) control (35% alfalfa silage, 25% corn silage, and 40% concentrate, dry matter [DM] basis); 2) control plus 3% fat (HF); and 3) high concentrate ([HC] 15% alfalfa silage, 25% corn silage, and 60% concentrate). Diets were isonitrogenous; diets HF and HC were isocaloric (1.60 Mcal of net energy for lactation [NE(L)] per kilogram DM) and higher energy than the control (1.52 Mcal/kg). No parity x diet interactions approached significance. DM intake (DMI) was greater when cows were fed HC than when they were fed HF (21.0, 20.1, and 21.3 kg/d for control, HF, and HC, respectively); intake of NE(L) tended to be increased only for HC. Milk yield was increased by higher-energy diets, but milk fat content was decreased. Milk total protein content was decreased by HF and increased by HC. Yield of solids-corrected milk (SCM) was not different among diets. Efficiency of milk production, expressed either as total milk solids yield per kilogram of DMI or as kilograms of SCM per megacalorie of NE(L) intake, was greater for HF than for HC. Plasma glucose was higher after feeding for cows fed HC; plasma nonesterified fatty acids were greater for HF. Respiration rate and rectal temperature were greater for HC than for HF. Regardless of parity, increased energy density from either fat or concentrate increased milk yield in midlactation cows, but diets caused energy to be partitioned differently among milk components and body storage. Supplemental rumen-active fat had modest advantages over additional starch-based concentrate during summer heat conditions.

show abstract

Section: Resultsmentioning

confidence: 96%

Responses of Primiparous and Multiparous Holstein Cows to Additional Energy from Fat or Concentrate During Summer

Drackley

Cicela²,

LaCount³

2003

Journal of Dairy Science

View full text Add to dashboard Cite

show abstract

“…Abomasal infusions of protein are as (or more) effective than dietary protein supplementation in improving grass silage intake (Chamberlain et al, 1989), however this response might be attributed to increased transfer of urea nitrogen to the rumen. In lactating dairy cows fed maize silage-based diets, feeding urea restored DM digestibility as effectively as an iso-nitrogenous amount of soybean meal, but only increased DM intake 1.3 kg/d, compared to an increase of 5.9 kg/d when soybean meal was fed (Tyrrell, 1980). It is known that urea is less effective than protein as a nitrogen supplement in dairy rations (Clark and Davis, 1980).…”

Section: Digestibilitymentioning

confidence: 99%

“…This was more often the case in the UK studies surveyed, where diets tended to have a higher digestibility than USA diets because of the use of high digestibility grass silages (Oldham and Smith, 1980). Increases in DM digestibility with increasing diet CP content can be attributed to the innately high digestibility of protein, or positive effects on microbial fermentation and digestion in the rumen (Tyrrell, 1980). Intake responses may be a result of both increases in digestibility and metabolic effects of improved amino acid supply (Oldham and Smith, 1980).…”

Section: Digestibilitymentioning

confidence: 99%

Forage evaluation using measurements of energy metabolism.

Reynolds

2000

Forage Evaluation in Ruminant Nutrition.

View full text Add to dashboard Cite

“…Dynamic estimates of k m may be considered to be at odds with the laws of thermodynamics. Although our analysis was limited to cattle growth data sets, the same lack of specificity for lactating and adult animals has long been recognized as a limitation to predictions of efficiencies of energy utilization (Tyrrell, 1980). In lactating animals, the inability of a single value for "maintenance" to describe the situation is even more limiting than in growth; as has been identified in the lactation models of Baldwin (1995), the previous NRC for dairy cattle (NRC, 2001) and in more sophisticated analyses of metabolic functions in dairy cattle and sows (McNamara et al, 1991;McNamara andBaldwin, 1994, 2000;McNamara, 2015;McNamara and Pettigrew, 2002).…”

Section: Stability Of Model 1 Parameter Estimatesmentioning

confidence: 99%

Energetic efficiency and the first law: the California net energy system revisited

Old¹,

Rossow

Lean

et al. 2018

Journal of Animal Science

View full text Add to dashboard Cite

Models of energy utilization used in livestock production predict input:output relationships well, for all the wrong reasons. Predictive accuracy in such models is not due to fidelity to biochemistry and laws of thermodynamics, but because they were developed to predict accurately, often with little regard to biochemical consistency. Relatively static linear statistical models limit thermodynamically relevant descriptions of energy utilization, especially maintenance, in growing beef cattle and are inadequate research tools, in either ordinary least squares (OLS) or Bayesian frameworks. Metabolizable energy intake (MEI) at recovered energy (RE) = 0 (MEm) and efficiencies of ME utilization for maintenance (km) and gain (kg) were estimated for 3 independent data sets using OLS or Bayesian frameworks. Estimates of MEm differed (P < 0.05) between OLS and Bayesian estimates and were not unique, indicating model misspecification. Bayesian estimates of MEm were monotonic, positive, and nonlinear f(MEI); the range was from 6.74 to 14.8 Mcal/d. Estimates of km, the ratio of heat energy (HE) at MEI = 0 to MEm, for the 3 data sets averaged 0.590 for OLS solutions, or 0.616 for the first derivative (km, dHE/dMEI for RE = 0) of a first-order function. The first derivative (dHE/dMEI) of the OLS function was > 1.0 for MEI > 22.1 Mcal/d, counter to the laws of thermodynamics and indicated model misspecification. The Bayesian estimate of km (0.420) differed (P < 0.05) from the OLS estimate and was consistent with the efficiency of ATP synthesis. Efficiency of ME use for gain for RE > 0 (kg, OLS solutions) averaged 0.397, solutions were nonunique and single-variable OLS models were misspecified (P < 0.050) for 2 of the 3 data sets. The OLS estimate of kg differed (P < 0.05) from the estimate of kg (0.676) determined in a Bayesian framework; the latter was calculated as dRE/dMEI for RE > 0. For OLS estimates km > kg; for estimates determined in a Bayesian framework km < kg, the former is inconsistent, while the latter is consistent with the thermodynamic favorability of reactions underlying maintenance and gain. Our results show that the use of relatively fixed coefficients of maintenance in current feeding standards, mathematical descriptions of metabolic processes and concepts regarding efficiencies of energy utilization in those systems need modification to be consistent with animal biology and the laws of thermodynamics.

show abstract

Limits to Milk Production Efficiency by the Dairy Cow

Cited by 17 publications

References 0 publications

Responses of Primiparous and Multiparous Holstein Cows to Additional Energy from Fat or Concentrate During Summer

Responses of Primiparous and Multiparous Holstein Cows to Additional Energy from Fat or Concentrate During Summer

Forage evaluation using measurements of energy metabolism.

Energetic efficiency and the first law: the California net energy system revisited

Contact Info

Product

Resources

About