Nutritional depletion of total mixed rations by red-winged blackbirds and projected impacts on dairy cow performance

This Research Communication describes an investigation of the nutritional depletion of total mixed rations (TMR) by pest birds. We hypothesized that species-specific bird depredation of TMR can alter the nutritional composition of the ration and that these changes can negatively impact the performance of dairy cows. Blackbirds selected the high energy fraction of the TMR (i.e., flaked corn) and reduced starch, crude fat and total digestible nutrients during controlled feeding experiments. For Holsteins producing 37·1 kg of milk/d, dairy production modeling illustrated that total required net energy intake (NEI) was 35·8 Mcal/d. For the reference TMR unexposed to blackbirds and the blackbird-consumed TMR, NEI supplied was 41·2 and 37·8 Mcal/d, and the resulting energy balance was 5·4 and 2·0 Mcal/d, respectively. Thus, Holsteins fed the reference and blackbird-consumed TMR were estimated to gain one body condition score in 96 and 254 d, and experience daily weight change due to reserves of 1·1 and 0·4 kg/d, respectively. We discuss these results in context of an integrated pest management program for mitigating the depredation caused by pest birds at commercial dairies.

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43 Cow Performance and Lameness Are Affected by Housing in Drylots vs Pasture During the Summer

Journal of Animal Science ◽

10.1093/jas/skab054.251 ◽

2021 ◽

Vol 99 (Supplement_1) ◽

pp. 147-148

Author(s):

Lucas Hofer ◽

Megan Myerscough ◽

Wes Chapple ◽

Travis T Meteer ◽

Keela Trennepohl ◽

...

Keyword(s):

Milk Production ◽

Binary Data ◽

Body Condition Score ◽

Hair Coat ◽

Milk Protein Content ◽

Condition Score ◽

Milk Urea ◽

Cow Performance ◽

Distillers Grain ◽

Dried Distillers Grain

Abstract The objective was to compare the performance of cows housed in drylots or on pasture. Spring-calving, Simmental × Angus cow-calf pairs (n = 108; 77 ± 18 days postpartum) were stratified by age, body weight (BW), body condition score (BCS), calving date, and calf sex. Cows were allotted into six groups which were randomly assigned to drylot or pasture. Drylot cows were limit-fed a ration consisting of corn silage, dried distillers grain, corn stalks, cracked corn, and a corn-based supplement to meet protein and energy requirements. Cows on pasture were rotationally grazed with access to free-choice mineral. Cows were artificially inseminated on day 0. Cow BW, BCS, hair coat scores, locomotion scores, and lameness treatments were evaluated throughout the 110-day experiment. Milk production and composition were evaluated on day 56. Data were analyzed using the MIXED and GLIMMIX (binary data) procedures of SAS. Artificial insemination and overall pregnancy rates did not differ (P ≥ 0.79) between groups. Drylot cows were 22 and 51 kg heavier (P ≤ 0.02) than pasture cows on days 83 and 110, respectively. Drylot cow BCS was greater (P = 0.03) on day 110. Hair coat scores were more desirable (P = 0.03) in drylot cows than pasture cows on day 110. Drylot cows had greater (P = 0.04) milk production than pasture cows. Pasture cows had greater (P ≤ 0.03) milk protein content and milk urea nitrogen. Although locomotion scores did not differ (P ≥ 0.45) on days 0 and 34, they were less desirable (P = 0.02) for the drylot cows on day 110. A greater (P = 0.02) percentage of drylot cows (33%) were treated for lameness than pasture cows (7%). Housing cows in drylots increased BW, BCS, and milk production, but resulted in poorer locomotion scores and increased lameness treatments.

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Overfeeding Extends the Period of Annual Cyclicity but Increases the Risk of Early Embryonic Death in Shetland Pony Mares

Animals ◽

10.3390/ani11020361 ◽

2021 ◽

Vol 11 (2) ◽

pp. 361

Author(s):

Nicky M. M. D’Fonseca ◽

Charlotte M. E. Gibson ◽

Iris Hummel ◽

David A. van Doorn ◽

Ellen Roelfsema ◽

...

Keyword(s):

Embryo Transfer ◽

Reproductive Activity ◽

High Energy ◽

Morphometric Parameters ◽

Net Energy ◽

Conceptus Development ◽

And Control ◽

Annual Duration ◽

Embryonic Death

Obesity has been associated with altered reproductive activity in mares, and may negatively affect fertility. To examine the influence of long-term high-energy (HE) feeding on fertility, Shetland pony mares were fed a diet containing 200% of net energy (NE) requirements during a three-year study. The incidence of hemorrhagic anovulatory follicles (HAF) and annual duration of cyclicity were compared to those in control mares receiving a maintenance diet. Day-7 embryos were flushed and transferred between donor and recipient mares from both groups; the resulting conceptuses were collected 21 days after transfer to assess conceptus development. HE mares became obese, and embryos recovered from HE mares were more likely to succumb to early embryonic death. The period of annual cyclicity was extended in HE compared to control mares in all years. The incidence of HAFs did not consistently differ between HE and control mares. No differences in embryo morphometric parameters were apparent. In conclusion, consuming a HE diet extended the duration of cyclicity, and appeared to increase the likelihood of embryos undergoing early embryonic death following embryo transfer.

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Net energy efficiencies of Holstein, Jersey and Holstein-Jersey F1-crosses

Animal Science ◽

10.1017/s1357729800055831 ◽

2001 ◽

Vol 72 (2) ◽

pp. 335-342 ◽

Cited By ~ 12

Author(s):

R. Schwager-Suter ◽

C. Stricker ◽

D. Erdin ◽

N. Künzi

Keyword(s):

Body Weight ◽

Body Condition ◽

Fixed Effects ◽

Energy Content ◽

High Energy ◽

Repeated Measurements ◽

Low Energy ◽

Body Tissue ◽

Net Energy ◽

Tissue Change

Abstract Net energy efficiencies were calculated from data of an experimental herd with respect to type of cow, lactation number, stage of lactation and diet. The trial consisted of 71 Holstein-Friesians, 71 Jerseys and 71 Holstein-Jersey F1-crosses in 1st, 2nd and > 2nd lactation. Data were collected during 210 days of lactation, from calving to week 30 and included total dry matter intake, energy content of foods, milk yield, milk solids, body weight, body condition scores and several body measurements. The cows were divided into four feeding groups : high and low energy content of roughage as well as high and low proportion of concentrates. Net energy efficiency was calculated as the ratio of milk energy to total net energy intake after subtracting energy utilized for maintenance and body tissue change. Body tissue change was calculated either via body-weight changes or body condition-score changes. Due to the distribution of the efficiencies being skewed, efficiencies were transformed applying a Box-Cox transformation. Transformed net energy efficiencies were analysed using a repeated measurements design considering the sequential nature of the observations. Mixed models with a compound symmetry structure for the variance components were applied. Final models contained the fixed effects of type, lactation number, feeding group and the covariates week of lactation and its square. Holstein-Jersey crosses were more efficient than purebreds, second lactation cows were least efficient, cows given low energy roughage and a lower proportion of concentrates were more efficient than cows on the other diets. Least efficient were the cows belonging to the high energy roughage and higher proportion of concentrates group. The coefficients of determination of the final models were between 0·357 and 0·492.

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4E Analysis of a Fuel Cell and Gas Turbine Hybrid Energy System

Biointerface Research in Applied Chemistry ◽

10.33263/briac111.75687579 ◽

2020 ◽

Vol 11 (1) ◽

pp. 7568-7579

Keyword(s):

Fuel Cell ◽

Cell Voltage ◽

Energy System ◽

High Energy ◽

Exergy Efficiency ◽

Combined Cycle ◽

Net Energy ◽

Exergy Destruction ◽

Molten Carbonate ◽

Ambient Temperatures

Exergy analysis of the expansion turbine hybrid cycle of integrated molten carbonate fuel cells is presented in this study. The proposed cycle was used as a sustainable energy curriculum to provide a small hybrid power plant with high energy efficiency. To generate electricity with the system mentioned above, and externally repaired fusion carbon fuel cell was used located at the top of the combined cycle. Moreover, the turbine and steam turbine systems are considered as complementary and bottom layers for co-generation, respectively. The results showed that the proposed system could reach net energy of up to 1125 kilowatts, while the total exergy efficiency (including electricity and heat) for this system is more than 68%. Moreover, the energy supplied and exergy efficiency derived from the proposed cycle are stable versus changes in ambient temperatures. Besides, the effect of increasing the current density on the cell voltage and the total exergy destruction was considered. Also, the new approaches of the exergoeconomics and exergoenvironmental analysis are implemented in this system. The results show that the hybrid system can decrease the exergy destruction costs more than 16%, and the environmental footprint of the system more than 23.4%.

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Feeding experiments of the seep-associated foraminifer Nonionellina labradorica with a marine methanotroph from the Arctic

10.5194/egusphere-egu21-14673 ◽

2021 ◽

Author(s):

Christiane Schmidt ◽

Geslin Emmanuelle ◽

Bernhard Joan M. ◽

LeKieffre Charlotte ◽

Roberge Helene ◽

...

Keyword(s):

Barents Sea ◽

Feeding Habits ◽

The Arctic ◽

Type I ◽

Intracytoplasmic Membrane ◽

Organic Detritus ◽

Feeding Experiments ◽

Food Vacuoles ◽

Species Specific

Foraminifera on the seafloor are known to have species-specific feeding habits. Among those are deposit feeders, eating organic detritus and bacteria. Little is known about the feeding habits of foraminifera from Arctic seep environments. That is, in particular, of interest as variable &#948;13C values in the tests of foraminifera have been suggested to be partly linked with a diet rich in bacteria, themselves lighter in &#948;13C values. As there is little information on the ecology of the foraminifer Nonionellina labradorica (Dawson, 1860), this study examined feeding habits on bacteria and compared them to in situ collected specimens, using Transmission Electron microscopy (TEM). As bacterial food, the marine methane-oxidizing bacterium Methyloprofundus sedimenti was chosen, which is an important representative of methanotrophs in the marine environment near methane seeps. Sediment samples containing living N. labradorica specimens collected in close vicinity(approx. 5 m) from an active methane seep in Storfjordrenna, Barents Sea (382-m water depth).&#160; We performed a feeding experiment on N. labradorica (n=17 specimen), which were incubated in the dark at in situ temperature. Specimens were fed at the beginning of the experiment, except the un-fed controls, and incubations terminated after 4, 8 and 20 h. After fixation in epoxy resin the ultrastructure of all specimens and their food vacuoles was observed and compared using a TEM. All examined specimens were living at the time of fixation, based on observation of intact mitochondrial membranes. In all specimens, inorganic detritus was preserved inside food vacuoles. Closer observation of food vacuoles also revealed that in addition to inorganic debris, such as clay, occasionally bacteria were visible. This led us to conclude that our N. labradorica can&#160; generally be classified as a deposit feeder, which is rather a generalist than a specialist. Regarding uptake of M. sedimenti, the timing of the experimentation seemed to be critical. We did not observe methanotrophs preserved in the resin at the 4 and 8 h incubations, but found two putative methanotrophs near the apertural region after the 20-h incubation. After closer observation, we could identify one of those two putative specimen as the menthanothroph M. sedimenti near the foraminiferal aperture, based on presence of a typical type I stacked intracytoplasmic membrane (ICM) and storage granules (SC). We concluded that N. labradorica may ingest M. sedimenti via &#8220;untargeted grazing&#8221; in seeps. Further studies must examine the exact relationship between diet and &#948;13C in foraminiferal test on several different paleo-oceanographically relevant species.

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Effects of housing beef cow-calf pairs on drylot or pasture in the Midwest on production parameters and calf behavior through feedlot receiving

Journal of Animal Science ◽

10.1093/jas/skab357 ◽

2021 ◽

Author(s):

Megan E Myerscough ◽

Lucas T Neira ◽

Keifer H Sexton ◽

Lucas S Hofer ◽

Keela M Trennepohl ◽

...

Keyword(s):

Milk Production ◽

Treatment Time ◽

Body Condition Score ◽

Average Daily Gain ◽

Beef Cow ◽

Condition Score ◽

Ad Libitum ◽

Cow Calf ◽

Cow Performance ◽

And Behavior

Abstract The objectives were to analyze the effects of housing cow-calf pairs in drylots (DL) or pasture (PAST) on cow performance and reproduction as well as calf performance and behavior through feedlot receiving. Simmental × Angus (2 yr; 108/yr; 81 ± 15.3 d postpartum) spring-calving cows were stratified by age, body weight (BW), body condition score (BCS), and calf sex and allotted to 6 groups/yr. Groups were randomly assigned to 1 of 2 treatments: DL or PAST. Cows in DL were limit-fed at maintenance and calves had ad libitum access to the cow diet in an adjacent pen. Pairs on PAST were rotationally grazed and calves received creep ad libitum three weeks prior to weaning. On d 110 calves were fence-line weaned and behavior was observed on d 111 and 112. On d 116 calves were transported 272 kilometers to a feedlot for a 42-d receiving period. Behavior was evaluated again on d 117 and 118. Data were analyzed using the MIXED procedure of SAS except reproductive data which was analyzed using the GLIMMIX procedure. Cows on DL had greater (P ≤ 0.01) BW and BCS at weaning. There were no differences (P ≥ 0.42) detected in reproductive data. Cows on DL had greater (P = 0.02) milk production. Calves on DL had greater BW (P ≤ 0.01) on d 55 and at weaning and greater preweaning average daily gain (ADG). There were treatment × time effects (P = 0.01) for lying and eating on d 111 and 112. More DL calves were eating in the morning and lying in the evening. More (P < 0.01) PAST calves were walking on d 111. Pasture calves vocalized more (P ≤ 0.01) on d 112. On d 117, more (P ≤ 0.05) pasture calves were lying and eating, and DL vocalized more. On d 118, treatment × time and treatment effects were detected (P ≤ 0.02) for lying and walking. More PAST calves were lying and more DL calves were walking. Drylot calves had greater (P ≤ 0.02) BW at the beginning and end of the receiving phase. Pasture calves had greater (P < 0.01) ADG and tended (P = 0.10) to have greater gain efficiency during feedlot receiving phase. In conclusion, housing cow-calf pairs in drylots improved BW, BCS, and milk production of cows but did not affect reproductive performance. Drylot calves had increased BW and ADG during the preweaning phase. Calf behavior at weaning and receiving was influenced by preweaning housing. Pasture calves had improved receiving phase ADG and feed efficiency but were still lighter than drylot calves after 42 d receiving phase.

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Milk Urea Concentration in Dairy Sheep: Accounting for Dietary Energy Concentration

Animals ◽

10.3390/ani9121118 ◽

2019 ◽

Vol 9 (12) ◽

pp. 1118 ◽

Cited By ~ 1

Author(s):

Valeria Giovanetti ◽

Filippo Boe ◽

Mauro Decandia ◽

Giovanni Cristoforo Bomboi ◽

Alberto Stanislao Atzori ◽

...

Keyword(s):

Mean Squared Error ◽

Energy Content ◽

High Energy ◽

Urea Concentration ◽

Energy Concentration ◽

Net Energy ◽

Dietary Energy ◽

Dairy Sheep ◽

Dairy Ewes ◽

Milk Urea

In dairy sheep milk urea concentration (MUC) is highly and positively correlated with dietary crude protein (CP) content and, to a lesser extent, with protein intake. However, the effect of dietary energy and carbohydrate sources on MUC of lactating ewes is not clear. Thus, the objective of this study was to assess the effects of diets differing in energy concentration and carbohydrate sources on MUC values in lactating dairy ewes. Two experiments were conducted (experiment 1, E1, and experiment 2, E2) on Sarda ewes in mid and late lactation kept in metabolic cages for 23 d. In both experiments, homogeneous groups of five ewes were submitted to four (in E1) or three (in E2) dietary treatments, consisting of pelleted diets ranging from low energy (high-fiber diets: 1.2–1.4 Mcal of net energy for lactation (NEL)) to high energy (high-starch diets: 1.7–1.9 Mcal of NEL) contents, but with a similar CP concentration (18.4% dry matter (DM), on average). Each diet had a different main ingredient as follows: corn flakes, barley meal, beet pulp, or corn cobs in E1 and corn meal, dehydrated alfalfa, or soybean hulls in E2. Regression analysis using treatment means from both experiments showed that the best predictor of MUC (mg/100 mL) was the dietary NEL (Mcal/kg DM, MUC = 127.6 − 51.2 × NEL, R2 = 0.85, root of the mean squared error (rmse) = 4.36, p < 0.001) followed by the ratio CP/NEL (g/Mcal, MUC = −14.9 + 0.5 × CP/ NEL, R2 = 0.83, rmse = 4.63, p < 0.001). A meta-regression of an extended database on stall-fed dairy ewes, including the E1 and E2 experimental data (n = 44), confirmed the predictive value of the CP/ NEL ratio, which resulted as the best single predictor of MUC (MUC = −13.7 + 0.5 × CP/NEL, R2 = 0.93, rmse = 3.30, p < 0.001), followed by dietary CP concentration (MUC = −20.7 + 3.7 × CP, R2 = 0.82, rmse = 4.89, p < 0.001). This research highlights that dietary energy content plays a pivotal role in modulating the relationship between MUC and dietary CP concentration in dairy sheep.

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Diet formulation method influences the response to increasing net energy in finishing pigs1

Translational Animal Science ◽

10.1093/tas/txz147 ◽

2019 ◽

Vol 3 (4) ◽

pp. 1349-1358 ◽

Cited By ~ 1

Author(s):

Danilo A Marçal ◽

Charles Kiefer ◽

Mike D Tokach ◽

Steve S Dritz ◽

Jason C Woodworth ◽

...

Keyword(s):

Control Diet ◽

Average Daily Gain ◽

High Energy ◽

Feed Ratio ◽

Net Energy ◽

White Grease ◽

Diet Formulation ◽

Finishing Pig ◽

Commercial Processing ◽

Dietary Energy Density

Abstract An experiment was conducted to compare the effects of increasing dietary net energy (NE) in finishing pig diets while either maintaining a standardized ileal digestible lysine:NE ratio (SID Lys:NE) or maintaining SID Lys as a constant percentage of the diet across increasing energy densities. A total of 150 pigs (Line 600 × 241; DNA, Columbus, NE; initially 35.7 kg) were used in a 91-d study. Pigs were blocked by sex and weight and randomly assigned to 1 of 5 treatments with 2 pigs per pen and 15 pens per treatment. Treatments included a low-energy control diet that was corn-soybean meal-based with added soybean hulls, and a 2 × 2 factorial arrangement of treatments with main effects of increasing dietary NE (medium or high by adding choice white grease) and formulation method (with a SID Lys:NE ratio or maintaining the same percentage SID Lys). Linear and quadratic contrasts were made using the control diet and the medium- and high-energy diets within each formulation method. Pigs and feeders were weighed approximately every 30 d to calculate average daily gain (ADG), average daily feed intake (ADFI), and gain-to-feed ratio (G:F). At the end of the experiment, pigs were sent to a commercial processing facility for carcass data collection. From days 0 to 34 and 34 to 61, ADG and SID Lys intake increased as NE increased (linear, P < 0.05) in pigs fed diets with a Lys:NE ratio, but not for those fed the same percentage Lys. As NE increased, NE intake and G:F increased (P < 0.01) in pigs fed diets with either formulation method. From days 61 to 91, increasing NE had no effect (P > 0.10) on ADG. There was no change in G:F in pigs fed diets with the same percentage Lys (P > 0.10), but G:F decreased then increased (quadratic, P < 0.01) in response to increasing NE in pigs fed diets with a SID Lys:NE ratio. Overall, increasing dietary NE increased (linear, P < 0.001) daily NE intake and G:F (linear, P < 0.018) with either formulation method. However, SID Lys intake, ADG, and hot carcass weight only increased (linear, P < 0.01) when a SID Lys:NE ratio was maintained. Increasing NE without maintaining a constant SID Lys:NE ratio increased backfat depth (quadratic, P = 0.01), whereas it did not in pigs fed diets with a SID Lys:NE ratio. In conclusion, increasing dietary energy density increased NE intake and G:F regardless of formulation method. However, a SID Lys:NE ratio must be maintained to achieve increased ADG and minimize fat deposition.

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Mathematical absurdities in the California net energy system

Translational Animal Science ◽

10.1093/tas/txz020 ◽

2019 ◽

Vol 3 (3) ◽

pp. 1018-1028

Author(s):

Carl A Old ◽

Ian J Lean ◽

Heidi A Rossow

Keyword(s):

Linear Models ◽

Energy System ◽

High Energy ◽

Ordinary Least Squares ◽

Mitochondrial Metabolism ◽

Energy Utilization ◽

Parameter Estimates ◽

Net Energy ◽

High Energy Phosphate ◽

Laws Of Thermodynamics

Abstract Net energy systems, such as the California Net Energy System (CNES), are useful for prediction of input:output relationships not because of fidelity to the laws of thermodynamics, but because they were designed to predict well. Unless model descriptions of input:output relationships are consistent with the laws of thermodynamics, conclusions regarding those relationships may be incorrect. Heat energy (HE) + recovered energy (RE) = ME intake (MEI) is basic to descriptions of energy utilization found in the CNES and is consistent with the laws of thermodynamics; it may be the only relationship described in the CNES consistent with the first law of thermodynamics. In the CNES, efficiencies of ME utilization for maintenance (km) and gain (kg) were estimated using ordinary least squares (OLS) equations. Efficiencies thus estimated using static linear models are often inconsistent with the biochemistry of processes underlying maintenance and gain. Reactions in support of oxidative mitochondrial metabolism are thermodynamically favorable and irreversible; these reactions yield ATP, or other high-energy phosphate bonds, used for what is generally termed maintenance. Synthesis of biomass (gain) is less thermodynamically favorable; reactions do not proceed unless coupled with hydrolysis of high-energy phosphate bonds and lie closer to equilibrium than those in support of oxidative mitochondrial metabolism. The opposite is described in the CNES (km > kg) due to failure of partitioning of HE; insufficient HE is accounted for in maintenance. Efficiencies of ME utilization (km and kg) as described in the CNES are variable. Further neither km nor kg are uniformly monotonic f (ME, Mcal/kg); for ME (Mcal/kg) <0.512 or >4.26, km are inconsistent with thermodynamically allowed values for efficiencies (>1.0); kg are a monotonically positive f (ME) concentration (Mcal/kg) for ME <3.27 Mcal/kg. For ME <1.42 Mcal/kg, kg are not in the range of thermodynamically allowed values for efficiencies (0 to 1.0). Variable efficiencies of ME utilization require that the first law may not be observed in all cases. The CNES is an excellent empirical tool for prediction of input:output relationship, but many CNES parameter estimates evaluated in this study lack consistency with biology and the laws of thermodynamics.

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Body condition at calving and the performance of dairy cows in early lactation under Australian conditions: a review

Australian Journal of Experimental Agriculture ◽

10.1071/ea01023 ◽

2001 ◽

Vol 41 (6) ◽

pp. 823 ◽

Cited By ~ 40

Author(s):

C. R. Stockdale

Keyword(s):

Dairy Cows ◽

Body Condition ◽

Dietary Protein ◽

High Energy ◽

Negative Energy ◽

Considerable Proportion ◽

Early Lactation ◽

Protein Supplements ◽

Grazed Pasture ◽

Feeding Experiments

With the current increases in genetic merit and feeding occurring at farm level, dairy cows are under increasing nutritional stress in early lactation. Cows obtain their energy at this time from the feeds they eat and from body reserves. The relationship between body condition at calving and productivity of dairy cows has been reviewed, with particular emphasis on interactions between body condition and nutrition in early lactation. Recent research on the influence of body condition at calving on subsequent milk productivity, conducted mainly in the United Kingdom with complete diets fed indoors, has produced results in apparent conflict with the previous results from southern Australia and New Zealand where cows grazed pasture. In particular, the overseas research suggests considerably less advantage to improvements in body condition than had been previously thought. It is concluded that more information is needed concerning the interaction between body condition at calving and nutrition in early lactation, with dietary energy and protein both being important. There is a suggestion that, when complete diets are fed, it is better to achieve high energy concentrations in post-calving diets by the use of high-fibre concentrates with a fat supplement, rather than with high-starch concentrates. This has implications for dairying in Australia, since cereal grains are the major energy supplement used on many farms in early lactation and recent research has indicated that immediate marginal milk production responses to the use of concentrates may be poorer with fat cows than with thin cows. Reports from controlled feeding experiments indicate that fat cows need more dietary protein than thin cows and undegradable dietary protein might be of more concern than rumen degradable protein. However, in dairy systems where pasture is a considerable proportion of the diet, benefits of supplying specific undegradable dietary protein supplements still need to be established. Recent research has suggested that pasture appears to provide considerable quantities of undegradable dietary protein, even though the crude protein in pasture is potentially highly degradable in the rumen. Body condition at calving may also affect subsequent reproductive performance. This is due to its association with the degree of negative energy balance occurring in early lactation and because fat cows may be more susceptible to metabolic disease(s). While the mechanisms involved are probably quite complex, increases in animal productivity will generate more stress in cows at a time of their annual cycle when stress needs to be minimised. Further understanding is required to link the relevancy of overseas research to Australian dairy farming conditions where pasture is a key input.

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