Energy For Milk Production Research Articles

Effect of Daily Exercise on Performance, Feed Efficiency and Energy Balance of Tied Dairy Cows

The effect of daily exercise on dairy cows was studied in 65 first and second calvers of the Swedish Red and White breed in a four-year experiment, starting in July 1985. Half of the group walked outdoors 3 km/day from May through October and 400-800 m/day from November through April. From July 1986 the distance walked in the summer period was 2 km daily.Daily exercise did not significantly affect voluntary DM intake, the overall energy consumption or production of milk, ECM, fat or protein. The efficiency of milk energy and protein production did not differ between the treatments in lactations 2-4. Mean energy efficiency in these lactations was 5.6 MJ/kg ECM and mean protein efficiency 1213 g AAT/kg protein. However, in lactation 1 and at restricted feeding, milk energy and protein production was significantly less efficient for exercised cows than for non-exercised cows. The difference was 0.39±0.12 MJ/kg ECM (p<0.01) and 132 ± 28 g AAT/kg protein (p<0.001). The discrepancy between the Swedish standard for ME in milk production above maintenance, 5.0 MJ/kg ECM, and the results obtained in this and other recent studies are discussed.Concentrations of serum free fatty acids and plasma glucose were measured once a week in lactation weeks 1-8. No significant differences between the treatment groups were observed. Feeding was ad lib. in lactation weeks 4-12.It was noticed that the cows never lay down in the exercise area, which was covered with sand and soil. Behavioural disturbance in the form of tongue rolling was not influenced by exercise.

Prediction of gross energy content of ewe milk

AbstractThe interpretation of the results of feeding trials with lactating ewes and their sucking lambs can be improved considerably when milk energy production is known. The determination of gross energy (GE) however is time consuming and expensive. Therefore an equation to predict GE from milk constituents would be helpful.Using multiple regression analysis a GE-prediction equation was derived with milk samples mainly from crossbred ewes. The concentrations of milk constituents were determined by infrared spectrometry (calibrated with cow milk). Fat concentration ranged between 43·8 and 125·0 g/kg, protein concentration between 32·4 and 53·1 g/kg and lactose concentration between 38·9 and 52·9 g/kg. GE (adiabatic bomb calorimetry) of the samples under consideration ranged between 3500 to 6800 kj/kg.The following equation, including fat (f), protein (p) and lactose (I), is recommended and predicts GE as kj/kg fresh milk using constituents in g/kg fresh milk:GE = 41·94 × f + 15·85 × p + 21·41 ×l (residual s.d. = 92, adj.R2 = 0·98).This equation has, in the GE range 4500 kj to 6000 kj, an almost constant confidence interval with an average of ±25 kJ and an almost constant prediction interval, with an average of ±87 kJ. In the period until weaning it would appear justified to use the derived equation regardless of stage of lactation. The equation is valid for milk samples from sheep breeds with relatively high fat and low protein contents and where milk constituents have been determined by cow milk calibrated infrared spectrometry.

Energy and protein utilization and partition in rabbit does concurrently pregnant and lactating

AbstractChanges in body composition during lactation in 40 primiparous rabbits were studied by comparative slaughter. The results were used to determine the utilization of digestible energy (DE) and digestible protein (DP) and their partitioning between maternal body, milk and foetal tissues.Twelve does were slaughtered immediately after their first parturition (first slaughter group) to estimate initial body composition. The 28 remaining does were remated 1 to 3 days after parturition and divided into two groups offered a pelleted diet at different levels: group L, fed ad libitum and group R, fed 0·75 of ad libitum. The 19 does that were pregnant (10 of L group, 9 of R group) were kept in individual metabolism cages until their second parturition. They were then slaughtered with their litters.Milk yield was higher (147·0 v. 117·2 g/day, P &lt; 0·02) and live-weight loss was lower (–42 v. –294 g) in group L than in group R. The food intakes were 304·7 and 234·4 g/day, respectively. Body composition of the does changed substantially between the first and second parturition, with a considerable loss of fat and some loss of protein. A large decrease in empty body (digesta-free body) weight was observed in both groups. The loss of energy corresponded to proportionately 0·32 and 0·41 of the initial body energy, in L and R groups respectively.The DE requirement for maintenance was estimated to be 468 kj/day per kg M0·75 and the efficiencies of utilization of DE and body energy for milk production were 0·63 and 0·76, respectively. The efficiency of utilization of DE for foetal tissue synthesis was estimated to be 0·27 throughout pregnancy. The DP requirement for maintenance was 3·80 g/day per kg M0·75 and the efficiency of utilization of DP for milk protein production was 0·76 and of body protein 0·61. The efficiency of utilization of DP for foetal protein synthesis was 0·46.

Milk-energy production by lactating mares

Summary Seven Quarter Horse mares were hand milked at 10, 30, 45, 60, 90, 120 and 150 days throughout a 150-day lactation. Milk samples were analyzed for gross energy concentration by oxygen-bomb calorimetry. Average milk-energy concentration over the 150-day lactation was 438.4 (mUg, ranging from 336.8 to 576.5 cal/g. Highest average energy concentration was observed 10 days postpartum and tended to decline linearly as lactation advanced. Milk -energy concentration was related to milk yield (r=.71, P

Effect of treating dairy cows of three breeds with recombinantly derived bovine somatotropin for three years

Jersey, Friesian (Fr) and Dutch Red and White (DRW) dairy cows were treated over three lactations with BST, recombinantly derived bovine somatotropin (somidobove), in a sustained-delivery vehicle injected subcutaneously once every 28 days. In the first data set (indoor+pasture trials: 243 lactations from 126 cows) the response to BST treatment in milk energy production was similar for the breeds: Jersey 7.4, Fr 8.5 and DRW 8.9 MJ day -1, respectively, was slightly higher in cows than in heifers: 9.5 and 7.1 MJ day -1, respectively; and was higher on concentrates than on roughage-based diets: 10.6 and 6.0 MJ day -1, respectively. Control cows gained more body weight (5–17 kg) in the treatment period than treated cows. Using the second data set (indoor trials: 163 lactations from 93 cows) the response to BST treatment during the treatment period of 168 days was 9, 1 and -2 MJ net energy (NE) day -1 for energy intake, 14.0, 12.2 and 10.6 MJ day -1 for milk energy production, and 7, -11 and -9 kg for body weight during the first, second and third successive lactations respectively. In this period, plasma 3-hydroxybutyrate levels were higher in treated than in control cows: 204, 188 and 266 μmol l -1 in the three successive lactations, respectively, as were plasma free fatty acid (NEFA) levels at 13, 76 and 72 μmol l -1, respectively. This indicated a higher body fat mobilization in treated cows, especially in the second and the third successive lactations. Somatic cell count in milk from treated cows was respectively 136, 54 and 25 × 10 3 cells ml -1 higher than in milk from control cows for lactations 1, 2 and 3. The repeatabilities of the maximum response to BST treatment for milk energy production between periods within lactations and between lactations were low: 0.25 and 0.57 respectively. Calves from treated cows had a 5% lower birth weight than calves from control cows. Over a 3-year period no differences in fertility traits, disease frequency and reasons for culling were found between control and treated cows.

The influence of season and management system on intake and productivity of confined dairy cows in a Mediterranean climate

The influence of season and management system on the productivity of Friesian cows in a Mediterranean climate was assessed. Intakes of food and water and milk yields were measured in 154 cows over 2·5 years while intensively managed in yards giving access to shelter (free stalls) or that were fully exposed to solar radiation (open lots). Food quality was also monitored to permit estimates of the efficiency of utilization of metabolizable energy for milk production over fortnightly periods.The highest milk yields and energetic efficiencies were recorded during spring. Energy intakes were highest but energetic efficiencies were lowest during winter. Cows consumed the least food during summer and autumn and drank the most water during summer. The only significant effect of management system was for water intake, which was higher in the open lots than in the free stalls. There was evidence of heat stress in summer and cold stress in winter, but there appeared to be little benefit with milk yields through the provision of shelter.

Parity effects on feed intake and feed efficiency in four dairy breeds fed ad libitum two different diets

Parity effects on feed intake and feed efficiency for milk production were analysed in Jerseys, Holstein Friesians, Dutch Friesians and Dutch Red and Whites. These cows were fed at libitum a complete diet of roughage only (R), or a complete diet of the same roughage and 50% concentrates on a dry-matter basis (C), for at least 39 weeks in first and second or in first and third lactation. Of 159 cows in total, 265 lactations were analysed. A significant three-way interaction parity × breed × diet was found, caused by unequal variances between breeds in the different parity × diet groups and by differences in ranking for the breed in the different parity × diet groups. In general, the differences between the C- and R-diet groups decreased with increasing parity. No differences existed between parities in the ratio between milk energy production and net energy intake. Repeatabilities for fat concentration (0.75), protein concentration (0.68) and average body weight (0.69) were high. Repeatability for dry-matter intake (0.39), milk yield (0.47) and biological efficiency (0.46) were lower. Gain during lactation had a low repeatability (0.27).

Influence of plane of nutrition and diet composition on rumen fermentation and energy utilization by dairy cows

SummaryMean digestible energy (DE) intakes of 147 cows of three parities receiving three levels of DE including one ad libitum (about 2·2, 2·6 and 3·3 multiples of maintenance (MM)) drawn from three mixed diets containing hay and 60, 75 or 90% compound were calculated.Rumen samples were taken from three-quarters of the cows at monthly intervals throughout the experiment. Molar proportions of volatile fatty acids (VFA) in the rumen were not affected by stage of lactation over the 36 weeks of the experiment. The proportion of acetic acid decreased and that of propionic acid increased with greater intakes and with higher proportions of compound in the diet. The proportion of n-butyric acid was little affected by level of intake but decreased with increasing proportions of compound. In young, non-lactating cattle given the same diets but at lower levels of intake, VFA proportions were unaffected by diet composition at intakes of about 0·7 MM but at intakes of about 1·3 MM the proportion of acetate decreased and that of propionate increased when the proportion of compound was increased from 75 to 90%.The efficiency of milk energy production in relation to DE or metabolizable energy (ME) above maintenance decreased with increasing level of intake but was little affected by the proportion of compound. Partition towards live weight increased with level of intake in early lactation but not in late lactation. It also increased with higher proportions of compound in mid and late lactation but not in early lactation.Estimates of the ME requirement for live-weight change (LWC) were in reasonable agreement with recently published standards in early lactation when live weight was decreasing, but later in lactation when live-weight gain was occurring, a much higher value was calculated which is difficult to reconcile with these standards.Rumen VFA proportions were related to dietary fibre concentration and level of intake additively. The relationship to VFA proportions was close for milk fat concentration, but less so for energy partition towards live weight and none was apparent for the efficiency of ME utilization for milk energy production. It is suggested that both the reduction in milk fat concentration and the increase in milk yield in response to reductions in the fibre content of diets may be independently related to the increase in the proportion of propionate in the rumen VFA.It is concluded that further progress in studies of the dietary factors affecting the efficiency of milk production will require measurements of nutrient uptake from the digestive tract and description of milk production and LWC in terms of their chemical composition rather than energy alone.

Nutrient balance of lactating sows fed supplemental tallow.

An experiment was conducted using 20 crossbred sows through two lactations in a crossover design to determine the effects of supplemental tallow on milk production and composition, sow nutrient balance and litter performance. Sows were paired on d 105 of gestation by farrowing date, parity, body weight and previous reproductive performance, then allotted to a 27% dextrose (D) or 15% tallow (T) diet. Diets were fed at the rate of 1.81 kg/d D and 1.54 kg/d T during gestation, and 5.56 kg/d D and 4.75 kg/d T during lactation. Calculated daily nutrient intake between diets varied only in the source of metabolizable energy (ME). Litters were standardized to 10 pigs and weaned on d 21. Milk yields were estimated on d 4 and 11 and milk samples were collected on d 5 and 12. A balance trial using total urine and fecal collection was conducted from d 5 to 10. Energy source did not affect number of pigs born, average birth weight or sow postpartum weight loss. Sows on T gained more (P<.05) during lactation than sows on D (7.8 vs 1.6 kg). Pigs from T sows had a higher rate of gain for each of the 3 wk of lactation, but only the third week was significant. Milk yield increased from d 4 to 11, but did not differ between diets. Addition of tallow increased milk fat as a percentage of whole milk (4.94 vs 6.57%; P<.005) or total g/d (258 vs 321; P<.01). The efficiency of milk energy production from ME was greater (P<.005) for T sows (31.5 vs 40.7%). Urinary N excretion was higher and N balance lower for T sows. Although dietary intakes were calculated to be isocaloric on a ME basis, energy retained was higher (P<.005) for T sows (17.8 vs 19.0 Mcal/d). Tallow did not affect Ca absorption or retention, but increased urine and milk Ca. Apparent absorption of P was increased by T (48.3 vs 57.8%), but urinary excretion also was higher. The ME value of tallow for the lactating sow seems considerably higher than reported values.

Influence of feeding pattern on the biological efficiency of high-yielding dairy cows

SUMMARYAn experiment has been made to study the effect of the pattern of distribution of a fixed amount of production compound on milk yield, milk composition and live-weight change in the first 20 weeks of lactation and any carry-over effects on performance in the remaining part. Adult British Friesian cows of predicted high yield potential were randomly allocated to a graded (G) or flat-rate (F) system of feeding.There was no significant effect of treatment on milk yield, milk composition or yield of milk constituents in the experimental period or in the whole lactation.Live-weight changes were not significantly different between treatments at any stage of lactation. Calculated energy balances showed losses until the 4th week of lactation. Thereafter positive balances occurred but it was not until the 9th week for treatment G and the 15th week for treatment F that the original zero balance was restored. The total balance was in good agreement with live-weight gain for treatment F but not for treatment G.Calculated efficiencies of utilization of metabolizable energy for milk production (Klo) were variable throughout lactation and lower than the currently accepted standards.

Utilization of dietary energy for maintenance, milk production and lipogenesis by lactating crossbred cows during their midstage of lactation.

1. Twenty-four energy and nitrogen balances were determined using twenty-four crossbred cows (Brown Swiss X Sahiwal) during their midstage of lactation. Energy balances were estimated by subtracting milk energy and heat production from the metabolizable energy (ME) intake. Heat production was estimated by indirect calorimetry, by collection and analysis of respiratory gases. The cows were given amounts corresponding to 90, 110 and 130% of the ME and 90 and 110% of the digestible crude protein (DCP) standards of the (US) National Research Council (1966). 2. Energy requirements were estimated by partitioning the ME intake for maintenance, milk production and energy gain or loss by multiple regression of energy balance values. Heat production (and thus energy balance) was corrected for excess N intake. 3. Energy requirements for maintenance were 585-18, 580-17 and 574-41 kJ ME/kg body-weight0.75 per d for cows in negative balance, cows in positive balance and for all cows, respectively. 4. The efficiency of utilization of ME for milk production was 68-52, 65-48 and 66-12% respectively, for cows in negative balance, for cows in positive balance and all cows. Energy required per kg fat-corrected milk production was 4-580, 4-791 and 4-746 MJ ME for the respective groups of cows. 5. The efficiency of utilization of ME for tissue gain was 67-67 and 64-86% for cows in positive balance and for all cows respectively.

The yield and composition of the milk of Finnish Landrace × Blackface ewes: II. Ewes and lambs grazed on pasture

SUMMARYThe milk production of 14 Finnish Landrace × Blackface ewes suckling either single, twin or triplet lambs was recorded while they were wholly maintained on a high-quality grazed pasture. Intravenous administration of oxytocin followed by hand milking was used to estimate milk production within 4 days of parturition and then at weekly intervals during a 12-week lactation period. At each milking the milk from each ewe was retained for analysis. Herbage samples for analysis were cut by hand shears at weekly intervals at a height simulating the harvesting by the sheep. In vitro analysis showed a decline in the digestible organic matter in the herbage from approximately 75% in the early stages, to around 67% at the end of lactation. The percentage crude protein in the dry matter of the herbage was variable but tended to increase towards the end of the lactation period. The estimated mean total milk production values were 125, 176 and 193 kg for single-, twin- and triplet-suckled groups of ewes, respectively. Almost all of the difference in total yield between the groups of multiplesuckled ewes occurred in the first 4 weeks of lactation. Analysis of variance showed no significant differences between suckling groups in the concentration of any of the milk constituents. Regression analysis showed significant evidence for differences between the linear and quadratic components of the regressions on stage of lactation for the suckling groups only in respect of daily milk yield, energy and protein production. The concentration of constituents other than lactose was higher in colostral milk but the differences were statistically significant only in respect of energy, total solids and fat. The lactose content of ordinary milk was significantly higher than that of colostral milk. The mean daily live-weight gains of the single- and twin-suckled lambs were significantly greater than that of the triplet-suckled group.

A Technique for Estimating Milk Production in Rats

Using lactating rats restricted in nursing time or in food intake, a range in milk productions and average daily pup gains suitable for establishment of a relationship between pup gains and milk energy consumption was obtained. First, a relationship between pup gains and water intake was established based on the fact that the only water intake of pups is as milk. Water turnover rates in pups were estimated using tritiated water. The quadratic equation for this relationship, water turnover (%/day) = 11.5ADG(g) - 1.92ADG2(g) + 12.1, had a correlation coefficient of 0.98 and was superior to a linear equation. Based on determinations of rat milk composition and energy content and computations of metabolic body water, the equation was converted to kcal consumed as milk = (11.5ADG(g) - 1.9ADG2(g) + 12.1) × BW(g) × 0.73 × 2.3/100. This equation was validated in a separate experiment and is considered suitable for accurate prediction of rat pup energy consumption and dam milk energy production from rates of pup gain and body weights during week 2 of lactation.

Utilization of nutrients by the dairy cow and optimal N:energy ratio in the diet

SummaryThe dietary and individual animal factors influencing the utilization of digestible nitrogen and of metabolizable energy for milk production were studied and change in the optimal nitrogen:energy ratio during lactation was investigated using 35 different experimental diets and the individual results obtained from 119 Friesian cows whose daily milk production varied from 4 to 30kg.The amount of N secreted in the milk and the daily milk production depended above all on the metabolizable energy intake and on the stage of lactation. They were related to the dietary N: energy ratio.The percentages of digestible N and of metabolizable energy utilized for milk production were also related to the dietary digestible N: metabolizable energy ratio of the diet.The optimal digestible N:metabolizable energy ratio ranged from about 2·2g/MJ during the first 3 months of lactation to about 1·7g/MJ in the sixth and seventh months and 1·3g/MJ from the tenth month. When expressed in g N intake per MJ energy intake, this optimal ratio ranged from 1·6 after calving to 1·1 at the end of lactation.

Relationships between End Products of Rumen Fermentation and Utilization of Metabolizable Energy for Milk Production

Summary Three rations in which the proportion of estimated net energy (ENE) derived from hay or a concentrate mixture of corn meal and soybean meal was varied from 50% hay–50% concentrate (Ration A) to 75% hay–25% concentrate (Ration B) or 100% hay (Ration C) were fed to six, mature, lactating Holstein cows. The end products of rumen fermentation (total methane production and molar proportions of volatile fatty acids in the rumen) were studied in relation to lactation efficiency. Indirect calorimetry was used to measure the efficiency of utilization of metabolizable energy (ME). The molar proportion of acetic acid present in the rumen declined from 71.4 to 65.3% (P The proportions of digestible carbohydrates calculated to be fermented, using a theoretical fermentation balance equation proposed by Wolin, were 86, 84, and 81% for Rations A, B, and C, respectively. The simple correlations between volatile fatty acid (VFA) proportions and lactation efficiency were: r = −0.73 for acetic acid, +0.43 for propionic acid, and +0.67 for butyric acid (P

The yield and composition of milk from sows fed varying proportions of separated milk and concentrates

Summary The results of two experiments are reported, in which the effects of three rations upon the yield and composition of sows' milk and the efficiency of production over the last seven weeks of an eight-week lactation were measured. In the first experiment, conducted in the summer, a ration consisting of 40% separated milk, plus 60% concentrates was compared with a ration of separated milk alone. In the second experiment, conducted in the spring, a milk plus concentrate ration was compared with one of concentrates alone. Milk only and milk plus concentrates were equally efficient in supporting milk production, and both were more efficient than concentra tes alone. The average milk energy production per sow and the mean gross efficiency of milk production for the sows on the four treatments were -Summer Experiment: Milk plus concentrate 313 therms* 47.2%; Milk only 341 therms, 47.6%. Spring Experiment: Milk plus concentrate 383 therms, 53.2%; Concentrates only 308 therms, 44.3%. Milk energy production ...

The Effect of Early Breeding upon the Milk Energy Production of Grade and Purebred Toggenburg Goats

The Effect of Early Breeding upon the Milk Energy Production of Grade and Purebred Toggenburg Goats