Total Metabolizable Energy Intake Research Articles

Simulation of the nutritional requirements and energy balance of adult cows in a northern temperate grassland.

The forage-livestock balance is an important component of natural grassland management, and realizing a balance between the nutrient energy demand of domestic animals and the energy supply of grasslands is the core challenge in forage-livestock management. This study was performed at the Xieertala Ranch in Hulunbuir City, Inner Mongolia. Using the GRAZPLAN and GrazFeed models, we examined the forage-livestock energy balance during different grazing periods and physiological stages of livestock growth under natural grazing conditions. Data on pasture conditions, climatic factors, supplemental feeding, and livestock characteristics, were used to analyze the metabolizable energy (ME), metabolizable energy for maintenance (MEm), and total metabolizable energy intake (MEItotal) of grazing livestock. The results showed that the energy balance between forage and animals differed for adult cows at different physiological stages. In the early lactation period, although the MEItotal was greater than MEm, it did not meet the requirement for ME. MEItotal was greater than ME during mid-lactation, but there was still an energy imbalance in the early and late lactation periods. In the late lactation period, MEItotal could meet ME requirements from April-September. Adult gestational lactating cows with or without calves were unable to meet their ME requirement, especially in the dry period, even though MEItotal was greater than MEm. Adult cows at different physiological stages exhibited differences in daily forage intake and rumen microbial crude protein (MCP) metabolism, and the forage intake by nonpregnant cows decreased as follows: early lactation > mid-lactation > late lactation, pregnant cows' lactation > dry period. For the degradation, digestion and synthesis of rumen MCP, early-lactation cows were similar to those in the mid-lactation group, but both were higher than those in the late-lactation group, while pregnant cows had greater degradation, digestion, and synthesis of MCP in the lactation period relative to the dry period. For lactating cows, especially those with calves, grazing energy requirements, methane emission metabolism and heat production were highest in August, with increased energy expenditure in winter. Overall, grazing energy, methane emissions and heat production by dry cows were low. In the context of global climate change and grassland degradation, managers must adopt different strategies according to the physiological stages of livestock to ensure a forage-livestock balance and the sustainable utilization and development of grasslands.

Effect of different feeding strategies and dietary fiber levels on energy and protein retention in gestating sows.

The aim of the study was to investigate whether increased inclusion of sugar beet pulp (SBP) alters retention of fat, protein, and energy when backfat (BF) is restored in early- and mid-gestation. In total, 46 sows were fed one of four dietary treatments with increasing inclusion of SBP providing dietary fiber (DF) levels of 119, 152, 185, and 217g/kg; sows were assigned to one of three feeding strategies (FS; high, medium, and low) depending on BF thickness at mating and again at day 30 for the following month. On days 0, 30, 60, and 108, body weight (BW) and BF thickness were measured and body pools of protein and fat were estimated using the deuterium oxidetechnique. On days 30 and 60, urine, feces, and blood samples were collected to quantify metabolites, energy, and nitrogen (N) balances. On days 15 and 45, heart rate was recorded to estimate heat energy. At farrowing, total born and weight of the litter were recorded. In early gestation, BW gain (P < 0.01) and body protein retention increased (P < 0.05) with increasing fiber inclusion, while body fat retention increased numerically by 59%. The increase in BF was greatest for sows fed the high FS, intermediate when fed the medium strategy, and negligible for sows fed the lowest FS (P < 0.001). Nitrogen intake, N loss in feces, and N balance increased linearly, whereas N loss in urine tended to decrease with increasing inclusion of fibers in early gestation. Concomitantly, fecal energy output and energy lost as methane increased linearly (P < 0.001), while energy output in urine declined linearly. Total metabolizable energy (ME) intake therefore increased from 36.5 MJ ME/d in the low fiber group to 38.5 MJ ME/d in the high fiber group (P < 0.01). Changing the ME towards more ketogenic energy was expected to favor fat retention rather than protein retention. However, due to increased intake of ME and increased N efficiency with increasing fiber inclusion, the sows gained more weight and protein with increasing fiber inclusion. In conclusion, increased feed intake improved both fat and protein retention, whereas increased DF intake increased protein retention.

Fat composition of milk replacer influences growth performance, feeding behavior, and plasma fatty acid profile in ad libitum–fed calves

Fat composition in milk replacers (MR) for calves differs from bovine milk fat in multiple ways. The aim of the study was to investigate the impact of different approaches of formulating fat in MR on growth, ad libitum intakes of MR and solid feeds, as well as blood metabolites in dairy calves. Upon 24 to 96 h after birth, 63 calves were acquired from dairy farms and incorporated into the study. Calves were blocked based on arrival day and randomly assigned within each block to one of 3 treatments differing in MR fat composition (n = 21 per group): VG was based on vegetable fats including 80% rapeseed and 20% coconut fats; AN was formulated with animal fats including 65% lard and 35% dairy cream; and MX with a mixture of 80% lard and 20% coconut fats. All 3 MR contained 30% fat, 24% crude protein, and 36% lactose and were formulated to have a fatty acid profile resembling that of milk fat. From arrival onward (3.1 ± 0.84 d of age; means ± standard deviation), calves were group housed and were offered an ad libitum supply of MR at 135 g/L (13.5% solids). Weaning was gradual and induced between wk 7 and 10, after which calves were fed only solid feeds. Starter feed, chopped straw, and water were offered ad libitum throughout the study. Calves were weighed, and blood was collected weekly until d 84 after arrival. Preweaning average daily gain was greater in calves fed AN (915 g/d) than other treatments (783 g/d), whereas no differences were detected in the weaning and postweaning phases. Preweaning MR intake was greater in calves fed AN than MX from wk 2 to 6 and was also higher in calves fed AN than VG in wk 5 and 6. Consistently, the number of rewarded visits during the ad libitum phase was greater in calves fed AN than MX, whereas VG showed no differences. This led to a higher preweaning total metabolizable energy intake in calves fed AN than in calves fed VG and MX. Serum cholesterol was higher, and serum albumin was lower in calves fed VG than other treatments. The proportion of high-density lipoprotein cholesterol in total plasma cholesterol was lower and that of low-density lipoprotein (LDL) cholesterol was higher in calves fed VG compared with other treatments. Overall, the fatty acid profile of plasma largely mirrored the MR fat composition during the preweaning period. Feeding AN enhanced MR intake and improved preweaning growth compared with other treatments. Feeding VG resulted in a marked increase in plasma cholesterol, particularly in the form of LDL cholesterol, which could be linked to an excessive intake of polyunsaturated fatty acids. These findings underscore the importance of formulating the fat content of MR to be similar to bovine milk fat.

Increased feed supply and dietary fiber from sugar beet pulp improved energy retention in gestating sows.

The aim of the study was to investigate whether increased inclusion of sugar beet pulp (SBP) alters retention of fat, protein, and energy when backfat (BF) is restored in early- and mid-gestation. In total, 46 sows were fed one of four treatments with increasing inclusion of SBP with dietary fiber (DF) levels of 119, 152, 185, and 217g/kg; sows were assigned to one of three feeding strategies (FS; high, medium, and low) depending on BF thickness at mating and again at day 30 for the following month. On days 0, 30, 60, and 108, body weight (BW) and BF thickness were measured, and body pools of protein and fat were estimated using the deuterium technique. On days 30 and 60, urine, feces, and blood samples were collected to quantify metabolites, energy, and N balances. On days 15 and 45, heart rates were recorded to estimate the heat production. At farrowing, total born and weight of the litter were recorded. In early gestation, BW gain (P < 0.01) and body protein retention increased (P < 0.05) with increasing fiber inclusion, while body fat retention increased numerically by 59%. Increase in BF was the greatest for sows fed the high FS, intermediate when fed the medium strategy, and negligible for sows fed the lowest FS. N intake, N loss in feces, and N balance increased linearly, whereas N loss in urine tended to decrease with increasing inclusion of fibers in early gestation. Concomitantly, fecal energy output and energy lost as methane increased linearly (P < 0.001), while energy output in urine declined linearly, and total metabolizable energy intake, therefore, increased from 40.5 MJ ME/d in the low-fiber group to 43.5 mega joule (MJ) metabolizable energy (ME)/d in the high-fiber group (P < 0.001). Changing the metabolizable energy toward more ketogenic energy was expected to favor fat retention rather than protein retention. However, due to increased intake of metabolizable energy and increased N efficiency with increasing fiber inclusion, the sows gained more weight and protein with increasing fiber inclusion. In conclusion, increased feed intake improved both fat and protein retention, whereas increased DF concentration increased protein retention.

Effects of step-down weaning implementation time on growth performance and blood metabolites of dairy calves

The current study evaluated the effects of step-down weaning implementation time on starter feed intake, growth performance, blood metabolites, and ruminal pH in dairy calves. A total of 48 Holstein dairy calves (24 male and 24 female; 3 ± 1 d old; 41.2 ± 1.8 kg of body weight) were assigned (n = 12 per treatment; 6 male and 6 female) to 4 experimental treatments in a completely randomized block design. All calves were fed 6 L/d of milk from d 3 to 10 of age, and the treatments consisted of the following: calves were offered 8 L/d of milk from d 11 to 28 of age and then 4 L/d from d 29 to 63 (Step-28; total milk offered = 326 L); calves were offered 8 L/d of milk from d 11 to 42 of age and then 4 L/d from d 43 to 63 (Step-42; total milk offered = 382 L); calves were offered 8 L/d of milk from d 11 to 56 of age and 4 L/d from d 57 to 63 (Step-56; total milk intake = 438 L); and calves were fed 8 L/d of milk from d 11 to 63 of age and abruptly weaned (control; total milk offered = 466 L). All calves were housed individually in pens and had ad libitum access to water and solid feed throughout the experiment. All calves were completely milk weaned on d 64, and their performance was measured until d 80 of age. During the experiment, the starter intake (kg/d and % of body weight) was greater in calves in the Step-28 group compared with those in the other groups. However, the total metabolizable energy intake was greater in the Step-56 calves compared with the other calves. Overall, the average daily gain (ADG), feed efficiency (ADG/dry matter intake), and ADG/total metabolizable energy intake were similar across the treatments. Circulating glucose, β-hydroxybutyrate, blood urea nitrogen, albumin, total protein, alanine aminotransferase, and aspartate aminotransferase, as well as ruminal pH, were not affected by the treatments. The implementation of step-down weaning in early life (4-6 wk of age) could stimulate solid feed intake compared with weaning at a later age with no negative effect on performance.

Living near the limits: Effects of interannual variation in food availability on diet and reproduction in a temperate primate, the Taihangshan macaque (Macaca mulatta tcheliensis).

Nutrient intake of animals is influenced by an interplay of external and internal factors, such as food availability and reproductive state, respectively. We used the nutritional geometry framework to analyze individual-based data on energy and nutrient intake in relation to reproductive state in a population of rhesus macaques (Macaca mulatta tcheliensis), which live in a harsh high-latitude habitat, the Taihangshan mountains of China, and exhibit strong reproductive seasonality. We combined data over a 3-year period on food availability, diets, reproductive output, and components of maternal investment to understand how Taihangshan macaques respond to variation in food availability and nutrition in reproduction. Our results show there was high interannual variation in availability of an important staple source of fat and carbohydrates (nonprotein energy), seeds of oak (Quercus spp). Despite this variability in seed availability skewing the dietary macronutrient ratios considerably (from 12.96% to 30.12% dietary energy from protein), total metabolizable energy intake was maintained across years during pregnancy. Lactating females had higher mean daily energy intakes than pregnant females. As in pregnant females, energy intake was maintained constant across years, but only when seed availability enabled the contribution of available protein to energy intake to be maintained between 15.32% (2013) and 17.97% (2015). In 2014, when seeds were scarce, lactating females had a shortfall in energy intake compared with 2013 and 2015. This corresponded with a reduction in the number of females giving birth (11 out of 23), but there was no interannual difference in survival rates. Compared to 2013 and 2015, in 2014 females had greater weight loss (drew on body reserves), moved less, and spent more time nursing their offspring. We discuss implications of these results for range limitation in Taihangshan macaques.

PSX-4 Performance of lambs born from ewes fed with different energy levels

Abstract The objective of this study was to evaluate the performance, under confinement conditions, of lambs born from ewes fed different energy levels during the final gestation and lactation period. Seventy-one ewes were distributed in two treatments according to the metabolizable energy (ME) levels in the diet: CTL = according to the NRC (2007) recommendations for each stage (gestation and lactation); PLUS = CTL plus 10% of energy per kilogram of dry matter. The total ME intake for the CTL group was 4 and 4.2 Mcal/day during the end of gestation and lactation, respectively, and for the Plus group, the ME intake were 4.8 and 5 Mcal/day. Thirty-five intact male lambs were weaned at 60 days and confined for an additional 60 days. In confinement, lambs were fed ad libitum with the same experimental diet their ewes received. The experimental design was analyzed as randomized complete blocks. The metabolic weight (BW0.75) at the confinement was influenced by maternal nutrition. Lambs of ewes fed with lower energy content were lighter compared to the PLUS group. At the beginning and the end of the confinement, the BW0.75 of the CTL was 8.80 and 15 kg0.75, and the PLUS was 11.4 and 17.6 kg0.75, respectively (P &amp;lt; 0.0001). The maternal diet containing higher energy content resulted in heavier carcass for commercialization. The values of weight gain and feed conversion were not influenced by maternal nutrition (P &amp;gt; 0.005), with mean values of 350 and 4.72 g/d, respectively. We concluded that lambs from ewes fed with greater energy intake had heavier body weights at the beginning and at the end of the confinement, possibly increasing the sustainability of the meat lamb production systems.

Effects of rate and amount of propionic acid infused into the rumen on feeding behavior of Holstein cows in the postpartum period

The objective of this study was to determine the effects of 2 amounts of propionic acid (PA) infused intraruminally at 2 rates of infusion at the initiation of meals on the feeding behavior of Holstein cows in the postpartum period. We hypothesized that the amount and length of time of infusions would interact to affect feeding behavior: rapid infusion of a higher dose of PA would result in larger meal size with greater time between meals compared with a slower rate, whereas faster infusion of a lower dose of PA would reduce meal size and the time between meals compared with a slower infusion of the same dose. Eight ruminally cannulated, multiparous Holstein cows were used in a 4 × 4 Latin square design experiment. Cows were blocked by parturition date and randomly assigned to treatment sequence within square. Treatments were infusion of 2.5 L of 0.5 M (HI) or 0.2 M (LO) solutions of PA at initiation of meals over 5 min (FST) or 15 min (SLW) for 12 h following feed delivery. Contrary to our hypothesis, no interaction between amount and rate of infusion was detected for any feeding behavior parameter measured. The FST treatments did not affect dry matter intake or metabolizable energy intake compared with SLW. The FST treatments tended to increase meal length compared with SLW (28.1 vs. 22.7) but did not affect meal size. The FST treatments tended to decrease total eating time (108 vs. 122 min/12 h) but did not affect meal frequency compared with SLW. The HI treatments decreased dry matter intake (7.4 vs. 11.5 kg/12 h) and total metabolizable energy intake (22.5 vs. 29.1 Mcal/12 h) compared with LO by decreasing meal frequency (5.8 vs. 7.5 meals/12 h). The HI treatments decreased eating time (103 vs. 127 min/12 h) compared with LO but did not affect meal size. Further research is warranted on the effects of the temporal supply of propionate on propionate metabolism and feeding behavior.

Fuels derived from starch digestion have different effects on energy intake and metabolic responses of cows in the postpartum period

Absorbed fuels from the digestion of starch include propionic acid (PA) produced by ruminal fermentation and glucose (GLU) from intestinal digestion, which may be partially metabolized to lactic acid (LA) by intestinal tissues. Our objective was to evaluate the effects of these fuels on dry matter intake (DMI) and feeding behavior of cows in the postpartum period. We hypothesized that these fuels affect feed intake differently and that their effects are related to differences in their hepatic metabolism. Glucose was expected to have little effect on feed intake because little or no GLU is extracted from the blood by the liver. Whereas both LA and PA are anaplerotic and can stimulate oxidation of acetyl CoA in hepatocytes, hepatic extraction of PA is greater than LA, which depends on cytosolic redox state. Continuous isoenergetic infusions (150 kcal of ME/h) of PA, LA, or GLU or no infusion were administered abomasally to 8 ruminally cannulated multiparous Holstein cows (12.4 ± 6.2 d postpartum) in a duplicate 4 × 4 Latin square design experiment, with four 1-d infusion periods, balanced for carry-over effects. Treatment sequences were assigned to cows randomly, and treatments included control (CON, no infusion), PA (0.41 mol/h), LA (0.46 mol/h), and GLU (0.22 mol/h). Solutions containing treatments were infused at 500 mL/h for 22 h/d and provided ∼3.3 Mcal/d. Feeding behavior was recorded by a computerized data acquisition system. Gross energy digestibility of the diet was determined for each cow and used to calculate metabolizable energy intake (MEI) from the diet. Total MEI was calculated as the sum of MEI from the diet plus energy from infusions. Data were analyzed statistically with a mixed model including the fixed effect of treatment and random effects of block and cow within block. Each treatment was compared with CON by contrasts. Compared with CON, PA decreased DMI by 24% (14.3 vs. 18.9 kg/d) and total MEI by 13% (34.8 vs. 40.2 Mcal/d) with a tendency to decrease meal frequency. Lactic acid decreased DMI by 14% (16.3 vs. 18.9 kg/d) compared with CON by decreasing meal size 20% but did not affect MEI. Glucose infusion did not affect DMI or MEI. Treatment effects on DMI and MEI were consistent with their expected effects on hepatic oxidation. Depression of feed intake in diets containing highly fermentable starch is likely because of differences in hepatic metabolism.

Increased anaplerosis of the tricarboxylic acid cycle decreased meal size and energy intake of cows in the postpartum period

The objective of this study was to determine the effects of anaplerosis of the tricarboxylic acid cycle on feeding behavior and energy intake of cows in the postpartum period. We infused propionic acid (PA) and glycerol (GL) continuously into the abomasum and hypothesized that PA will decrease meal size and energy intake compared with GL because PA enters the tricarboxylic acid cycle, likely stimulating oxidation of acetyl CoA and satiety compared with GL. Three experiments (Exp.) were conducted using 20 Holstein cows between 3 and 22 d postpartum (8 cows in Exp. 1 and 6 cows each for Exp. 2 and 3). Treatments were compared using isoenergetic (Exp. 1, 193 kcal/h) and isomolar (Exp. 2, ∼0.5 mol/h) continuous infusions of PA (99.5%) and GL (99.7%) to the abomasum using a double crossover design with four 2-d infusion periods each, and 2 mol of PA or GL pulse-dosed to the abomasum using a crossover design (Exp. 3). Treatment sequences were assigned alternately to cows based upon date of parturition. Feeding behavior was recorded by a computerized data acquisition system for Exp. 1 and 2. Propionic acid decreased dry matter intake (DMI) compared with GL 16.7 and 23.4% in Exp. 1 and 2, respectively. The decrease in DMI was because PA decreased meal size compared with GL by 12.6 and 15.3% in Exp. 1 and 2, respectively. Propionic acid decreased total metabolizable energy intake (diet plus treatment infusions) compared with GL for both experiments. Compared with PA, GL increased plasma glucose and insulin concentrations for Exp. 2 only. In Exp. 3, PA decreased hepatic acetyl CoA content 34%, whereas GL increased hepatic acetyl CoA content 32%, resulting in lower hepatic acetyl CoA content for PA compared with GL at 30 min (18.0 vs. 36.9 nmol/g), which persisted at 60 min after dosing (21.9 vs. 32.8 nmol/g). Consistent with our hypothesis, the obligatory anaplerotic metabolite PA decreased meal size, DMI, and total metabolizable energy intake compared with GL, likely because of differences in their hepatic metabolism.

Different milk feeding intensities during the first 4 weeks of rearing in dairy calves: Part 1: Effects on performance and production from birth over the first lactation

We aimed to test the effects of ad libitum feeding of whole milk (WM) or milk replacer (MR) versus restrictive feeding of MR during the first 4 wk of life on growth performance and on milk yield in the first lactation. We studied 57 German Holstein calves (29 females, 28 males) from birth until d 110 of life (trial 1). The 28 females from trial 1 were further studied during their first lactation (trial 2). In trial 1, all calves were randomly allocated at birth to 1 of 3 groups: MR-res [n = 20, 6.78 kg MR (11.5% solids)/calf per day], MR-ad lib (n = 17, 13.8% solids) or WM-ad lib (n = 20). All calves received colostrum ad libitum from their dam until d 3 of age. From d 4 to 27, calves were fed according to their group regimen. From d 28 to 55, all calves received MR-res feeding and were then gradually weaned until d 69. We recorded body weight (until d 110) and feed intake (amount, metabolizable energy, and frequency of liquid feed intake until weaning). We estimated the profitability of the different feeding regimens, taking into account income from milk yield (trial 2) and feed costs during rearing. In trial 1, the calves from WM-ad lib and MR-ad lib had total metabolizable energy intakes 2.02- and 1.65-fold greater than the MR-res group during the first 4 wk of life. During this period, concentrate intake did not differ among groups, but tended to be greater in WM-ad lib than in MR-ad lib calves from d 28 to 69. The MR-res calves visited the automatic feeders more often than the ad libitum-fed groups during differential feeding, but 70% of the visits were unrewarded (<10% in the ad libitum-fed calves). When all calves were fed at the MR-res level, the average proportion of unrewarded visits was 65% in all groups. Average daily gain and body weight were greater among MR-ad lib and WM-ad lib calves than among MR-res animals during the first 4 wk of life, but not from d 1 to 110. In trial 2, age at first calving, dry matter intake, and body weight over the first 10 mo of lactation were not different among groups, nor was milk composition. Milk yields (305 d) were numerically but not statistically greater in the ad libitum-fed groups during the first lactation (+765 kg for WM-ad lib vs. MR-res; +612 kg for MR-ad lib vs. MR-res). Feeding WM-ad lib and MR-ad lib was 1.37- and 1.21-fold more costly than MR-res, respectively, but amounted to 18, 15, and 13% of the total estimated feed costs until first calving in WM-ad lib, MR-ad lib, and MR-res, respectively. Our study confirms that ad libitum feeding is an attractive measure for rearing dairy calves, both for animal welfare and-with the caveat of a small sample size in trial 2 that led to insufficient power-economic profit from milk.

Study on the on-Farm Post-Natal Nutritional Status of Red Chittagong Cows in Selected Breeding Habitat of Satkania Upazila of Chittagong District of Bangladesh

The aim of the on farm feeding trials was to investigate the post-natal nutritional status of Red Chittagong (RC) cows. Farmers who had at least one post-natal RC cow were involved in this study. A total of ten farmers were randomly selected. The study was carried out in Satkania Upazila of Chittagong district of Bangladesh for a period of six months from July 2010 to December 2010. Immediately after calving ten post-natal RC cows from each of 10 farmers between 2 and 3 parities were selected in this experiment. The offered feeds and leftover feeds were weighted and recorded daily. The cows and calves were weighed individually at weekly interval by using portable digital weighing balance and recorded. The milking was done by hand milking. The milk yield of ten cows was measured immediately after milking and recorded regularly. The milk yield in morning and afternoon were considered as daily milk yield in kg. The average total dry matter, metabolizable energy and crude protein intake were 3.53 kg, 27.56 MJ and 281 g per cow per day, respectively, whereas, the average total DM, ME and CP requirements were 5.11 kg, 39.88 MJ and 465g, per cow per day, respectively. The requirement was higher than the intake. The DM, ME and CP were deficit by 1.58 kg, 12.32 MJ and 184 g per cow per day, respectively. The average daily live weight loss of cows was 12 g. The average daily milk yield of RC cows was 2.45 kg. The milk fat was 4.15 g per 100g milk. The nutritional status of post-natal Red Chittagong cows was negative balance. Consequently, their production performances are affected. Therefore, the farmers feeding system is urgent to improve.

Supplemental fat for dairy calves during mild cold stress

Eighty-one Holstein and Holstein-cross dairy calves fed calf milk replacer (CMR) were used to determine response to increasing amounts of supplemental fat during mild cold stress. Calves (n=27) were randomly assigned to 1 of 3 treatments: (1) low fat [LF; 28% crude protein:15% fat milk replacer (28:15 MR)]; (2) medium fat [MF; 28:15 MR+113g/d of commercial fat supplement (FS)]; (3) high fat (HF; 28:15 MR+227g/d of FS). The MF and HF calves received FS from d 2 to 21, and all calves were fed LF from d 22 to 49. The CMR was fed at 1.4% of birth body weight (BBW) from d 1 to 10, at 1.8% of BBW from d 11 to 42, and at 0.9% of BBW from d 43 to 49. Calves were weaned on d 49 and remained in hutches until d 56. The CMR was reconstituted to 13% solids. Calves were fed a commercial starter grain (19.2% crude protein on a dry matter basis) ad libitum and offered warm water after CMR feeding. Calves were fed CMR twice daily at 0630 and 1730h in hutches bedded with straw. Starter intake, CMR intake, and ambient temperature were measured daily, and body weight (BW), hip height, and body length were measured weekly. Data were analyzed using PROC MIXED in SAS (SAS Institute Inc., Cary, NC) as a randomized design with linear and quadratic contrasts. Calf BBW averaged 42.0±1.0kg, total serum protein averaged 5.8±0.1mg/dL, and birth ambient temperature averaged 5.0±1.1°C. Feeding FS increased metabolizable energy intake (MEI) over maintenance but decreased efficiency of conversion of BW gain:MEI. Starter intake by LF calves was greatest until the beginning of weaning, after which starter intake was similar among treatments. Because of higher starter intake, total MEI was similar among treatments. Feed efficiency through d 49 was greater for calves fed MF and HF. Average daily gain during fat supplementation was greater for MF and HF than for LF. Lack of increase in BW gain and feed efficiency between MF and HF treatments indicated that HF did not result in advantages over MF. Supplementing fat to preweaned calves fed CMR increased BW gain and decreased starter intake through d 21 which had carryover effects on starter intake on d 49 and reduced hip height and tended to reduced withers height and body length by d 56. The addition of supplemental fat to LF, during mild cold stress, may result in a suboptimal ratio of crude protein to metabolizable energy in the CMR.

Voluntary selection of starter feed ingredients offered separately to nursing calves

The objective of this study was to evaluate whether calves exposed to different ingredients would consume solid feed in a similar manner than those offered the same ingredients mixed in a starter concentrate. Thirty-eight Holstein calves (initial live weight 41.0kg and 7 days of age) were randomly assigned to a control (CTR) treatment consisting of a starter feed composed of ground corn (47.2%), soybean meal (20%), oats meal (11%), barley meal (10.1%), soybean hulls (8%), and full fat soybean (1.2%), or to a choice (CH) treatment consisting of 6 ingredients, that composed the starter of CTR calves, offered in separated buckets to each animal. Intake was recorded daily, and calves were weighed twice a week. Samples of fresh feed were taken every week and pooled for subsequent determination of nutrient composition. No differences were observed between treatments on total dry matter intake (DMI), solid feed intake, average daily gain (ADG), and gain to feed ratio. However, animals in the CH group consumed more crude protein (CP; P<0.01) and fat (P<0.01) than CTR calves. On the other hand, CH calves ingested less non-fibrous carbohydrates (NFC; P<0.01) than those in the CTR group. Despite these differences in nutrient intake, there were no differences in total metabolizable energy (ME) intake between CH and CTR animals. However, the CP to ME ratio was greater (P<0.01) in CH (81g of CP/Mcal of ME) than in CTR calves (53g of CP/Mcal of ME). Calves in CH group consumed less (P<0.01) corn and oats meal, and more (P<0.01) full fat soybean than CTR animals. Within the CH group of calves, soybean meal was most (P<0.01) preferred (32.8% of solid feed intake), whereas oats meal (3.5% of solid feed intake) was the least preferred (P<0.01). In terms of total amount consumed, no differences were observed among corn meal, full fat soybean, and barley meal. In conclusion, compared with calves fed a single starter feed, calves that were offered a choice of ingredients selected a diet with greater levels of CP and fat, and lower in NFC. Despite differences in nutrient consumption of the final diet consumed, no differences were observed in total DMI, solid feed intake, ADG, and gain to feed ratio. It is concluded that young calves are unable to select ingredients based on their nutrient requirements.

Hypophagic effects of propionate increase with elevated hepatic acetyl coenzyme A concentration for cows in the early postpartum period

Thirty multiparous lactating dairy cows were used in a randomized block design experiment to evaluate factors related to the degree of hypophagia from intraruminal infusion of propionate. Cows between 3 and 40 d postpartum at the start of the experiment were blocked by calving date and randomly assigned to treatment. Treatments were 1.0mol/L propionic acid or 1.0mol/L acetic acid adjusted to pH 6 with sodium hydroxide and infused at 0.5mol of volatile fatty acid/h from 6h before feeding until 12h after feeding. Propionate infusion decreased dry matter intake by 20.0%, total metabolizable energy intake by 22.5%, and plasma β-hydroxybutyrate concentration by 54.3% compared with acetate infusion. Effects of treatment on dry matter intake were related to concentration of acetyl coenzyme A (CoA) in the liver; hypophagic effects of propionate compared with acetate increased as liver acetyl CoA concentration increased. Hypophagic effects of propionate are greater for cows with elevated concentrations of acetyl CoA in the liver.

EFFICIENCY ANALYSIS OF CASPIAN CATTLE FEEDLOT FARMS BY DATA ENVELOPMENT ANALYSIS

Data envelopment analysis (DEA) is an excellent approach for evaluating the performance of decision making units (DMUs) that use multiple inputs to produce multiple outputs. This research utilizes the DEA to analyze the operating efficiency of Caspian cattle feedlot farms in Iran. The inputs utilized by the farms are number of calve, number of labors, total metabolizable energy intake, total crude protein intake and total cost of hygiene-treatment of calve; and the output considered is total live weigh gain of calve. By using two DEA models, the efficiency score for each farm is calculated and the efficient farms are ranked.

Effects of substitution of a proportion of the concentrate in grass silage/concentrate-based diets with extruded linseed on performance and meat quality of dairy bulls

This study investigated effects of substituting a proportion of the concentrate in a grass silage:concentrate-based diet with 0, 400, 800 or 1200 g extruded linseed/head/day on the performance and meat quality of dairy bulls. Forty-eight dairy-breed bulls ( i.e. 18 Holstein-Friesian, 6 Norwegian, 4 Norwegian × Holstein-Friesian, 12 Holstein × Norwegian and 8 Jersey × Holstein-Friesian), initial live weight (LW) and age 350 ± 30.9 kg and 11 ± 0.7 months, respectively were used. Grass silage was fed ad libitum and concentrates were fed daily on top of the silage. Concentrate intake was adjusted to ensure that total metabolizable energy intake from the supplement component of the diet ( i.e. concentrate plus linseed) was constant among all treatments. Animals were slaughtered at a target LW at slaughter of 540 kg and so were slaughtered in three batches after 120, 147 and 185 days on experiment. Substitution of a proportion of the concentrate diet with extruded linseed had no effects on animal performance ( i.e. dry matter intake, LW gain or carcass characteristics). Meat quality, in terms of cooking loss, sarcomere length, Warner Bratzler Shear Force, Commision Internationale de l’Eclairage (CIELAB) colour parameters L*, a*, b*, C* and Hue angle were not affected by dietary treatment. Substitution of a proportion of the concentrate diet with extruded linseed decreased palmitic acid (C16:0) and arachidonic acid (C20:4) concentrations ( P<0.05), saturated:unsaturated fatty acid (FA) ratio ( P<0.05) and the n-6:n-3 polyunsaturated FA (PUFA) ratio ( P<0.001) in muscle. Trans vaccenic acid (C18:1 t11), α-linolenic acid (C18:3n-3), n-3 PUFA ( P<0.05) and the ratio of PUFA:saturated (P:S) FA ( P<0.01) in muscle were increased by the linseed treatment. Results demonstrate the ability to manipulate the FA composition of the meat of dairy bulls by substituting a proportion of the concentrate diet with extruded linseed, with no detrimental effects on their performance or instrumental meat quality.

Effect of suckling (‘restricted suckling’) on dairy cows’ udder health and milk let-down and their calves’ weight gain, feed intake and behaviour

The aim of this study was to evaluate the effects of restricted suckling (RS) in Holstein cattle on the weight gain, health and behaviour of calves and on udder health and milk let-down in cows compared to artificial rearing (AR). The study was conducted in Mexico. The 27 cows with calves were assigned to one of the two treatments and studied until weaning 8 weeks postpartum. Cows were milked three times daily. RS calves were allowed to suckle for 30 min 2 h after morning and afternoon milking, whereas AR calves were fed milk from buckets through a floating nipple at the same time. During suckling/milk feeding, the AR calves performed more oral behaviours such as ‘cross-suck’ and ‘lick object’ than RS calves. The RS calves spent a longer time suckling on the front teats than the rear teats. During observations of general behaviour when calves were not milk fed, AR calves displayed more often ‘cross-suck’, ‘lick object’, ‘eat concentrate’, ‘eat hay’ and ‘ruminate’ than RS calves. Milk consumption (286 kg) over 8 weeks in both groups and live weight gain (LWG) were similar in RS (26.2 ± 3.9 kg) and AR calves (26.1 ± 1.4 kg), but the individual variation in LWG was higher in RS calves. The milk suckled by RS calves contained more fat and metabolisable energy (ME) per kg than the parlour milk fed to AR calves (6.1% vs. 4.2% and 3.5 MJ/kg vs. 2.9 MJ/kg) whereas AR calves ingested more than fourfold as much concentrate as RS calves (21.6 kg vs. 4.8 kg), which resulted in similar total ME intake in treatments. The California Mastitis Test scores revealed a tendency to improved udder health in RS cows compared to AR cows. The average time to milk let-down was similar in treatments. In conclusion, the RS system with the Holstein dairy cattle reduced ‘cross-sucking’ and ‘licking objects’ in the calves and tended to improve udder health in the cows, compared to the AR system.

Aporte de energia, composição e eficiência microbiana em bovinos alimentados com feno de capim-marandu e concentrado balanceados para diferentes ganhos de peso e potenciais de fermentação microbiana

Um experimento foi realizado com o objetivo de avaliar o aporte de energia, a composição de bactérias e a eficiência microbiana por tourinhos Santa Gertrudes canulados no rúmen e no duodeno alimentados com dietas compostas de feno de capim-marandu e concentrado. Empregou-se o delineamento em quadrado latino 4 &lt;FONT FACE=Symbol&gt;´&lt;/FONT&gt; 4, no qual os tratamentos foram concentrados ajustados para ganho de peso corporal (GPC) diário de 0,5 e 1 kg/animal e potencial de fermentação microbiana (y) de 9,5 e 11 g de PB microbiana/MJ energia metabolizável fermentável. Houve diferença para as concentrações de nutrientes digestíveis totais (NDT) e energia metabolizável fermentável (EMFe) ingeridos e para a composição em matéria orgânica e mineral das bactérias ruminais para as dietas ajustadas para diferentes GPC. Houve interação significativa GPC &lt;FONT FACE=Symbol&gt;´&lt;/FONT&gt; y para a ingestão de NDT como porcentagem do peso corporal e a composição em PB e carboidratos totais das bactérias ruminais. Não foram encontradas diferenças para os potenciais de fermentação microbiana. A eficiência de síntese microbiana também não diferiu entre as dietas e apresentou valores de 12,7 g PB microbiana/100 g NDT e 9,2 g PB microbiana/MJ EMFe. As diferenças encontradas não justificaram o balanceamento dos concentrados para os diferentes potenciais de fermentação microbiana avaliados.

Partitioning of metabolizable energy intake in sucking altricial and precocial rodent pups

AbstractWe partitioned the metabolizable energy intake (MEI) into energy for maintenance (MEm) and for growth (MEg) in sucking precocial and altricial rodent pups. Each of the two components includes energy loss due to the heat increment of feeding. MEm of precocial pups expressed as average daily energy costs or as a proportion of MEI was greater than in altricial pups of similar size and, therefore, less energy was available for growth. Consequently, the overall energy cost (via total MEI) per unit postnatal growth of precocial pups was greater than for altricial pups of similar size. We used the proportion of calculated MEm to that predicted by body mass as an index of precociality in rodent pups. The proportion of MEg to MEI in precocial pups was lower than in altricial pups and was inversely related to the index of precociality.