Mean Dry Matter Intake Research Articles

Short communication: Effect of a stable pen management strategy for precalving cows on dry matter intake, plasma nonesterified fatty acid levels, and milk production

During the close-up transition period, dairy cows are at risk for negative energy balance due to increasing energy demands and decreasing feed intake. This can result in postparturient health problems and decreased milk production after calving. Cows are frequently regrouped during this period, which can negatively affect feeding and resting behavior. The hypothesis was that housing in a stable pen during the close-up transition period should result in a more settled environment resulting in fewer displacements from the feed bunk, which would result in improved feed intake, energy balance [lower nonesterified fatty acid (NEFA) concentrations], and lactation performance. This study addresses precalving pen grouping strategies, which have the potential to affect feed intake and energy balance. A randomized complete block design with pen as the experimental unit was used to compare a stable (S) housing strategy (cows with similar calving dates added to a precalving pen at once) to the more traditional dynamic (D) housing strategy (cows added up to 2 times per week to a precalving pen). Twice-weekly blood samples were collected for NEFA analysis and cow interactions within the pen were observed. Dry matter intake (DMI), milk production, and postparturient health problems were recorded. Mean DMI for the duration of the 28 d of the study was not different (S: 25.5±1.6 vs. D: 25.7±1.0 kg/d), and when examined over time relative to calving, no treatment by time interaction was observed. Concentrations of NEFA were not different when cows initially entered the pens (S: 0.21±0.10 vs. D: 0.18±0.04 mEq/L) and remained not different for the time intervals closer to calving (d −9 to −14: S: 0.28±0.09 vs. D: 0.21±0.04; d −3 to −6: S 0.36±0.10, D 0.32±0.05 mEq/L). Pen grouping strategy did not affect DMI, plasma NEFA concentrations, or milk production.

Energy and protein as nutritional drivers of lactation and calf growth of farmed red deer

Red deer calf growth rates from birth to 12weeks of age seldom exceed 450g/day on the best quality ryegrass/white clover pastures offered to lactating hinds over summer. However, the genetic potential for calf growth exceeds that observed on most farms. The metabolisable energy (ME) content of feed is traditionally used as the measure of feed quality for lactating hinds. The present study investigated the possibility that protein, rather than energy, content of forage may be a more important determinant of hind lactation performance and calf growth for red deer. A total of 16 mature red deer hinds pregnant to a red deer stag were calved indoors in individual pens. For the duration of their 12-week lactation they were each given daily ad libitum offers of pellet ration (+5% by weight of lucerne hay) that contained either low energy/low protein (LE/LP), low energy/high protein (LE/HP), high energy/low protein (HE/LP) or high energy/high protein (HE/HP) (i.e. n=4 per treatment). Calves and hinds were weighed weekly during the study. The mean dry matter intake of hinds was significantly higher (by about 35–40%) for hinds receiving low energy rations (i.e. LE/LP and LE/HP groups) irrespective of protein content. This resulted in all treatment groups exhibiting the same average energy intake, providing strong evidence for ‘energy balancing’ of feed intake (i.e. intake compensates for energy content of feed). As a consequence of “energy balancing” there was substantial between-treatment group variance in mean protein intake (400–1200gcrudeprotein/hind/day). However, there was no relationship between protein intake and calf growth performance. In contrast, regression analysis of individual hind variation in energy intake and calf growth revealed that energy intake during lactation was a major determinant of calf growth performance. Overall, calf growth during the 10–12weeks of lactation was lower than expected within the indoor system, and probably reflects a low intake of pellets by the calves themselves. The results of the study support the concepts of energy maximisation and do not support the central hypothesis of potential protein deficiency. Data from this experiment suggest that 400g/day crude protein intake is adequate for lactation in red deer hinds.

Intake, digestibility and nitrogen balance in Mithun (Bos frontalis) offered urea-treated paddy straw based feed blocks

The aim of the study was to determine the effect of feeding feed blocks containing varying proportion of urea-treated paddy straw (UTPS) on dry matter (DM) intake (DMI), nutrient utilization and N balance in Mithun. For the purpose, four adult male Mithun (279.5 ± 8.2 kg) were selected and offered four experimental rations viz. R(1) (Napier fodder + concentrate at 60:40), R(2) (UTPS + concentrate at 50:50), R(3) (UTPS + concentrate at 60:40) and R(4) (UTPS + concentrate at 70:30) in 4 × 4 Latin square design. The DMI % of body weight was 2.59, 2.96, 2.85 and 2.77 and the DMI g kg(-1) W(0.75) was 107, 123, 118 and 115 in Mithun fed R(1), R(2), R(3) and R(4), respectively. The mean DMI was (P < 0.01) higher in animals fed R(2) and R(3) than R(1) and R(4), whereas the water intake was (P < 0.01) higher in Mithun fed R(2), R(3) and R(4) than R(1). The digestibility of DM, organic matter, crude protein, crude fibre, neutral detergent fibre and cellulose were (P < 0.05) higher in animals fed R(2), R(3) and R(4) than R(1). A positive N balance was observed in all the experimental animals, with higher (P < 0.05) values among the animals offered R(2), R(3) and R(4) than R(1). The digestible crude protein and total digestible nutrient intakes were higher (P < 0.05) in Mithun fed R(2) and R(3) than R(1) and R(4). It is concluded that the UTPS can be incorporated up to 70% to formulate the complete feed/feed block and can be used for feeding of Mithun under complete confinement system.

An evaluation of production efficiencies among lactating Holstein-Friesian, Jersey, and Jersey × Holstein-Friesian cows at pasture

The objectives of this study were 1) to investigate production and energetic efficiencies among lactating dairy Holstein-Friesian (HF), Jersey (J), and Jersey×Holstein-Friesian (F1) cows over a total lactation at pasture and 2) to measure the associations among efficiency variables and performance traits. Data from 110 cows were available (37 HF, 36J, and 37F1). Breed groups were not balanced for parity; 16 HF, 10J, and 9F1 were in parity 1, whereas the remainder were in parity 2. Milk production, body weight (BW), body condition score (BCS), and estimates of dry matter intake (DMI) corresponding to 51, 108, 149, 198, and 233 d in milk were available. Breed group had a significant effect on all the production parameters investigated: milk yield, solids-corrected milk (SCM), milk fat, protein and lactose concentrations, and milk solids (MLKS; fat+protein yield). Daily MLKS yield was similar for HF and J (1.33 and 1.28kg/d, respectively). There was a tendency for F1 (1.41kg/d) to produce more MLKS compared with HF. The HF breed had higher BW throughout the study compared with F1 and J. Mean BCS was higher for F1 (3.00) and J (2.93) compared with HF (2.76). Mean DMI was similar with HF (16.9kg) and F1 (16.2kg) and was lowest with J (14.7kg). Breed group had a significant effect on all the efficiency parameters investigated: total DMI per 100kg of BW, SCM per 100kg of BW, MLKS per 100kg of BW, and MLKS per total DMI, which tended to be highest for J. Production efficiency based on net energy intake per MLKS was most favorable for F1 and J compared with HF [12.5, 13.0, and 14.1 UFL, respectively, where 1 UFL is defined as the net energy content of 1kg of standard barley for milk production (O’Mara, 2000)]. Significant estimates of hybrid vigor were evidenced for milk yield, milk lactose content, SCM, MLKS, net energy for lactation, BW, BCS, and net energy intake per MLKS. The correlations examined indicated that production efficiency was positively associated with MLKS yield.

Comportamento ingestivo e digestão de nutrientes em bovinos de corte alimentados com silagem de capim

The main objective was to study the effect of dry matter content, the addition of bacterial inoculant and particle size reduction on Tanzania grass (Panicum maximum) silage on digestive parameters. Seven ruminally cannulated Nellore beef steers were randomly assigned to a 7 x 7 Latin Square design. Treatments were described as follows: T1: wet forage + small particle; T2: T1 + inoculant; T4: wilting + large particle; T3: T4 + inoculant; T6: wet forage + large particle; T5: T6 + inoculant; T7: T6 + ground pearl millet grain. The ruminal passage rate of solid (2.35% h-1) and liquid (3.17% h-1) phases were similar across treatments. The animal intake behavior was not significantly changed by treatments, averaging 293 (minutes d-1) and 68 (minutes DM kg-1) for time and rate of eating, respectively. For rumination and chewing, the mean values observed were 432 (minutes d-1), 102 (minutes DM kg-1) and 725 (minutes d-1), 170 (minutes DM kg-1), respectively. No significant differences were observed for the DM (61.40%), ADF (59.69%), CP (43.93%) and NDF (60.34%) digestibilities. The mean DM intake (1.1% BW) was not different among treatments. It was concluded that the strategies adopted during the ensiling of Tanzania grass did not result in significant changes on the parameters.

Effect of several doses of zeolite A on feed intake, energy metabolism and on mineral metabolism in dairy cows around calving

The object of the present study was to determine the influence of different zeolite A doses on dry matter intake (DMI) and mineral metabolism, and to evaluate an optimum dosage for preventing hypocalcaemia. Eighty pregnant dry cows were assigned to four groups (I-IV). They were fed a total mixed ration (TMR) ad libitum. Groups II, III and IV received an average daily dose of 12, 23 and 43 g zeolite A/kg DM for the last 2 weeks prepartum. Individually DMI was recorded daily. Blood and urine samples were taken before, during and after zeolite A supplementation. Serum was analysed for Ca, Mg, P(i), K, non-esterified fatty acids and beta-hydroxybutyrate (BHB). Urine was analysed for Ca, Mg, P(i), K and net acid-base excretion (NABE). After calving, milk yield (fat corrected milk) and milk composition were determined. During zeolite A supplementation, mean DMI of Group IV (7.3 +/- 1.3 kg/cow/day) was significantly lower compared to Groups I-III (10.1, 10.9, 9.5 kg/cow/day). The reduced feed intake of Group IV resulted in significantly increased BHB as well as decreased NABE after calving. Zeolite A supplementation in higher doses (III and IV) had a stabilizing effect on Ca metabolism around calving for older cows, whereas cows in Groups I and II showed a subclinical hypocalcaemia. The mean serum Mg concentration decreased significantly in older cows in Group IV at calving. The mean P(i) concentration in cows of Group IV decreased into ranges of hypophosphataemia already 1 week after beginning of zeolite A feeding. The mean DMI postpartum as well as the milk yield was not affected by zeolite A supplementation. Feeding of 23 g zeolite A/kg DM TMR prepartum proved to be an adequate dosage for reducing subclinical hypocalcaemia frequency without significant effects on feed intake and P(i) concentration in serum.

Inter- and intra-individual differences in serum copper and zinc concentrations after feeding different amounts of copper and zinc over two lactations

The influence of different copper and zinc contents in rations on blood serum concentrations was tested in a feeding trial at the Institute of Animal Nutrition of the Federal Research Institute for Animal Health (FLI). A total of 60 German Holstein breed cows (38 first lactating and 22 second lactating cows) were tested. All animals received a diet based on maize- and grass silage ad libitum. The animals were divided into two groups with 30 cows each. Group A received concentrates supplemented with copper and zinc as recommended, whereas Group B was offered a concentrate with roughly double the amount of copper and zinc. Blood samples were taken several times during the lactation. The concentrations of copper and zinc in the serum were measured and correlations between trace element intake and their serum concentrations were calculated. The mean dry matter intake was significantly higher for cows in the second lactation (19.1 kg/day) than for cows in the first lactation (16.4 kg/day), whereas the DM-intake was constant in the different feeding groups (17.3 and 17.4 kg/day). The correlation between feed intake in the first and the second lactation was r = 0.76. The copper concentration in the serum was not influenced by the different feedings (11.9 and 12.5 micromol/l), but high variations were found between the cows. The influence of the lactation number was not significant (12.1 and 12.4 micromol/l). In contrast to copper, the zinc concentration in the serum was significantly higher for Group B (14.0 micromol/l) than for Group A (12.2 micromol/l), respectively, for second lactating cows (13.8 micromol/l) in relation to 12.7 micromol/l for first lactating cows. The individual variation was also high as for copper. Neither the correlation between copper intake and copper serum concentration nor the correlation between zinc intake and zinc serum concentration was significant.

QUANTIFICATION OF THE EFFICIENCY OF RUMEN MICROBIAL PROTEIN SYNTHESIS IN STEERS FED GREEN TROPICAL GRASS

MULLIK, M.L., POPPI, D.P. and S.R. MC LENNAN. 2009. Quantification of the efficiency of rumen microbial protein synthesis in steers fed green tropical grass. JITV 14(2): 110-117. The rate of rumen microbial crude protein (MCP) supply to the intestines is a crucial element in the current rumen models to predict respond of ruminants to a certain diet. Data from tropical pastures are always below predicted results from the existing rumen models. Thus, quantification of the rumen MCP supply from tropical forage will improve predictive rate under tropical feeding conditions. Four Brahman crossbred steers (457 ± 20.1 kg) were used in a metabolism study. Pangola grass (Digitaria erianthe cv. Steudal) was harvested every morning and fed to the animals soon afterward. Parameters measured were EMPS, intake, fractional passage rates, and rumen ammonia concentration. The EMPS was estimated using purine derivative excretion in urine. Mean crude protein and water soluble carbohydrate was 6.3 and 7.4% of dry matter (DM) respectively. Mean DM intake was 1.6% liveweight. Average rumen ammonia concentration was 69 mg/L whilst rumen passage rates were 7.84 and 6.92%/h for fluid and solids respectively. Mean EMPS was only 72 g MCP/kg digestible organic matters. It is concluded that EMPS in steers consuming green pangola grass was at the level below the minimum recommended value for forage diets adopted in the current feeding standards.

Coeficiente de digestibilidade e características ruminais de bovinos alimentados com rações contendo resíduo de cervejaria fermentado

Avaliaram-se os coeficientes de digestibilidade (CD) parcial e total dos nutrientes, o pH, a concentração de nitrogênio amoniacal (N-NH3) do líquido ruminal e a eficiência de síntese microbiana em bovinos alimentados com rações contendo 0; 8; 16 e 24% de resíduo de cervejaria fermentado (RCF). O resíduo de cervejaria foi conservado em silo de superfície (5.000 kg). Foram utilizados quatro bovinos da raça Holandesa com peso corporal de 480 ± 100 kg, portadores de cânula ruminal e duodenal, distribuídos em delineamento quadrado latino 4 × 4. O consumo médio de MS pelos animais foi de 1,7% do peso corporal (PC). Os coeficientes de digestibilidades total e ruminal dos nutrientes não diferiram entre os níveis de RCF utilizados nas rações. Os níveis de RCF nas rações tiveram efeito linear crescente sobre o coeficiente de digestibilidade intestinal de matéria seca e carboidratos totais, calculado em porcentagem do que chegou ao compartimento. Não houve efeito dos níveis de RCF nas rações sobre o pH e a concentração de N-NH3 do líquido ruminal. Os níveis de RCF nas rações não influenciaram a eficiência de síntese microbiana em g N-Mic/kg de matéria orgânica aparentemente degradável no rúmen (MOADR) e da matéria orgânica verdadeiramente degradável no rúmen (MOVDR). A inclusão de até 24% do RCF na MS em rações para bovinos não altera os processos de fermentação ruminal e digestão dos nutrientes.

Lack of relationship between either specific weight or presence of the 1B1R gene and nutritive value of wheat in broiler diets

1. A study of the relationship between specific weight (SW) and nutritive value of wheat in diets offered to broilers up to 4 weeks of age was carried out using 10 varieties of wheat grown at three different locations; this gave rise to a range of specific weights from 59 to 76 kg/hl. 2. Because five varieties contained the 1B1R translocation and 5 did not, this allowed the effects of 1B1R on the performance of birds given high concentrations of dietary wheat to be further investigated. 3. The diets, which contained wheat at 744 g/kg with casein (142 g/kg) as the sole protein supplement, were heat-treated and pelleted. They were fed ad libitum to male, Ross broiler chicks from 7 to 28 d, in individual cages in a controlled environment room. 4. A 7 d excreta collection was made from 14 to 21 d for determination of apparent metabolisable energy (AME) content and wheat AME was calculated from the diet values. A separate determination of true metabolisable energy (TME) was undertaken using the method of McNab and Blair (British Poultry Science, 29: 697-707, 1988). 5. Wheat samples were analysed for proximate constituents, starch, total and soluble non-starch polysaccharides (NSP), amino acid content and gross energy and specific weight, thousand grain weight and in vitro viscosity were recorded. They were also subjected to near infrared reflectance spectroscopy (NIRS) with a view to establishing relationships with chemical constituents and performance parameters. 6. At 28 d the birds were humanely killed and in vivo viscosity was determined on the jejunal digesta supernatant. 7. There was quite a narrow range of crude protein content (N x 5.83) across the 30 wheat samples, the means for the three locations (Crossnacreevy, Downpatrick and Limavady, respectively) being 112, 121 and 122 g/kg. Starch contents of individual samples ranged from 604 to 679 g/kg, total NSP from 92.1 to 122.6 g/kg, soluble NSP from 17.6 to 32.6 g/kg and in vitro viscosity from 10.6 to 26.3 cps. 8. There were no significant varietal effects for dry matter intake (DMI), live weight gain (LWG) or gain:feed ratio. Apparent metabolisability of energy (ME:GE) for the diets ranged from 0.738 (Hussar) to 0.778 (Harrier) the effect being significant (P 0.05). TME values ranged from 16.3 to 16.6 MJ/kg DM (NS). 9. In vivo viscosity ranged from 12.3 (Ritmo) to 23.7 cps (Hussar), the varietal effects being significant (P < 0.001). Viscosity was significantly higher for the 1B1R varieties than for the non-1B1R (22.7 vs 16.3 cps) but there were no significant effects on mean DM intake, LWG, gain:feed, ME:GE, calculated wheat AME, ME:gain (MJ AME per kg gain) or TME. 10. Wheat AME was negatively correlated (P < 0.05) with total NSP (slope -0.035) but was significantly affected by variety, constants ranging from 16.74 to 17.79. For wheat TME there were significant variety*total NSP interactions with slopes ranging from 0.29 to -0.07. There was no significant relationship between wheat AME and soluble NSP and there were significant variety*soluble NSP interactions for TME with slopes ranging from 0.09 to -0.14. 11. Despite the relatively wide range of in vitro viscosity there was no significant correlation of either calculated wheat AME or wheat TME with in vitro viscosity. For TME there were significant variety*viscosity interactions with slopes ranging from 0.21 to -0.13 (P < 0.001). There was also no significant correlation between soluble NSP and in vivo viscosity. 12. AME values for the NIRS calibration set varied from 13.7 to 15.6 MJ/kg and averaged 14.6 MJ/kg, whereas for the validation set, the values ranged from 14.0 to 16.1 MJ/kg with the mean value being 14.7 MJ/kg. The best correlation coefficient (r(2)) of 0.90 was obtained when the calibration sample set was subjected to SMLR using the second-order derivatised data. However, moving to validation, the outcome was extremely poor with 1-VR values being 0.12 and 0.09, respectively, for the external validation and an internal validation subset. 13. In summary, none of the production characteristics showed a good correlation with specific weight. Using the linear estimates for wheat AME and TME the effect of a 10 kg/hl change in SW equates to a 3 or 1.4% change, respectively. The estimate for AME is likely to be a worst-case value due to the high inclusion level of wheat. The range of calculated wheat AME (approximately 1 MJ) across the 30 wheat samples is similar to that seen in previous studies for wheat grown in Northern Ireland and much lower than in some other studies. 14. None of the other parameters examined gave any better relationship with nutritive value (assessed as AME or TME) than SW. This is a disappointing outcome, particularly in view of some previous studies which suggested that in vitro viscosity provides a good prediction of nutritive value.

Prepartum Feeding of Cationic or Anionic Diets to Holstein Cows Given 30 or 60 Day Dry Periods: Comparison of Dry Matter Intake, Physiological Measures and Milk Production

: Eighty-four Holstein cows were used to evaluate effects of feeding two diets that differed in dietary cation-anion difference (cationic; +28 or anionic; -138 mEq/kg DM) on prepartum and postpartum dry matter intake (DMI), body weight (BW), body condition score (BCS), serum Ca concentrations and on subsequent milk production and composition. Treatments were in a 2x3x2 factorial arrangement that included prepartum diet, dry period length (30 d dry, 30 d dry+estradiol cypionate (ECP), and 60 d dry), and prepartum and postpartum bST (POSILAC®, 10.2 mg/d). No interaction of prepartum diet with dry period length or bST supplementation was detected for any measure evaluated either prepartum or postpartum. No significant effects of prepartum diet on prepartum DMI, BW or BCS were observed. Mean DMI during the first 28 d postpartum were similar for cows fed the cationic or anionic diets prepartum (25.5 vs. 26.1 kg/d). During postpartum wk 1 to 14, no differences in mean BW or BCS were detected due to prepartum diet fed but decreases for both groups were observed during the first 6 wk postpartum. No differences due to prepartum diet were observed for mean milk or 3.5% FCM yields or for milk composition during the first 10 wk of lactation. Similarly, mean milk yield of cows during the first 21 wk did not differ significantly due to prepartum diet fed (38.5 vs. 38.6 kg/d). Overall, cows fed the prepartum cationic or anionic diets had similar mean postpartum serum concentrations of Ca (9.34 vs. 9.35 mg/dl). Subsequent milk production, milk composition and concentrations of Ca did not differ. Importantly, the two prepartum diets were equally satisfactory in minimizing incidence of milk fever and in supporting initiation of lactation, irrespective of dry period length and supplemental ECP and bST.

Diurnal Shifts in Nutritive Value of Alfalfa Harvested as Hay and Evaluated by Animal Intake and Digestion

Forages accumulate nonstructural carbohydrates during the day, with animals showing preference and improved daily responses from afternoon compared with morning cut hays. This study evaluated alfalfa (Medicago sativa L.) hay harvested at 0700, 1000, 1300, 1600, and 1900 h to determine how nutritive value changes during the day and to assess the impact of these changes on animal preference using cattle (Bos taurus L.), sheep (Ovis aries L.), and goat (Capra hircus L.) responses. Total nonstructural carbohydrates were altered by time of cut (cubic contrast, P &lt; 0.01) ranging from 85 g kg−1 at 0700 h to 83 g kg−1 at 1000 h, then increasing to 97 g kg−1 by 1600 h with little change at 1900 h (96 g kg−1). Fiber fractions also varied diurnally, with a quadratic decrease from 418 g kg−1 at 0700 h to 387 g kg−1 by 1900 h in neutral detergent fiber. A combined analysis of three animal trials showed a linear increase in dry matter intake (DMI) with later hay harvest, a cubic response for dry matter digestion (DMD), and a linear increase in digestible DMI. Mean DMI increased from 27.5 g kg−1 body weight at 0700 h to a maximum of 30.8 g kg−1 body weight at 1600 h, whereas DMD decreased from 658 g kg−1 at 0700 to 647 g kg−1 at 1300 h and peaked at 664 g kg−1 at 1600 h. Digestible DMI increased from 18.1 g kg−1 body weight at 0700 h to a maximum of 20.5 g kg−1 body weight at 1600 h. No additional advantages in animal responses were noted by cutting after 1600 h.

Effects of different levels of ergot in concentrates on the growing and slaughtering performance of bulls and on carry-over into edible tissue

The aim of the present study was to examine long-term effects of low levels of ergot alkaloids on growing bulls. Natural grown ergot with a mean total alkaloid concentrations of 633 mg/kg, and ergotamine (25%), ergocristine (15%) and ergosine (13%) as the most prominent alkaloids, was used. In a dose-response study 38 Holstein Friesian bulls were fed with three different doses of this ergot (0, 0.45 and 2.25 g/kg concentrate corresponding to an average total alkaloid concentration of the daily ration of 0, 69 and 421 µg/kg DM) over a period of approximately 230 days. Live weight, feed intake and health condition were monitored over the entire test period. The bulls were slaughtered at a live weight of approximately 550 kg. Carcass composition and quality were recorded and samples of liver, muscle, kidneys, fat, bile, urine and blood were analysed for ergot alkaloids. Liver enzyme activities and total bilirubin were measured in the blood. Statistically, no significant differences were detectable between the three feeding groups. Mean live weight gain over all groups was 1.41 kg/d with a mean dry matter intake of 7.35 kg/d. No carry over into tissues could be proved out of the experiment. To derive a no-effect level for beef cattle further research including higher ergot doses will be necessary.

Lower Pregnancy Losses in Lactating Dairy Cows Fed a Diet Enriched in α-Linolenic Acid

The objectives were to determine if a diet enriched in α-linolenic acid (ALA) would influence ovarian function, early embryo survival, conception rates, and pregnancy losses in lactating dairy cows. Beginning 28 d before breeding, Holstein cows (55±22 d postpartum; mean±SD) were assigned to diets supplemented with either rolled flaxseed (FLAX; 56.7% ALA, n = 62) or rolled sunflower seed (SUNF; 0.1% ALA, n = 59) to provide approximately 750g of oil/d. Diets continued for 32 d after timed artificial insemination (TAI, d 0) following a Presynch/Ovsynch protocol. Barley silage- and barley grain-based TMR were formulated to meet or exceed National Research Council requirements. Metabolizable protein and net energy for lactation concentrations were similar in the 2 diets. Based upon a mean dry matter intake of 22 kg/d, cows fed FLAX or SUNF consumed>410g or<1g of ALA, respectively. Pregnancy was confirmed by ultrasound 32 d after TAI. Nonpregnant cows were placed on a second Ovsynch regimen and reinseminated 42 d after first TAI, and received oilseeds for 32 d after second TAI. Relative to prediet levels, FLAX increased the ALA content of milk by 187%. Ovarian ultrasonography was performed in 8 cows per diet; the mean diameter of ovulatory follicles was larger in cows fed FLAX compared with SUNF (16.9±0.9 vs. 14.1±0.9mm), but follicle number, corpus luteum size, and plasma progesterone concentrations remained unaffected. Presumptive conception (progesterone<1 ng/mL on d 0 and>1 ng/mL on d 21) rates to first TAI were greater in FLAX than in SUNF (72.6 vs. 47.5%). Pregnancy losses were lower in cows fed FLAX (9.8%) compared with those fed SUNF (27.3%). Including flaxseed in the ration of dairy cows increased the size of the ovulatory follicle and reduced pregnancy losses.

Intake, utilization, and composition of browses consumed by the Sumatran rhinoceros (Dicerorhinus sumatrensis harissoni) in captivity in Sabah, Malaysia

AbstractThe significant threats to the fewer than 30 wild Dicerorhinus sumatrensis harrissoni, the Bornean sub‐species of the Sumatran rhinoceros, are obvious and include poaching, habitat loss, and environmental changes. Subtle effects on population survival, however, include nutritional or other diseases, which affect morbidity and reproductive success. To address these issues and focus on animals within their natural range, this feeding trial and analysis characterizes the diet fed to the only three captive D. s. harissoni in the world housed at the Sumatran Rhino Breeding Center (SRBC) in Sabah, Malaysia. The study provides an indication of the variance in nutrient composition in local browse, and a comparison with other captive feeding studies. Mean dry matter intake (DMI), comprising ∼90% native browse species, equaled 3.55% (range=2.8–4.1%) of body mass, with a dry matter digestibility averaging 82%. The mean crude protein content of native browses (n=8 spp.) averaged 11.2% (DM basis; range=5–23%, depending on plant part), with available protein measured at 7.8%. Leaves contained significantly (P&lt;0.001) more crude protein, and less (P&lt;0.001) fiber (neutral detergent fiber, acid detergent fiber, and lignin) than twig fractions analyzed, but animals consumed both fractions rather non‐selectively. Of minerals quantified, Na and P were potentially limiting in native browses compared to equid nutrient requirements, and Se may have been marginal. Ca, K, and Fe levels in particular were high in most native browses. Specifically, iron ranged from 45–1,400 mg/kg (mean=230 mg/kg DM), with only three preferred species containing this nutrient at &lt;100 mg/kg. Excess dietary iron has been linked with health issues in browsing rhinos. Additionally, high levels of other minerals (for example Mn, with a mean of 382 mg/kg DM in this study), can precipitate deficiencies in crucial elements such as calcium. In view of the structural and chemical variations of the different parts of the same plants, dietary guidelines should be developed and incorporated into the basic husbandry of these animals that include increasing the number and combinations of species of browse offered daily to adjust for variance in protein, fiber, other nutritional components and food preference, to increasing the quantity of food offered per day based on desired weight gain and reproductive status. This, combined with information on the free‐ranging rhinoceros diet composition, and additional intake and digestibility trials (with concurrent serum analysis to evaluate nutritional status) should greatly assist in providing optimal diets for this highly endangered species. Zoo Biol 0:1–15, 2006. © 2006 Wiley‐Liss, Inc.

Examination of the Persistency of Milk Fatty Acid Composition Responses to Fish Oil and Sunflower Oil in the Diet of Dairy Cows

Based on the potential benefits of cis-9, trans-11 conjugated linoleic acid (CLA) for human health, there is a need to develop effective strategies for enhancing milk fat CLA concentrations. Levels of cis-9, trans-11 CLA in milk can be increased by supplements of fish oil (FO) and sunflower oil (SO), but there is considerable variation in the response. Part of this variance may reflect time-dependent ruminal adaptations to high levels of lipid in the diet, which lead to alterations in the formation of specific biohydrogenation intermediates. To test this hypothesis, 16 late lactation Holstein-British Friesian cows were used in a repeated measures randomized block design to examine milk fatty acid composition responses to FO and SO in the diet over a 28-d period. Cows were allocated at random to corn silage-based rations (8 per treatment) containing 0 (control) or 45g of oil supplement/kg of dry matter consisting (1:2; wt/wt) of FO and SO (FSO), and milk composition was determined on alternate days from d 1. Compared with the control, the FSO diet decreased mean dry matter intake (21.1 vs. 17.9kg/d), milk fat (47.7 vs. 32.6g/kg), and protein content (36.1 vs. 33.3g/kg), but had no effect on milk yield (27.1 vs. 26.4kg/d). Reductions in milk fat content relative to the FSO diet were associated with increases in milk trans-10 18:1, trans-10, cis-12 CLA, and trans-9, cis-11 CLA concentrations (r2=0.74, 0.57, and 0.80, respectively). Compared with the control, the FSO diet reduced milk 4:0 to 18:0 and cis 18:1 content and increased trans 18:1, trans 18:2, cis-9, trans-11 CLA, 20:5 n-3, and 22:6 n-3 concentrations. The FSO diet caused a rapid elevation in milk cis-9, trans-11 CLA content, reaching a maximum of 5.37g/100g of fatty acids on d 5, but these increases were transient, declining to 2.35g/100g of fatty acids by d 15. They remained relatively constant thereafter. Even though concentrations of trans-11 18:1 followed the same pattern of temporal changes as cis-9, trans-11 CLA, the total trans 18:1 content of FSO milk was unchanged because of the concomitant increases in the concentration of other isomers (Δ4–10 and Δ12–15), predominantely trans-10 18:1. In conclusion, supplementing diets with FSO enhances milk fat cis-9, trans-11 CLA content, but the high level of enrichment declines because of changes in ruminal biohydrogenation that result in trans-10 replacing trans-11 as the major 18:1 biohydrogenation intermediate formed in the rumen.

Development and Evaluation of Models to Predict the Feed Intake of Dairy Cows in Early Lactation

Inaccurate prediction of dry matter intake (DMI) limits the ability of current models to anticipate the technical and economic consequences of adopting different strategies for production management on individual dairy farms. The objective of the present study was to develop an accurate, robust, and broadly applicable prediction model and to compare it with the current NRC model for dairy cows in early lactation. Among various functions, an exponential model was selected for its best fit to DMI data of dairy cows in early lactation. Daily DMI data (n=8,547) for 3 groups of Holstein cows (at Illinois, New Hampshire, and Pennsylvania) were used in this study. Cows at Illinois and New Hampshire were fed totally mixed diets for the first 70 d of lactation. At Pennsylvania, data were for the first 63 d postpartum. Data from Illinois cows were used as the developmental dataset, and the other 2 datasets were used for model evaluation and validation. Data for BW, milk yield, and milk composition were only available for Illinois and New Hampshire cows; therefore, only these 2 datasets were used for model comparisons. The exponential model, fitted to the individual cow daily DMI data, explained an average of 74% of the total variation in daily DMI for Illinois data, 49% of the variation for New Hampshire data, 67% of the variation for Pennsylvania data, and 64% of the variation overall. Based on all model selection criteria used in this study, the exponential model for prediction of weekly DMI of individual cows was superior to the current NRC equation. The exponential model explained 85% of the variation in weekly mean DMI compared with 42% for the NRC equation. Compared with the relative prediction error of 6% for the exponential model, that associated with prediction using the NRC equation was 14%. The overall mean square prediction error value for individual cows was 5-fold higher for the NRC equation than for the exponential model (10.4 vs. 2.0kg2/d2). The consistently accurate and robust prediction of DMI by the exponential model for all data-sets suggested that it could safely be used for predicting DMI in many circumstances.

Influence of prepartum and postpartum supplementation of a yeast culture and monensin, or both, on ruminal fermentation and performance of multiparous dairy cows

Sixty multiparous Holstein-Friesian cows were utilized in a randomized complete block design experiment to evaluate effects of feeding a yeast culture ( Saccharomyces cerevisiae), monensin, or both, on their rumen fermentation patterns and performance. The basal diet was a total mixed ration (TMR) containing 383 g/kg alfalfa hay and 617 g/kg concentrates (dry matter (DM) basis). Treatments were: (1) control diet (C), (2) control diet plus 2550 ppm (DM basis) of a yeast culture (YC), (3) control plus 10 ppm (DM basis) of monensin (M) and (4) control plus 2550 ppm (DM basis) of a YC plus 10 ppm (DM basis) of monensin. Cows were fed their TMR twice daily at 07:00 and 16:00 h from 3 weeks prepartum until 8 weeks postpartum. Cows were milked twice daily at 06:00 and 17:00 h. Compared to C, all treatments increased mean postpartum ruminal propionate concentration and decreased the ratio of acetate:propionate. Mean postpartum rumen pH and ammonia N concentrations were not affected by treatment, although pH and ammonia N progressively decreased with either YC or M as the level of pH or ammonia N in the cows increased. Mean milk yield, milk composition and body weight change of treatment groups did not differ from those of the C group, although milk crude protein (CP) yield progressively increased with YC, and decreased with M, as the level of milk CP production of the cows increased. Mean DM intake (DMI) varied between 20.8 kg/day (M) and 22.2 kg/day (C), with DMI progressively increased with YC, and decreased with M, as the DMI level of the cows increased. Results suggest a modest complimentary effect between YC and M, as YC tended to alleviate the depression in mean DMI caused by M. However, results can also be interpreted to suggest that YC may be a better choice than M in cows with high DMI potential, and/or inherent milk production capability, whereas M may be a better choice than YC in cows with lower DMI potential, and/or inherent milk protein production potential.

The nutritional value of cocksfoot (Dactylis glomerata L.), midribbed snow‐tussock (Chionochloa pallens Zotov), and red tussock (Chionochloa rubra Zotov) for the takahe (Porphyrio hochstetteri Meyer)

A feeding trial was carried out to determine the nutritional value of midribbed snow‐tussock (Chionochloa pallens Zotov), red tussock (Chionochloa rubra Zotov), and cocksfoot (Dactylis glomerata L.) for the takahe (Porphyrio hochstetteri Meyer), an endangered flightless herbivorous rail endemic to New Zealand. Three captive‐reared birds were fed each of the diets for 11 days, during which food intake, faecal plus urinary output, nutrient balances and coefficients of absorption/retention of energy, nitrogen, soluble sugars, starch, and mineral elements were determined. The mean dry matter (DM) intake was of the order cocksfoot > midribbed snow‐tussock > red tussock. The proportions of total soluble sugars absorbed from all grasses were in the range 0.8–0.96, whilst the proportions of energy absorbed (0.24, 0.17, ‐0.29) and nitrogen retained (0.19, 0.15, ‐0.04) from all grasses were low. Cocksfoot was nutritionally superior to the tussocks for most parameters measured, suggesting that islands with pasture habitat should adequately meet the requirements of takahe.

Nutritional Evaluation of Graded Levels of Aspergillus-treated Rice Husk on the Performance of Pregnant West African Dwarf Goats

Nine pregnant West African dwarf (WAD) goats were fed untreated (control diet A with 30% inclusion level) and Aspergillus treated diet, B (10%) and diet C (20%) in total mixed rations. The effect of treatment was evaluated on feed intake, digestibility, BW and growth rate. Fungus-treated rice husk appeared to be well accepted by goats even when included in rations at 20% of total DM. Mean DM intake averaged 595, 611 and 623gld for goats fed diets A, B and C respectively. The crude protein intake was greatest (P Key Words: Rice husk, Aspergillus niger, pregnant goats, performance characteristics. Int. J. Agric. Rural Dev. , 2003, 4: 87-91