Increased Fat Yield Research Articles

Milk production responses to altering the dietary ratio of palmitic and oleic acids varies with production level in dairy cows

We evaluated the effects of altering the dietary ratio of palmitic (C16:0; PA) and oleic (cis-9 C18:1; OA) acids on production responses of cows with a wide range of milk production (32 to 65 kg/d) in a crossover design experiment with a preliminary period. Thirty-two multiparous Holstein cows (144 ± 54 d in milk) were assigned randomly to a treatment sequence. Treatments were diets supplemented with fatty acid (FA) blends (1.5% of diet dry matter) that provided 80% C16:0 + 10% cis-9 C18:1 (PA) and 60% C16:0 + 30% cis-9 C18:1 (PA+OA). The corn silage and alfalfa-based diets contained 20.0% forage neutral detergent fiber (NDF), 28.5% starch, and 17.1% crude protein. Treatment periods were 21 d with the final 5 d used for data and sample collection. Treatment did not affect dry matter intake (DMI), milk yield, energy-corrected milk (ECM), body weight, or body weight change. The PA+OA diet increased total, 16-carbon, and 18-carbon FA digestibility compared with the PA diet. Compared with PA+OA, PA increased fat yield (1.97 vs. 1.91 kg/d) and protein yield (1.61 vs. 1.55 kg/d). The PA diet also increased the yield of de novo (448 vs. 428 g/d) and mixed (749 vs. 669 g/d) milk FA and decreased the yield of preformed FA (605 vs. 627 g/d) compared with PA+OA. Interactions were detected between treatment and preliminary milk yield for DMI, total FA intake, 16-carbon FA intake, ECM, 3.5% fat-corrected milk (linear interaction), and a tendency for milk yield (linear interaction); lower-producing cows (<45 kg/d) had increased DMI and ECM on the PA diet, whereas higher-producing cows (>55 kg/d) had increased DMI and ECM on the PA+OA diet. A linear interaction was detected between treatment and preliminary milk yield for mixed milk FA yield (linear interaction) and a tendency for de novo milk FA yield (linear interaction). Our results demonstrate that feeding a fat supplement containing more cis-9 C18:1 replacing C16:0 increased production responses (DMI, milk yield, and ECM) in higher-producing cows, but decreased production responses in lower-producing cows.

Timing of initiation and duration of feeding rumen-protected choline affects performance of lactating Holstein cows

Objectives were to evaluate the effects of altering timing of initiating and duration of supplementing rumen-protected choline (RPC) on lactation performance in dairy cows. The hypothesis was that RPC increases yields of milk and milk components, regardless of when supplementation is initiated, and that the effects of supplementing RPC starting prepartum and continuing post-transition would be additive. Cows at 241 ± 2.2 d of gestation were blocked by parity group (49 entering lactation 2, 50 entering lactation >2) and 305-d milk yield and, within block, assigned randomly to 1 of 4 treatments arranged as a 2 × 2 factorial with 2 levels of choline in transition, from 21 d pre- to 21 d postpartum, and 2 levels of choline in post-transition, from 22 to 105 d postpartum. The 2 levels of RPC supplemented were either 0 g/d or 12.9 g/d of choline ion fed as 60 g/d of an RPC product that was top-dressed onto the total mixed ration. Thus, treatments were as follows: NN (n = 25): no choline in transition or post-transition; NC (n = 25): no choline in transition and choline in post-transition; CN (n = 25): choline in transition and no choline in post-transition; CC (n = 24): choline in transition and in post-transition. Prepartum, treatments were supplemented (mean ± SD) for the last 18.8 ± 5.7 and 19.2 ± 5.0 d of gestation in treatments with 0 or 12.9 g/d of choline ion, respectively. Supplementing RPC prepartum did not affect dry matter intake (DMI), body weight (BW), or body condition score (BCS) in the last 3 weeks of gestation. Likewise, RPC did not affect the yield or the composition of colostrum. Supplementation with RPC during transition increased fat percent by 0.02 percentage units, fat yield by 0.16 kg/d, and energy-corrected milk (ECM) by 3.1 kg/d in the first 21 d postpartum, and increased fat yield by 0.10 kg/d and ECM by 2.4 kg/d from 22 to 105 d postpartum. Supplementing RPC during transition did not affect DMI postpartum, but it improved feed efficiency, and cows produced 0.11 kg/d more ECM per kg of DMI. Changes in BW and BCS during the first 21 d postpartum did not differ between treatments. Cows fed RPC during transition had more negative net energy balance and 0.1 unit smaller BCS in the first 105 d postpartum than non-supplemented cows. Supplementing RPC in post-transition did not influence productive performance in dairy cows, and choline supplementation during transition or post-transition did not affect measures of reproduction. Collectively, supplementing RPC to supply 12.9 g/d of choline ion benefited productive performance in dairy cows when supplementation occurred during the transition period, but no additional benefit was observed from supplementing RPC past 22 d postpartum.

PSXII-42 The lactational response in dairy cows to supplementation of calcium gluconate embedded in a fat matrix

Abstract Functional nutrients that facilitate gastrointestinal health may serve as an alternative to the use of antimicrobials in animal production systems. Gluconic acid has been used as a prebiotic health promoter in non-ruminant applications. It is poorly absorbed in the small intestine and is fermented to butyrate in the lower gastrointestinal tract. The gut health benefits of butyrate have been demonstrated in both non-ruminant and ruminant models, but effects of post-ruminal gluconic acid supplementation are not well described. The objective of this study was to determine the effects of calcium gluconate embedded in a fat matrix (CGFM; 40% CaGlu) on dry matter intake, blood metabolites, milk production and fecal short chain fatty acid (SCFA) production in early lactation dairy cows (21 ± 2 DIM) fed to 100% of energy and protein requirements. The experiment was a 3 x 3 replicated Latin square with 13 replicates (3 cows/replicate), 3 experimental periods (each 28 d) and 3 dietary treatments of control (0 g/d), 16 g/d and 25 g/d of CGFM. There was no treatment effect on DMI and milk yield. The relationship between dose of CGFM (i.e. 0, 16, 26 g/d) and milk fat and protein yield, energy corrected milk was significantly quadratic (P &amp;lt; 0.05) while feed efficiency tended to be quadratic (P = 0.08). The greatest response was in milk fat yield, which increased 90 g/d over control at 16 g/d of CGFM. No significant changes in blood metabolite concentrations or fecal SCFA concentrations were observed between treatments, although there was a numerical increase in non-esterified fatty acid concentration in response to the 16 g/d CGFM dose (P = 0.16). The response to supplementation of fat-embedded calcium gluconate appears to alter energy partitioning in the lactating dairy cow, as demonstrated with subtle changes in circulating lipid and increased fat yield.

Mammary gland utilization of amino acids and energy metabolites differs when dairy cow rations are isoenergetically supplemented with protein and fat

Mammary gland utilization of AA and other metabolites in response to supplemental energy from protein (PT) and supplemental energy from fat (FT) was tested in a 2 × 2 factorial arrangement using a randomized complete block design. Fifty-six Holstein-Friesian dairy cows were adapted during a 28-d control period to a basal total mixed ration consisting of 34% grass silage, 33% corn silage, 5% grass hay, and 28% concentrate on a dry matter (DM) basis. Experimental rations were fed for 28 d immediately following the control period and consisted of (1) low protein, low fat (LP/LF), (2) high protein, low fat (HP/LF), (3) low protein, high fat (LP/HF), and (4) high protein, high fat (HP/HF). To obtain the high-protein (HP) and high-fat (HF) diets, intake of the basal ration was restricted and supplemented isoenergetically [net energy (MJ/d) basis] with 2.0 kg/d rumen-protected protein (soybean + rapeseed, 50:50 mixture on a DM basis) and 0.68 kg/d hydrogenated palm fatty acids on a DM basis. Arterial and venous blood samples were collected on d 28 of both periods. Isoenergetic supplements (MJ/d) of protein and fat independently and additively increased milk yield, PT increased protein yield, and FT increased fat yield. A PT × FT interaction affected arterial concentration of all essential AA (EAA) groups, where they increased in response to PT by a greater magnitude at the LF level (on average 35%) compared with the HF level (on average 14%). Mammary gland plasma flow was unaffected by PT or FT. Supplementation with PT tended to decrease mammary clearance of total EAA and decreased group 1 AA clearance by 19%. In response to PT, mammary uptake of total EAA and group 2 AA increased 12 and 14%, respectively, with significantly higher uptake of Arg, Ile, and Leu. Energy from fat had no effect on mammary clearance or uptake of any AA group. The mammary gland uptake:milk protein output ratio was not affected by FT, whereas PT increased this ratio for EAA and group 2 AA. Arterial plasma insulin concentration decreased in response to FT, in particular on the HP/HF diet, as indicated by a PT × FT interaction. Arterial concentrations of nonesterified fatty acids, triacylglycerol, and long-chain fatty acids increased in response to FT, and concentrations of β-hydroxybutyrate and acetate decreased in response to FT only at the HP level. Mammary clearance and uptake of triacylglycerol and long-chain fatty acids increased in response to FT. Energy from PT and FT increased lactose yield despite no change in arterial glucose concentration or mammary glucose uptake. Mammary-sequestered glucose with PT or FT was used in the same amount for lactose synthesis, and a positive net mammary glucose balance was found across all treatments. Results presented here illustrate metabolic flexibility of the mammary gland in its use of aminogenic versus lipogenic substrates for milk synthesis.

The effects of varied plant density and nitrogen fertilization on quantity and quality yield of Camelina sativa L.

False flax (Camelina sativa L.), is an oil plant, of the Brassicaceae (Cruciferae) family. It is a rediscovered crop with multiple uses, it is a frost proof, low-soil and climatic conditions plant. In Poland the variety is not very widespread, despite of its health benefits. The particular value of camelina oil is given by its content in polyunsaturated fatty acid (50-60%), by its content in omega 3 (35-40%) and by its content in omega 6 (15-20%). The seeds are used for the extraction of oil (used in medicine or as bio fuel) or directly as animal feed. The research was carried out in the years 2012-2014 at the Experimental Station of Cultivar Assessment in Przecław, Poland. The summer Camelina sativa cv. ‘Omega’was used for the experiment. The studied factors were: A-plant density (200, 300, 400 pcs. m-2) and B-nitrogen fertilization (50, 100 kg∙ha-1). With the increase of the sowing density significantly increased plant density after emergence and before harvest, but reduced the number of silicles per plant. Increase in the rates of sowing from 200 to 400 pcs. m-2 decreased the 1000 seeds weight. Sowing 200 seeds m-2 compared to higher norms had significant effect on reduction the number of seeds in silicle, seed yield and the content of the seeds Fe, but resulted in an increase in the content of the seeds Mn and Zn. On the other hand, sowing 400 seeds m-2 caused a reduction the protein in the seeds, K, and Mg, and an increase fat yield and crude fat content in seeds. The higher nitrogen dose significantly increased the number of silicles per plant, total protein content, Fe, Zn in the seeds, seed yield, yield total protein and the percentage of linoleic and linolenic acids, while reduced the number of seeds per silicle, the crude fat content in seeds and the percentage of oleic acid.

Ethyl-cellulose rumen-protected methionine enhances performance during the periparturient period and early lactation in Holstein dairy cows

The onset of lactation in dairy cows is characterized by severe negative energy and protein balance. Increasing Met availability during this time may improve milk production, hepatic lipid metabolism, and immune function. The aim of this study was to evaluate the effect of feeding ethyl-cellulose rumen-protected methionine (RPM; Mepron, Evonik Nutrition and Care GmbH, Hanau-Wolfgang, Germany) on the performance of dairy cows during prepartum and early-lactation periods. Sixty multiparous Holstein cows were used in a block design and assigned to either a control or an ethyl-cellulose RPM diet. Ethyl-cellulose RPM was supplied from -28 to 60 d relative to parturition at a rate of 0.09% and 0.10% of dry matter during the prepartum and postpartum periods, respectively. That rate ensured that the ratio of Lys to Met in metabolizable protein was close to 2.8:1. Cows fed ethyl-cellulose RPM had dry matter intakes (DMI) that were 1.2 kg/d greater during the prepartum period and consequently had overall greater cumulative DMI than cows in the control group. Compared with controls, during the fresh period (1-30 d in milk; DIM) feeding ethyl-cellulose RPM increased DMI by 1.7 kg/d, milk yield by 4.1 kg/d, fat yield by 0.17 kg/d, milk protein yield by 0.20 kg/d, 3.5% fat-corrected milk by 4.3 kg/d, and energy-corrected milk by 4.4 kg/d. Although ethyl-cellulose RPM supplementation increased milk protein content by 0.16 percentage units compared with the control during the fresh period, no differences were observed for milk fat, lactose, and milk urea nitrogen concentration. During the high-producing period (31-60 DIM), cows fed ethyl-cellulose RPM increased DMI and milk yield by 1.45 and 4.4 kg/d, respectively. Ethyl-cellulose RPM also increased fat yield by 0.19 kg/d, milk protein yield by 0.17 kg/d, 3.5% fat-corrected milk by 4.7 kg/d, and energy-corrected milk by 4.8 kg/d compared with controls. Ethyl-cellulose RPM supplementation reduced plasma fatty acids in the fresh period and decreased γ-glutamyl transferase, indicating better liver function. In conclusion, when lysine was adequate, feeding ethyl-cellulose RPM to achieve a ratio close to 2.8:1 in metabolizable protein improved dairy cow performance from parturition through 60 DIM. The greater milk production was, at least in part, driven by the greater voluntary DMI and better liver function.

Effect of high-oleic-acid soybeans on production performance, milk fatty acid composition, and enteric methane emission in dairy cows

The objective of this study was to investigate the effect of 3 soybean sources differing in fatty acid profile and processing method on productivity, milk composition, digestibility, rumen fermentation, and enteric methane emission in lactating dairy cows. The soybean sources were conventional, high-linoleic-acid variety extruded soybean meal (ESBM; 8.7% ether extract with 15% oleic and 54% linoleic acids); extruded Plenish (DuPont Pioneer, Johnston, IA), high-oleic-acid variety soybean meal (EPSBM; 8.4% ether extract with 73% oleic and 8% linoleic acids); and whole, heated Plenish soybeans (WPSB; 20.2% ether extract). The study involved 15 Holstein cows in a replicated 3 × 3 Latin square design experiment with three 28-d periods. The inclusion rate of the soybean sources in the diet was (dry matter basis) 17.1, 17.1, and 7.4% for ESBM, EPSBM, and WPSB, respectively, which resulted in ether extract concentration of the diets of 3.99, 3.94, and 4.18%, respectively. Compared with ESBM, the Plenish diets tended to increase dry matter intake and decreased feed efficiency (but had no effect on energy-corrected milk feed efficiency). The Plenish diets increased milk fat concentration on average by 5.6% and tended to increase milk fat yield, compared with ESBM. The WPSB diet tended to increased milk true protein compared with the extruded soybean meal diets. Treatments had no effect on rumen fermentation and enteric methane or carbon dioxide emissions, except pH was higher for WPSB versus EPSBM. The Plenish diets decreased the prevalence of Ruminococcus and increased that of Eubacterium and Treponema in whole ruminal contents. Total-tract apparent digestibility of organic matter and crude protein were decreased by WPSB compared with ESBM and EPSBM. Compared with the other treatments, urinary N excretion was increased by EPSBM and fecal N excretion was greater for WPSB. Treatments had marked effects on milk fatty acid profile. Generally, the Plenish diets increased mono-unsaturated (mostly cis-9 18:1) and decreased polyunsaturated, total trans-, and conjugated linoleic fatty acids concentrations in milk fat. In this study, compared with conventional, high-linoleic-acid variety extruded soybean meal, the Plenish soybean diets increased milk fat concentration and tended to increase fat yield, decreased feed efficiency, and modified milk fatty acid profile in a manner expected from the greater concentration of oleic acid in Plenish soybean oil.

COMPARATIVE DESCRIPTION OF MILK PRODUCTIVITY OF COWS UKRAINIAN RED-AND-WHITE DAIRY CATTLE AND UKRAINIAN BLACK-AND-WHITE DAIRY CATTLE AND HOLSTEIN BREEDS IN SERF «OLEKSANDRIVSKE»

The main goal of dairy breeds selection should be improving breeding and productive qualities of animals under modern conditions. The majority of farms, using native breeds to produce milk, has created optimal conditions for keeping and feeding, selection and matching, growing of replacements etc. Further improvement of created native dairy breeds for economically useful traits occurs at total use of purebred Holstein bulls (semen) of foreign selection. In order to realistically assess milk productivity (milk yield, fat content in milk and fat yield) of Ukrainian Black-and-White and Red-and-White Dairy cows should be conducted a comparative analysis of Holstein cows under the same conditions of feeding and keeping.&#x0D; It was established that Ukrainian Red-and-White Dairy cows were characterized by the highest milk yields for 305 days of all lactations, taken into account, the among three investigated breeds. Their milk yield during the first lactation was 5933 kg of milk, during the second – 6393 kg, the third – 6391 kg and during higher lactation – 6650 kg. Ukrainian Black-and-White Dairy cows were second by milk yield (except for the second lactation), during the first lactation – 5932 kg of milk, the third – 6462 kg and higher – 6541 kg, and Holstein cows were third, during the first lactation – 5794 kg of milk, the second – 6381 kg, the third – 6335 kg and higher – 6469 kg.&#x0D; The fat content was almost the same and varied within 3.49-3.58% in milk of Ukrainian Red-and-White Dairy cattle, 3.50-3.60% in milk of Ukrainian Black-and-White Dairy cattle and 3.50-3.56% in Holsteins’ milk. The difference between the breeds was within 0.01-0.04%.&#x0D; All the investigated breeds had predominance in fat yield for three lactations over standards of these breeds: Ukrainian Red-and-White Dairy cows from 75.1 to 93.4 kg, Ukrainian Black-and-White Dairy cows – 75.1-89.0 kg respectively and Holstein cows – 41.9-60.2 kg.&#x0D; It was found different level of positive correlation between milk yield and fat yield in all the cases and high correlation (r = 0.604-0.921, P &lt; 0.001) in five cases (41.7%)&#x0D; Negative correlation coefficients indicate that selection of animals to higher milk yield in the herd will decrease the second trait – fat content in milk. Positive and highly significant correlation between milk yield and fat yield indicates that selection of cows in the herd to higher milk yields will increase fat yield.&#x0D; It was revealed that bulls were among the factors impacted the milk productivity (milk yield, fat content, fat yield) of three investigated breeds. So, the force (η²x) of father’s impact on milk yield was15.4-47.9%, fat content – 22.0-43.4% and fat yield – 14.9-47.7% taking into account a lactation and a breed. The force of lines impact (η²x) was second; it was on milk yield 6.1-24.5%, fat content – 4.1-17.1 and fat yield – 5.8-23.5%. The force of breeds impact (η²x) was last; it was on milk yield 0.3-2.9%, fat content – 0.2-0.3% and fat yield – 0.6-2.7%.&#x0D; So, the comparative studies of milk productivity of Ukrainian Red-and-White and Black-and-White Dairy cattle with Holsteins indicate that under similar conditions of feeding and keeping, these native breeds can compete with Holstein cattle. The milk yield for 305 days of higher lactation was 6650 kg of milk in Ukrainian Red-and-White Dairy cows, 6541 kg in Ukrainian Black-and-White Dairy cows and 6469 kg in Holsteins.&#x0D; It was found the inverse correlation r = -0.025-0.316 between milk yield and fat content in milk in most cases. Selection and matching of animals in the herd should be carried out simultaneously on these traits. It was found positive repeatability of milk yields between the first and second, the third and higher lactations (rs = 0.036-0.741), indicating the reliability of forecasting increase in milk productivity during the next lactations in all herd. Bulls have the greatest impact (η²x) on milk productivity among the factors taken into account: milk yield – 15.4-47.9%, fat content in milk – 22.0-43.4% and fat yield – 14.9-47.7%.

Effect of corn silage particle size and supplemental hay on rumen pH and feed preference by dairy cows fed high-starch diets

The objectives of this experiment were to determine the effects of corn silage particle size and supplemental hay on rumen pH and feed preference in lactating dairy cows experiencing a bout of subacute ruminal acidosis (SARA). In this study, 12 lactating (8 ruminally cannulated), multiparous Holstein cows averaging 91±40d in milk and weighing 695±95kg (mean ± SD) were randomly assigned to a replicated 4×4 Latin square. During each of the four 21-d periods, animals were offered 1 of 4 diets that were chemically similar but varied in corn silage particle size and supplemental second cutting orchardgrass hay: short corn silage total mixed ration (TMR; ST); short corn silage TMR with 5.6% supplemental hay (SH); long corn silage TMR (L); and long corn silage TMR with 5.6% supplemental hay (LH). Cows were allowed to adapt to this feeding scheme for 14d, and cannulated cows were then subjected to a rumen challenge to induce a bout of SARA by restricting feed before the challenge and providing 4kg of ground wheat via the rumen cannula. Although baseline pH was low, the SARA challenge lowered ruminal pH further for all cows regardless of diet. Daily average rumen pH decreased from 5.44 and 5.45 to 5.33 and 5.38 for ST and SH, respectively, and from 5.64 and 5.54 to 5.47 and 5.39 for L and LH, respectively, from baseline to challenge phase. Following the rumen challenge, rumen concentrations of acetate, propionate, butyrate, and valerate increased. Decreasing corn silage particle size significantly increased TMR and total DMI during all phases of the model. Feeding short corn silage TMR increased milk, protein, and lactose yields. Cows fed supplemental hay had increased fat yield and protein concentration in the milk and responded minimally to the effects of particle size selection when challenged with SARA. Cows consuming short corn silage TMR changed feed preference for longer forage particles during the course of the SARA challenge. During the recovery phase, however, cows refused an average of 13.5% of the offered TMR and 78.7% of the supplemental hay. These results indicate that cows did not prefer the supplemental hay regardless of corn silage particle size during a bout of SARA, which may have been due to the possible adaptation of a low ruminal pH throughout the study.

The effect of exogenous oxytocin on milkability and milk composition in ewes differed in milk flow pattern

During milking routine in sheep, the cluster is attached without pre-stimulation and milk ejection occurred (or not) as a consequence of liner movement on teat. The goal was to describe the importance of milk ejection before cluster attachment on milk flow patterns, milk composition and other parameters of milkability of ewes with two different physiological responses to usual milking (ewes with one emission of milk, i.e. expected no milk ejection (1P) and ewes with two emissions of milk i.e. expected milk ejection (2P)). On the base of three pre-experimental consecutive milkings, 22 adult lactating dairy ewes of two breeds Tsigaj (n=11) and Improved Valachian (n=11) were selected from the herd of experimental farm of APRC Nitra for this study. The animals were divided into two groups (first group 1P – ewes, and second group 2P – ewes). Ewes were regularly milked two times a day. Milk flow data were recorded during two evening milkings with 48h in between. During the first measurement the half of the animals in each group was treated by 5UI i.m. of oxytocin (OT) and the second half by physiological saline (SA) 60s before the cluster attachment. The application of OT and SA in both groups was changed in cross-over design during the second evening milking. Milk flow kinetics were recorded individually using an electronic jar with 2-wire compact magnetostrictive level. The OT treatment caused shortening of the milking time, increasing of peak milk flow rate and milk yield in thirty seconds in both groups. There were not any changes in milk composition in 2P ewes between SA and OT treatment. In 1P ewes, there was significantly increased total milk yield, machine milk yield, peak flow rate, milk yield in thirty and in 60s in OT treatment. Moreover, the increased fat yield was recorded in 1P group after OT treatment only. In conclusion, milk ejection occurrence before cluster attachment influences differently the milkability and milk composition in ewes differed in milk flow patterns during usual milking. Thus milk ejection is crucial in our breed for milk yield and composition recording.

The Nutritive Value of Live Yeast Culture (Saccharomyces cerevisiae) and Its Effect on Milk Yield, Milk Composition and Some Blood Parameters of Dairy Cows

This study was conducted to determine the nutritive value of live yeast culture (RumiSacc, Saccharomyces cerevisiae) and to investigate its effects on milk yield, milk composition and some blood parameters in lactating cows. Six multiparous Holstein cows were allocated to two groups of three cows and assigned randomly to one of two diets in a cross-over experiment. Daily 50 g RumiSacc was top dressed at the p.m. feeding for the treatment group. RumiSacc supplied a high protein and energy with high organic matter digestibility values (83.35%) determined by in vitro enzymatic analysis. Yeast culture supplementation significantly increased milk yield, tended to increase fat yield, protein yield and lactose yield of milk. Methylated fatty acid level of 18:3 (n-3) in milk fat was increased by yeast culture supplementation. The concentrations of methionine, phenyalanine, tyrosine, tryptophan and taurine were significantly increased with dietary inclusion of yeast culture. Live yeast culture supplementation did not affect other performance

The effect of crop maturity on the nutritional value of maize silage for lactating dairy cows. 3. Food intake and milk production

AbstractFifty-five multiparous Holstein-Friesian cows were used in a 20-week continuous design study to determine the effect of maize silage maturity on food intake and milk production. Forage maize (cv. Hudson) was harvested and ensiled at target dry matter (DM) contents of 230 (T23), 280 (T28), 330 (T33) and 380 (T38) g per kg fresh weight (FW). The mean values for volatile-corrected DM (VCDM), starch, neutral-detergent fibre (NDF), crude protein and predicted metabolizable energy (ME) content of the four maize silages were 226, 290, 302 and 390 g/kg FW, 114, 274, 309 and 354 g/kg VCDM, 574, 447, 431 and 448 g/kg VCDM, 96, 80, 74 and 75 g/kg VCDM and 10·3, 11·5, 11·6 and 11·2 MJ/kg DM, respectively. Grass silage containing 296 g VCDM per kg FW was produced from the primary growth of a perennial ryegrass sward. At week 3 of lactation cows were allocated to one of five forage treatments offered ad libitum. The forage treatments were either grass silage alone (TGS) or a 3 : 1 DM ratio of maize and grass silage designated as T23, T28, T33 and T38. All cows also received 8·7 kg DM per day of a dairy concentrate. Forage VCDM intake for TGS was lower (P &lt; 0·001) than for T23 to T38. Increasing maize silage DM content from 226 (T23) to 290 (T28) g/kg increased (P &lt; 0·05) forage VCDM intake from 10·9 to 13·3 kg/day but a further increase to 390 (T38) g/kg tended to reduce VCDM intake. When compared with TGS, the inclusion of maize silage increased milk yield from 28·0 kg/day to 29·4, 32·7, 33·0 and 30·8 kg/day for T23 to T38, respectively, the increases being significant for T28 to T38. However, milk yield was reduced (P &lt; 0·05) when the DM content of the maize silage increased from 302 to 390 g/kg. Increasing maize silage DM content from T23 to T33 reduced (P &lt; 0·05) milk fat content from 45·8 to 41·8 g/kg, which was also lower (P &lt; 0·05) than for TGS. The inclusion of maize silage increased fat yield with a significant difference (P &lt; 0·05) between TGS and T28. The inclusion of maize silage increased milk protein content (P &lt; 0·05) and protein yield (P &lt; 0·001) when compared with TGS. While increasing maize silage maturity did not affect (P &gt; 0·05) milk protein content, protein yield was higher (P &lt; 0·05) for the two intermediate DM contents. There were no treatment effects on body condition score. It is concluded that the changes in composition of maize silage with increasing maturity, which are associated with increased starch and reduced NDF content, resulted in large increases in food intake and yield of milk and protein as crops matured from T23 to T33. However, when crop maturity increased further to T38 there was a tendency for DM intake and yield of milk and protein to decline.

Effect of timing and level of protein supply on silage intake, feeding behaviour and milk yield of lactating dairy cattle

Previous studies have shown that the timing of supplement distribution and supplement type can have implications on forage intake and/or production. For example, Robinson et al. (1997) showed that feeding a protein supplement at 00.30 h compared with 08.30 h increased fat yield through stimulation of rumen fermentation. The objective of the present trial was to test the hypothesis “that supplying a protein supplement either before or after silage was offered would affect feeding pattern and silage intake”.Twelve multiparous cows, with average starting milk yield of 25.4 (s.d. 5.95) kg/day were allocated to one of six treatments in an incomplete Latin square with four periods of 21 days. Grass silage (219 g/kg DM, 151 g CP/kg DM) was fed ad libitum mixed with barley in the ratio 3:1 on a DM basis.

Role of Insulin in the Regulation of Milk Fat Synthesis in Dairy Cows

Five lactating Holstein cows were fitted with rumen fistulas and subjected to a hyperinsulinemiceuglycemic clamp and abomasal casein infusion to examine the effects on milk fat synthesis and the composition of milk fatty acids. The experiment consisted of two periods of abomasal infusions (water or 0.5 kg/d of casein); each period was divided into three 4-d intervals. The initial interval allowed for acclimation, and baseline measurements were established during the second interval. During the third 4-d interval, a hyperinsulinemic-euglycemic clamp was maintained, and insulin was infused continuously at the rate of 1μg/kg of body weight per h. Circulating concentrations of insulin were increased more than fourfold, and euglycemia was maintained by infusion of glucose at variable rates. Insulin had no effect on milk fat yield but casein infusion increased milk yield and tended to increase fat yield. A trend toward higher milk yield during the clamp, combined with a slight numerical decrease in milk fat yield, resulted in decreased fat percentage. Calculated net energy balance was positive throughout the study, although feed intake decreased during the insulin clamp, particularly for the water infusion period. Minor changes occurred in the composition of milk fatty acids during the clamp when the balance between de novo and preformed fatty acids shifted slightly toward de novo. Overall, results demonstrated that a relatively constant rate of milk fat synthesis was maintained during chronic hyperinsulinemia. Effects on milk fat yield and composition of fatty acids offered no support for the role of insulin on milk fat depression.

Application of enzyme‐assisted aqueous fat extraction to cocoa fat

AbstractAn enzyme‐assisted aqueous fat extraction method was used to extract fat from dry cocoa beans. The beans were dehulled and finely ground. Samples were mixed with water in predetermined ratios. A protease and an enzyme with high activities of both cellulase and hemicellulase were added at 1% of the sample weight, mixed, and incubated for about 6 h at 37°C. The treated samples were then extracted by a water flotation technique. The preextraction treatment with enzymes effectively increased fat yield by about 26%. The observation suggests that the enzyme‐assisted aqueous fat extraction method could improve the efficiency of rural fats and oils technologies currently in use in many developing countries.

Fatty Acids, Calcium Soaps of Fatty Acids, and Cottonseeds Fed to High Yielding Cows

We examined the effects of dietary fat as cottonseed, fatty acids, or calcium soaps of fatty acids in the rations of high yielding lactating cows receiving low forage. Experiments were with isoenergetic, isonitrogenous diets containing equal amounts of forage. Inclusion of up to 510 g/d of fatty acids in the ration enhanced FCM yield. With cottonseed, increased FCM was mainly due to increased fat yield. Dietary fatty acids tended to increase milk in mid and late lactation and to decrease fat percentage. Calcium soaps of fatty acids enhanced FCM, particularly in early lactation. Feeding cottonseed and fatty acids together did not enhance yield. Effects described may be attributed in part to changes in ruminal fermentation in which cottonseed increased acetate concentrations and fatty acids decreased the ratio of acetate and butyrate to propionate and in part to enhanced efficiency of milk yield when fat was included in the ration.

Effects of Propionic Acid Added to Supplemental Corn on Utilization of Complete Ensiled Diets by Lactating Dairy Cows

Two bottom unloading silos were filled with alternate loads of alfalfa (Medicago sativa L.) and ground shelled corn grain mix (1:5, grain:forage, wet basis) to determine effects of propionic acid added to supplemental corn on performance of lactating dairy cows consuming a complete ensiled diet. One silo received grain mix containing 1% propionic acid. Each of two groups of six lactating cows was fed one of the complete ensiled diets supplemented with high moisture corn, dried-shelled corn, or no supplemental corn for 4 mo. Cows that consumed the acid-treated diet produced less milk, fat, and protein than cows consuming the untreated diet. Supplemental high moisture corn and dried shelled corn increased milk and protein yields, and high moisture corn increased fat yields compared to the unsupplemented. Daily variation of the ratio of grain:forage indicated that alternate load additions of forage and grain resulted in poor mixing of ration components and may be related to some of the differences in performance.

Effects of anthelmintics on dairy cow yields

Abstract In the first of two trials with Friesian crossbred cows, monthly drenching starting about 9 weeks after calving increased milkfat yield per cow by almost 10 kg over the last 6 months of lactation. In the second trial, in which drenching began about 6 weeks after calving, there was no response in fat production from the treatment group as a whole, or from 2 and 3 year olds, but fortnightly drenching increased fat yield of mature cows by about 15 kg/cow over the lactation. Responses were most pronounced during the second half of lactation (December-May) and were due largely to a significant increase in milk yield. No effects on live weight were observed. There were no clinical symptoms of lielminthiasis at any stage, and the responses are attributed to small variations in immunity associated with seasonal changes in the availability of infective larvae on pasture.

Complete Rations for Dairy Cattle. III. Evaluation of Protein Percent and Quality, and Citrus Pulp-Corn Substitutions

An experiment with complete rations containing 25.0% sugarcane bagasse pellets evaluated protein requirements of lactating cows and how well these requirements could be satisfied with urea. Several other objectives also were evaluated with 3×3 Latin squares. Treatments of basal rations and two increments of soybean meal were factorialized with two percents of citrus pulp and two quantities of methionine hydroxy analog which were fed continuously. The experiment involved 36 cows fed one of the three urea or one of the three soybean meal percents in each of three 4-wk periods. (1) High-corn (8.0% citrus pulp) depressed fat percent compared to 43.1% citrus pulp diets. (2) Urea depressed feed intake at 1.7 and 3.0%, particurlary in the high-corn diets. (3) Increments of soybean meal increased solids corrected milk production as compared to basal, but urea increments did not. Methionine hydroxy analog increased fat yield in cows receiving soybean meal diets but was a detriment to feed intake and solids corrected milk in high urea rations.