Evaluation of the allergenicity of goat milk, cow milk, and their lactosera in a guinea pig model

The object of this study was to determine the allergenicity of goat milk (GM) and cow milk (CM) and that of their respective lactosera (GML and CML), by in vivo and in vitro assays. Two systemic tests for anaphylaxis were carried out in guinea pigs, the animals being sensitized orally with the 2 types of milk and lactosera. Sera were taken from the orbital sinus of the experimental animals at 0 and 22 d of the experiment to perform the serological study and the passive cutaneous anaphylaxis test. For the latter, the guinea pigs were sensitized passively with antibodies against the 4 antigen solutions. Enzyme-linked immunosorbent assay and Western blot were used to determine the specific antibodies of the isotypes immunoglobulin G1 and immunoglobulin G(Fc) developed against the same 4 antigen solutions. From these anaphylaxis and antibody-production tests, it was concluded that GM is hypoallergenic when compared with CM. The lactosera produced more closely grouped results, with values always below those of the corresponding milk. None of the proteins in the 4 immunizing solutions were identified as being their main allergen. These results show the hypoallergenicity of GM versus CM, and also that both casein and lactoserum proteins may be responsible for allergy in each case. To analyze the possibility of producing an innocuous food for those allergic to milk proteins, it would be of interest to identify the epitope(s) responsible for such allergenicity.     

Beneficial effect of goat milk on nutritive utilization of iron and copper in malabsorption syndrome

The search for diets that improve the digestive and metabolic use of iron and copper in malabsorption syndrome led us to study goat milk for particular nutritional characteristics and compare it with cow milk, which is usually supplied. We studied the metabolism of iron and copper in transected rats (control) and in resected rats (resection of 50% of the distal small intestine). The diets used were the standard diet recommended by the American Institute of Nutrition and diets based on goat or cow milk. Intestinal resection reduced the apparent digestibility coefficient (ADC) of iron in the three diets tested. In the transected and resected rats, the ADC of iron was highest with the goat milk diet, followed by the standard diet and lowest with the cow milk diet. The ADC of copper was not affected by intestinal resection in the animals fed the goat milk diet, and was higher than that in the two groups of animals fed the other diets. Intestinal resection reduced the ADC of copper with the standard diet and the cow milk diet. When both groups of animals were fed the goat milk diet, the deposit of iron in the organs was greater than with those fed the cow milk diet and similar to that in those animals given the standard diet. The copper content in the kidneys was lower in the resected than in the transected animals, except in the case of those fed the goat milk diet, in which it was similar to that of the control (transected) rats. This study shows the beneficial effect of goat milk, with respect to cow milk, on the metabolism of iron and copper in control rats, especially those with malabsorption syndrome.     

Goat milk during iron repletion improves bone turnover impaired by severe iron deficiency

The effect of goat or cow milk-based diets, with either normal Fe content or an Fe overload, on bone turnover and the mineralization process was studied in control and anemic rats during chronic Fe repletion. One hundred eighty male Wistar rats were studied during a pre-experimental period of 40 d in which they were randomly divided into 2 groups, a control group receiving the AIN-93G diet with normal Fe content (45 mg/kg of diet) and the Fe-deficient group receiving the AIN-93G diet with low Fe content (5 mg/kg of diet) for 40 d. After the pre-experimental period, the rats were fed for 10, 30, or 50 d with goat or cow milk-based diets with a normal Fe content (45 mg/kg of diet) or an Fe overload (450 mg/kg of diet). In anemic rats, goat milk with normal Fe content increased levels of the biomarker of bone formation N-terminal propeptides of type I procollagen and diminished parathyroid hormone levels after only 10 d of supplying this diet, indicating the beginning of restoration of the bone demineralization induced by the anemia, which was not observed with cow milk. After 30 d of supplying the milk-based diets with normal Fe content or an Fe overload, biomarkers of bone formation and bone resorption were not different between control and anemic rats, indicating that the bone demineralization induced by the Fe-deficiency anemia had recovered, although the process of stabilization of bone turnover began earlier in the animals fed goat milk. In addition, a higher Ca deposit was observed in femur, which positively affects bone mineralization, as well as an increase of Fe in sternum, which indicates that the hematopoietic process essentially recovered earlier on the goat milk diet compared with the cow milk diet.     

原子吸收法测定奶粉中的钙、铁、锌

用硝酸和高氯酸处理奶粉后，以质量分数为0.22％硝酸镧为释放剂，采用火焰原子吸收法测定同一样品中的钙、铁、锌元素的含量．结果表明．在选用浓度为0．15mol／L硝酸作介质条件下，共存离子不干扰．测定的RSD均小于1．59％(n=5)．回收率在98.6％-101．6％之间，与国家标准方法测定的结果基本相符。     

Levels of Se,Zn, Mg and Ca in commercial goat and cow milk fermented products: Relationship with their chemical composition and probiotic starter culture

We determined Se, Zn, Mg and Ca levels in 42 samples of goat and cow fermented milks which are widely consumed in Spain were determined. Atomic absorption spectrometry (hydride generation for Se and flame atomisation for remaining elements) was used as an analytical technique. Reliability of the procedure was checked. Only Mg levels in goat fermented milks were significantly higher to those found in cow fermented milks (p < 0.022). Important similarities in concentrations and behaviours for Mg and Ca have been observed. Mg contents were significantly correlated with Zn (r = 0.590; p < 0.001) and Ca (r = 0.344; p < 0.028) concentrations, Zn, Mg and Ca levels with protein content (r = 0.554, r = 0.479, r = 0.388, respectively), Mg levels with fats (r = 0.403; p = 0.011) and Se levels with carbohydrates (r = −0.379; p = 0.031). Mineral and macronutrient levels in yogurts with traditional probiotic starter cultures were not significantly different to those found in fermented milks with additional probiotic microorganisms (p > 0.05). It was concluded that goat fermented milks are a better source for Mg than cow samples.     

火焰原子吸收法测定牛毛和牛奶中微量元素的含量及二者相关性

湿法消解样品后，采用火焰原子吸收法对同栏饲养的成年健康奶牛牛毛与牛奶中锌、镁、钙、铜、铁等5种微量元素进行了测定．其中钙平均含量最高，铜平均含量最低。二者的微量元素含量之间具有很好的相关性，这可能为间接、方便、快速了解奶牛的健康状况及监测牛奶营养质量提供了一条新的途径，有助于全面了解牛奶的质量和奶牛自身健康状况及饲料营养添加之间的关系。同时，通过对比分析不同年龄段奶牛牛毛中微量元素的含量，探讨了这些微量元素含量与奶牛年龄之间的相关性。     

A randomized herd-level field study of dietary interactions with monensin on milk fat percentage in dairy cows

This field trial evaluated the effects of dietary supplementation with 16 mg/kg (based on total dry matter intake) of monensin sodium on bulk tank milk fat percentage (MFP) of commercial dairy herds. Interactions between monensin and nutritional factors on MFP were studied. The trial was conducted in 47 Holstein dairy herds in Québec, Canada, between November 2005 and May 2006. The herd was the unit of interest. Enrolled herds were followed for a 7-mo period. Monensin treatment was randomly allocated in a crossover design where monensin was supplemented to the lactating dairy cow diet for a consecutive 12-wk period. Twenty-four herds were allocated to monensin treatment for the first period of trial, and 23 herds were allocated for the second period. Diet composition and ration physically effective particle level were collected every 8 wk. Milk fat percentage data were retrieved from weekly bulk tank measures. Data were analyzed in linear mixed models using repeated measures within herd where MFP was considered the outcome variable. In addition to the main effect of monensin treatment, the following covariates were forced a priori into all statistical models: treatment period, weekly herd mean parity, and weekly herd mean days in milk. The majority of herds were fed a total mixed ration (n = 29) and were housed in tie-stalls (n = 42). Monensin significantly decreased bulk tank MFP by 0.12 percentage points. The reduction of MFP associated with monensin was larger for herds having a diet high (>39.7%) in nonfiber carbohydrates, having a low level of physically effective particles in ration (>45.0%; ≥8 mm), and not feeding dry hay as first meal in the morning. Significant interactions between monensin and nutritional factors on bulk tank MFP were related to nonfiber carbohydrate and fiber concentrations in the diet.     

Determination of polycyclic aromatic hydrocarbons in Italian milk by HPLC with fluorescence detection

The presence of polycyclic aromatic hydrocarbons (PAHs) in Italian commercial milk samples is reported. The study was carried out on lactating (cow and goat) and plant (rice, soya, oat) milk. The quantitative determination involved liquid–liquid extraction of PAHs, a pre-concentration and determination by HPLC using a fluorescence detector. The recovery of analytes was in the range of 70–115%. The precision of the method was found to be between 6% and 24%. The detection limit ranged from 0.66 to 33.3 µg l^–1 corresponding to 0.03–1.66 µg kg^–1 milk (wet weight), at a signal-to-noise ratio of 3, depending on the compound. By this procedure, the levels of more volatile PAHs (two to three aromatic rings) were confirmed in 34 commercial milk and three plant milk samples, whereas benzo[a]pyrene was found only in five pasteurised milk samples at a mean concentration of 0.17 µg kg^–1 milk. These results provide evidence that PAH levels are influenced by heat treatments and skimming processes of milk production.     

A field study of dietary interactions with monensin on milk fat percentage in lactating dairy cattle

Ninety-one Ontario Holstein dairy herds were surveyed about their lactating cow ration and use of a premix containing monensin to identify possible dietary interactions with monensin on milk fat suppression. All herds were enrolled in Ontario Dairy Herd Improvement (DHI) milk recording, and results from four DHI tests were used. Herd mean fat tests were calculated only for cows between 100 and 200 d in milk to avoid potential confounding due to stage of lactation. Wet forage and total mixed ration (TMR) samples from all herds were evaluated for particle size using the Penn State Particle Size Separator. Of the herds using monensin (n = 58), the dose (per kg of dry matter) ranged from 9 to 14 mg/kg in TMR-fed herds and from approximately 9 to 23 mg/kg in herds in which concentrates were fed separately from forages (component-fed). Of the samples submitted for particle size evaluation, 15% of the haylage (n = 80), 14% of the corn silage (n = 79), and 42% of the TMR (n = 58) samples were classified as having low fiber. There was a significant negative univariable association between monensin and mean milk fat percentage. Monensin significantly reduced milk fat percentage in TMR-fed but not component-fed herds. Fiber length significantly interacted with monensin in TMR-fed herds: Herds that had low fiber in their TMR (< or = 6.0% in the top screen) were susceptible to milk fat decrease by monensin, whereas herds that had adequate fiber (> 6.0%) were not. Monensin also significantly reduced milk fat percentage in herds receiving diets low in nonstructural carbohydrate (< 40.2%) but not in those receiving diets high in NSC (> or = 40.2%). The results of this study suggest that there are significant interactions between monensin and certain dietary factors on milk fat suppression in Holstein dairy herds.     

Improved milk production efficiency in early lactation dairy cattle with dietary addition of a developmental fibrolytic enzyme additive

A 3-part study was conducted to evaluate the effect of a developmental fibrolytic enzyme additive on the digestibility of selected forages and the production performance of early-lactation dairy cows. In part 1, 4 replicate 24-h batch culture in vitro incubations were conducted with alfalfa hay, alfalfa silage, and barley silage as substrates and ruminal fluid as the inoculum. A developmental fibrolytic enzyme additive (AB Vista, Marlborough, UK) was added at 5 doses: 0, 0.5, 1.0, 1.5, and 2.0 μL/g of forage dry matter (DM). After the 24-h incubation, DM, neutral detergent fiber (NDF), and acid detergent fiber (ADF) disappearance were determined. For alfalfa hay, DM, NDF, and ADF disappearance was greater at the highest dosage compared with no enzyme addition. Barley silage NDF and ADF and alfalfa silage NDF disappearance tended to be greater for the highest enzyme dosage compared with no enzyme addition. In part 2, 6 ruminally cannulated, lactating Holstein dairy cows were used to determine in situ degradation of alfalfa and barley silage, with (1.0 mL/kg of silage DM) and without added enzyme. Three cows received a control diet (no enzyme added) and the other 3 received an enzyme-supplemented (1.0 mL/kg of diet DM) diet. Enzyme addition after the 24 h in situ incubation did not affect the disappearance of barley silage or alfalfa silage. In part 3, 60 early-lactation Holstein dairy cows were fed 1 of 3 diets for a 10-wk period: (1) control (CTL; no enzyme), (2) low enzyme (CTL treated with 0.5 mL of enzyme/kg of diet DM), and (3) high enzyme (CTL treated with 1.0 mL of enzyme/kg of diet DM). Adding enzyme to the diet had no effect on milk yield, but dry matter intake was lower for the high enzyme treatment and tended to be lower for the low enzyme treatment compared with CTL. Consequently, milk production efficiency (kg of 3.5% fat-corrected milk/kg of DM intake) linearly increased with increasing enzyme addition. Cows fed the low and high enzyme diets were 5.3 (not statistically significant) and 11.3% more efficient, respectively, compared with CTL cows. This developmental fibrolytic enzyme additive has the potential to increase fiber digestibility of forages, which could lead to greater milk production efficiency for dairy cows in early lactation.     

Rapid detection of cows' milk in sheeps' and goats' milk by a species-specific polymerase chain reaction technique

A polymerase chain reaction (PCR) assay was developed for the specific identification of cows' milk in sheep's and goats' milk by using primers targeting the mitochondrial 12S rRNA gene. The use of a forward primer complementary to a conserved DNA sequence, along with a reverse primer specific for cow, yielded a 223-bp fragment from cows' milk DNA, whereas no amplification signal was obtained in sheep's and goats' milk DNA. The technique was applied to raw, pasteurized, and sterilized milk binary mixtures of cow-sheep and cow-goat, enabling the specific detection of cows' milk with a good sensitivity threshold (0.1%). The proposed PCR assay represents a rapid and straightforward method applicable to the authentication of milk and other dairy products in routine analysis.     

Goat milk feeding causes an increase in biliary secretion of cholesterol and a decrease in plasma cholesterol levels in rats

The hypocholesterolemic effect of goat milk with respect to cow milk observed in a previous study led us to examine the influence of goat and cow milk in the diet on certain aspects of biliary physiology in normal rats. The fat content in all diets was 10% but the lipid quality was varied: the standard diet was based on virgin olive oil, and the other 2 diets included fat obtained from lyophilized cow milk and goat milk. We characterized the bile secretion, including biliary phospholipid, cholesterol, and bile acid outputs, the interrelation between bile acids and bile lipids, and the lithogenic index. The consumption of goat milk in the diet, compared with that of cow milk, caused an increase in the biliary secretion of cholesterol together with a decrease in plasma cholesterol concentration, whereas values for bile phospholipids, biliary acid concentrations, and the lithogenic index remained normal. Moreover, consumption of this type of milk decreased plasma triglyceride concentration and therefore had a positive effect, similar to that of olive oil (standard diet), on the lipid metabolism; hence, it may be recommended for consumption by the general population.     

Determination of fluorine in milk samples via calcium-monofluoride by electrothermal molecular absorption spectrometry

The determination of fluorine in milk samples via the molecular absorption of calcium mono-fluoride (CaF) was performed using a HR-CS-ETAAS. For this purpose, calcium was pipetted to graphite furnace together with samples. The amount of Ca and the graphite furnace program were optimised. Fluorine was determined in pyrolytically coated platforms at 606.440 nm applying a pyrolysis temperature of 700 °C and a molecule forming temperature of 2250 °C. Finally, applying standard addition technique, F contents of several milk samples were determined. The results obtained by linear calibration and standard addition techniques were significantly different which can be attributed to non-spectral interferences in milk due to matrix concomitants. Therefore, in order to tolerate the errors, the F contents of several milk samples were determined applying standard addition technique. However, since the ingredients of milk samples change for different kinds, the F in each sample was determined from its own standard addition curve. The range of F content for the milk samples were 0.027–0.543 μg mL⁻¹. The limit of detection and characteristic mass of the method were 0.26 and 0.13 ng of F, respectively.     

Inorganic anions in goat and ovine milk from Calabria (Italy) by suppressed ion chromatography

Forty-seven samples of milk taken from goat and ovine farms in Calabria (southern Italy) between April and May 2010 were analysed. Analyses were carried out by ion chromatography (ICS 1000; Dionex). For method validation, RSDs (%) on retention times and on peak area were determined by considering a mixture of standard anions at the concentration level of 0.1–30?mg?l^?1 for chloride, bromide, nitrite, nitrate, sulfate and phosphate. The higher RSDs were 1.4% and 2.2% for retention times and 2.4% and 3.7% for areas for intra- and inter-day repeatability, respectively. Good linearity was observed in each concentration range, with linear correlation coefficients (R ²) better than 0.987. The LODs and LOQs were calculated experimentally as signal-to-noise ratios of 3 and 10, respectively. Analysis of the results obtained indicated that phosphates were the most abundant anion (1409–3050?mg?l^?1) followed by chloride (679–2568?mg?l^?1) and sulfates (25–341?mg?l^?1). Nitrates were found to be lower at 146?mg?l^?1 (the maximum value observed). The values of anions found in this work are in agreement with those reported in the literature for cow's milk. There are no significant differences between ovine and goat's milk samples. The method used for this analysis of anions combines rapidity with high precision, accuracy and sensitivity; therefore, it is suitable for routine analysis. Moreover, one of the most obvious advantages of this technique is that multiple elements can be determined in one sample with no serial dilutions and the complete analysis can be performed by using only one instrument.     

Ratio of dietary rumen degradable protein to rumen undegradable protein affects nitrogen partitioning but does not affect the bovine milk proteome produced by mid-lactation Holstein dairy cows

Little is known about the bovine milk proteome or whether it can be affected by diet. The objective of this study was to determine if the dietary rumen degradable protein (RDP):rumen undegradable protein (RUP) ratio could alter the bovine milk proteome. Six Holstein cows (parity: 2.5 ± 0.8) in mid lactation were blocked by days in milk (80 ± 43 d in milk) and milk yield (57.5 ± 6.0 kg) and randomly assigned to treatment groups. The experiment was conducted as a double-crossover design consisting of three 21-d periods. Within each period, treatment groups received diets with either (1) a high RDP:RUP ratio (RDP treatment: 62.4:37.6% of crude protein) or (2) a low RDP:RUP ratio (RUP treatment: 51.3:48.7% of crude protein). Both diets were isonitrogenous and isoenergetic (crude protein: 18.5%, net energy for lactation: 1.8 Mcal/kg of dry matter). To confirm N and energy status of cows, dry matter intake was determined daily, rumen fluid samples were collected for volatile fatty acid analysis, blood samples were collected for plasma glucose, β-hydroxybutyrate, urea nitrogen, and fatty acid analysis, and total 24-h urine and fecal samples were collected for N analysis. Milk samples were collected to determine the general milk composition and the protein profile. Milk samples collected for high-abundance protein analysis were subjected to HPLC analysis to determine the content of α-casein, β-casein, and κ-casein, as well as α-lactalbumin and β-lactoglobulin. Samples collected for low-abundance protein analysis were fractionated, enriched using ProteoMiner treatment, and separated using sodium dodecyl sulfate-PAGE. After excision and digestion, the peptides were analyzed using liquid chromatography (LC) tandem mass spectrometry (MS/MS). The LC-MS/MS data were analyzed using PROC GLIMMIX of SAS (version 9.4, SAS Institute Inc., Cary, NC) and adjusted using the MULTTEST procedure. All other parameters were analyzed using PROC MIXED of SAS. No treatment differences were observed in dry matter intake, milk yield, general milk composition, plasma parameters, or rumen volatile fatty acid concentrations, indicating no shift in total energy or protein available. Milk urea N and plasma urea N concentrations were higher in the RDP group, indicating some shift in N partitioning due to diet. A total of 595 milk proteins were identified, with 83% of these proteins known to be involved in cellular processes. Although none of the low-abundance proteins identified by LC-MS/MS were affected by diet, feeding a diet high in RUP decreased β-casein, κ-casein, and total milk casein concentration. Further investigations of the interactions between diet and the milk protein profile are needed to manipulate the milk proteome using diet.     

Study of nutritive utilization of protein and magnesium in rats with resection of the distal small intestine. Beneficial effect of goat milk

The search for diets to improve the nutritive utilization of protein and magnesium in malabsorption syndrome led us to study goat milk, because of its particular nutritional characteristics, and to compare it with cow milk, which is most commonly consumed. We studied the nutritive utilization of protein and magnesium in transected rats (control) and in rats with resection of 50% of the distal small intestine. The diets used were the standard diet recommended by the American Institute of Nutrition and diets based on lyophilized goat or cow milk. The consumption of goat milk produces better protein efficiency ratio and food conversion efficiency values, particularly in rats with intestinal resection, together with a higher nutritive utilization of protein. Magnesium apparent digestibility coefficient is not modified by intestinal resection in rats fed with goat milk-based diet, on the contrary to the standard and cow milk diets. Magnesium apparent digestibility coefficient is greater for the goat milk group, which is reflected in the greater quantity of this mineral stored in bone. These results demonstrate the beneficial effect of goat milk on the nutritive utilization of protein and on magnesium bioavailability, especially in animals with resection of the distal small intestine.     

Short communication: Effects of milk fat depression induced by a dietary supplement containing trans-10, cis-12 conjugated linoleic acid on properties of semi-hard goat cheese

Dietary supplements of conjugated linoleic acid (CLA) containing trans-10, cis-12 CLA reduce milk fat synthesis in lactating goats. This study investigated effects of milk fat depression induced by dietary CLA supplements on the properties of semi-hard goat cheese. Thirty Alpine does were randomly assigned to 1 of 3 groups and fed diets with lipid-encapsulated CLA that provided trans-10, cis-12 CLA at 0 (control), 3 (CLA-1), and 6 g/d (CLA-2). The experiment was a 3 × 3 Latin square design. Periods were 2 wk in length, each separated by 2-wk periods without CLA supplements. Bulk milk was collected on d 3 and 13 of each of 3 periods for cheese manufacture. The largest decrease (23.2%) in milk fat content, induced by the high dosage (6 g/d per doe) of trans-10, cis-12 CLA supplementation at d 13 of treatment, resulted in decreases of cheese yield and moisture of 10.2 and 10.0%, respectively. Although CLA supplementation increased the hardness, springiness, and chewiness, and decreased the cohesiveness and adhesiveness of cheeses, no obvious defects were detected and no significant differences were found in sensory scores among cheeses. In conclusion, milk fat depression induced by a dietary CLA supplement containing trans-10, cis-12 CLA resulted in changes of fat-to-protein ratio in cheese milk and consequently affected properties of semi-hard goat cheese.     

Effect of duration and level of supplementation of diets of lactating dairy cows with selenized yeast on selenium concentrations in milk and blood after the withdrawal of supplementation

Cows’ milk containing elevated concentrations of Se provides a rich nutritional source of this essential element for meeting daily nutritional requirements or providing health benefits in humans with low immune function or at risk of cancer. An experiment involving either 2 or 6 wk of dietary supplementation with Se yeast (with the yeast supplying about 30, 40, and 60 mg of Se/d for cows supplemented for 2 wk, and about 20, 30, 40, and 60 mg of Se/d for cows supplemented for 6 wk), and 21 wk of monitoring of Se status after the withdrawal of supplementation, was undertaken between September 2008 and April 2009 using 35 multiparous Holstein-Friesian cows. Using milk and blood Se concentrations as surrogates, the research examined the time taken for Se build-up in tissue due to supplementation of lactating dairy cows with Se yeast to dissipate back to normal levels. At the end of Se supplementation, a significant relationship was found between milk Se concentration and Se intake, whereby milk Se concentration had increased by 4.5 μg of Se/kg of milk for each mg of Se eaten per day, but no effect of duration of supplementation on this relationship was observed. At the same time, both Se intake and duration of supplementation affected blood Se concentration; it increased by 3.6 μg of Se/kg of blood for each mg of Se eaten per day, and was 86 μg of Se/kg higher after 6 wk compared with 2 wk of supplementation. After the withdrawal of Se supplementation, milk Se concentrations responded quickly to the change in the quantity of Se consumed, and again, duration of supplementation had no effect on the response, but any effect that Se intake had on milk Se had completely dissipated by 4 wk. In contrast to milk, blood Se concentrations continued to be affected by both amount and duration of Se supplementation for at least 4 mo after the withdrawal of supplementation, although by 5 mo the effects of the previous supplementation treatments had virtually disappeared. The slow decline in blood Se concentrations after the withdrawal of supplementation would most likely be due to the protracted clearance of Se from the various tissues that had accumulated Se during supplementation and the rate of erythrocyte turnover. When undertaking an on-farm Se enhancement program to generate milk for the manufacture of Se-enriched milk products, post-supplementation milk Se concentrations are unlikely to create any problems at the milk factory beyond 4 wk, but the high residual blood/tissue Se concentrations that take considerably more time to dissipate may provide the potential for possible unintended consequences at the food chain/farm environment level.     

Effects of dietary supplementation with extruded linseed and oregano in autochthonous goat breeds on the fatty acid profile of milk and quality of Padraccio cheese

The study aimed to evaluate the effects of linseed and oregano supplementation to the diet of goats on fatty acid profile and sensory properties of Padraccio, a typical cheese produced during spring through summer in the Basilicata region (southern Italy). Extruded linseed and dried oregano inflorescences were integrated in the pelleted concentrate supplementation (500 g/head per day) in 21 grazing goats that were randomly assigned, 7 per group, to the following experimental treatments: concentrate, concentrate with addition of linseed, and concentrate with addition of linseed and oregano. Pooled milk from each group was used in cheesemaking. From a nutritional perspective, integration of extruded linseed in the goat diet improved the fatty acid profile of Padraccio cheese. Moreover, the cheese from this group evidenced the highest scoring on color, flavor, texture, and overall liking.     

Feeding reduced-fat dried distillers grains with solubles to lactating Holstein dairy cows does not alter milk composition or cause late blowing in cheese

Feeding dried distillers grains with solubles (DDGS) to lactating dairy cows has been implicated as a cause of late blowing defects in the production of Swiss-style cheeses. Our objectives were (1) to test the effect of feeding reduced-fat DDGS (RF-DDGS; ～6% fat) to lactating dairy cows on the composition of milk and on the suitability of the milk for production of baby Swiss cheese and (2) to evaluate the effect of diet on cow lactation performance. Lactating Holstein dairy cows were fed both dietary treatments in a 2 × 2 crossover design. Cows were housed in a 48-cow freestall pen equipped with individual feeding gates to record feed intake. The control diet was a corn, corn silage, and alfalfa hay diet supplemented with mechanically expelled soybean meal. The experimental diet was the same base ration, but 20% (dry matter basis) RF-DDGS were included in place of the expelled soybean meal. The RF-DDGS diet was additionally supplemented with rumen-protected lysine; diets were formulated to be isoenergetic and isonitrogenous. Cows were allowed ad libitum access to feed and water, fed twice daily, and milked 3 times daily. For cheese production, milk was collected and pooled 6 times for each dietary treatment. There was no treatment effect on milk yield (35.66 and 35.39 kg/d), milk fat production (1.27 and 1.25 kg/d), milk fat percentage (3.65 and 3.61%), milk protein production (1.05 and 1.08 kg/d), lactose percentage (4.62 and 4.64%), milk total solids (12.19 and 12.28%), and somatic cell count (232.57 and 287.22 × 10³ cells/mL) for control and RF-DDGS, respectively. However, dry matter intake was increased by treatment, which implied a reduction in feed efficiency. Milk protein percentage also increased (3.01 and 3.11%), whereas milk urea nitrogen decreased (14.18 and 12.99 mg/dL), indicating that protein utilization may be more efficient when cows are fed RF-DDGS. No differences in cheese were observed by a trained panel except cheese appearance; control cheese eyes were significantly, but not practically, larger than the RF-DDGS cheese. These results indicate that RF-DDGS can be effectively used in the rations of lactating Holstein cows with no deleterious effects on milk production and composition and metrics of the physiology of the cow (i.e., blood glucose and nonesterified fatty acids); however, feeding RF-DDGS increased dry matter intake, which decreased feed efficiency. Finally, feeding RF-DDGS did not negatively influence quality and suitability of milk for production of baby Swiss cheese.