Presence of Mycoplasma species and somatic cell counts in bulk-tank goat milk

This cross-sectional study performed on dairy goat herds was designed to establish the relationship between the presence of Mycoplasma species in bulk-tank milk samples from different farms and the bulk-tank milk somatic cell count (BTMSCC) in an area where contagious agalactia (CA) is endemic. Three BTMSCC thresholds, used in payment schemes or as legal requirements for milk quality in Europe and the USA, were considered: (1) 2,000,000 cells/ml; (2) 1,500,000 cells/ml and (3) 1,000,000 cells/ml. Of the 1068 milk samples tested, 7.9% (n = 84) showed the presence of Mycoplasma spp. (Mycoplasma agalactiae 82% and Mycoplasma mycoides subsp. mycoides large colony 17%). Somatic cell counts for bulk-tank samples containing mycoplasmas were higher than those recorded for negative samples (1,176,000 cells/ml vs. 875,000 cells/ml; P < 0.001). Two-by-two table analyses revealed that the presence of mycoplasmas in bulk-tank milk increased the risk of surpassing all SCC thresholds considered, with the highest risk for Mycoplasma positive bulk-tank milk samples exceeding the threshold of 1500 × 10³ cells/ml (odds ratio = 2.42 (1.49 < OR < 3.91). Our results indicate that the presence of mycoplasmas in goat milk had yet another economic consequence and a further incentive to encourage the implementation of specific programs for disease control.     

Characteristics of goat milk collected from small and medium enterprises in Greece,Portugal and France

Characteristics of goat milk collected from seven small and medium enterprises (SMEs) in Greece, France and Portugal were compared. Results of microbiological, biochemical and technological characteristics (whey draining capacity after lactic or rennet coagulation, acidification aspects, and heat stability) of goat milk with identical and standardised techniques are discussed in relation to effects on technological processes and quality of final products. Results revealed variability of goat milk characteristics collected from the different European areas. Hygienically, goat milk production conditions in Greece and Portugal, under extensive breeding systems were: total bacteria—3.6×10⁷ and 4×10⁷ CFU/ml; coliforms—1.8×10⁶ and 2.5×10⁶ CFU/ml; staphylococci coagulase+—1.7×10⁵ and 7.6×10⁴ CFU/ml, respectively. For France, using intensive breeding systems, microbiological quality was: total bacteria—1.08×10⁵ CFU/ml; coliforms—1.40×10² CFU/ml; staphylococci coagulase+—2.75×10² CFU/ml. Goat milk from Greek farms had the highest fat and protein contents: 51.4 and 37.0 g/kg, compared to goat milk in France: 36.5 and 32.5 g/kg, respectively. Portuguese goat milk was intermediate: 42.7 and 34.9 g/kg, respectively.Regarding technological aspects, Greek and Portuguese milks showed poor whey draining capacity and Greek milks presented low heat stability (100.5 °C on average) but a good propensity to acidify. Systems of production of goat milk, ways of transport of raw goat milk, and the procedures applied inside factories regarding receiving and storage of the raw goat milk are discussed and should be useful for the definition of technological adaptations, that are necessary for best milk and product quality.     

The effect of machine or hand milking on milk production,composition and SCC in mountainous Greek breed (Boutsiko) ewes

The aim of this work was to determine the effect of two different milking methods (machine versus hand milking) on milk yield, milk composition and somatic cell counts (SCC) in mountainous Greek Boutsiko ewes. Ninety-six ewes were divided in two groups of 48 ewes each. Milk yield, lactation number (parity) and type of lambing were taken into consideration for the separation of the ewes. One group was milked by machine and the other by hand. Milk production, milk composition (with Milkoscan 104) and SCC (with Fossomatic) were performed every 14 days, in the morning and evening milking; during the experimental period seven samplings were performed in total. The results of this study have shown that ewes milked by machine gave a greater daily milk yield as compared to those milked by hand (698 ml versus 652 ml; P < 0,05) and less log SCC (5.37 versus 5.62; P < 0,05). The composition of milk did not differ between the two treatments. Also, no phenotypic correlations were established between SCC and milk production or composition, apart from a negative correlation, which was noted between SCC and the percentage of lactose. The results of this experiment have shown that ewes of the Boutsiko breed can be milked by machine without any problems.     

Characteristics of Korean-Saanen goat milk caseins and somatic cell counts in comparison with Holstein cow milk counterparts

Characteristics of α- and β-casein fractions in the milk of Korean-Saanen goats were compared with those of Holstein cow milk using capillary electrophoresis (CE) analysis. The αs₁-CN content of the Saanen goat milk samples varied from 2.4% to 9.3% of total proteins. Total αs-CN content of the goat milk varied from 10.1% to 17.0%. Total β-CN content containing β₁-CN and the β₂-CN varied from 49.6% to 61.0% of total proteins. Average αs-CN to β-CN ratio of the Saanen goat milk from different farms was 0.24 ± 0.04, ranging from 0.17 to 0.33. The αs-CN (αs₁-CN + αs₀-CN) to β-CN (β_A1-CN + β_A2-CN) ratio of Holstein cow milk was 0.81, which was much higher than that of Korean-Saanen goat milk. The goat milk samples having more than 1.5 million cells/ml somatic cell counts (SCC) contained higher αs-CNs (P < 0.01) and lower β-CNs (P < 0.05) contents than milks with <1.5 million SCC. This resulted in a higher αs-CN to β-CN ratio (P < 0.01) in the milk with >1.5 million SCC.     

Phenotypic and genetic relationships between udder morphology and udder health in dairy ewes

The aim of this paper was studying the phenotypic and genetic relationships between udder morphology traits and udder health in dairy sheep. From 2000 to 2008 udder traits, somatic cell count (SCC) and clinical mastitis cases were recorded in an experimental flock consisting each year of around 900 ewes. A logistic regression was performed to evaluate the risk for a ewe of showing either a mastitis or at least 2 daily SCC records greater than 1 × 10⁶ cells/ml in one of its lactations as function of udder traits scored in 1st lactation. 1587 individual udder scores and 39,950 SCC daily records were used for the analysis. Secondly, genetic correlation between lactation mean of somatic cell score and udder traits were estimated by a REML method applied to four bi-trait animal models, using data from 2251 primiparous ewes. Logistic regression results indicated that the risk of mastitis or high SCC values during the productive life increased as the cistern height increased and the degree of udder suspension and udder depth decreased. This suggests that the appraisal of the udder is a useful tool for culling decision aimed at increasing the sanitary status of the flock. The genetic correlation between lactation SCS and udder traits were favourable for udder depth (−0.50 ± 0.12), teat placement (0.39 ± 0.011) and degree of udder suspension (−0.42 ± 0.011) and closed to zero for the degree of separation of the two halves. Thus selection for udder morphology, already implemented in some dairy sheep breeds with the aim of improving machine milkability, will lead to a favourable correlated genetic response on SCC.     

Effects of pelleted total mixed rations with different rumen degradable protein on milk yield and composition of Jonica dairy goat

The present study was conducted in order to examine the effects of diets with different ruminal degradable protein sources on the performance of lactating goats fed pelleted total mixed rations (PTMR). Forty multiparous Jonica goats in early-lactation were divided into two equal groups and fed for 135 days the experimental diets. Two types of PTMR were formulated to be isonitrogenous and isocaloric while providing different rumen degradable levels of crude protein: (1) high-degradable protein diet (HD) containing soybean meal, sunflower meal and urea (46% N), and (2) low-degradable protein diet (LD) including only corn gluten meal. Apparent digestibility of the two PTMR was tested using Jonica bucks placed in individual pens and results indicated significant differences (P < 0.05) for crude protein, crude fibre, neutral detergent fibre and acid detergent fibre nutrients’ utilization. In milk performance trial, no significant differences (P > 0.05) were registered in dry matter intake and milk yield. Goats fed LD diet containing corn gluten meal showed the highest milk fat, protein and casein concentration, but not significant differences (P > 0.05) were observed on other milk components and renneting properties. It was concluded that a decrease of rumen degradable protein (RDP) level in PTMR does not negatively influence nutrient utilization and milk production and composition of Jonica dairy goat.     

Impact of three THI levels on somatic cell count,milk yield and composition of multiparous Holstein cows in a subtropical region

In Egypt, cow's milk represents 52.11% of the total milk production. Climatic condition is mainly expected to impact the welfare and productive performance of livestock animals. Thus, we aimed to explore the impact of temperature-humidity index (THI) on somatic cell count (SCC), milk production and composition on daily milk test records (33600) of Holstein cows under subtropical Egyptian conditions with different levels of THI. Our results revealed that daily milk yield and composition (fat%, protein %, yielded fat, yielded protein and the percentage of lactose) were higher in low THI (31.91 kg, 3.91%, 3.22%, 418 kg, 349 kg and 4.20%, respectively) when compared with high THI. SCC significantly increased 36% from low to high THI. In addition to, it was increased with advanced parities 231.11% from 2nd to 7th parities. At high THI level, SCC was negatively correlated with total MY (r=−0.12 P<0.05), 305 MY (r=−0.16 P<0.05), protein % (r=−0.15 P<0.01), fat% (r=−0.14 P<0.01) and lactose % (r=−0.26 P<0.01). The current study concluded that dairy cows performance was better in most of the investigated parameters at low THI than those in high THI. Thus, indicating a detrimental effect of THI on both welfare and economic return.     

Predictive formulae for goat cheese yield based on milk composition

Prediction of the yield and quality of different types of cheeses that could be produced from a given type and/or amount of goat milk is of great economic benefit to goat milk producers and goat cheese manufacturers. Bulk tank goat milk was used for manufacturing hard, semi-hard and soft cheeses (N = 25, 25 and 24, respectively) to develop predictive formulae of cheese yield based on milk composition. Fat, total solids, total protein and casein contents in milk and moisture-adjusted cheese yield were determined to establish relationships between milk composition and cheese yield. Soft, semi-hard and hard cheeses in this study had moisture contents of 66, 46 and 38%, respectively, which could be used as reference standards. In soft cheese, individual components of goat milk or a combination of two or three components predicted cheese yield with a reasonably high correlation coefficient (R² = 0.73–0.81). However, correlation coefficients of predictions were lower for both semi-hard and hard cheeses. Overall, total solids of goat milk was the strongest indicator of yield in all three types of cheeses, followed by fat and total protein, while casein was not a good predictor for both semi-hard and hard cheeses. When compared with moisture-adjusted cheese yield, there was no difference (P > 0.05) in predicting yield of semi-hard and hard goat milk cheeses between the developed yield formulae in this study and a standard formula (the Van Slyke formula) commonly used for cow cheese. Future research will include further validation of the yield predictive formulae for hard and semi-hard cheeses of goat milk using larger data sets over several lactations, because of variation in relationships between milk components due to breed, stage of lactation, season, feeding regime, somatic cell count and differences in casein variants.     

Effects of grass silage harvesting time and level of concentrate supplementation on nutrient digestibility and dairy goat performance

The effect of harvesting time (HT) of timothy-dominated grass silage and level of concentrate on the chemical composition of silage, and on feed intake and milk production by Norwegian dairy goats, were evaluated. The silages were prepared from the primary growth at three stages of maturity: very early (HT 1), early (HT 2) and normal (HT 3). The silages were fed ad libitum to 18 goats of the Norwegian dairy goat breed in early lactation and supplemented with a low (LC; 0.6 kg per goat daily) or normal (NC; 1.2 kg per goat daily) level of concentrate. The experiment was conducted as a cyclic changeover design with four periods of 28 days using three blocks of goats according to their initial body condition (poor, medium or high body condition). Silages contained 771, 696 and 619 g digestible organic matter per kg dry matter in silage (D-value) for HT 1, 2 and 3, respectively. Postponing the harvesting time decreased (P<0.001) silage dry matter intake (DMI) and silage DMI per kg body weight (BW). Increased concentrate allowance decreased silage DMI, with substitution rates (decrease in silage DMI when concentrate dry matter intake is increased, kg/kg) of 0.43, 0.21 and 0.27 at HT 1, HT 2 and HT 3, respectively. Milk yield and yields of milk constituents decreased (P<0.001) with delayed harvesting time and thus reflected the changes in silage D-value. Milk free fatty acids (FFA) concentration was not affected by dietary treatments. The efficiency of nutrient utilization was best when LC was fed and increased with postponed harvesting time. The higher energy efficiency of the HT 3 LC fed goats indicates that these goats canalized a higher proportion of energy intake to milk production, compared to goats fed NC and earlier harvested silage. Marginal ECM production response to increased net energy lactation (NEL) intake were higher when intake was increased due to higher silage digestibility (0.14 kg ECM/MJ NEL) compared with increased NEL intake due to increased concentrate level (0.12 kg ECM/MJ NEL). Improving silage quality by earlier harvesting time resulted in higher feed intake and milk yield than obtained by the same increase in NEL intake by concentrate supplementation.     

Effect of administration of live Saccharomyces cerevisiae on milk production,milk composition,blood metabolites,and faecal flora in early lactating dairy goats

The effects of live Saccharomyces cerevisiae (CNCM I-1077) supplementation to 72 Saanen dairy goats in early lactation were investigated. Animals were divided into treatment and control groups balanced for parity and milk production in the first 3 weeks of lactation. Treated animals received 0.2 g/day yeast supplement (Levucell SC20) corresponding to 4 × 10⁹ cfu/day S. cerevisiae, beginning week 3 of lactation, and lasting 15 weeks. Dry matter intake (DMI), body condition score (BCS), milk production and composition were recorded to day126 postpartum. Milk samples were analysed weekly for fat, protein, lactose, urea and SCC. Blood samples were analysed monthly for glucose, BHBA, NEFA, GOT and GGT. Intestinal microflora were assessed monthly in faeces, assaying total bacteria, enterobacteria, E. coli, coliform bacteria, clostridia, lactobacilli, molds and yeast. BCS was not affected by the treatment, but treated animals had greater DMI (2.71 kg/day versus 2.35 kg/day, S.E. ±0.12, P < 0.001) and produced more (P < 0.05) milk (2.38 kg/day versus 2.08 kg/day, S.E. ±0.14) of lower fat content (P < 0.05). Plasma metabolites and liver enzymes (GOT, GGT) were similar between groups, although BHBA levels tended to be lower (P = 0.06) in treated animals. Faecal E. coli were reduced (0.72 log₁₀ cfu/g versus 2.39 log₁₀ cfu/g, S.E. ±0.38, P < 0.05) and lactobacilli increased (P < 0.05) by the treatment. Yeast faecal levels were higher (P < 0.001) in treated animals during supplementation. In this study, live yeast supplementation to early lactating dairy goats significantly increased milk production, in relation to increased DMI, without decreasing BCS. Plasma metabolites (glucose, BHBA and NEFA) were consistent with the BCS findings (no differences between groups) and in addition there was a significant reduction of faecal E. coli content together with increase in lactobacilli in the treated animals, suggesting greater stability of the intestinal ecosystem. Results suggest that the inclusion of Saccharomyces cerevisae in the diet of early lactating dairy goats can be recommended under field conditions.     

Inactivation of IL-6 and soluble IL-6 receptor by neutrophil derived serine proteases in cystic fibrosis

The ability of IL-6 to signal via both membrane bound and soluble receptors is thought to explain the capacity of this cytokine to act in both the initiation and resolution of acute inflammatory responses. In cystic fibrosis (CF), poorly resolved neutrophillic inflammation of the lungs is a primary cause of morbidity and mortality. Expression of IL-6 has been reported to be low in CF lung secretions, despite ongoing inflammation, but the status of soluble IL-6 receptor (sIL-6R) in these patients is unknown. We hypothesised that sIL-6R may be an important potentiator of IL-6 activity in CF associated lung disease. IL-6, sIL-6R and sgp130 (a natural antagonist of responses mediated by the sIL-6R) were analysed by ELISA and Western blot in bronchoalveolar lavage fluid (BALF) from 28 paediatric CF patients and nine non-CF controls. Total cell counts in CF were four fold higher compared to controls (median: 1.4 × 10⁶ cells/ml v. 0.35 × 10⁶ cells/ml in controls) (p < 0.001) and the infiltrate was dominated by neutrophils which were elevated by 89 fold (0.62 × 10⁶ cells/ml v. 0.007 × 10⁶ cells/ml in controls) (p < 0.001). Other markers of inflammation such as IL-8 and MCP-1 were elevated 17.5 and 3.8 fold respectively (IL-8; median: 1122 pg/ml v. 64 pg/ml in controls, p < 0.01 and MCP-1; median: 692 pg/ml v. 182 pg/ml in controls, p < 0.05). IL-6, although present in 23/32 CF BALF specimens compared to 1/9 controls (p < 0.01), was weakly expressed (median: 50 pg/ml). Expression of sIL-6R and sgp130 in CF was no different to control patients. We tested whether weak expression of all three molecules was due to degradation by CF BALF. Degradative activity was observed in association with BALF elastase activity and could be specifically blocked by serine protease inhibitors. Degradation of sIL-6R by purified serine proteases (elastase, cathepsin G and proteinase 3) was also observed leading to a loss of trans-signalling activity. Interestingly, sIL-6R was protected from proteolysis by interaction with IL-6. Our data identify and define a novel protease mediated deficiency of IL-6 signalling in the CF lung.     

Microbiological quality and related factors of sheep milk produced in farms of NE Greece

Sheep herds are a significant capital of dairy industry in Greece, but as dairy farming becomes more complex and intense the need to provide assistance to dairy producers on milk quality is critical. In this study, the quality of raw milk produced in sheep farms of NE Greece was surveyed and the role of various factors was explored. In total, 21 dairy ewe’s farms from the regions of Xanthi and Evros, in the north-eastern Greece were monitored. Milk samples were sampled after the morning milking every 15 days throughout the dairy period (March–June). For the study, a questionnaire was also filled by personal interview with the owners in order to collect information about herd characteristics, health status, handling practices etc. From each farm, air was also sampled for microbiological analysis. Milk samples were examined for chemical components: fat content, protein, lactose, non-fat dry matter (NFDM) and somatic cells count (SCC). Microbiological examination involved the estimation of Total Bacterial Counts (TBC), coliform count (CC), Staphylococcus aureus, Streptococcus sp., and preliminary incubation count (PIC). The possible correlation among different bacterial species and their interaction with SCC and chemical components of milk was also considered. It was examined whether farm management practices could influence the hygiene and the quality of milk. Our results show that as an average TBCs were 5.48 log cfu/ml, SCC: 6.05 log cells/ml, CC: 4.49 log cfu/ml, S. aureus: 3.94 log cfu/ml, Streptococcus sp.: 4.95 log cfu/ml and PIC: 5.7 log cfu/ml. The mean fat, protein, lactose and NFDM were 6.17%, 5.28%, 4.73% and 10.95% respectively. The study revealed significant positive correlation between TBC and PIC (0.825), while SCC was marginally positive correlated with protein and NFDM. No statistically significant correlations observed among SCC with any of the bacterial species. Herd size and farm management practices had considerable influence on SCC and bacterial species.     

Effect of serum albumin supplementation on in vitro capacitation and fertilization of caprine oocytes

The aim of the investigation was to study the effect of purity and the type of serum albumin on in vitro fertilization (IVF) and cleavage rate of in vitro matured goat oocytes. Ovaries were collected from the local abattoir and transported within 4 h to the laboratory in warm saline (37 °C) containing 100 IU penicillin-G and 100 μg streptomycin sulfate per ml. A total of 2509 cumulus oocyte complexes (COCs) were collected from 1313 ovaries. Oocytes were matured in TCM-199 medium containing FSH (5 μg/ml), LH (5 μg/ml) and estradiol-17β (1 μg/ml), supplemented with 20% fetal bovine serum at 38.5 °C and 5% CO₂ in an incubator under humidified air for 27 h. After 27 h of in vitro maturation (IVM), oocytes were denuded, washed and randomly divided into 4 groups. Group 1 consisted of in vitro matured oocytes (n = 627) co-incubated with sperm in a 50 μl drop of TALP medium containing a 6 mg/ml crystalline bovine serum albumin (BSA) fraction V and 10 μg/ml heparin. Group 2 was comprised of in vitro matured oocytes (n = 470), co-incubated with sperm in a 50 μl drop of TALP medium containing 3 mg/ml crystalline BSA fraction V, 10% estrous goat serum and 10 μg/ml heparin. Group 3 was comprised of in vitro matured oocytes (n = 489) co-incubated with sperm in a 50 μl drop of TALP medium containing a 6 mg/ml fatty acid free BSA and 10 μg/ml heparin. Group 4 consisted of in vitro matured oocytes (n = 422) co-incubated with sperm in a 50 μl drop of TALP medium containing 20% estrous goat serum and 10 μg/ml heparin. After 18 h of co-incubation, the oocyte–sperm mixture was washed in the culture medium 15–20 times and cultured in 50 μl EDM. Cleavage of the in vitro fertilized oocytes were recorded 48 h post-insemination under an inverted phase contrast microscope. The average oocyte recovery rate/ovary and maturation rate was 1.91% and 80.03%, respectively. The cleavage rate in Group 1, Group 2, Group 3 and Group 4 was 1.59%, 8.93%, 11.86% and 35.30%, respectively. It could be concluded that the use of fatty acid free albumin resulted in a significantly higher (P < 0.05) cleavage rate, compared to unmodified albumin, and the supplementation of 20% estrous goat serum in the fertilization medium, significantly (P < 0.05) increased the cleavage rate of in vitro matured goat oocytes, compared to defatted albumin.     

Effects of untreated and heat-treated canola presscake on milk yield and composition of dairy cows

Five primiparous and five multiparous Holstein cows were used in two Latin square design experiments to determine effects of feeding unheated and heated canola presscake on milk yield and composition, and milk fatty acid concentrations of lactating dairy cows. Five diets that differed in level and source of dietary fat were formulated: a low fat control diet with 30 g kg⁻¹ fat from tallow, an unheated canola presscake supplemented diet (50 g kg⁻¹ fat), a heated canola presscake supplemented diet (50 g kg⁻¹ fat), a high tallow plus unheated canola meal supplemented diet (50 g kg⁻¹ fat), and a high tallow plus heated canola meal supplemented diet (50 g kg⁻¹ fat). In sacco ruminal degradability of heated and unheated canola presscake was compared with that of heated and unheated canola meal in a randomized complete block design using two ruminally fistulated cows. Heat treatment reduced ruminal DM and CP degradability of canola presscake. Multiparous cows fed diets supplemented with heated or unheated canola presscake produced more milk than those fed diets containing similar levels of fat from tallow with heated or unheated canola meal, respectively. High levels of fat from any diet reduced milk fat percentage for cows of either parity. Feeding heated canola products increased milk and milk protein yields in primiparous cows only, but cows of both parities fed diets containing canola presscake produced milk with lower concentrations of C12:0, C14:0, and C16:0 fatty acids than cows fed the canola meal and tallow diets, although concentrations of C18:1 n-9 were unaffected by fat source or level. Feeding canola products to dairy cows can alter milk fatty acid profile, but only primiparous cows have increased productivity as a result of feeding heated, versus unheated, canola presscake.     

Genetic polymorphism of αs1- and αs2-caseins in Hungarian Milking Goats

The aim of this study was to perform an initial characterization of milk quality and to determine genetic polymorphism at the CSN1S1 and CSN1S2 locus in two herds of local dairy goats (Hungarian Milking). The fat, protein and lactose level of milk samples in Hungarian Milking Goats were compared to other local goat breeds worldwide and it was concluded that the mean milk production of the Hungarian goats should be improved. The presence of the A, B, C + D, E, F and O alleles of CSN1S1 locus and A + B + C + E, D, F and O alleles of CSN1S2 locus were genotyped for by PCR-AS and PCR-RFLP methods in 103 goats. The strong B allele of CSN1S1 is more frequent in the local Hungarian Milking than in the imported Alpine and Saanen goats. The relatively high incidence of the O allele of CSN1S2 gene is also characteristic for the Hungarian Milking Goats and those special allele distribution patterns could be used to develop selection strategies to breed specialised lines of Hungarian local breeds.     

Variation in blood leucocytes,somatic cell count,yield and composition of milk of crossbred goats

Ten multiparous crossbred goats, five each of alpine × beetal (AB) and saanen × beetal (SB) were selected from the National Dairy Research Institute goat herd immediately after parturition. These were managed as per the practices followed in the institute’s goatherd. Blood and milk samples were collected at biweekly intervals from day 14 post-kidding for 22 weeks (154 days). Somatic cell count, electrical conductivity, fat, protein and lactose contents of milk were determined using standard methods. In the blood samples total leucocytes and differential leucocytes were also determined. Somatic cell counts were high immediately after parturition on day 14 of lactation and declined gradually with advanced lactation. There were individual variations (P < 0.01) in somatic cell counts between different lactation periods. Somatic cell count of milk was negatively correlated with neutrophils only (P < 0.05) and was neither correlated with milk yield, or with fat, protein, lactose content of milk. Electrical conductivity of milk was low up to four weeks of lactation and thereafter increased as the lactation advanced. Lactose content of milk declined gradually with the advancement of lactation. Fat content of milk was stable up to the eighth week and thereafter increased with advancement of lactation while the protein content of milk did not change significantly during lactation.     

Comparative analysis of milk fat decomposition activity by Mrakia spp. isolated from Skarvsnes ice-free area,East Antarctica

Milk fat curdle is difficult to remove from sewage. In an attempt to identify an appropriate agent for bio-remediation of milk fat curdle, Mrakia strains were collected from the Skarvsnes ice-free area of Antarctica. A total of 27 strains were isolated and tested for their ability to decompose milk fat at temperatures ranging from 4 °C to 15 °C. All strains could decompose milk fat at 4 °C and 10 °C. Phylogenetic analysis and comparison of the decomposition ability of milk fat (DAMF) revealed that the DAMF may be useful for predicting the outcome of phylogenetic analysis based on ITS sequences.     

Milk fatty acid composition of dairy cows grazing at two pasture allowances and supplemented with different levels and sources of concentrate

Milk fatty acid (FA) composition of dairy cows from two grazing studies was examined. In the first study, effects of concentrate supplementation and pasture allowance were evaluated using 20 multiparous Holstein cows in five 4 × 4 Latin squares. The four treatments resulted from the combination of two pasture allowances (i.e., low, 25 versus high, 40 kg dry matter/cow/day) and two concentrate supplementation levels (i.e., 0 versus 1 kg concentrate/4 kg milk). No interactions occurred between concentrate supplementation and pasture allowance for milk FA composition. Concentrate supplementation increased short-chain FA content, and reduced the content of long-chain FA, trans11 C18:1, and cis9, trans11 conjugated linoleic acid (CLA) (1.36 versus 1.18 g/100 g). Concentrate supplementation increased saturated FA (58.6 versus 54.0 g/100 g) and reduced unsaturated FA content (39.9 versus 43.8 g/100 g). Grazing at high pasture allowance increased short-, medium-, and long-chain FA content, without affecting cis9, trans11 CLA content. Saturated FA content was higher (57.1 versus 55.6 g/100 g), and unsaturated FA content was lower (41.3 versus 42.5 g/100 g), when cows grazed at high pasture allowance. Concentrate supplementation reduced unsaturated FA and cis9, trans11 CLA in milk of dairy cows grazing at two pasture allowances. In the second study, two experiments evaluated effects of different energy supplements in grazing dairy cows. In Experiment 1, 25 multiparous Holstein cows were assigned to a cracked corn (CC) or a steam flaked corn (SFC) supplement containing 667 g/kg of corn grain plus a pelleted protein/mineral supplement. In Experiment 2, 22 multiparous Holstein cows were assigned to a ground corn grain (GC) or a non-forage fiber (NFF) supplement. The GC supplement contained 850 g/kg of corn grain, and the NFF supplement contained 440 g/kg of non-forage fiber sources (i.e., beet pulp, soyhulls, wheat middlings) that partially replaced corn grain. Milk FA composition was not affected by corn processing or carbohydrate source. The content of short-, medium-, long-chain FA, and cis9, trans11 CLA (2.5 g/100 g in Experiment 1; 2.1 g/100 g in Experiment 2) was similar between supplements in both experiments. The type of supplement did not affect the content of saturated (62.6 g/100 g in Experiment 1; 65.4 g/100 g in Experiment 2) and unsaturated FA (37.5 g/100 g in Experiment 1; 34.6 g/100 g in Experiment 2). Supplementation with supplements differing in the rate and extent of ruminal carbohydrate digestion did not affect the milk FA composition of grazing dairy cows.     

Effect of grass silage harvesting time and level of concentrate supplementation on goat milk quality

Milk fat lipolysis giving high concentrations of free fatty acids (FFA) and off-flavor in the goat's milk is a challenge for the dairy industry in Norway. This has been considered to be caused by underfeeding of the goats and thereby energy mobilization in early and mid lactation. Energy intake can be improved by feeding silage of early harvesting time (HT) and supplementation with concentrate. In the present experiment, 18 goats in early lactation were fed grass silages prepared from the primary growth at a very early, early or normal stage of maturity (HT 1, HT 2 and HT 3, respectively), supplemented with a low (LC; 0.6 kg per goat daily) or normal (NC; 1.2 kg per goat daily) level of concentrate. The experiment was conducted as a cyclic change-over design with four periods of 28 days using three blocks of goats according to their initial body condition (poor, medium or high). Milk and blood samples were collected at the end of each period. Milk yield and yields of milk constituents decreased with delayed harvesting time and with LC. Sensory milk taste quality was not affected by dietary treatment, and milk FFA was highest when NC was fed. The proportion of short and medium chain fatty acids in milk fat decreased with postponed harvesting time and LC, while most of the long chain fatty acids (including C18:1c9) increased with postponed harvesting time and LC. The calculated energy balance decreased and the serum concentration of non-esterified fatty acids (NEFA) increased with decreasing energy content in the diet (postponed harvesting time and low level of concentrate). Goats with initial poor body condition had higher milk FFA concentrations than goats in higher initial body condition. High milk FFA concentration was correlated to poor milk taste quality, low serum NEFA concentration, low C18:1c9 proportion and high energy balance. Our findings suggest that increasing energy intake and energy balance during the first 4 months of lactation does not reduce FFA concentration in goats’ milk.     

Effect of artificial vs. natural rearing on milk yield,kid growth and cost in Payoya autochthonous dairy goats

Seventy full lactations of Payoya dairy goats were used to study the effect of two different kid-rearing systems, natural or artificial, on milk yield, composition, hygiene-sanitary quality, kid growth and rearing cost. Two animal groups were established, one with goats under natural rearing (NS) and the other under artificial rearing (AR). In the NS group, the kids had free access to goat milk 18–20 h a day and were suckled up to 5 weeks of age and then the dams were milked twice daily. Dams in the AR were separated from their kids at 48 h post-partum; then, kids were reared artificially, and the dams were milked twice daily. The number of animals used in each type of rearing system was 35 (23 goats giving birth to twins and 12 goats giving birth to a single kid). Each week during suckling phase the volume of milk produced was measured, and individual samples were taken. From 5th week and until 210 days lactation, test-day yields recorded at intervals of 30 ± 3 days were obtained. The chemical composition of the milk, the bacteriology, and the somatic cell count was analyzed. The kids of both sexes were assigned to two groups, natural suckling (NS, n = 58) and ad libitum artificial rearing (AR, n = 58). Within each treatment, two groups of kids were formed depending on prolificacy: first group with kids from single birth (n = 12) and the second with twin kids (n = 46). Birth weight and weight every week upto the 4th week of life were recorded. During the 5 weeks of lactation the total milk yield per goat was higher for the NS group (140.2 L vs. 95.4 L; P < 0.001), although the total amount of marketable milk was greater for the AR group, with a difference of some 21 L (P < 0.05). Throughout the entire lactation the milk yield was higher in the group of natural rearing (total yield of 508 L vs. 400 L; P < 0.05). Although a significant effect of prolificacy was found during suckling phase (P < 0.001), during 30 weeks of lactation this factor did not affect milk yield (P > 0.05). For the milk composition and hygiene-sanitary quality there were no effects on the type of rearing system or the type of birth (P > 0.05). No significant effect was observed either for the feeding system or the sex or the prolificacy on the live weight of the kids at 28 days and the postnatal growth rate from birth to 28 days (P > 0.05). Natural rearing system had higher cost per kid comparing with artificial rearing system (€18.63/kid vs. €14.70/kid, respectively). However, when comparing total incomes during a full lactation, goats with natural rearing system had a higher income because of increment of total milk production (€29.95/kid).