Dairy, Volume 2, Issue 2 (June 2021) – 11 articles

This work reviews the current impact and manifestation of ketosis (hyperketonemia) in dairy cattle, emphasizing the practical use of laboratory methods, field tests, and milk data to monitoring this disease. Ketosis is a major issue in high-producing cows, easily reaching a prevalence of 20% during early postpartum when the negative energy balance is well established. Its economic losses, mainly related to decreasing milk yield, fertility, and treatment costs, have been estimated up to €250 per case of ketosis/year, which can double if associated diseases are considered. A deep relationship between subclinical or clinical ketosis and negative energy balance and related production diseases can be observed mainly in the first two months postpartum. Fourier transform infrared spectrometry methods gradually take place in laboratory routine to evaluates body ketones (e.g., beta-hydroxybutyrate) and probably will accurately substitute cowside blood and milk tests at a farm in avenir. Fat to protein ratio and urea in milk are largely evaluated each month in dairy farms indicating animals at risk of hyperketonemia. At preventive levels, other than periodical evaluation of body condition score and controlling modifiable or identifying non-modifiable risk factors, the ruminatory activity assessment during the peripartum seems to be a valuable tool at farms. We conclude that a technological advance progressively takes place to mitigate the effects of these metabolic diseases, which challenge the high-yielding cows. Full article

Milk is considered a complete food because all of the nutrients important to fulfill a newborn’s daily requirements are present, including vitamins and minerals, ensuring the correct growth rate. A large amount of global milk production is represented by cow, goat, and sheep milks; these species produce about 87% of the milk available all over the world. However, the milk obtained by minor dairy animal species is a basic food and an important family business in several parts of the world. Milk nutritional properties from a wide range of minor dairy animal species have not been totally determined. Hot temperatures and the lack of water and feed in some arid and semi-arid areas negatively affect dairy cows; in these countries, milk supply for local nomadic populations is provided by camels and dromedaries. The nutritional quality in the milk obtained from South American camelids has still not been completely investigated, the possibility of creating an economic resource for the people living in the Andean highlands must be evaluated. Both mare and donkey milks show a chemical composition very similar to human milk, and they represent a good replacer of cows’ milk for infants nutrition, especially for children affected by cow milk proteins allergy. In this review, differences and similarities in the quality parameters of milk from minor dairy animals, such as camelids and equids, have been compared. Full article

Fiore Sardo (FS), a traditional Italian cheese, is present in the market as a heterogeneous variety of products. The use of heat-treated (HT) milk is forbidden by the official production protocol, but no official analytical method able to detect heat application is yet available. Here, a combined magnetic resonance imaging (MRI) relaxometry and image analysis approach to recognize FS made from raw milk is presented. Artisanal FS cheeses were produced from raw milk (RC) by five shepherds in accordance with the official protocol. They were compared to HT-milk counterparts (HTC). Additionally, industrially manufactured commercial FS cheeses (I) were also purchased and compared to RC and HTC. Relaxometry data of FS indicated the presence of two water populations; the ratio of characteristic relaxation time constant T₂ and area fraction (Score, Ṩ) of the fastest relaxing population was used to compare RC, HTC and I samples. RC from HTC were successfully discriminated, the latter exhibiting lower Ṩ (enhanced protein hydration). I cheeses exhibited the lowest Ṩ values, sometimes comparable to HTC. Since visual appearance of RC and HTC is appreciably different, an image analysis deep learning approach using MRI and photographic pictures was adopted to discriminate the two productions, with promising percentages (>93%). Full article

The effect of acoustic pulse technology (APT) on recovery, culling, milk yield, and economic benefits for 118 cows with subclinical mastitis was compared with a no-treatment control (59 vs. 59), and another 118 APT-treated cows with clinical mastitis were compared with antibiotic-treated controls (59 vs. 59). Recovery was defined as a decrease in somatic cell count (SCC) to <250 × 10³ cells/mL in at least two out of three monthly milk recordings after treatments. For the subclinically infected cows, APT treatment resulted in 65.5% recovery, 0% culling, and additional milk yield of 2.74 L/cow per day compared to 35.6% recovery and 5.1% culling in the no-treatment controls. For the clinically infected cows, APT treatment resulted in 67.8% recovery, 6.8% culling, and additional milk yield of 3.9 L/cow per day compared to 35.6% recovery and 32.2% culling in the antibiotic-treated group. Bacteriological analysis was run for 95 (80%) cows with clinical mastitis (APT-46; AB-49). For cows with Escherichia coli infection, 85.7% (18/21) treated with APT recovered vs. 17.6% (3/17) in the antibiotic-treated group; for cows with streptococcal infection, 66.0% (12/18) in the APT-treated group recovered vs. 44.4% (8/18) in the antibiotic-treated group. Full article

This work aimed to study the effects of using ewe’s milk from Churra, Assaf, or both breeds on the physicochemical and sensory characteristics of Zamorano cheese at the end of ripening. Zamorano cheese is a hard variety with protected designation of origin (PDO) produced in the province of Zamora (Spain) with raw or pasteurized ewe’s milk. Five batches of Zamorano cheese were produced with pasteurized ewe’s milk. One batch was elaborated using milk from the Churra breed, the other using milk from the Assaf breed, and the remaining three employed milk mixtures of Churra and Assaf breeds in the proportions 75:25, 50:50 and, 25:75, respectively. Cheeses made with a higher proportion of Churra milk showed a predominance of hydrophilic peptides, while hydrophobic peptides predominated in cheeses with a greater percentage of milk from the Assaf breed. The largest content of most free amino acids was found in cheeses produced with the highest percentage of Churra milk. These cheeses presented the highest values for fat acidity index and free fatty acids content and showed greater elasticity and adhesiveness, as well as lower granularity and hardness. In the sensory evaluation, aftertaste and persistence were higher in these cheeses, being scored with the best overall values. Full article

Leptospirosis is a zoonotic disease of major public health concern in India. Bovines play an important role in maintaining and transmitting this disease and proximity between dairy cows and humans makes the dairy cow-human nexus a transmission route of public health interest, yet one currently under-examined in North Eastern India. We report a cross-sectional survey carried out on small-scale dairy farms in the states of Assam and Bihar in North Eastern India investigating seroprevalence for Leptospira interrogans serovar Hardjo, the most common pathogenic serovar reported in cattle worldwide. Higher seroprevalence was reported on dairy farms in Bihar 4.5% (95% CI 2.6–7.5%) than in Assam 1.2% (95% CI 0.42–3.6%), but overall seroprevalence levels were low. The study is the first indication of leptospirosis circulating in small-scale dairy farms in these states. To correlate farming practices with zoonotic risk, we combined results from a dairy farmer questionnaire with cow seroprevalence. However, low seroprevalence levels found in this study made the identification of risk factors difficult. Nevertheless, poor farming practices around hygiene and biosecurity on dairy farms have been highlighted. Implementing simple measures could mitigate environmental contamination, and therefore, reduce the risk of Leptospira interrogans, and other zoonoses transmission, at the animal-environment-human interface. Full article

Vegetable by-products have great potential for use as animal feeds and thus could improve the sustainability of the food system. The objective was to evaluate the milk production potential of potato by-product (PBP) replacing cereal grains in grass silage-based total mixed ration (TMR). Additionally, a laboratory scale experiment was conducted to assess the effect of PBP and chemical preservatives on the aerobic stability of TMRs. A change-over dairy cow feeding experiment was conducted to evaluate the inclusion of 135 g/kg (on a dry matter (DM) basis) of PBP in TMR. Additionally, the aerobic stability of TMR was evaluated by preparing TMRs with increasing levels of PBP and treated with different doses of formic and propionic acid or salt-based preservatives. The inclusion of PBP in dairy cow diets decreased feed intake, but organic matter digestibility was greater in the PBP diet, resulting in only slightly decreased production (milk protein 1435 vs. 1363 g/day, p < 0.05; milk lactose 1716 vs. 1606 g/day, p < 0.05). The aerobic stability of TMR was negatively affected by the inclusion of PBP, but it could to a limited extent be prolonged using chemical preservatives. The inclusion of PBP decreased feed intake and milk production to some extent when included in the diet of high-producing dairy cows. The utilization of PBP may, however, be justified from a sustainability point of view, as it provides a way to circulate the nutrients of a non-human edible feed material back into the food chain. Full article

Milk lipids are composed of milk fat globules (MFGs) surrounded by the milk fat globule membrane (MFGM). MFGM protects MFGs from coalescence and enzymatic degradation. The milk lipid fraction is a “natural solvent” for macronutrients such as phospholipids, proteins and cholesterol, and micronutrients such as minerals and vitamins. The research focused largely on the polar lipids of MFGM, given their wide bioactive properties. In this review we discussed (i) the composition of MFGM proteome and its variations among species and phases of lactation and (ii) the micronutrient content of human and cow’s milk lipid fraction. The major MFGM proteins are shared among species, but the molecular function and protein expression of MFGM proteins vary among species and phases of lactation. The main minerals in the milk lipid fraction are iron, zinc, copper and calcium, whereas the major vitamins are vitamin A, β-carotene, riboflavin and α-tocopherol. The update and the combination of this knowledge could lead to the exploitation of the MFGM proteome and the milk lipid fraction at nutritional, biological or technological levels. An example is the design of innovative and value-added products, such as MFGM-supplemented infant formulas. Full article

A new type of cow’s milk, called A2 milk, has appeared in the dairy aisles of supermarkets in recent years. Cows’ milk generally contains two major types of beta-casein as A1 and A2 types, although there are 13 genetic variants of β-casein: A1, A2, A3, A4, B, C, D, E, F, H1, H2, I and G. Studies have shown that A1 β-casein may be harmful, and A2 β-casein is a safer choice for human health especially in infant nutrition and health. The A2 cow milk is reportedly easier to digest and better absorb than A1 or other types of milk. The structure of A2 cow’s milk protein is more comparable to human breast milk, as well as milk from goats, sheep and buffalo. Digestion of A1 type milk produces a peptide called β-casomorphin-7 (BCM-7), which is implicated with adverse gastrointestinal effects on milk consumption. In addition, bovine milk contains predominantly α_s1-casein and low levels or even absent in α_s2-casein, whereby caprine milk has been recommended as an ideal substitute for patients suffering from allergies against cow milk protein or other food sources. Since goat milk contains relatively low levels of α_s1-casein or negligible its content, and α_s2-casein levels are high in the milk of most dairy goat breeds, it is logical to assume that children with a high milk sensitivity to α_s1-casein should tolerate goat milk well. Cow milk protein allergy (CMPA) is considered a common milk digestive and metabolic disorder or allergic disease with various levels of prevalence from 2.5% in children during the first 3 years of life to 12–30% in infants less than 3 months old, and it can go up to even as high as 20% in some countries. CMPA is an IgE-mediated allergy where the body starts to produce IgE antibodies against certain protein (allergens) such as A1 milk and α_s1-casein in bovine milk. Studies have shown that ingestion of β-casein A1 milk can cause ischemic heart disease, type-1 diabetes, arteriosclerosis, sudden infant death syndrome, autism, schizophrenia, etc. The knowledge of bovine A2 milk and caprine α_s2-casein has been utilized to rescue CMPA patients and other potential disease problems. This knowledge has been genetically applied to milk production in cows or goats or even whole herds of the two species. This practice has happened in California and Ohio, as well as in New Zealand, where this A2 cow milk has been now advanced commercially. In the USA, there have been even promotions of bulls, whose daughters have been tested homozygous for the A2 β-casein protein. Full article

The dairy industry produces large amounts of wastewater, including white and cleaning wastewater originating principally from rinsing and cleaning-in-place procedures. Their valorization into process water and non-fat milk solids, in the case of white wastewater, or the renewal of cleaning solutions could be achieved using pressure-driven membrane processes. However, it is crucial to determine the intrinsic characteristics of wastewaters, such as proximate composition and bacterial composition, to optimize their potential for valorization. Consequently, white and cleaning wastewaters were sampled from industrial-scale pasteurizers located in two different Canadian dairy processing plants. Bacterial profiles of dairy wastewaters were compared to those of tap waters, pasteurized skim milk and unused cleaning solutions. The results showed that the physicochemical characteristics as well as non-fat milk solids contents differed drastically between the two dairy plants due to different processing conditions. A molecular approach combining quantitative real-time polymerase chain reaction (qPCR) and metabarcoding was used to characterize the bacteria present in these solutions. The cleaning solutions did not contain sufficient genomic DNA for sequencing. In white wastewater, the bacterial contamination differed depending on the dairy plant (6.91 and 7.21 log10 16S gene copies/mL). Psychrotrophic Psychrobacter genus (50%) dominated white wastewater from plant A, whereas thermophilic Anoxybacillus genus (56%) was predominant in plant B wastewater. The use of cold or warm temperatures during the pasteurizer rinsing step in each dairy plant might explain this difference. The detailed characterization of dairy wastewaters described in this study is important for the dairy sector to clearly identify the challenges in implementing strategies for wastewater valorization. Full article

In milk and milk products, small membrane-enclosed vesicles can be found, commonly termed extracellular vesicles (EVs). Milk-derived EVs have previously been suggested to have immunoregulatory properties, especially important for infants without a fully functioning immune system. In the present study, EV fractions were isolated from human milk, mature and colostrum bovine milk, and two dairy fractions, and successively surveyed for their immunomodulating effects on lipopolysaccharide (LPS)-stimulated macrophages (RAW264.7). RAW264.7 cell material and supernatant were evaluated by monitoring degradation of IκBα in the NF-κB pathway, and IL-6 and IL-1β cytokine production, using Western blotting and enzyme-linked immunosorbent assaying, respectively. The results revealed that preincubation with EVs derived from raw human and bovine milk lowered the LPS-activated response of the NF-κB pathway. Additionally, it was found that preincubation with EVs, from human and bovine milk as well as dairy whey or skim milk-derived fractions, decreased secretion of proinflammatory cytokines from LPS-activated RAW264.7 cells. The findings that milk-derived EVs can change the inflammatory response in macrophages support the notion that milk EVs have an important role in mother-to-infant communication and protection of a newborn. Full article