SciCombinator

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Concept: Dairy farming

258

A quarter of all anthropogenic methane emissions in the United States are from enteric fermentation, primarily from ruminant livestock. This study was undertaken to test the effect of a methane inhibitor, 3-nitrooxypropanol (3NOP), on enteric methane emission in lactating Holstein cows. An experiment was conducted using 48 cows in a randomized block design with a 2-wk covariate period and a 12-wk data collection period. Feed intake, milk production, and fiber digestibility were not affected by the inhibitor. Milk protein and lactose yields were increased by 3NOP. Rumen methane emission was linearly decreased by 3NOP, averaging about 30% lower than the control. Methane emission per unit of feed dry matter intake or per unit of energy-corrected milk were also about 30% less for the 3NOP-treated cows. On average, the body weight gain of 3NOP-treated cows was 80% greater than control cows during the 12-wk experiment. The experiment demonstrated that the methane inhibitor 3NOP, applied at 40 to 80 mg/kg feed dry matter, decreased methane emissions from high-producing dairy cows by 30% and increased body weight gain without negatively affecting feed intake or milk production and composition. The inhibitory effect persisted over 12 wk of treatment, thus offering an effective methane mitigation practice for the livestock industries.

Concepts: United States, Milk, Affect, Cattle, Dairy farming, Dairy cattle, Dairy, Methane

216

Mammalian females pay high energetic costs for reproduction, the greatest of which is imposed by lactation. The synthesis of milk requires, in part, the mobilization of bodily reserves to nourish developing young. Numerous hypotheses have been advanced to predict how mothers will differentially invest in sons and daughters, however few studies have addressed sex-biased milk synthesis. Here we leverage the dairy cow model to investigate such phenomena. Using 2.39 million lactation records from 1.49 million dairy cows, we demonstrate that the sex of the fetus influences the capacity of the mammary gland to synthesize milk during lactation. Cows favor daughters, producing significantly more milk for daughters than for sons across lactation. Using a sub-sample of this dataset (N = 113,750 subjects) we further demonstrate that the effects of fetal sex interact dynamically across parities, whereby the sex of the fetus being gestated can enhance or diminish the production of milk during an established lactation. Moreover the sex of the fetus gestated on the first parity has persistent consequences for milk synthesis on the subsequent parity. Specifically, gestation of a daughter on the first parity increases milk production by ∼445 kg over the first two lactations. Our results identify a dramatic and sustained programming of mammary function by offspring in utero. Nutritional and endocrine conditions in utero are known to have pronounced and long-term effects on progeny, but the ways in which the progeny has sustained physiological effects on the dam have received little attention to date.

Concepts: Pregnancy, Female, Milk, Lactation, Mammal, Cattle, Dairy farming, Dairy cattle

66

Many dairy cows in the developed world are now housed exclusively indoors with fewer than 5% of the 10 million lactating cows in the United States having access to pasture during the grazing season. Indoor housing systems are designed to meet biological needs for food, water, hygiene, and shelter, but surveys of public and farmer opinion suggest that people think that pasture access is also important for the well-being of dairy cows. To determine if pasture access is important to the cows themselves, we investigated to what extent cows will work to access pasture (by pushing on a weighted gate), and compared it to the motivation to access fresh feed. Cows worked at least as hard to access pasture as they did to access the fresh feed and worked hardest for outdoor access in the evening hours. Echoing public views on what allows for a good life for cattle, these results show that cows are highly motivated for outdoor access.

Concepts: United States, Milk, Cattle, Dairy farming, Dairy cattle, Pasture, Livestock, Veal

40

Milk from dairy cows contains the protein β-lactoglobulin (BLG), which is not present in human milk. As it is a major milk allergen, we wished to decrease BLG levels in milk by RNAi. In vitro screening of 10 microRNAs (miRNAs), either individually or in tandem combinations, identified several that achieved as much as a 98% knockdown of BLG. One tandem construct was expressed in the mammary gland of an ovine BLG-expressing mouse model, resulting in 96% knockdown of ovine BLG in milk. Following this in vivo validation, we produced a transgenic calf, engineered to express these tandem miRNAs. Analysis of hormonally induced milk from this calf demonstrated absence of BLG and a concurrent increase of all casein milk proteins. The findings demonstrate miRNA-mediated depletion of an allergenic milk protein in cattle and validate targeted miRNA expression as an effective strategy to alter milk composition and other livestock traits.

Concepts: Gene, RNA, Milk, Cattle, Dairy farming, Dairy cattle, Livestock, Veal

28

Despite their production potential and ability to survive on marginal resources in extreme conditions, dromedaries have not been exploited as an important food source. Camels have not been specifically selected for milk production, and genetic improvement has been negligible. High individual variation in milk production both within the population and within breeds provides a good base for selection and genetic progress. In this paper, we discuss the possibilities and constraints of selective breeding for milk production in camels, and include a summary of the use of embryo transfer at the world’s first camel dairy farm. Embryo transfer is an integral part of the breeding strategy at the camel dairy farm because it increases selection intensity and decreases the generation interval. Using high milk-producing camels as donors and low producing camels as recipients, 146 embryos were recovered (6.1±1.0embryos/donor; range: 0-18). Embryos were transferred non-surgically into 111 recipients (83 single and 28 twin embryo transfers). Pregnancy rate at 21 days and 5 months was 55% (61/111) and 45% (50/111), respectively. Finally, a total of 46 recipients delivered a live calf. These results document the utility of embryo transfer using high milk producing dromedaries as donors.

Concepts: Pregnancy, Milk, Cattle, Dairy farming, Livestock, Camel, Dromedary, Camelid

28

Milk and dairy products constitute an important ingredient in the human diet. Ultra-high temperature (UHT) milk is the main dairy product consumed in Portugal and its production entails large inputs of resources which derive on negative environmental effects such as nutrient enrichment of the ecosystem and climate change. In this study, Life Cycle Assessment (LCA) methodology was considered for the environmental assessment of packaged UHT milk produced in Portugal, including simple (whole, semi-skimmed and skimmed) and cocoa milk from a cradle-to-gate perspective and to identify the environmental hot spots. Results showed that the production of the raw milk in the dairy farm is the main hot spot in almost all the categories under assessment mainly due to the emissions from enteric fermentation, manure management and fertilisers production and application. Furthermore, on-site emissions derived from dairy factory are remarkable together with the packages and energy requirements production. The values reported in this study are in the range of other related papers. However, differences were also identified due to several reasons such as allocation approach, data sources, characterisation factors, farm management regimes and assumptions considered. Therefore, these aspects should be carefully addressed and sensitivity to the assumptions and uncertainty of the results should be evaluated.

Concepts: Milk, Cattle, Dairy farming, Dairy cattle, Dairy, Bulk tank, Pasteurization, Dairy product

27

Cows with left displaced abomasum (LDA), a costly disease occurring primarily in multiparous dairy cows during early lactation, have been reported to have 40% lower circulating concentrations of vitamin E. It is unknown, however, whether the lower circulating α-tocopherol concentrations precede LDA or remain after LDA. Using a nested case-control design, blood samples taken at d -21, -14, -7, -3, -1, 0, 1, 3, 7, 14, 21, 28, 35, 42, and 49 postpartum from 7 multiparous Holstein cows diagnosed with LDA between d 6 and 32 postpartum and 10 healthy Holstein cows from the same herd were analyzed for serum concentrations of α-tocopherol and indicators of energy and nutrient status and inflammation. In addition to indicators of negative energy balance and inflammation, lower serum α-tocopherol concentrations preceded LDA and persisted after LDA correction. At the last blood sampling before LDA diagnosis, cows had serum α-tocopherol concentrations 45% lower (5.0 ± 0.9 vs. 9.1 ± 0.9 μM) and α-tocopherol to cholesterol molar ratios 39% lower (1.90 ± 0.19 vs. 3.09 ± 0.26) than those of healthy cows. Serum α-tocopherol concentrations remained lower (<10 vs. ∼15 μM) up to d 49 postpartum in cows that had LDA. These findings indicate that lower serum α-tocopherol concentrations are a potential early indicator for the development of LDA in multiparous cows.

Concepts: Nutrition, Milk, Addition, Cattle, Dairy farming, Dairy cattle, Veal, Abomasum

27

Milk protein expression in healthy cows and cows with mastitis will provide information important for the dairy food industry and immune function in the mammary gland. To facilitate protein discovery, milk was fractioned into whey, milk fat globule membranes (MFGM) and exosomes from healthy and Staphylococcus aureus infected cows. Amine-reactive isobaric tags (iTRAQ) were used to quantify protein changes between milk fractions isolated from healthy and S. aureus infected cows. 2971 milk proteins were identified with a false discovery rate of 0.1 %. Greater than 300 milk proteins associated with host defense were identified and 94 were significantly differentially regulated in S. aureus infected milk compared to their uninfected controls. These differentially regulated host defense proteins were selectively segregated in the 3 milk compartments examined. An example of this segregation of host defense proteins was the partitioning and high concentration of proteins indicative of neutrophil extracellular traps (NETs) formation in the MFGM preparations from S. aureus infected milk as compared to exosomes or whey. Protein composition changes found in milk exosomes, MFGM and whey during an infection provides new and comprehensive information on milk protein composition in general as well as changes occurring during an infection. Biological Significance: The significance of this study is the identification and quantification of the individual components of the neutrophil extracellular traps (NET) functional proteome in an apparent stable complex with MFGM and/or milk fat globules during an intra-mammary infection. NETs could be functionally relevant in intra-mammary infection, as it is known that during an infection neutrophils ingest large amounts of milk fat that down regulates many of their traditional immune functions. Thus the presence of NETs in milk fat provides new insights to mammary immune function and suggests a role for NETs in clinical mastitis. These in vivo NETs can now be tested to determine if they retain functional antimicrobial activity when primarily associated with milk fat. Then we can estimate their real world functional relevance during an intra-mammary infection, which is one key to understanding clinical mastitis in dairy cows.

Concepts: Nutrition, Staphylococcus aureus, Infection, Milk, Butter, Cattle, Dairy farming, Cheese

27

Dairy cattle are becoming increasingly complicated to treat in the USA due to the great limitation of approved drugs. Additionally, most drugs require withdrawal times for milk that are not viable for treating entire dairy herds. The objective of this field trial was to determine the efficacy of eprinomectin, one of only two parasiticides approved for lactating dairy cattle, for eradication of naturally occurring chorioptic mange on a commercial dairy farm. All animals present on the farm were treated on the same day and, later, new animals introduced to the premises were treated on arrival. All cows were re-treated at dry-off. Lesion scoring was performed five times over a period of 12months. A reduction in the proportion of cows with lesions was apparent 3months after treatment and, although the proportion stayed low, it increased again at 12months post-treatment. Logistic regression to evaluate factors associated with the presence of mange lesions showed that older cows, late lactation, and recent treatment, were associated with presence of lesions. It also showed that multiple treatments (whole-herd treatment and at dry-off) helped to reduce the presence of lesions. No increase in milk production could be measured, but animal wellbeing improved. The results of this study show that chorioptic mange can be controlled in entire herds, although multiple treatments will be required to potentially eradicate the parasite. The value of the study is that it shows that mange can be controlled in dairy cattle with approved drugs, eliminating the need to use non-approved agents.

Concepts: Milk, Mammal, Cattle, Dairy farming, Dairy cattle, Dairy, Bulk tank, Calf

26

We studied the effects of changes in the milking routine (lack or presence of 30-s prestimulation, 0 or 1, 2 or 4-min delay between preparation and cluster attachment) and environmental perturbation (unusual loud sounds capable of frightening animals just after stall entry or during the course of milking) on milk removal and milking-related behaviour in dairy dromedary camels. A 30-s prestimulation decreased incidence of bimodal milk flow curves and increased occurrence of the best milk ejection patterns with higher milk flow but had limited effect on milk production in our well-trained animals within a good machine milking setting. However, unusual sounds heard from the beginning of milking or even after milk ejection caused inhibition or disruption of milk removal and modification of camels' behaviour. Milk ejection was significantly delayed (1·58±0·17 min), residual milk increased over 40% of total milk yield and average and peak milk flow rates were significantly lowered when unusual noises were heard from the beginning of milking. These environmental perturbations increased signs of vigilance and the number of attempts to escape the milking parlour. Delaying cluster attachment for over 1 min after the end of udder preparation caused serious milk losses. Up to 62% of total milk was withheld in the udder when the delay reached 4 min. Average and peak milk flow rates also decreased significantly with delayed milking. Signs of vigilance and attempts to escape from the milking parlour appeared when camels waited for over 2 min. After a 4-min delay, camels showed signs of acute stress. Defaecation prior to milk ejection (solid faeces) and rumination during milking can be used to assess camels' milk ejection during milking. Animal welfare and milking efficiency can be ensured when camels are pre-stimulated, milked in calm conditions and with cluster attachment within a maximum of a 1-min delay after stimulation.

Concepts: Milk, Cattle, Dairy farming, Dairy, Delay, Tom DeLay, Camel, Dromedary