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The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. Methane is a potent greenhouse gas produced during the ruminal fermentation and is associated with a loss of feed energy. Therefore, efforts to reduce methane emissions have been ongoing in the last decades. Methane production is highly influenced by factors such as the ruminal microbiome and host genetics. Previous studies have proposed to use the ruminal microbiome to reduce long-term methane emissions, as ruminal microbiome composition is a moderately heritable trait and genetic improvement accumulates over time. Lactation stage is another important factor that might influence methane production, but potential associations with the ruminal microbiome have not been evaluated previously. This study sought to examine the changes in ruminal microbiome over the lactation period of primiparous Holstein cows differing in methane intensity (MI) and estimate the heritability of the abundance of relevant microorganisms. Ruminal content samples from 349 primiparous Holstein cows with 14 to 378 DIM were collected from May 2018 to June 2019. Methane intensity of each cow was calculated as methane concentration/milk yield. Up to 64 taxonomic features (TF) from 20 phyla had a significant differential abundance between cows with low and high MI early in lactation, 16 TF during mid lactation, and none late in lactation. Taxonomical features within the Firmicutes, Proteobacteria, Melainabacteria, Cyanobacteria, Bacteroidetes , and Actinobacteria phyla were associated with low MI, whereas eukaryotic TF and those within the Euryarchaeota, Verrucomicrobia, Kiritimatiellaeota , and Lentisphaerae phyla were associated with high MI. Out of the 60 TF that were found to be differentially abundant between early and late lactation in cows with low MI, 56 TF were also significant when cows with low and high MI were compared in the first third of the lactation. In general, microbes associated with low MI were more abundant early in lactation (e.g., Acidaminococcus, Aeromonas , and Weimeria genera) and showed low to moderate heritabilities (0.03 to 0.33). These results suggest some potential to modulate the rumen microbiome composition through selective breeding for lower MI. Differences in the ruminal microbiome of cows with extreme MI levels likely result from variations in the ruminal physiology of these cows and were more noticeable early in lactation, probably due to important interactions between the host phenotype and environmental factors associated with that period. Our results suggest that the ruminal microbiome evaluated early in lactation may be more precise for MI difference, and hence, this should be considered to optimize sampling periods to establish a reference population in genomic selection scenarios. [ABSTRACT FROM AUTHOR]

ABSTRACT: Methane is a potent greenhouse gas produced during the ruminal fermentation and is associated with a loss of feed energy. Therefore, efforts to reduce methane emissions have been ongoing in the last decades. Methane production is highly influenced by factors such as the ruminal microbiome and host genetics. Previous studies have proposed to use the ruminal microbiome to reduce long-term methane emissions, as ruminal microbiome composition is a moderately heritable trait and genetic improvement accumulates over time. Lactation stage is another important factor that might influence methane production, but potential associations with the ruminal microbiome have not been evaluated previously. This study sought to examine the changes in ruminal microbiome over the lactation period of primiparous Holstein cows differing in methane intensity (MI) and estimate the heritability of the abundance of relevant microorganisms. Ruminal content samples from 349 primiparous Holstein cows with 14 to 378 DIM were collected from May 2018 to June 2019. Methane intensity of each cow was calculated as methane concentration/milk yield. Up to 64 taxonomic features (TF) from 20 phyla had a significant differential abundance between cows with low and high MI early in lactation, 16 TF during mid lactation, and none late in lactation. Taxonomical features within the Firmicutes, Proteobacteria, Melainabacteria, Cyanobacteria, Bacteroidetes, and Actinobacteria phyla were associated with low MI, whereas eukaryotic TF and those within the Euryarchaeota, Verrucomicrobia, Kiritimatiellaeota, and Lentisphaerae phyla were associated with high MI. Out of the 60 TF that were found to be differentially abundant between early and late lactation in cows with low MI, 56 TF were also significant when cows with low and high MI were compared in the first third of the lactation. In general, microbes associated with low MI were more abundant early in lactation (e.g., Acidaminococcus, Aeromonas, and Weimeria genera) and showed low to moderate heritabilities (0.03 to 0.33). These results suggest some potential to modulate the rumen microbiome composition through selective breeding for lower MI. Differences in the ruminal microbiome of cows with extreme MI levels likely result from variations in the ruminal physiology of these cows and were more noticeable early in lactation, probably due to important interactions between the host phenotype and environmental factors associated with that period. Our results suggest that the ruminal microbiome evaluated early in lactation may be more precise for MI difference, and hence, this should be considered to optimize sampling periods to establish a reference population in genomic selection scenarios.

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. Greenhouse gas emission from the activities of all productive sectors is currently a topic of foremost importance. The major contributors in the livestock sector are ruminants, especially dairy cows. This study aimed to evaluate and compare 21 equations for predicting enteric methane emissions (EME) developed on the basis of milk traits and fatty acid profiles, which were selected from 46 retrieved through a literature review. We compiled a reference database of the detailed fatty acid profiles, determined by GC, of 992 lactating cows from 85 herds under 4 different dairy management systems. The cows were classified according to DIM, parity order, and dairy system. This database was the basis on which we estimated EME using the selected equations. The EME traits estimated were methane yield (20.63 ± 2.26 g/kg DMI, 7 equations), methane intensity (16.05 ± 2.76 g/kg of corrected milk, 4 equations), and daily methane production (385.4 ± 68.2 g/d, 10 equations). Methane production was also indirectly calculated by multiplying the daily corrected milk yield by the methane intensity (416.6 ± 134.7 g/d, 4 equations). We also tested for the effects of DIM, parity, and dairy system (as a correction factor) on the estimates. In general, we observed little consistency among the EME estimates obtained from the different equations, with exception of those obtained from meta-analyses of a range of data from different research centers. We found all the EME predictions to be highly affected by the sources of variation included in the statistical model: DIM significantly affected the results of 19 of the 21 equations, and parity order influenced the results of 13. Different patterns were observed for different equations with only some of them in accordance with expectations based on the cow's physiology. Finally, the best predictions of daily methane production were obtained when a measure of milk yield was included in the equation or when the estimate was indirectly calculated from daily milk yield and methane intensity. [ABSTRACT FROM AUTHOR]

Solid fat content at 10°C (SFC10) is an important parameter of milk fat that influences the spreadability of butter. This study aimed to evaluate the effect of breed and stage of lactation on SFC10 of milk fat from cows milked once a day (OAD) or twice a day (TAD). Milk was collected from 39 Holstein-Friesian (F), 27 Jersey (J), and 34 Holstein-Friesian × Jersey (F × J) cows from a OAD herd and 104 F and 83 F × J cows from a TAD herd in early, mid and late lactation. The SFC10 was predicted using a regression model using milk fatty acid composition. The lower the SFC10, the higher the spreadability of butter. The SFC10 was lower (P < 0.05) for F cows compared with J cows milked OAD. The SFC10 was lower (P < 0.05) for F cows compared with F × J cows milked TAD. The SFC10 was lower in early lactation compared with mid- and late lactation in both milking frequencies. This study revealed that F cow milk and early lactation milk would be suitable for making more easily spreadable butter in OAD and TAD milking. These results could be applicable in the New Zealand dairy industry if consumer preference for more easily spreadable butter increases. [ABSTRACT FROM AUTHOR]

This study investigated the impact of proportion of pasture in the cow diet on the concentration of selected fat-soluble compounds in milk including β-carotene, lutein, retinol (vitamin A), α-tocopherol (vitamin E) and zeaxanthin. Bulk tank milk samples (n = 102) were collected weekly (n = 34) across an entire lactation from three herds operating either a high (GRS), medium (PMR) or no pasture allowance (TMR) feeding system. Concentrations of β-carotene and lutein increased significantly with increasing pasture allowance, with a > 2 fold increase of β-carotene in milk, between high and no pasture allowance treatments. GRS feeding system resulted in milks with higher concentrations of retinol, α-tocopherol, and zeaxanthin, compared to both PMR and TMR systems. A biomarker model based on the fat-soluble compounds concentration in milk, demonstrated excellent differentiation of high pasture allowance derived milks from that of medium and no pasture milks, with area under the curve scores of 0.955 and 0.971 respectively. Strong correlations were observed between the concentrations of lutein and zeaxanthin in milk and the milks corresponding yellow colour, while a significant correlation was exhibited between β-carotene and b*-value. Such correlations with milk colour may have a significant impact on the consumer preference of milk and dairy products produced therefrom.

The objective of this study was to identify cow-level factors associated with poor body hygiene. Cows (n = 2644) from 68 commercial dairy herds (free-stall (n = 43); tie-stall (n = 25)) in Ontario, Canada were enrolled. Cows were hygiene scored on each of three visits (7 days apart). Older cows were at higher risk of having a dirty udder and dirty upper legs and flanks in free-stall barns and younger cows were at higher risk of having dirty upper legs and flanks in tie-stall barns. Higher days in milk was associated with better hygiene for cows housed in both free-stall and tie-stall barns. [ABSTRACT FROM AUTHOR]

Aim: This study aimed to characterise the between‐batch variability of pasteurised donor human milk (PDHM) produced from single‐donor pools at Australian Red Cross Lifeblood's milk bank and identify key donor characteristics that predict macronutrient content. Methods: Macronutrient content from 200 batches of PDHM was measured using a mid‐infrared human milk analyser (Miris, Uppsala, Sweden). Linear mixed models were used to study the impact of stage of lactation and gestational age on macronutrient content. Coefficients of determination (R2) were calculated to estimate the impact of the individual donor on overall variability. Results: Macronutrient content of PDHM varied considerably, with between‐batch variations of 2.8 and 6.4‐fold for protein and fat content, respectively. Mean crude protein content was 1.16 g/100 mL, ranging from 0.7 to 1.96 g/100 mL. Mean fat content was 3.85 g/100 mL, ranging from 1.46 to 9.39 g/100 mL. Stage of lactation was identified as a predictor for protein content and gestational age at birth for fat content. Individual donor effect explained 55 and 35% of the variance for fat and protein content, respectively. Conclusions: This study highlights the variation in macronutrient content in PDHM at an Australian milk bank. Variability could be reduced through the implementation of targeted multiple‐donor pooling using the key donor characteristics identified in this study along with the measurement of macronutrient content of individual donors at the time of first donation. However, the clinical benefit of a reduction in between‐batch variation, achieved through multiple‐donor pooling, would need to be assessed to justify additional efforts associated with PDHM processing changes. [ABSTRACT FROM AUTHOR]

In general, it can be stated that the economics of non-dairy sheep breeding in the Czech Republic experienced a worsening trend in recent years. One of the ways to improve this situation is to use some of these breeds also for milk production. One of the possible breeds usable for milk production, especially for the good milk production of mothers, is the Clun Forest (CF). The aim of our experiment was to evaluate the daily milk yield (DMY) and the contents of fat (F), total protein (TP) and lactose (L), pH, titratable acidity (TA), concentration of urea (CU) and somatic cell count (SCC) in CF ewes during lactation. In our experiment, the following means of individual traits for the whole lactation were found: DMY: 579 g, contents of F, TP and L: 6.73%, 5.82% and 4.98%, pH: 6.55, TA: 8.74 °SH, CU: 36.08 mg/100 ml and log SCC: 4.71. The stage of lactation had a significant (P < 0.01) effect on DMY, contents of F and TP and pH and TA. The results of our experiment show that CF ewes had lower DMY than dairy breeds (DB). However, the majority of the milk quality traits was comparable to DB. Moreover, the high fat and protein contents and the values of most other milk quality traits are good prerequisites for high cheese yield and optimal final quality of other sheep's milk products. The results of our experiment suggest that CF ewes could be used for milk production while the milk production of CF ewes should ensure an improvement in the economics and competitiveness of smaller farms in particular.

The purpose of the research was to determine the effect of breed, lactation number, and lactation stage on milk efficiency and goat milk ingredients, these being indicators of milk technological parameters and homeostasis disturbances. Goat breed and number of lactation affected energy-corrected milk, value-corrected milk yield, fat corrected milk, protein, casein, lactose contents and free fatty acids. Additionally, differences in non-fat solids and urea contents were found between two Polish common dairy breeds White Improved (PWI) and Fawn Improved (PFI) goats. Moreover, parity affected milk yield, its acidity and somatic cell count (SCC). Milk yield and milk components were found to vary according to lactation stage. At the beginning of lactation, milk is richer in ingredients which have effect on cheese and yoghurt production. All the goats undergo similar changes related to the lactation stage that is at the same time and this can affect the yield and quality of the curd. In production focused on liquid milk, the age structure of the herd should be properly managed, as the goats in their third lactation or above have higher milk yields, regardless of breed. For cheese production, the PWI breed would be more suitable than PFI as the PWI goat milk contains less SCC and more components essential for milk processing, including caseins.

The quality of milk is fundamental to producing safe milk and dairy products that are suitable for consumption. The objective of this study was to determine the influence that the content of dietary polyunsaturated fatty acids (PUFA) has on the total mixed ration (TMR) and lactation stage of milk's composition and the fatty acid profile (FA) of the dairy Najdi breed. During the lactation period, 48 Najdi ewes used the following four treatments: traditional feed (TR) and three total mixed rations (TMR1, TMR2, and TMR3) with different PUFA content. Milk samples were taken from whole milk in the morning. The chemical composition and FA profile were analyzed. The results show that the ewes fed TMR1 with a PUFA content (25.20%) produced high-quality milk as they contained high levels of polyunsaturated fatty acids (PUSF), linoleic acid (LA), α-linolenic acid (ALA) and omega-3 (n3). On the other hand, the milk of ewes fed TMR2 with PUFA (15.06%) contained high levels of unsaturated fatty acids (USF) and monounsaturated fatty acids (MUFA) and had significantly reduced hypercholesterolemia (HFA). It can be concluded that milk fat, protein, and total solids in the milk of Najdi sheep increased as lactation progressed, while lactose remained constant. Furthermore, as lactation progressed, saturated fatty acids (SFA), stearic acids, and oleic acids (OA) increased while USF and MUFA decreased. TMR diets can directly benefit the producer and livestock by producing high-quality milk while reducing its economic value. [ABSTRACT FROM AUTHOR]

This article discusses the risk factors associated with bovine clinical mastitis in Tamil Nadu, India. The study surveyed 300 dairy farmers and found that species, breed, parity, lactation stage, and milk yield were significant risk factors for mastitis in lactating dairy cows. The article emphasizes the economic importance of the dairy industry in India and the need for prevention and control measures. Another document provides a list of references and citations for various research articles and studies on mastitis in dairy cows. These articles cover topics such as prevalence, risk factors, economic impact, and prevention strategies, offering a diverse perspective on the issue. [Extracted from the article]

In general, it can be stated that the economics of non-dairy sheep breeding in the Czech Republic experienced a worsening trend in recent years. One of the ways to improve this situation is to use some of these breeds also for milk production. One of the possible breeds usable for milk production, especially for the good milk production of mothers, is the Clun Forest (CF). The aim of our experiment was to evaluate the daily milk yield (DMY) and the contents of fat (F), total protein (TP) and lactose (L), pH, titratable acidity (TA), concentration of urea (CU) and somatic cell count (SCC) in CF ewes during lactation. In our experiment, the following means of individual traits for the whole lactation were found: DMY: 579 g, contents of F, TP and L: 6.73%, 5.82% and 4.98%, pH: 6.55, TA: 8.74 °SH, CU: 36.08 mg/100 ml and log SCC: 4.71. The stage of lactation had a significant (P < 0.01) effect on DMY, contents of F and TP and pH and TA. The results of our experiment show that CF ewes had lower DMY than dairy breeds (DB). However, the majority of the milk quality traits was comparable to DB. Moreover, the high fat and protein contents and the values of most other milk quality traits are good prerequisites for high cheese yield and optimal final quality of other sheep’s milk products. The results of our experiment suggest that CF ewes could be used for milk production while the milk production of CF ewes should ensure an improvement in the economics and competitiveness of smaller farms in particular. [ABSTRACT FROM AUTHOR]

ABSTRACT: Dairy cow responses to dietary crude protein (CP) may depend on stage of lactation. The primary objective of this study was to evaluate the effects of 4 concentrations of dietary CP on dry matter intake (DMI), production performance, net energy for lactation (NEL) output in milk, feed efficiency (FE: milk NEL/DMI), and nitrogen use efficiency (100 × milk protein-N/N intake) when fed to cows grouped as early, mid-early, mid-late, and late lactation. Our secondary objective was to determine the range of CP concentration at which production responses were not negatively affected across days in milk (DIM). Multiparous Holstein cows (n = 64) were stratified by DIM [initial average ± standard deviation: 86 ± 14.9 (early), 119 ± 10.0 (mid-early), 167 ± 22.2 (mid-late), and 239 ± 11.1 (late)] and then randomly assigned within DIM group to receive 1 of 4 total mixed rations containing 13.6, 15.2, 16.7, and 18.3% CP (dry matter basis) according to a 4 × 4 factorial arrangement of treatments. Cows were individually fed a covariate diet for 14 d, followed by 56 d of treatment diets. Milk yield and DMI were recorded daily and milk components were analyzed weekly for 2 consecutive days at 3 daily milkings. Data were analyzed using a categorical mixed-effect model to evaluate the effects of CP concentration and DIM using linear, quadratic, and cubic contrasts, and their interactions. Additionally, a mixed-effect cubic regression model was fit with DIM, dietary CP concentration, and their interaction as continuous independent variables. Dietary CP concentration deemed optimal across DIM was determined as the range of CP for which the dependent responses did not differ from the predicted maximum. With advancing stage of lactation, DMI, milk NEL output, and FE decreased linearly (from 30.4 to 28.4 kg/d for DMI, from 33.2 to 23.3 Mcal/d for NEL output, and from 1.09 to 0.82 Mcal milk NEL/kg DMI for FE for early and late lactation cows, respectively). Responses to dietary CP concentration were linear, quadratic, and cubic with the greatest values observed when cows were fed the 16.7% CP diet across DIM (30.8 kg/d, 31.0 Mcal/d, and 1.01 Mcal/kg for DMI, milk NEL output, and FE, respectively). There was an interaction between dietary CP concentration and stage of lactation for DMI, milk NEL output, milk component yield, and FE, which was due to the decline in response to additional CP as lactation progressed. Compared with the 16.7% CP diet, feeding the 18.3% CP diet decreased milk NEL 0.81 and 5.3 Mcal/d for early and late lactation cows, respectively, indicating that feeding a higher CP concentration in late lactation had a negative effect on cow performance. Nitrogen use efficiency declined linearly with increasing CP concentration and DIM. Regression analysis suggested that dietary CP ranging from 16.3 to 17.4% maintained production in early and mid-early lactation. However, dietary CP could be reduced to between 15.7 and 17.1% in late lactation. This research suggested that there are distinct ranges of dietary CP concentrations that maintain cow performance at each stage of lactation.

A study was conducted at Deir Al-Hajar Research Station for Shami Camels, Administration of Livestock Research, General Commission for Scientific Agricultural Research (GCSAR) during 2019 and 2020 to find the relation between vitamin c concentrations in milk, and either stage of lactation, parity (lactation number) or the presence of mastitis. For this purpose, thirty lactating Shami camels from different parties were used.Milk samples were collected monthly over one entire lactation season lasting 11 months. The concentration of vitamin c was 35.01±9.81 mg/l milk during considered parities without significant differences in its concentration. However, vitamin c concentration was affected by lactation month P

The objective of this study was to evaluate the effect of breed on the overall composition and fatty acid composition of milk from cows milked once a day (OAD) and twice a day (TAD) in different stages of lactation. Milk samples were taken from 39 Holstein-Friesian (F), 27 Jersey (J), and 34 Holstein-Friesian × Jersey (F × J) crossbred cows from a OAD milking herd and 104 F and 83 F × J cows from a TAD milking herd in early (49 ± 15 days in milk), mid (129 ± 12 days in milk), and late (229 ± 13 days in milk) lactation. Calibration equations to predict the concentrations of individual fatty acids were developed using mid-infrared (MIR) spectroscopy. There was a significant interaction between breed within the milking frequency and stage of lactation for the production traits and composition traits. Holstein-Friesian cows milked OAD produced milk with lower concentrations of C18:0 in early and mid lactations compared to F × J and J cows. Holstein-Friesian cows milked TAD produced lower concentrations of C18:0 in early lactation and lower concentrations of C16:0 and C18:0 in late lactation compared to F × J. Lower concentrations of these fatty acids would reduce the hardness of the butter when the milk is processed. In the OAD milking herd, F cows were superior for daily milk yield compared to J cows, but Jersey cows produced significantly (p < 0.05) higher percentages of fat and a higher concentration of C18:0 fatty acid. The relative concentrations of C18:0 and C18 cis-9 in F and J cows milked OAD imply there is no breed effect on the activity of delta-9-desaturase, whereas stages of lactation likely have an effect. These results can be used to assist with selecting breeds and cows that are suitable for either OAD or TAD milking, allowing closer alignment with milk processing needs.

Dairy cow responses to dietary crude protein (CP) may depend on stage of lactation. The primary objective of this study was to evaluate the effects of 4 concentrations of dietary CP on dry matter intake (DMI), production performance, net energy for lactation (NE L) output in milk, feed efficiency (FE: milk NE L /DMI), and nitrogen use efficiency (100 × milk protein-N/N intake) when fed to cows grouped as early, mid-early, mid-late, and late lactation. Our secondary objective was to determine the range of CP concentration at which production responses were not negatively affected across days in milk (DIM). Multiparous Holstein cows (n = 64) were stratified by DIM [initial average ± standard deviation: 86 ± 14.9 (early), 119 ± 10.0 (mid-early), 167 ± 22.2 (mid-late), and 239 ± 11.1 (late)] and then randomly assigned within DIM group to receive 1 of 4 total mixed rations containing 13.6, 15.2, 16.7, and 18.3% CP (dry matter basis) according to a 4 × 4 factorial arrangement of treatments. Cows were individually fed a covariate diet for 14 d, followed by 56 d of treatment diets. Milk yield and DMI were recorded daily and milk components were analyzed weekly for 2 consecutive days at 3 daily milkings. Data were analyzed using a categorical mixed-effect model to evaluate the effects of CP concentration and DIM using linear, quadratic, and cubic contrasts, and their interactions. Additionally, a mixed-effect cubic regression model was fit with DIM, dietary CP concentration, and their interaction as continuous independent variables. Dietary CP concentration deemed optimal across DIM was determined as the range of CP for which the dependent responses did not differ from the predicted maximum. With advancing stage of lactation, DMI, milk NE L output, and FE decreased linearly (from 30.4 to 28.4 kg/d for DMI, from 33.2 to 23.3 Mcal/d for NE L output, and from 1.09 to 0.82 Mcal milk NE L /kg DMI for FE for early and late lactation cows, respectively). Responses to dietary CP concentration were linear, quadratic, and cubic with the greatest values observed when cows were fed the 16.7% CP diet across DIM (30.8 kg/d, 31.0 Mcal/d, and 1.01 Mcal/kg for DMI, milk NE L output, and FE, respectively). There was an interaction between dietary CP concentration and stage of lactation for DMI, milk NE L output, milk component yield, and FE, which was due to the decline in response to additional CP as lactation progressed. Compared with the 16.7% CP diet, feeding the 18.3% CP diet decreased milk NE L 0.81 and 5.3 Mcal/d for early and late lactation cows, respectively, indicating that feeding a higher CP concentration in late lactation had a negative effect on cow performance. Nitrogen use efficiency declined linearly with increasing CP concentration and DIM. Regression analysis suggested that dietary CP ranging from 16.3 to 17.4% maintained production in early and mid-early lactation. However, dietary CP could be reduced to between 15.7 and 17.1% in late lactation. This research suggested that there are distinct ranges of dietary CP concentrations that maintain cow performance at each stage of lactation. [ABSTRACT FROM AUTHOR]

In this case study, we compared the gross composition and fatty acid (FA) composition of milk from cows milked once a day (OAD) and twice a day (TAD) at different stages of lactation in real farm conditions with no control on feed. Seventy-two cows from a OAD milking herd and 181 cows from a TAD milking herd were sampled in early, mid and late lactation. Calibration equations were developed to enable the prediction of proportions of individual FAs using mid-infrared (MIR) spectroscopy. Cows milked OAD produced 25% lower daily milk yield (MY) compared to cows milked TAD. Percentages of fat and protein were 21% and 9% higher in cows milked OAD compared to cows milked TAD, respectively. The proportion of saturated fatty acids (SFA) (molecules with unbranched hydrocarbon chains and all single bonds) was significantly lower, while the proportions of de novo synthesised FAs from C8:0 to C14:0 were significantly higher, in cows milked OAD compared to cows milked TAD. OAD milking improved the energy balance of cows, which led to higher proportions of de novo synthesised FAs and lower proportions of long-chain fatty acids (16:0 and above). The proportion of SFA was significantly higher in mid lactation (ML) compared to early lactation (EL) and late lactation (LL) in cows milked OAD and TAD. In EL, the proportions of C4:0 to C12:0 FAs in cows milked OAD were significantly higher compared to the cows milked TAD due to the improved energy status of cows milked OAD. Understanding the proportions of individual FAs in cows milked OAD and TAD will enable further studies on milk fat characteristics and on butter hardness and coagulation properties of milk.

The quality of milk is fundamental to producing safe milk and dairy products that are suitable for consumption. The objective of this study was to determine the influence that the content of dietary polyunsaturated fatty acids (PUFA) has on the total mixed ration (TMR) and lactation stage of milk’s composition and the fatty acid profile (FA) of the dairy Najdi breed. During the lactation period, 48 Najdi ewes used the following four treatments: traditional feed (TR) and three total mixed rations (TMR1, TMR2, and TMR3) with different PUFA content. Milk samples were taken from whole milk in the morning. The chemical composition and FA profile were analyzed. The results show that the ewes fed TMR1 with a PUFA content (25.20%) produced high-quality milk as they contained high levels of polyunsaturated fatty acids (PUSF), linoleic acid (LA), α-linolenic acid (ALA) and omega-3 (n3). On the other hand, the milk of ewes fed TMR2 with PUFA (15.06%) contained high levels of unsaturated fatty acids (USF) and monounsaturated fatty acids (MUFA) and had significantly reduced hypercholesterolemia (HFA). It can be concluded that milk fat, protein, and total solids in the milk of Najdi sheep increased as lactation progressed, while lactose remained constant. Furthermore, as lactation progressed, saturated fatty acids (SFA), stearic acids, and oleic acids (OA) increased while USF and MUFA decreased. TMR diets can directly benefit the producer and livestock by producing high-quality milk while reducing its economic value.

The objective of this study was to evaluate the effect of breed on the overall composition and fatty acid composition of milk from cows milked once a day (OAD) and twice a day (TAD) in different stages of lactation. Milk samples were taken from 39 Holstein-Friesian (F), 27 Jersey (J), and 34 Holstein-Friesian × Jersey (F × J) crossbred cows from a OAD milking herd and 104 F and 83 F × J cows from a TAD milking herd in early (49 ± 15 days in milk), mid (129 ± 12 days in milk), and late (229 ± 13 days in milk) lactation. Calibration equations to predict the concentrations of individual fatty acids were developed using mid-infrared (MIR) spectroscopy. There was a significant interaction between breed within the milking frequency and stage of lactation for the production traits and composition traits. Holstein-Friesian cows milked OAD produced milk with lower concentrations of C18:0 in early and mid lactations compared to F × J and J cows. Holstein-Friesian cows milked TAD produced lower concentrations of C18:0 in early lactation and lower concentrations of C16:0 and C18:0 in late lactation compared to F × J. Lower concentrations of these fatty acids would reduce the hardness of the butter when the milk is processed. In the OAD milking herd, F cows were superior for daily milk yield compared to J cows, but Jersey cows produced significantly (p < 0.05) higher percentages of fat and a higher concentration of C18:0 fatty acid. The relative concentrations of C18:0 and C18 cis-9 in F and J cows milked OAD imply there is no breed effect on the activity of delta-9-desaturase, whereas stages of lactation likely have an effect. These results can be used to assist with selecting breeds and cows that are suitable for either OAD or TAD milking, allowing closer alignment with milk processing needs. [ABSTRACT FROM AUTHOR]

Donkey milk is of increasing interest lately, thus being studied in depth its physicochemical compositions. Colostrum of this species has proven to be rich in nutritional principles, and its composition defines it as called a functional food. Also, as in the other milk-producing species, the composition and the quantity obtained, it is dependent on a multitude of factors, among which were highlighted during the studies, the breed, the stage of lactation, the state of health of the female, the time of collection and external factors such as season, temperature and light. The quality of donkey colostrum shows changes during the lactation period, being thus much richer in nutritional principles in the innate health of the udder of this species beneficially influences the quality of milk and colostrum compared to other farm animals. Due to the research carried out, the beneficial qualities of this product have been discovered and all the time the benefits that it would have on human health. [ABSTRACT FROM AUTHOR]

This research aims to determine the chemical composition of Lacaune ewe milk produced in Estonia, as well as the correlations and the influence the stages of lactation have on milk. The study was carried out on fifty-one second-parity ewes. The analysis involved a total of 178 milk samples collected monthly from the second to the seventh month of lactation. Milk analyses included the determination of the contents of total solids, fat, total protein, casein, casein index, lactose, ash, P, Ca, K, Na, Mg, somatic cell count and pH. The Lacaune ewes’ milk contained on average 18.62% total solids, 7.75% fat, 5.74% total protein, 4.32% casein, 4.76% lactose, 0.89% ash, 160.26 mg 100 g-1 Ca, 140.07 mg 100 g-1 P, 135.21 mg 100 g-1 K, 46.44 mg 100 g-1 Na, 17.66 mg 100 g-1 Mg. Overall means for casein index, pH value and somatic cell scores were 75.35%, 6.61 and 12.62, respectively. It was found that the month of lactation significantly affected almost all monitored traits except somatic cell score, casein index and Ca content. The contents of total solids, fat, total protein, casein, ash, P, and Mg increased, while the lactose content, and pH value decreased with the advancing lactation. Sodium content was highest and potassium content lowest value during mid-lactation. Producers must take into account that the composition of Lacaune ewe milk depends on the stage of lactation and may, therefore, affect the production process and the final quality of the product. [ABSTRACT FROM AUTHOR]

In this case study, we compared the gross composition and fatty acid (FA) composition of milk from cows milked once a day (OAD) and twice a day (TAD) at different stages of lactation in real farm conditions with no control on feed. Seventy-two cows from a OAD milking herd and 181 cows from a TAD milking herd were sampled in early, mid and late lactation. Calibration equations were developed to enable the prediction of proportions of individual FAs using mid-infrared (MIR) spectroscopy. Cows milked OAD produced 25% lower daily milk yield (MY) compared to cows milked TAD. Percentages of fat and protein were 21% and 9% higher in cows milked OAD compared to cows milked TAD, respectively. The proportion of saturated fatty acids (SFA) (molecules with unbranched hydrocarbon chains and all single bonds) was significantly lower, while the proportions of de novo synthesised FAs from C8:0 to C14:0 were significantly higher, in cows milked OAD compared to cows milked TAD. OAD milking improved the energy balance of cows, which led to higher proportions of de novo synthesised FAs and lower proportions of long-chain fatty acids (16:0 and above). The proportion of SFA was significantly higher in mid lactation (ML) compared to early lactation (EL) and late lactation (LL) in cows milked OAD and TAD. In EL, the proportions of C4:0 to C12:0 FAs in cows milked OAD were significantly higher compared to the cows milked TAD due to the improved energy status of cows milked OAD. Understanding the proportions of individual FAs in cows milked OAD and TAD will enable further studies on milk fat characteristics and on butter hardness and coagulation properties of milk. [ABSTRACT FROM AUTHOR]

Dairy cows face precipitous metabolic adaptations during the first postpartum week. Increasing knowledge of their hematologic profiles during this period could benefit both veterinary clinical pathologists and bovine practitioners. The objectives of this study were: (a) to establish period‐specific RIs for Holstein dairy cows and (b) to assess the potential simultaneous effect of several factors on hematology parameters. Blood samples from clinically healthy cows of nine herds were used to establish hematology RIs for these periods. There were 68 cows in the prepartum period (PP), 247 and 218 cows at 2 and 8 days after calving (2 and 8 days in milk [DIM 2 and DIM 8], respectively), and 87 cows in peak lactation (PL). A complete blood count evaluation was performed using the ADVIA 120 analyzer. Linear models estimated the analytes associated with parity. RIs were calculated with Reference Value Advisor. Parity had a significant effect on analytes at all stages. Marked differences were evident between DIM 2 and 8 regarding red blood cell (RBC) counts, hematocrits, hemoglobin concentrations, and white blood cell (WBC), monocyte, and eosinophil counts. Reference intervals of RBC counts, hematocrits, and hemoglobin concentrations at DIM 2 were higher than those at PP and PL. This study provides evidence that period‐specific RIs should be used for Holstein cows when making clinical decisions, especially during the critical first week postpartum. [ABSTRACT FROM AUTHOR]

The optimal concentration of urea in cow's milk is known and is often used to assess the balance of energy and protein in diets. While in goat (and sheep) milk it is not controled nor defined. Main determinants of urea formation in milk are the amount of crude protein intake and the ratio betwwen protein and energy proportion in diet. Goat diet with excessive amount of crude protein and energy unbalanced diet cause the excess of nitrogenous substances in rumen along with release of ammonia and rise in concentration of urea in blood and milk, which adversely affects the production, milk coagulation propreties, environmental pollution and reproductive capabilities of goats. However, besides diet, there are other factors that influence milk urea concentration: breed, stage of lactation, parity, season, body mass, litter size, production and chemical composition of milk. Numerous studies conducted on cow milk included the influence of sources of variability listed above, while there are only few studies available for goat milk due to its less economic importance, seasonal polyesterity and different way of breeding and keeping goats. The aim of this paper is to comparatively and critically combine the previous research results on the importance of determining the milk urea concentration as well as on individual sources of variability of urea concentration in goat milk.

Adiponectin and resistin are vital adipokines which influence the energy homeostasis, insulin sensitivity and mobilization of body fat stores. The present investigation was performed to elucidate the influence of the stage of lactation (early, mid and late lactation) and parity (first, second and third) on circulating levels of adipokines and lipid profile in Indian dairy cows. Blood samples were collected from 18 Sahiwal cows, six each in their first, second and third parity in their early (30th day), mid (90th day) and late (200th day) lactation. The Body condition score (BCS), plasma levels of resistin, progesterone, estrogen and high density lipoprotein (HDL) affected with stages of lactation, insulin and Ttriglyerides (TG) were found to be affected by different parities while cholesterol, low density lipoprotein (LDL) and non-esterified fatty acids (NEFA) were found to be affected with both parity and stage of lactation of cows. The plasma levels of adiponectin showed positive association with progesterone, TG, cholesterol, HDL and LDL and negative association with NEFA in first lactation, and showed positive correlation with resistin (RETN) in third lactation in Sahiwal cows. The plasma levels of resistin showed a positive association with adiponectin and NEFA and negative correlation with BCS, progesterone and HDL in second lactation in Sahiwal cows. In conclusion, this investigation is endow with data of plasma levels of adipokines and lipid profile at different stages of lactation in cows of different parities that may be useful for clinical and experimental interpretations. However further studies are needed to elucidate the physiological significance of adipokines in lactogenesis in dairy animals. [ABSTRACT FROM AUTHOR]

This study was conducted to investigate the relationships between body weight (BW) and milk yield, and post-partum BW and their changes during parity and stage of lactation in Holstein cows. This study was conducted on a private dairy cattle farm in Kastamonu province in the Mid-Black Sea Region of Turkey. The study material included 2133 records from 273 Holstein cows calved between 2016 and 2017 years. Parity (from 1 to 5) and stage of lactations (from 1 to 10) were used to be environmental factors affecting traits. The effect of parity and stage of lactation on BW and milk yield were significant (P<0.05). BW and milk yield increased with advancing lactation until the fourth parity, then declined in the fifth parity. The lowest BW was observed in the first two months of lactation, and it increased linearly with following lactation periods. Milk yield was low in the first month of lactation and then decreased linearly until the end of lactation. Correlations between BW and milk yield were all positive and ranged from 0.201 to 0.588. BW changes in early to mid-lactation were phenotypically correlated with milk yield. Finally, based on the findings in present study, it is suggested that monitoring BW change in early and mid-lactation can be used as a management tool to improve the milk yield in dairy herds. [ABSTRACT FROM AUTHOR]

The current study aimed to determine the effect of season and lactation stages on certain physico-chemical parameters in Holstein crossbred cows in Tiaret city (Algerian west high lands). A total of 245 milk samples from 45 cows were analyzed by lactoscan SP in two seasons (spring and winter), and from different stage of lactation (early, mid and late). The results showed that all the chemical constituents were higher in the spring and lower in winter, with no significant difference. However, the season had a significant influence on milk conductivity (p <0.05). On the other hand, Fat was the only component that was highly significantly affected by the lactation stage (p <0.001). Further, there was an increase in protein, fat, SNF, and conductivity values during the progress of lactation, unlike the values of lactose and density that decrease when the lactation stage progresses. [ABSTRACT FROM AUTHOR]

Copyright of Agriculture / Poljoprivreda is the property of Josip Juraj Strossmayer University of Osijek, Faculty of Agriculture in Osijek and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of our experiment was to assess changes in milk yield, composition and renneting parameters (pH, titratable acidity, coagulation time and curd quality) of sheep milk in the course of lactation and their relationships in the Lacaune ewes (n = 8), reared under intensive nutrition. The stage of lactation (SL) had a conclusive effect on the daily milk yield (DMY) and contents of all basic milk compounds. The DMY and fat content were relatively high during whole lactation. In our opinion these trends were influenced by the quite intensive nutrition. The SL had inconclusive effect on pH. In contrast, the SL had a conclusive effect on titratable acidity (TA) of milk. The correlations between the pH and all other indicators, with the exception of the coagulation time (CT), were inconclusive. Also most correlations between the TA and all other indicators monitored were inconclusive. The SL had inconclusive effect on the CT and curd quality (CQ). In our opinion, relatively balanced values of the CT and CQ during lactation indicate on the good health state and correct nutrition of ewes.

The objectives of this study were to determine milk yield and constituents’ levels of Holstein cows under Moroccan conditions and to assess the effects of environmental factors influencing them. Data including 93,815 test day records of 6343 Holstein cows in 162 herds were analyzed for milk yield, contents of fat, protein, lactose and solids-not-fat (SNF), milk urea nitrogen (MUN), and somatic cell score (SCS). Averages were 25.1 ± 7.33 kg/day, 3.54 ± 0.76%, 3.02 ± 0.34%, 4.89 ± 0.24%, 8.72 ± 0.36%, 17.6 ± 8.17 mg/dl, and 4.12 ± 2.06 units, respectively. The effects of herd and calving year were found to be significant on all the studied traits. Parity was determined to have significant effects on all analyzed traits, with the exception of MUN concentration. Milk yield, fat content, protein content, and SCS increased with parity, whereas lactose percentage decreased in later parities. Except fat and lactose contents, all the other studied variables were significantly influenced by calving season. Milk yield and MUN were highest for cows calving during humid season, whereas protein content, SNF content, and SCS tended to be higher in dry season. All the studied traits changed significantly according to stage of lactation. The peaks of milk yield and lactose content occurred between 35 and 65 days, whereas that of MUN between 95 and 125 days after parturition. Protein and SNF contents and SCS attained their lowest values between days 35 and 65, while fat content between days 65 and 95. It was concluded that these environmental factors should be taken into consideration if the milk yield and quality in Morocco is to be optimized. [ABSTRACT FROM AUTHOR]

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Copyright of Journal of Central European Agriculture is the property of Journal of Central European Agriculture and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The concentration of milk urea (MU) can be used to evaluate crude protein in ration of sheep, which is particularly important for grazing animals whose assessment of intake is a major problem. Although the concentration of milk urea is mainly influenced by nutrients, its level could be influenced by some non-nutritional factors such as breed, season, pregnancy and stage of lactation, milkiness, milking time and somatic cell count. The aim of the study was to investigate the lactation stage and rainfall effects during the studied period on the average daily milk yield and milk urea level in sheep from the Bulgarian Synthetic Milk Population. The results from the current study show that the urea content of ewes' milk increases at the end of lactation (P < 0.001). During the active grass growth period there is an increase in milk urea level (P < 0.001). In early spring and autumn, as well as during periods with heavy rainfalls, sheep should be fed with high-quality cereal feed and simultaneously the level of nitrogen release to the environment should be monitored using milk urea level as indicator. It is highly imperative to develop appropriate nutrition strategies in order to provide the necessary nutrients for sustaining life and productivity, by using indicators of protein and energy levels, taking into consideration the impact of farming activities on the environment. [ABSTRACT FROM AUTHOR]

ABSTRACT: Worldwide, milk analysis is an satisfactory measurement of milk quality on dairy farms. Milk composition is the base for payment systems, so knowledge of its characteristics at different periods is essential for modern dairy producer. The aim of the study was to evaluate the effects of year, season, stage of lactation, and lactation number on variations in milk yield and composition of Holstein cows (n=148,604). Milk yield estimated by multiple regression was 25,50L/cow/day. Winter was the season with the highest milk yield and the highest protein and lactose content. Milk fat was highest in the fall, in cows in late lactation and also in primiparous cows. Lactating cows from 6 to 60 days in lactation and those in 2nd or 3rd lactation showed the highest milk yield. Lactose concentration was positively correlated with milk yield. Somatic cell score was negatively correlated with milk yield and with lactose concentration. Most important variations in milk characteristics occur among seasons, lactation stages and parities. Mammary gland health is yet the greatest challenge to be overcome.

In the last decade, FT-IR spectroscopy has been introduced in methodological portfolio specific for analyzing food products, because it is a very efficient, and non-destructive analytical tool. Vibrational spectral techniques, as FT-IR, offer several advantages in the context of current research and using this techniques we can identify molecular components in the studied samples. In this study FT-IR spectroscopy technique is applied to detect fat, protein, and lactose content of buffalo milk, and compositional differences between samples corresponding to different lactations. The results emphasizes specific evolutions corresponding to the increase of protein, lactose, and fat buffalo milk contents, from the first lactation up to the fifths/fourths lactations. [ABSTRACT FROM AUTHOR]

The aim of our experiment was to assess changes in milk yield, composition and renneting parameters (pH, titratable acidity, coagulation time and curd quality) of sheep milk in the course of lactation and their relationships in the Lacaune ewes (n = 8), reared under intensive nutrition. The stage of lactation (SL) had a conclusive effect on the daily milk yield (DMY) and contents of all basic milk compounds. The DMY and fat content were relatively high during whole lactation. In our opinion these trends were influenced by the quite intensive nutrition. The SL had inconclusive effect on pH. In contrast, the SL had a conclusive effect on titratable acidity (TA) of milk. The correlations between the pH and all other indicators, with the exception of the coagulation time (CT), were inconclusive. Also most correlations between the TA and all other indicators monitored were inconclusive. The SL had inconclusive effect on the CT and curd quality (CQ). In our opinion, relatively balanced values of the CT and CQ during lactation indicate on the good health state and correct nutrition of ewes. [ABSTRACT FROM AUTHOR]

Worldwide, milk analysis is an satisfactory measurement of milk quality on dairy farms. Milk composition is the base for payment systems, so knowledge of its characteristics at different periods is essential for modern dairy producer. The aim of the study was to evaluate the effects of year, season, stage of lactation, and lactation number on variations in milk yield and composition of Holstein cows (n=148,604). Milk yield estimated by multiple regression was 25,50L/cow/day. Winter was the season with the highest milk yield and the highest protein and lactose content. Milk fat was highest in the fall, in cows in late lactation and also in primiparous cows. Lactating cows from 6 to 60 days in lactation and those in 2nd or 3rd lactation showed the highest milk yield. Lactose concentration was positively correlated with milk yield. Somatic cell score was negatively correlated with milk yield and with lactose concentration. Most important variations in milk characteristics occur among seasons, lactation stages and parities. Mammary gland health is yet the greatest challenge to be overcome. [ABSTRACT FROM AUTHOR]

Istrian sheep has the highest milk yield among indigenous Croatian sheep breeds though originally belongs to a group of sheep of combined production traits. Since milk of Istrian sheep is traditionally processed into cheese and that processing possibilities of milk, among other things, are defined by its chemical composition and hygienic quality, the aim of this study was to determine the influence of some environmental factors (year, parity, stage of lactation, season (month) of lambing) on daily and lactation milk yield, lactation length, milk chemical composition and the somatic cell count (SCC) in the milk of Istrian ewes. A total of 83 purebred, dairy Istrian sheep, during three consecutive lactations (from 2012 to 2014), were involved in this research. Due to conditions of feeding, care and housing, all ewes were kept in identical (semi-intensive) farming conditions throughout the whole study period. During milking period of lactation regular milking controls were carried out (AT method) and, on these occasions, individual milk samples for chemical composition analysis and determination of somatic cell count were taken. During average lactation length of 206 days Istrian ewes produced on average 190.77 kg of milk, or 1.1 kg of milk per day. Milk of Istrian ewes on average contained 6.81% fat, 5.90% protein, 4.32% lactose, 18.08% total solids and 11.31% non-fat solids. The geometric mean of SCC was 316*103*mL-1 of milk (log 5.50±0.02). A significant (P < 0.001) effect of the year is determined on the milk yield and the lactation length, as well as the chemical composition of milk (with the exception of protein) and SCC. Ewes in the fourth lactation achieved the highest average daily (P < 0.001) and lactation milk yield (P < 0.05), while the first-lambing ewes produced milk with the highest content of total solids, milk fat and proteins. Stage of lactation significantly (P < 0.001) affected the daily milk yield, milk chemical composition, as well as the somatic cell count in ewe’s milk. Ewes born in December produced significantly (P < 0.001) more milk than ewes born in January and February. There was a negative correlation between SCC (log10) and daily milk yield (P < 0.001), while the SCC (log10) was positively correlated (P < 0.001) with the contents of total solids, milk fat and proteins.

The aims of the present study were to monitor the changes in gross chemical composition of individual dromedary camel milk over a 5-yr period, to provide reference values, and to determine the effect of genetic and nongenetic factors influencing camel milk composition under intensive management. A total of 1,528 lactating dromedary camels were included in the study. Animals were fed a constant diet and were milked twice a day in a herringbone parlor. Milk samples were collected at monthly intervals using a sampling device and then fat, protein, lactose, total solids (TS), and solids-nonfat (SNF) concentrations of raw camel milk were determined with an automatic milk analyzer. For each milk sample, production parameters were recorded and quantities (grams) of milk constituents were calculated. The overall mean quantity and fat, protein, lactose, SNF, and TS concentrations of the morning milk were 4.0 kg, 2.58%, 2.95%, 4.19%, 8.08%, and 10.46%, respectively. Milk quantity showed a positive correlation with lactose and a negative correlation with all other components. Parity exerted a strong effect on all milk parameters. Primiparous dromedaries (n = 60) produced less milk with higher concentrations of components than did multiparous animals (n = 1,468). Milk composition varied among the 7 breeds tested, but none of the genotypes was found to be superior to the others in this respect. We detected a significant, yet small calf sex-biased difference in milk yield and composition. Stage of lactation and season strongly influenced milk yield and all milk components. We also found a significant interaction between month postpartum (mPP) and month of the year. The concentration of all milk components decreased from 1 to 5 mPP. Later, lactose concentration and quantity continued to decrease parallel with decreasing milk production. The concentration of other components showed a temporary increase in mid-lactation, from 6 to 11 mPP, and in late lactation, from 18 to 23 mPP. Mean fat, protein, SNF, and TS concentrations showed a high seasonal variation (9.5 to 28.7%), with the lowest and highest values being measured during summer and winter, respectively. This seasonal variation was independent of nutrition and may reflect an endogenous circannual rhythm. We observed a noticeable variation among years. Dromedary camels could provide a useful in vivo model to study the homeorhetic regulation of mammary cell function by endogenous and environmental factors. [ABSTRACT FROM AUTHOR]

This trial aimed to study the changes in the yield, composition, and fatty acid (FA) profile of ewes’ milk during suckling and milking periods. Nineteen multiparous Najdi ewes were kept under identical management and feeding conditions during a 12-week trial that was divided into two periods. Milk samples were collected on each sampling day from the total yield during the suckling (3rd, 6th, and 9th week) and milking (12th week) periods. The milk yield and the total solids, fat, protein, and lactose contents of the milk remained constant throughout the suckling weeks, but the protein content increased and milk yield and lactose content decreased after weaning. There were no differences in milk saturated FA (SFA), unsaturated FA (UFA), and monounsaturated FA (MUFA) contents during the suckling and milking periods, whereas the polyunsaturated FA content increased during the milking period. There were no differences in the individual milk SFA during the weeks of suckling, but the contents of caproic acid (C6:0), caprylic acid (C8:0), margaric acid (C17:0), and stearic acid (C18:0) decreased. However, myristic acid (C14:0), lauric acid (C12:0), and isomers of pentadecanoic (C15:0) acid increased during the milking period. The percentage of vaccenic acid (C18:1Δ11t), rumenic acid (C18:2Δ9c,11t; conjugated linoleic acid (CLA)), ω-3 FA group, and the atherogenicity index did not differ during the suckling period, but increased after weaning in the 12th week of lactation. This study demonstrated that weaning lambs in Najdi ewes is probably a factor that strongly affects milk traits by changing yield, composition, and FA profile. [ABSTRACT FROM AUTHOR]

The aim of the study was to investigate the effect of parity, stage of lactation and udder type on milkability of crossbred dairy cows milked in automated Herringbone milking system. Crossbred cows (218; Karan Fries and Karan Swiss) of different parities, stages of lactation and udder types were milked in 8×2 low-line automated Herringbone milking parlour having automatic cluster removal (ACR) settings for a period of 3 months. The milkablity of cows in automated herringbone milking parlour was based on parameters such as total milk yield, milk yield/session, machineon time, yield first 2 min, and milk flow rates generated automatically in herd management Software during each session of milking. The results showed that milkability of cows was affected significantly based on parity and stage of lactation. The udder types had no effect on milkability except type D (pendulous) udders having least flow rate, which caused increased machine-on time. The overall mean milk flow rates over different intervals during the first two minutes of milking differed significantly in parity and udder types. Similarly, significant differences were observed in the flow rates over different intervals of milking. The milking efficiency benchmarks in terms of cow throughput and milk harvesting efficiency with 2 operators in the milking pit were 69.75±0.57 cows/h and 305.21±2.75 kg/h, respectively. The operators had idle time during milking in batches of around 4.28 minutes/batch. It can be concluded from the present study that the milkability of crossbred dairy cows was significantly affected by parity, stage of lactation and type of udder in automated Herringbone milking parlour. [ABSTRACT FROM AUTHOR]

Milkability traits have an increasing importance in modern cattle production, although they are the secondary selective trait. The machine milking of cows has indicated that there is no complete alignment between the machine and the animals, what lead to increasing duration of milking and disturbances in health of udder. Because of that, the aim of this study was to investigate the influence of the ordinal number of lactation and stage of lactation on milkability traits (amount of milk per milking (KMM), maximum milk flow rate (MPM), average milk flow rate (PPM), duration of the start of milk flow (tS500), duration of the ascending phase of milking (tUFM), duration of the plateau phase of milking (tPFM), duration of the descending phase of milking (tSFM), duration of the main phase of milking (tGFM)), and recommend the same for the selection work. The study was done on 322 Holstein cows in the period from the first to third lactation, arranged in three stages of lactation (the first of the 50-90 day, the second stage of the 91-135 day and a third of 136-180 day of lactation). The results showed that the ordinal number of lactation had a highly statistically significant influence (P