Total Milk Research Articles

Effects of the Individual and Pair Housing of Calves on Long-Term Heifer Production on a UK Commercial Dairy Farm.

Pair housing of pre-weaning dairy calves has previously demonstrated positive impacts on their growth, health and behaviour, but longer-term effects on production are still relatively unknown. This study followed a cohort of 431 Holstein heifers, recruited from a single UK commercial dairy farm, from weaning until either culling or the end of their first lactation. All animals were allocated to either individual or pair housing as a pre-weaning calf. Following weaning, all heifers were similarly managed through group housing, feeding with total mixed rations, the use of automatic heat detection for artificial insemination and weighing every two months until conception. Farm staff identified disease occurrences, which were treated following standard operating procedures. First-lactation monthly milk recording was used to measure milk yields and somatic cell counts. Overall mortality (voluntary and involuntary) was 26.6%, with a decreased hazard of exiting the herd if the heifer was pair housed as a calf (HR 0.70; p = 0.067). The voluntary cull rate was highest in the post-insemination period (13.0%) due to poor fertility. Heifers that were pair housed as calves had significantly increased odds of developing udder health issues as a primiparous cow (OR = 1.93, p = 0.022). Despite this, the 305-day milk yields were not associated with the housing group. However, the total milk produced per calf recruited into the original study was greater for pair-housed compared with individually housed calves (8088 kg vs. 7115 kg; p = 0.071), which is likely due to the significantly higher hazard of individually housed calves exiting the herd prematurely.

Evaluation of ELISA Test Kits for Detection of Milk Protein in Frying Oil Treated at Different Temperatures

Milk is a common ingredient in fried foods. Allergen cross-contact can occur through the reuse of frying oil. To enable assessment of the allergy risk of reused oil, methods for quantification of milk protein in oil are needed. This study evaluated four commercial ELISA test kits in comparison with the 660 nm total protein assay for the detection of milk protein in oil after frying. Corn oil spiked with nonfat or whole milk powder were fried at 150 °C or 180 °C for 3 min and were analyzed by ELISA kits either directly or after preextraction with phosphate-buffered saline containing 0.05% Tween (PBST). All four ELISA kits performed well in quantifying milk protein in unheated oil, achieving normalized recoveries of 72.1–115.9% compared with that determined in reference solutions (PBST spiked with nonfat or whole milk powder, 100%). Frying lowered the amount of protein detected, but the extent of reduction differed between test kits. In nonfat milk powder-spiked oil fried at 150 °C, normalized recoveries determined by Veratox Total Milk and BioKits BLG Assay (49.9% and 43.6%, respectively) were higher than that determined by the 660 nm assay (25.4%). Normalized recoveries determined by ELISA Systems Casein and Beta-Lactoglobulin (BLG) kits were substantially lower (9.7% and 2.4%, respectively). In samples fried under typical frying temperature (180 °C), very little protein (0.1–7.4%) was detected. Inclusion of PBST preextraction improved the detection of the two test kits targeting BLG but lowered the level of protein detected by Veratox and ELISA Systems Casein in fried samples. Overall, the ELISA kits evaluated could effectively quantify milk protein in unheated oil without the need to remove the oil phase prior to analysis. Heat treatment was the key factor negatively affecting protein quantitation. Such impact needs to be considered when ELISA test results are used for assessing the allergy risk of reused frying oil.

The Effect of Dairy Farm Size on the Economic Structure and Feed Consumption: A Case Study of the Aegean Region

Dairy farming has an important place in the agricultural activities in Türkiye. Cow's milk production constitutes 92.11% of the total milk production in Türkiye. The purpose of this study is to demonstrate the effect of scale size on the economic structure and feed consumption in dairy farms. The research data were obtained from face-to-face surveys conducted with 143 farmers in the Aegean Region. In the study, the farms were divided into four groups based on the number of cows: 5-15 cows, 16-25 cows, 26-40 cows, and 41 cows and above. The total variable cost per livestock unit in the 4th group farms was 26.07% less than the farms in the 1st group. The total production cost per livestock unit in the largest farm group is 25.81% less than that of the smallest farm group. The research findings indicate that large-scale farms take advantage of economies of scale, resulting in lower cost per livestock unit. Additionally, it was observed that as farm size increases, the feed conversion ratio also increases. As farms grow larger, they often have access to economies of scale, better management practices, and improved infrastructure.

The association between calf birth weight and the postcalving performance of its dairy dam in the absence of dystocia

The objective of the study was to quantify the association between the birth weight of a calf and the subsequent performance of its dairy dam in the absence of any recorded calving assistance. A total of 11,592 lactation records from 4,549 spring-calving dairy cows were used. The association between a series of quantitative cow performance metrics (dependent variable) and calf birth weight (independent variable) was determined using linear mixed models; logistic regression was used where the dependent variable was binary. Nuisance factors in the models were calf sex, heterosis coefficient of both the cow and calf, dry period length immediately before the birth of the calf, cow age at calving relative to the median cow age per parity, breed proportion of the cow, cow live weight between 100 and 200 d of lactation relative to the mean cow weight per parity, and contemporary group. Calf birth weight was included in the model as either a continuous or a categorical variable. Primiparous and multiparous cows were analyzed separately. Mean (SD) calf birth weight was 36.2 (6.8) kg. In primiparous cows, calf birth weight was associated with milk yield in the first 60 d of lactation, calving to first service interval, calving body weight (BW), and both nadir BW and body condition score (BCS). In multiparous cows, calf birth weight was associated with total milk, fat, and protein yield in the first 60 and 305 d of lactation, peak milk yield, total milk solids, both calving and nadir BW, and BCS loss from calving to nadir. Relative to primiparous cows that gave birth to calves weighing 34 to 37 kg (i.e., population mean), their contemporaries who gave birth to calves that weighed 15 to 29 kg produced 9.82 kg more milk in the first 60 d of lactation, had a 2-d shorter interval to first service, and were 8.08 kg and 5.51 kg lighter at calving and nadir BW, respectively; the former was also 0.05 units lower in BCS (5-point scale, 1 = emaciated and 5 = obese) at nadir. Relative to multiparous cows that gave birth to calves that were 34 to 37 kg birth weight, multiparous cows that gave birth to calves that were 15 to 29 kg yielded 59.63 kg, 2.44 kg, and 1.76 kg less milk, fat, and protein, respectively, in the first 60 d of lactation; produced 17.69 kg less milk solids throughout the 305-d lactation; and were also 10.49 kg lighter at nadir and lost 0.01 units more BCS to nadir. In a separate series of analyses, sire breed was added to the model as a fixed effect with and without calf birth weight. When calf birth weight was not adjusted for, 60-d milk yield for multiparous cows who gave birth to calves sired by a traditional beef breed (i.e., Angus, Hereford) produced 59.63 kg more milk than multiparous cows who gave birth to calves sired by a Holstein-Friesian. Hence, calf birth weight is associated with some subsequent dam performance measures; however, where associations do exist, the effect is biologically small.

The impact of controlling diseases of significant global importance on greenhouse gas emissions from livestock production

BackgroundA considerable body of evidence has reported the beneficial effects of improving productivity on reducing environmental impacts from livestock production. However, despite the negative impacts of animal diseases on reproduction, growth and milk production, there is little information available upon the impacts of animal disease on greenhouse gas emissions (GHGe). This study aimed to partially address this knowledge gap by investigating the effects of globally important vaccine-preventable diseases on GHGe from various livestock systems, namely: intensive dairy, extensive beef, commercial swine and backyard poultry production.MethodsSimple deterministic models were developed within Microsoft Excel to quantify the impacts of livestock disease on productivity (defined as total milk and/or meat yield, MMY) adjusted for disease prevalence both at the population level (high or low), and at the herd or flock level. Disease-induced changes in MMY were applied to the GHGe per kg of milk or meat according to the consequent changes in livestock populations required to maintain milk or meat production. Diseases investigated comprised foot and mouth, brucellosis, anthrax, lumpy skin disease, classical swine fever, porcine reproductive and respiratory syndrome (PRRS), low and high pathogenicity avian influenza (LPAI and HPAI), avian infectious bronchitis and Newcastle disease.ResultsAll diseases investigated had multifactorial impacts on total MMY, yet diseases that increased mortality in breeding or growing livestock (e.g. anthrax, classical swine fever and HPAI) showed greater impacts on GHGe per unit of milk or meat produced than those that primarily affecting yields or reproduction (e.g. brucellosis or LPAI). Prevalence also had considerable effects on potential GHGe. For example, maintaining backyard poultry meat production from a 100,000 hen population with 70% prevalence of HPAI increased GHGe by 11,255 MT CO2eq compared to a 30% prevalence at 3475 MT CO2eq above the baseline (0% prevalence). Effective reduction of the prevalence of PRRS in swine from 60 to 10%, FMD in beef cattle from 45 to 5% prevalence, or AIB in poultry from 75 to 20% prevalence would reduce GHGe intensities (CO2eq/kg CW) by 22.5%, 9.11% and 11.3% respectively.ConclusionsControlling livestock disease can reduce MMY losses at the farm level, which improves food security, reduces GHGe and enhances livestock system sustainability.

Strategic supplementation of novel feed supplement improved the lactation and reproductive performance in post-partum dairy cows

The present experiment aimed to establish the efficacy of dietary inclusion of a novel feed supplement on plane of nutrition, milk yield, and its characteristics, reproductive events and circulating concentrations of reproductive hormones in dairy cows during early lactation. Twelve post-partum crossbred lactating cows were equally and randomly assigned to two dietary treatments for 90 days. The cows in CON (control) group were fed on green fodder and wheat straw-based diet with concentrate mixture, whereas, cows in NFS (Novel Feed Supplement) group were fed according to CON group with additional novel feed supplement @0.25% of BW. A comparative study of plane of nutrition revealed that both DCP and TDN were deficient in CON by 12.0 and 18.99%, respectively, however, it was sufficient in NFS group. The daily and total milk yield (kg), 4% FCM, ECM, fat and protein yields (g/d) were improved in NFS than CON group. The average composition of milk showed no significant difference throughout the study. The supplement fed cows had an evident early return of heat (26.20 d in NFS v/s 42.60 d in CON) with enhanced conception rate (66.7% in NFS v/s 50% in CON). The estradiol concentration (pg/ml) was reduced and progesterone concentration (ng/ml) was enhanced in NFS fed cows. In conclusion, incorporation of the novel feed supplement @0.25% of BW significantly improved the plane of nutrition, milk production and reproduction in lactating crossbred cows during the early post-partum period.

The Protein Composition of Bovine Milk from Once-a-Day and Twice-a-Day Milking Production Systems in New Zealand

An increasing number of dairy farmers in New Zealand (NZ) have adopted a once-a-day (OAD) milking production system, and little is known about the impact of this production system on milk protein composition. The objective of this study was to evaluate the effect of OAD milking on the protein composition in milk from individual cows. Milk was sampled in early, mid-, and late lactation from cows kept at Massey University farms Dairy No. 1 (OAD milking) and Dairy No. 4 (TAD milking) in Palmerston North, NZ. The yields of total milk and milk solids, the proximate composition, and the protein composition were determined. Results showed that OAD milking yielded less milk and milk solids than TAD milking. However, no significant differences in protein, fat, and lactose contents were found. While the proportions of total casein (CN), total whey proteins, αs1-CN, β-CN, and β-lactoglobulin were not affected by the milking frequency, milk from a OAD milking system contained higher proportions of αs2-CN and κ-CN and lower proportions of α-lactalbumin. These proteins also changed differently throughout the milking season in a OAD milking system than in a TAD milking system. These changes in the protein composition of the milk observed in a OAD milking system could have implications for its processing properties and product quality.

Association Between Genetic Polymorphism of Mutation (G5736A) in the BMP-15 Gene with Productive Performance of Local and Shami Goats

The study was conducted at the ruminant research station of the Agricultural Research Department / Ministry of Agriculture on a sample consisting of 44 local goats and 52 Shami goats, while the laboratory part was conducted in Scientific Progress Laboratory, for the period from 12/20/2021 to 9/1/2022. The nucleotide sequencing technique was used to detect mutations in The second exon region of the (BMP15) gene to determine the relationship of the resulting genotypes to economic traits (growth, milk production and litter size). The results showed that there are two genotypes, the wild (GG) and the hybrid (GA), as the percentage of individuals carrying the wild genotype was (90.91, 67.31) % compared to the hybrid individuals (9.09, 32.6) % respectively, in the local and Shami goat samples, and the allelic frequency of the wild allele G in both groupss was (0.95, 0.66)% compared to the mutant allele A (0.05, 0.34)%. for both groupss goats, the wild type individuals were superior in birth weight and did not show any significant effect of this mutation on the rest of the growth traits (19.03, 21.0) kg, as for the characteristics of milk production, the individuals carrying the wild genotype also excelled in the characteristic of total milk production in both groupss. (467.4, 490.4) kg compared to individuals carrying the hybrid genotype GG (422.1, 457.1) kg respectively, While no significant effect of the mentioned mutation appeared in litter size for both groups.

A study of the Relationship of Polymorphisms of the PPARGC1A Gene with Milk Production and its Components, in Holstein Friesian Cows

This research was done at a Molecular Genetics lab at the College of Agriculture at the University of Basrah. The objective of this study is to determine how Holstein Friesian cows’ PPARGC1A genetic polymorphism affects milk production and its constituent parts. For milk production and quality standards, 59 Holstein Friesian cows from Taj Al-Nahrain station in Al-Diwaniyah are employed. Blood was drawn for genomic DNA, and the PPARGC1A gene was amplified using PCR. The samples were then transferred to the Korean firm Macrogene for DNA sequencing analysis. Morning milk 50ml samples were collected once each week., and after taking the samples during the milking process, they were evaluated for quality using the Julie Z7 milk analyzer. Association analysis was performed using SPSS statistical software. According to the current study’s findings, the stage of milk production had a significant impact on both daily and total production (p ≤0.05). The results also shows that there is a significant differences (p≤0.05) of stage of milk production on the chemical composition of milk, while there are no significant differences between Genetic Polymorphisms in daily and total milk production. The results show that hap1 is superior on hap2 in the chemical contents of milk, except for the percentage of milk fat, which has not reach a significant level.

ПРОИЗВОДСТВО ТОВАРНОГО МОЛОКА И КОНКУРЕНТОСПОСОБНЫЕ КАЧЕСТВА МОЛОЧНОГО СЫРЬЯ В РЕСПУБЛИКЕ БАШКОРТОСТАН

The article considers the indicator of marketability of milk, which directly affects the formation of competitiveness of raw milk produced in the Republic of Bashkortostan, and raw materials for further export and production of dairy products. The factors and features influencing the indicator of the volume of commercial milk production in the Russian Federation and the analyzed region, the quality of milk are revealed. The volume of commercial milk production is the main key indicator of the development of dairy cattle breeding, since it is commercial (and not all raw) milk that is the resource base for the industrial production of dairy products and only commercial milk can be reliably accounted for. To date, in the republic, the share of commercial milk from the total milk yield is only 51%, with the average Russian indicator of 73.7%. Based on this, possible ways to solve the problem of increasing the volume of commercial milk production in the Republic of Bashkortostan, as well as the impact of modernization of production facilities, state subsidies and investments in the development of the industry are considered. Statistical information on the state of the dairy industry in the region is provided.

Lifetime dairy product consumption and breast cancer risk: a prospective cohort study by tumor subtypes

BackgroundPrevious literature on dairy products and risk of breast cancer is inconsistent, and the relationship may depend on the life-period of dietary assessment. ObjectiveWe examined dairy consumption from adolescence through later adulthood and incidence of breast cancer by menopausal status and tumor molecular subtypes in the Nurses’ Health Study (NHS), a prospective cohort study. MethodsWe analyzed data from 63,847 females in the NHS collected from 1980 to 2018. Average intake of dairy products during adulthood was assessed by validated semiquantitative food frequency questionnaires throughout follow-up. Participants recalled adolescent dietary intake in 1986. Multivariable Cox proportional hazards models were used to estimate hazard ratios (HRs) relating dairy product consumption to breast cancer risk overall, by menopausal status, and by subtypes. ResultsWe documented 5733 incident cases of invasive breast cancer during 32 y of follow-up (n = 5298 postmenopausal). Lifetime, adolescent, adulthood, and postmenopausal total dairy and milk intakes were not associated with overall breast cancer risk (nonsignificant HRs comparing highest with lowest quintile range = 0.97–1.08), although there was a suggestive positive association between adolescent milk intake and breast cancer risk (HR: 1.09; 95% CI: 1.00, 1.18). Higher lifetime and premenopausal cheese intakes were associated with modestly lower risks of breast cancer (comparing highest with lowest quintile, HR for lifetime cheese intake: 0.90; 95% CI: 0.82, 0.98; HR for premenopausal cheese intake: 0.89; 95% CI: 0.79, 1.00). Results varied by tumor subtype and some evidence for heterogeneity was observed for an association between premenopausal milk intake and breast cancer (HR for estrogen receptor [ER]-positive: 0.84; 95% CI: 0.72, 0.99; ER-negative: 1.36; 95% CI: 1.00, 1.84; P heterogeneity = 0.04). ConclusionsThese findings suggest that overall dairy consumption was not associated with risk of breast cancer. However, heterogeneity was observed for type of dairy food, period of life, and tumor subtypes.

Optimizing selection strategy for enhancing reproduction efficiency in Indian crossbred goats using milk productivity as a selection criterion.

The present study was aimed at optimizing the selection strategy for enhancing reproductive efficiency and milk productivity of Alpine × Beetal crossbred goats. The data set included 2949 milk trait records across parities and 1389 milk records from first parity and corresponding reproductive traits. The traits included for analysis were 150-day milk yield (150DMY), days in milk (DIM), peak yield (PY) and total milk yield (TMY). The litter size (LS) and litter weight (LW) were used for specifically formulating selection plan using indirect selection. The least squares mean for lactation traits during the first parity were 150DMY: 195.32 ± 2.09 kg, DIM: 236.42 ± 3.04 days, PY: 1.82 ± 0.02 kg, TMY: 269.62 ± 4.52 kg. Notably, Alpine × Beetal goats demonstrated genetic superiority pan India for milk productivity as compared to other native goat breeds. The least squares mean for 150DMY across all parities was 236 ± 3.13 kg. An animal model employing average information restricted maximum likelihood was used for (co)variance component estimation to get the genetic parameters. The analysis revealed total heritability estimates for 150DMY, DIM, PY and TMY as 0.18 ± 0.06, 0.04 ± 0.04, 0.12 ± 0.06 and 0.08 ± 0.05, respectively. Repeatability estimates for 150DMY, DIM, and TMY were 0.28 ± 0.04, 0.21 ± 0.03 and 0.37 ± 0.03, respectively. Bivariate analysis of 150DMY with reproductive traits revealed heritability for LS and LW as 0.05 ± 0.01 and 0.10 ± 0.01, respectively using Gibbs sampling. Strong and positive genetic correlations of 150DMY with other production and reproduction traits was observed, such as DIM (0.72), PY (0.98), TMY (0.88), LS (0.57) and LW (0.33). Moderate heritability and repeatability estimate of 150DMY, along with its positive correlation with production and reproductive traits suggested it as a suitable selection criterion for early selection and overall genetic progress of lactation traits. The genetic trend analysis showed an overall improvement in all these traits, with observed gain of 98.4 g per year for 150DMY, 0.04 days per year for DIM, 0.5 g per year for PY and 220.5 g per year for TMY. We observed that selecting based on 150DMY would lead to a favourable indirect improvement for LW as 79 g and LS 0.04 units per generation. We, therefore, recommend employing 150DMY as the single trait selection criteria to enhance both milk productivity and reproductive potential of Alpine × Beetal goats.

Optimization of dairy cows diets for crude protein

The influence of the composition of the diet on the productive indicators of cows, in particular on the chemical composition of milk, is analyzed. A reduction in the supply of succulent feed to 46.6% of the total energy nutrition and an increase in the proportion of concentrates (up to 53.4% of the exchange energy) for dairy cows were unacceptable. During the study, the level of milk productivity of black-andwhite cows increased very slightly – by 0.7 kg head /day. It is possible that in the first days of the change of the cow's diet, the total gross milk yield increases, but this period does not last long, and soon cows with acidosis and other metabolic disorders appear on the farm. The increase in the level of concentrated feed in the farm negatively affected the physico-chemical composition of milk, which became unsorted. A negative consequence of the change in the diet of cows was a deterioration in the quality of milk. Thus, the ratio of «fat – protein» has changed in the opposite direction, the urea content has increased (to 48.58–52.97 mg / 100 ml), the titrated acidity of milk has increased (to 19.49–21.04 °T) and the content of somatic cells in milk (to the level of 354.41–450.54 thousand / cm3) in cows of all lactations.

Strategy for Developing Dairy Farming for All-Business Cooperatives in Tandangsari, Sumedang Regency

The livestock sector has proven itself to be a crisis-resistant sector. The Ministry of Agriculture stated that the total national milk demand in 2019 reached 4,332.88 thousand tons. One of the dairy cattle center areas that has developed and become the focus of the Sumedang Regency Government is Tanjungsari District. The breeders joined the Tandangsari KSU. The supply and demand for pure milk has fluctuated at KSU Tandangsari in the last five years. The problems in the dairy cattle business at KSU Tanjungsari are currently related to production factors as inputs in the development of a dairy cattle business including livestock seeds, feed availability, land as living space for livestock, livestock production facilities (procurement of equipment and maintenance of livestock production), labor (breeders), as well as the cost of production.The goal of preparing the RIP is to formulate alternative strategies for developing a dairy cattle business. By identifying strengths and weaknesses, as well as opportunities and threats based on internal and external factors that affect the dairy cattle business at KSU Tandangsari.The strategy for developing a dairy cattle business is the S-O (1) strategy. Development of cattle population to increase production, (2). Building a place (factory) for processing dairy products, W-O strategy (1). Build a cow nursery, (2). Establishing cooperation with third parties in producing processed HPT, strategy S-T (1). Increasing the quality and quantity of beef cattle, (2). Moving the location of the fresh milk business activity center (MCU), W-T strategy (1). The application of appropriate technology is increased by breeders, (2). Establish cooperation with financial institutions in capital facilities.

The relationship between creamatocrit and cumulative percentage of total milk volume: a cross-sectional study in mothers of very preterm infants in Bangkok, Thailand

BackgroundHuman hindmilk contains higher concentrations of fat than foremilk and is more desirable for growth in preterm infants who can tolerate limited volumes of breastmilk. There is currently no clear demarcation between foremilk and hindmilk. This study characterized the change in breastmilk’s fat content from the start to end of milk flow and defined this demarcation.MethodsMothers of infants born at ≤ 32 weeks gestational age and ≥ 14 days after childbirth in a University hospital in Bangkok, Thailand between July, 2011, and April, 2012 were included in this cross-sectional study. Breastmilk samples were sequentially collected from the start to end of milk flow in 5-mL aliquots using breast pumps. The fat content of each aliquot from each breast was determined through creamatocrit. The average creamatocrit of foremilk and hindmilk were compared in predefined foremilk to hindmilk ratios of 20:80, 25:75, 33:67, and 50:50. Creamatocrit of the first and last aliquots were compared for mothers who expressed low- (≤ 25-mL per breast) and high-volumes (> 25-mL per breast) of breastmilk.ResultsOf the 25 mothers enrolled, one was excluded due to unsuccessful creamatocrit measurement. The last aliquot of breastmilk had a significantly higher creamatocrit than the first from the same breast (median [interquartile range] of 12.7% [8.9%, 15.3%] vs. 5.6% [4.3%, 7.7%]; test statistic 1128, p < 0.001). Mean creamatocrit in hindmilk portions (9.23%, 9.35%, 9.81%, and 10.62%, respectively) was significantly higher than foremilk portions (6.28%, 6.33%, 6.72%, and 7.17%, respectively) at all predefined ratios. Creamatocrit increased by 1% for every 10% incremental increase in expressed breastmilk volume until the breast was emptied. Low-volume mothers had a significantly higher creamatocrit in the first aliquot compared with high-volume mothers (U = 437, p = 0.002). No significant difference in breastmilk volume was observed between mothers with and without breastfeeding experience.ConclusionsFat content in breastmilk increased on an incremental basis. More fluid definitions of foremilk and hindmilk should be adopted. Mothers should prepare their breastmilk into aliquots based on the required feeding volume of their infant. Hindmilk aliquots can be prioritized over foremilk aliquots to ensure infants obtain optimal caloric intake.

DNA methylation of GDF-9 and GHR genes as epigenetic regulator of milk production in Egyptian Zaraibi goat

BackgroundDNA methylation is an epigenetic mechanism that takes place at gene promoters and a potent epigenetic marker to regulate gene expression.ObjectiveThe study aimed to improve the milk production of Zaraibi goats by addressing the methylation pattern of two milk production-related genes: the growth hormone receptor (GHR) and the growth differentiation factor-9 (GDF-9).Methods54 and 46 samples of low and high milk yield groups, respectively, were collected. Detection of methylation was assessed in two CpG islands in the GDF-9 promoter via methylation-specific primer assay (MSP) and in one CpG island across the GHR promoter using combined bisulfite restriction analysis (COBRA).ResultsA positive correlation between the methylation pattern of GDF-9 and GHR and their expression levels was reported. Breeding season was significantly effective on both peak milk yield (PMY) and total milk yield (TMY), where March reported a higher significant difference in PMY than November. Whereas single birth was highly significant on TMY than multiple births. The 3rd and 4th parities reported the highest significant difference in PMY, while the 4th parity was the most effective one on TMY.ConclusionThese results may help improve the farm animals' milk productive efficiency and develop prospective epigenetic markers to improve milk yield by epigenetic marker-assisted selection (eMAS) in goat breeding programs.

Combined mechanistic and genetic modelling to benchmark body reserve traits as proxies of dairy cows’ lifetime efficiency in grass-based production systems

Improving lifetime lactation efficiency of dairy cows by selection is difficult due to the complexity of this trait and the existence of genotype-by-environment interactions. This study aimed at assessing the relevance of traits derived from body reserves as lifetime efficiency indicators under contrasting nutritional environments. Given the absence of large-scale datasets covering a panel of feeding regimes, phenotypes were simulated for populations of 20 000 dairy cows using a mechanistic bioenergetic model. Ten phenotypes were computed for third-lactation cows. Analysed phenotypes comprised total milk production, lactation efficiency, BW at calving (BWcalv), DM intake (DMI) and interval between first insemination and conception. Five traits described levels and changes of body reserves at different periods during lactation. Lifetime lactation efficiency was computed for all cows (Life_Eff). Three nutritional environments were defined considering a grass-based production system with seasonal calving: a high non-limiting scenario (HS) mimicking ad libitum access to feed and two limiting environments with moderate (MS) and low (LS) feed offer. Variance components were estimated for all traits within and between environments using REML. Heritabilities estimated for milk production, lactation efficiency, BWcalv and DMI were moderate in the different environments (0.27–0.35 ± 0.04). The heritability of body reserve levels and dynamics were moderate in the HS and MS scenarios (0.23–0.30 ± 0.03) and lower in the LS scenario (0.14–0.25 ± 0.03). The heritability of Life_Eff was low in the HS environment (0.07 ± 0.01) and slightly increased in the limiting environments. All genetic correlations estimated between environments were moderate to high (≥0.66 ± 0.07), suggesting low to moderate genotype-by-environment interactions. Estimated genetic correlations were moderate between Life_Eff and body reserve levels (from 0.39 to 0.51 ± 0.08) and moderate but negative between Life_Eff and change in body reserves traits (−0.27 to −0.37 ± 0.09) in the HS environment. The genetic correlations between Life_Eff and body reserve levels increased to higher values in the limiting environments. In contrast, genetic correlations between Life_Eff and the changes in body reserves were closer to zero. In conclusion, this study showed that body reserve levels were relevant proxies of lifetime irrespective of the environment. In contrast, changes in body reserves that reflected energy mobilisation in early lactation were less informative about lifetime efficiency in environments with severe feed restrictions.

Genetic relationships between reproductive and production traits in Jersey crossbred cattle

The study aimed to estimate the genetic parameters of different reproductive traits namely age at first calving (AFC), calving interval (CI), days open (DO) and number of service per conception (NSPC) and their associations with productive traits including 305-day milk yield (305DMY), total lactation milk yield (TLMY) and lactation length (LL) of Jersey crossbred cattle maintained at Kalyani, Nadia, West Bengal, India. Genetic parameters of reproductive traits and their correlations with productive traits were estimated by Restricted Maximum Likelihood method and Bayesian approach. Using both analytical approaches, the estimates of heritability for AFC, CI, DO and NSPC ranged from 0.12 −0.15, 0.05–0.08, 0.08–0.09 and 0.04–0.06, respectively. Low proportion of variances associated with permanent environmental effect of animals (c2 effect) were detected for CI (0.08–0.10), DO (0.09–0.11) and NSPC (0.05–0.06) in both the methods. Repeatability measures for all the reproductive traits considered in this study were low to moderate in nature, which ranged from 0.09 to 0.17. Genetic correlations between different reproductive traits were positive and low (0.05) to high (0.98) in magnitude except AFC-NSPC. Low and negative genetic correlations of AFC with 305DMY and TLMY were favourable and indicated animals with high milk yield had early age of maturity. Positive genetic correlations between CI, DO and NSPC with all production traits implied the antagonism relationships among these traits, therefore in any breeding program for improvement of production traits via selection, the reproductive traits should be taken into account as well.

PSX-22 Effects Of Milk Replacer Supplementation with Beta-Glucans on Male Dairy Calf Performance

Abstract The objective of this randomized controlled trial was to determine the performance effects of milk replacer supplemented with a feed additive high in beta-glucans for male dairy calves. Holstein male calves (n = 147) were enrolled in a 76-day randomized block trial in two blocks. Upon enrollment, calves were assigned to one of the four following treatments: Control with no beta-glucan supplementation (BG0; n = 36; BW = 48.32 ± 3.73 kg), 1 g· animal-1· d-1 (BG1; n = 38; BW = 48.29 ± 2.89kg), 3 g· animal-1· d-1 (BG3; n = 37; BW = 48.31 ± 3.23 kg), and 5 g· animal-1· d-1 (BG5; n = 36; BW = 48.47 ± 3.00 kg) of beta-glucans. The beta-glucan supplement was blended with milk replacer (24% CP, 20% fat; 130 g/L) and fed to calves during the morning milking. Calves were individually housed, had unlimited access to water, and a pelletized calf starter (20% CP). Calves were fed 5 L/d of milk replacer divided into two equal meals until d 15; milk feeding plan increased until d 35 (8 L/d), on d 36, milk allowance was gradually reduced until weaned on d 56 (2.5 L/d). Calf starter intake and body weight were recorded weekly until d 77. Disease treatment was recorded daily. A mixed linear model determined the effect of treatment on calf starter intake and average daily gain. The model included treatment if the calf was ever treated with antibiotics for respiratory disease and/or diarrhea, study period, and a treatment by period interaction. Block was considered a random factor. The total milk replacer intake was 5.73 ± 0.08, 5.71 ± 0.08, 5.73 ± 0.01, 5.73 ± 0.01 L/d for BG0, BG1, BG3 and BG5, respectively. Calf grain intake by treatment was 58.10 ± 12.02, 54.58 ± 8.11, 56.86 ± 11.8, 56.73 ± 15.52 for BG0, BG1, BG3 and BG5, respectively. Overall, 55% and 71% of all calves were treated at least once for diarrhea, and respiratory disease respectively. The percentage of animals treated for diarrhea by treatment were 45.00, 57.50, 50.00, and 32.50% for BG0, BG1, BG3, and BG5, respectively. For respiratory disease, the percentage of animals treated was 72.5, 72.5, 70.0, and 70.00 for BG0, BG1, BG3, and BG5 treatments, respectively. There was a significant interaction between treatment and study period where the control group had greater starter intake during the postweaning period (BG0 = 0.78 ± 0.01, BG1= 0.82 ± 0.01, BG3 = 0.81 ± 0.02, BG5 = 0.82± 0.01 kg/d; P &amp;lt; 0 .001). No treatment or treatment by study period effects was observed for average daily gain (P = 0.79, P = 0.89, respectively). Future research should investigate the effects of beta-glucans on blood metabolites and palatability throughout the calf-rearing period.

Selection of dairy goats using milk recording and multivariate analysis in a family farming system

Although dairy control is a widely used tool in herds with numerous animals (mainly cows), it is often neglected in small farms. The aim of the present work was to select the most suitable animals for milk production using dairy control and multivariate statistics. Results indicate a great dispersion of the data as a consequence of milk production variation from each goat. These results demonstrate the need to identify and select the most productive animals in order to have a selected and controlled flock. The analysis of hierarchical conglomerates showed that the herd can be divided into three groups: Cluster 1 is integrated by 31 goats with the highest productive parameters, above the herd average and together produce 59.1% of the accumulative milk yield; Cluster 2 consists of 24 animals whose production parameters are close to the current average of the herd and accumulates 27.7% of milk production and Cluster 3 groups animals with the lowest production. From the results obtained, it was possible to make the selection of the 55 most productive animals for milk production. This represents 64.70% of the herd and they are responsible for 86.8% of the total milk production.