Metabolic and productive parameters of lactating dairy cows under heat stress conditions supplemented with plant polyphenol extract.

The impact of heat stress on dairy cattle leads to significant economic losses and a negative impact on the welfare of the animals. The objective of this research was to evaluate the effect of the nutritional additive (Thermoplus®) in dairy cows under postpartum heat stress conditions, and its effects on the metabolic profile, production and quality of milk. Eighteen lactating Holstein cows (8 multiparous and ten primiparous), in a free-stall system, with a mean body condition score (BCS) of 3.14 ± 0.05, live weight of 624.55 ± 18, 61 kg, with initial mean days in milk (DIM) of 90 ± 10.11, were selected. The animals were grouped into a control (CG, n = 9) and a treatment (TG, n = 9). Both groups underwent 14 days of diet adaptation, the TG received the basal diet supplemented with 50 g of the additive, once a day, individually, while the control group received only the total diet. Data collection of metabolic and productive parameters were evaluated on days -14 (before adaptation), 1 (after the diet adaptation period), 16, 30, and 44. Milk, blood, and body condition score (BCS) were collected once a day, and heart rate, respiratory rate, and rectal temperature were collected twice a day. Serum concentrations of albumin, calcium, magnesium, glucose, gamma-glutamyl transferase (GGT), beta-hydroxybutyrate (BHBA), non-esterified fatty acids (NEFAs), and paraoxonase-1 (PON-1) were evaluated. In the milk, the percentage of fat, protein, lactose, and total solids were determined in each sampling. Milk yield was measured daily. Humidity and ambient temperature values were collected on the days of the collection every 30 min, from 5:30 am to 5:00 pm, to calculate the temperature-humidity index (THI). Statistical analyzes were performed using the SAS software (version 9.3, SAS Institute Inc., Cary, NC, USA). The THI ranged from 62.22 to 79.47. Our findings showed that when the THI was greater than 72, the animals in the TG were able to maintain milk yield (Odds ratio (OD) = -0.0577,), and the animals in the CG had a greater chance of reducing it (OD = -0.2301). Multiparous cows in the TG had higher milk yield than CG (32.57 ± 0.34 vs 30.50 ± 0.36 kg per day; P = 0.0078) and lower SCC (34.110 ± 6,940 vs 665.50 ± 214.41 cells per ml; P = 0.03), with the same percentages of total solids (P > 0.05). In multiparous metabolic markers, TG when compared CG had higher albumin concentrations (2.50 ± 0.07 vs 2.12 ± 0.07 g/dl; < 0.001), equal PON-1 (P > 0.05), and higher BHBA levels (0.49 ± 0.03 vs 0.39 ± 0.04 mmol/l). Primiparous from the CG had higher concentrations of NEFA (0.18 ± 0.02 mmol/l) than multiparous from the same group (0.09 ± 0.02 mmol/l) P = 0.0265. The use of the plant polyphenol extract in postpartum Holstein cows challenged by heat stress had beneficial effects on the production and health of the mammary gland in multiparous cows without decreasing milk solids. The non-reduction of the activities of the acute phase proteins indicates an immunomodulatory and inflammatory-reducing effect of the product used.

Contribution of genetic variability to phenotypic differences in on-farm efficiency metrics of dairy cows based on body weight and milk solids yield.

Milk solids per kilogram of body weight (BW) is growing in popularity as a measure of dairy cow lactation efficiency. Little is known on the extent of genetic variability that exist in this trait but also the direction and strength of genetic correlations with other performance traits. Such genetic correlations are important to know if producers are to consider actively selecting cows excelling in milk solids per kilogram of BW. The objective of the present study was to use a large data set of commercial Irish dairy cows to quantify the extent of genetic variability in milk solids per kilogram of BW and related traits but also their genetic and phenotypic inter-relationships. Mid-lactation BW and body condition score (BCS), along with 305-d milk solids yield (i.e., fat plus protein yield) were available on 12,413 lactations from 11,062 cows in 85 different commercial dairy herds. (Co)variance components were estimated using repeatability animal linear mixed models. The genetic correlation between milk solids and body weight was only 0.05, which when coupled with the observed large genetic variability in both traits, indicate massive potential to select for both traits in opposite directions. The genetic correlations between both milk solids and BW with BCS; however, need to be considered in any breeding strategy. The genetic standard deviation, heritability, and repeatability of milk solids per kilogram of BW was 0.08, 0.37, and 0.57, respectively. The genetic correlation between milk solids per kilogram of BW with milk solids, BW, and BCS was 0.62, -0.75, and -0.41, respectively. Therefore, based on genetic regression, each increase of 0.10 units in genetic merit for milk solids per kilogram of BW is expected to result in, on average, an increase in 16.1 kg 305-d milk solids yield, a reduction of 25.6 kg of BW and a reduction of 0.05 BCS units (scale of 1-5 where 1 is emaciated). The genetic standard deviation (heritability) for 305-d milk solids yield adjusted phenotypically to a common BW was 27.3 kg (0.22). The genetic correlation between this adjusted milk solids trait with milk solids, BW, and BCS was 0.91, -0.12, and -0.26, respectively. Once also adjusted phenotypically to a common BCS, the genetic standard deviation (heritability) for milk solids adjusted phenotypically to a common BW was 26.8 kg (0.22) where the genetic correlation with milk solids, BW and BCS was 0.91, -0.21, and -0.07, respectively. The genetic standard deviation (heritability) of BW adjusted phenotypically for differences in milk solids was 35.3 kg (0.61), which reduced to 33.2 kg when also phenotypically adjusted for differences in BCS. Results suggest considerable opportunity exists to change milk solids yield independent of BW, and vice versa. The opportunity is reduced slightly once also corrected for differences in BCS. Inter-animal BCS differences should be considered if selection on such metrics is contemplated.

Milk production of Holstein-Friesian cows of divergent Economic Breeding Index evaluated under seasonal pasture-based management.

The objective of this study was to validate the effect of genetic improvement using the Irish genetic merit index, the Economic Breeding Index (EBI), on total lactation performance and lactation profiles for milk yield, milk solids yield (fat plus protein; kg), and milk fat, protein, and lactose content within 3 pasture-based feeding treatments (FT) and to investigate whether an interaction exists between genetic group (GG) of Holstein-Friesian and pasture-based FT. The 2 GG were (1) extremely high EBI representative of the top 5% nationally (referred to as the elite group) and (2) representative of the national average EBI (referred to as the NA group). Cows from each GG were randomly allocated each year to 1 of 3 pasture-based FT: control, lower grass allowance, and high concentrate. The effects of GG, FT, year, parity, and the interaction between GG and FT adjusted for calving day of year on milk and milk solids (fat plus protein; kg) production across lactation were studied using mixed models. Cow was nested within GG to account for repeated cow records across years. The overall and stage of lactation-specific responses to concentrate supplementation (high concentrate vs. control) and reduced pasture allowance (lower grass allowance vs. control) were tested. Profiles of daily milk yield, milk solids yield, and milk fat, protein, and lactose content for each week of lactation for the elite and NA groups within each FT and for each parity group within the elite and NA groups were generated. Phenotypic performance was regressed against individual cow genetic potential based on predicted transmitting ability. The NA cows produced the highest milk yield. Milk fat and protein content was higher for the elite group and consequently yield of solids-corrected milk was similar, whereas yield of milk solids tended to be higher for the elite group compared with the NA group. Milk lactose content did not differ between GG. Responses to concentrate supplementation or reduced pasture allowance did not differ between GG. Milk production profiles illustrated that elite cows maintained higher production but with lower persistency than NA cows. Regression of phenotypic performance against predicted transmitting ability illustrated that performance was broadly in line with expectation. The results illustrate that the superiority of high-EBI cattle is consistent across diverse pasture-based FT. The results also highlight the success of the EBI to deliver production performance in line with the national breeding objective: lower milk volume with higher fat and protein content.

Evaluation of genotype by environment interactions on milk production traits of Holstein cows in southern Brazil.

OBJECTIVE: This study assessed the possible existence of genotype by environment interactions for milk, fat and protein yields in Holstein cattle raised in one of the most important milk production basins in Brazil. METHODS: Changes in the genetic parameters and breeding values were evaluated for 57,967 animals from three distinct regions of southern Brazil, divided according to differences in climate. The genotype by environment interaction was determined by genetic correlations between regions, estimated by the restricted maximum likelihood, considering the animal model. Bull rankings were investigated to verify the ratio of coincident selected animals between regions for each trait. RESULTS: The estimates of heritability coefficients were similar between two regions, but were lower in the third evaluated area, for all traits. Genetic correlations between regions were high, ranging from 0.91 to 0.99 for milk, fat and protein yields, representing the absence of a genotype by environment interaction for productive traits. The percentage of selection error between regions for the top 10% of animals ranged from 0.88% to 2.07% for milk yield, 0.99% to 2.46% for fat yield and 0.59% to 3.15% for protein yield. CONCLUSION: A slight change in genotype between areas was expected since no significant genotype by environment interactions were identified, facilitating the process of selecting Holstein cattle in southern Brazil.

Effect of culture levels, ultrafiltered retentate addition, total solid levels and heat treatments on quality improvement of buffalo milk plain set yoghurt.

Studied the effect of culture (2, 2.5 and 3%), ultrafiltered (UF) retentate addition (0, 11, 18%), total milk solids (13, 13.50, 14%) and heat treatments (80 and 85 °C/30 min) on the change in pH and titratable acidity (TA), sensory scores and rheological parameters of yoghurt. With 3% culture levels, the required TA (0.90% LA) was achieved in minimum 6 h incubation. With an increase in UF retentate addition, there was observed a highly significant decrease in overall acceptability, body and texture and colour and appearance scores, but there was highly significant increase in rheological parameters of yoghurt samples. Yoghurt made from even 13.75% total solids containing nil UF retentate was observed to be sufficiently firm by the sensory panel. Most of the sensory attributes of yoghurt made with 13.50% total solids were significantly better than yoghurt prepared with either 13 or 14% total solids. Standardised milk heated to 85 °C/30 min resulted in significantly better overall acceptability in yoghurt. Overall acceptability of optimised yoghurt was significantly better than a branded market sample. UF retentate addition adversely affected yoghurt quality, whereas optimization of culture levels, totals milk solids and others process parameters noticeably improved the quality of plain set yoghurt with a shelf life of 15 days at 4 °C.

The prevalence, temporal and spatial trends in bulk tank equivalent milk fat depression in Irish milk recorded herds.

BACKGROUND: Milk fat is important in terms of economic value and in its potential to provide information concerning cow diet and health. Under current milk payment schemes in Ireland farmer income is directly linked to milk fat production. METHODS: A descriptive analysis of milk fat depression (MFD) as calculated from test day milk recording data across all milk recording herds from 2004 to 2014 was undertaken. A dataset of 17 million test day records was used to calculate the prevalence of MFD in Irish milk recorded herds and to create a graphical description of the major descriptive epidemiological trends in milk fat depression in time and space in Ireland. The bulk tank equivalent (BTE) for test day milk fat was calculated for each herd and for cohorts of cows within herds using the formula; BTE milk fat = sum test day fat kg/sum test day milk kg. Milk fat depression was defined as BTE <3.3% milk fat and BTE > 3.2% milk protein. RESULTS: The annual prevalence of MFD decreased significantly over time in a linear manner until 2014. Across all years the highest prevalence of MFD occurred in April or May. The highest prevalence occurred most commonly in May, with 9.1% of herds experiencing MFD in 2014. The highest prevalence of MFD in autumn calved cohorts occurred at 181-210 days in milk whereas it occurred at days 61-90 in milk in spring calving cohorts. The stage of lactation for the most common occurrence of MFD in both the spring and autumn cohorts corresponded with the month of May. There were some notable spatial patterns regarding variations in prevalence of MFD across the country. Cohorts of cows with the highest genetic values for milk yield had the highest prevalence of MFD whereas cohorts of cows with the highest breeding values for milk fat percent had the lowest prevalence of MFD. CONCLUSIONS: A subpopulation of Irish herds experienced the condition of MFD. Descriptive analysis suggested spatial, temporal and animal level associations. This condition warrants further investigation.

Milk production and enteric methane emissions by dairy cows grazing fertilized perennial ryegrass pasture with or without inclusion of white clover.

An experiment was undertaken to investigate the effect of white clover inclusion in grass swards (GWc) compared with grass-only (GO) swards receiving high nitrogen fertilization and subjected to frequent and tight grazing on herbage and dairy cow productivity and enteric methane (CH4) emissions. Thirty cows were allocated to graze either a GO or GWc sward (n=15) from April 17 to October 31, 2011. Fresh herbage [16 kg of dry matter (DM)/cow] and 1 kg of concentrate/cow were offered daily. Herbage DM intake (DMI) was estimated on 3 occasions (May, July, and September) during which 17 kg of DM/cow per day was offered (and concentrate supplementation was withdrawn). In September, an additional 5 cows were added to each sward treatment (n=20) and individual CH4 emissions were estimated using the sulfur hexafluoride (SF6) technique. Annual clover proportion (± SE) in the GWc swards was 0.20 ± 0.011. Swards had similar pregrazing herbage mass (1,800 ± 96 kg of DM/ha) and herbage production (13,110 ± 80 kg of DM/ha). The GWc swards tended to have lower DM and NDF contents but greater CP content than GO swards, but only significant differences were observed in the last part of the grazing season. Cows had similar milk and milk solids yields (19.4 ± 0.59 and 1.49 ± 0.049 kg/d, respectively) and similar milk composition. Cows also had similar DMI in the 3 measurement periods (16.0 ± 0.70 kg DM/cow per d). Similar sward and animal performance was observed during the CH4 estimation period, but GWc swards had 7.4% less NDF than GO swards. Cows had similar daily and per-unit-of-output CH4 emissions (357.1 ± 13.6g of CH4/cow per day, 26.3 ± 1.14 g of CH4/kg of milk, and 312.3 ± 11.5 g of CH4/kg of milk solids) but cows grazing GWc swards had 11.9% lower CH4 emissions per unit of feed intake than cows grazing GO swards due to the numerically lower CH4 per cow per day and a tendency for the GWc cows to have greater DMI compared with the GO cows. As a conclusion, under the conditions of this study, sward clover content in the GWc swards was not sufficient to improve overall sward herbage production and quality, or dairy cow productivity. Although GWc cows had a tendency to consume more and emitted less CH4 per unit of feed intake than GO cows, no difference was observed in daily or per-unit-of-output CH4 emissions.

Heat penetration characteristics and physico-chemical properties of in-pouch processed dairy dessert (kheer).

Kheer, a traditional milk product of South East Asia, containing cooked rice grains in a creamy sweetened concentrated milk, has no large-scale production due to its poor shelf life. Shelf-life was improved by development of a process based on in-pouch thermal processing employing a rotary retort. Product development included optimization of rice-to-milk solids ratio (0.18-0.52) and total milk solids levels (16-26 %) to simulate the conventional product in taste, appearance and textural attributes. Various Fo values (12.4-14.8) were examined with regard to product quality. While the TBA value tended to increase (0.073-0.081) the reflectance value (35.3-43.4) declined with increasing Fo. The pH of the product (6.04-6.10) showed a slight tendency to increase with Fo. Sensorily, the product was found to be acceptable for a period of 150 days at 37 °C.

Suplementação de vacas leiteiras com homeopatia: desempenho e digestibilidade / Supplementation of dairy cows with homeopathy: performance and digestibility

Avaliou-se o efeito da suplementação de uma combinação homeopática sobre o desempenho e a digestibilidade de nutrientes em vacas leiteiras. Trinta e duas vacas Holandesas foram blocadas em pares e aleatoriamente alocadas a um de dois tratamentos por 63 dias, posterior a um período de padronização de 14 dias. Variáveis mensuradas no final da padronização ajustaram medidas semanais da mesma variável no modelo de análise estatística. Os tratamentos foram: Suplementação diária com 150 gramas de uma combinação homeopática (Hypothalamus, 10-30; Colibacilinum, 10-30; Streptococus Beta Hemolyticum, 10-60; Streptococus Uberis, 10-60; Phytolacca, 10-60; Calcium Phosphoricum, 10-30; Natrum Muriaticum, 10-60; Urtica Urens, 10-30; Silicea Terra, 10-400) em veículo mineral, ou 150 gramas do mesmo veículo mineral (controle). A suplementação com homeopatia aumentou o teor de proteína no leite de 3,09 para 3,19 por cento (P=0,01) e tendeu a aumentar a secreção diária de proteína de 0,737 para 0,776kg (P=0,10). A queda na digestibilidade da fibra e da matéria orgânica (P=0,10), e a similaridade na relação entre alantoína e creatinina na urina (P=0,32), sugerem que houve aumento na eficiência de síntese de proteína microbiana no rúmen. Apesar de o mecanismo não ter sido elucidado, a combinação homeopática aumentou o teor de proteína do leite.

The effect of supplementing a homeopathic combination on dairy cow performance and nutrient digestibility was evaluated. Thirty-two Holstein cows were paired blocked and randomly assigned to one of two treatments for 63 days, following a 14-day standardization period. Variables measured at the end of the standardization period adjusted weekly measurements of the same variable in the statistical analysis model. Treatments were: Daily supplementation of 150 grams of a homeopathic combination (Hypothalamus, 10-30; Colibacilinum, 10-30; Streptococcus Beta Hemolyticum, 10-60, Streptococcus Uberis, 10-60; Phytolacca, 10-60; Calcium Phosphoricum, 10-30; Natrum Muriaticum, 10-60; Urtica Urens, 10-30, Silicea Terra, 10-400) in mineral vehicle, or 150 grams of the same mineral vehicle (Control). Supplementation with homeopathy increased milk protein content from 3.09 to 3.19 percent (P=0.01) and tended to increase the daily secretion of protein from 0.737 to 0.776kg (P=0.10). The trend for decreased fiber and organic matter digestibilities (P=0.10), and the similar allantoin to creatinine ratio in urine (P=0.32), suggests that there was an increase in the efficiency of microbial protein synthesis in the rumen. Although the mechanism could not be elucidated, the homeopathic combination increased milk protein content.