Management-related factors in dry cows and their associations with colostrum quantity and quality on a large commercial dairy farm

The objective of this observational study was to evaluate the association of management-related factors in dry cows and colostrum quantity and quality in Holstein cows on a large commercial dairy farm. This study was conducted from January 2018 to December 2020 on a commercial dairy farm in Germany, milking approximately 2,500 Holstein cows. Dairy personnel recorded colostrum quantity (n = 7,562) and evaluated colostrum quality in a subsample of animals (n = 2,600) using a digital Brix refractometer. Generalized linear mixed models were constructed to evaluate the association of management-related factors and colostrum quantity and quality. Models were run separately for primiparous or multiparous cows. The outcome variable was either colostrum quantity (kg) or quality (% Brix). Average colostrum quantity was 4.0 ± 2.5 kg, 5.1 ± 3.4 kg, and 5.5 ± 3.5 kg for cows in lactation 1, 2, and ≥3, respectively. In primiparous cows (n = 2,351), colostrum quantity was affected by month of calving (greatest in April = 4.1 kg, and lowest in November = 3.2 kg), sex of the calf (female singleton = 3.50 ± 0.26 kg; male singleton = 3.76 ± 0.27 kg; twins = 2.97 ± 0.66 kg), stillbirth (stillbirth = 3.14 ± 0.39 kg; no stillbirth = 3.68 ± 0.31 kg). In multiparous cows (n = 5,216), colostrum quantity was affected by month of calving (greatest in May = 5.5 kg, and lowest in October = 3.8 kg), calving ease (calving ease 0 = 4.23 ± 0.26 kg; score 1 = 4.77 ± 0.21 kg; score 2 = 4.98 ± 0.22 kg; score 3 = 5.30 ± 0.22 kg), sex of the calf (female singleton = 4.42 ± 0.21 kg; male singleton = 5.00 ± 0.21 kg; twins = 5.03 ± 0.30 kg), stillbirth (stillbirth = 4.24 ± 0.38 kg; no stillbirth = 5.39 ± 0.11 kg), milk yield in previous lactation (+0.1 kg increase for 1,000 kg more milk yield in previous lactation), days spent in the far-off group (0.05 ± 0.003 kg for every day), and days in the close-up pen (0.06 ± 0.010 kg for every day). Average colostrum quality was 25.1 ± 3.4% Brix, 24.7 ± 3.3% Brix, and 27.6 ± 4.4% Brix for cows in lactation 1, 2, and ≥3, respectively. In primiparous cows (n = 817), colostrum quality was affected only by month of calving. Colostrum quality in primiparous cows was greatest in December (26.8% Brix) and lowest in August (23.9% Brix). In multiparous cows (n = 1,783), colostrum quality was affected by parity (lactation 2 = 25.2 ± 2.7% Brix; lactation 3+ = 27.9 ± 2.7% Brix), month of calving (greatest in February = 27.5% Brix, and lowest in August = 25.7% Brix), milk yield in previous lactation, and colostrum quantity. We observed a seasonal pattern for colostrum quantity and quality. Future intervention studies using multiple farms need to elucidate whether management of the photoperiod or length of exposure to close-up diets, or both, can help to optimize colostrum production.

Evaluation of 2 different treatment procedures after calving to improve harvesting of high-quantity and high-quality colostrum

The objective of this study was to evaluate 2 different treatment procedures at the first milking after calving to increase colostrum quantity and to improve colostrum quality in dairy cows. We hypothesized that either exogenous treatment with oxytocin or the presence of the calf at first milking would lead to higher colostrum quantity and higher IgG concentration. The study was conducted from October to December 2017 on a commercial dairy farm in Germany. A total of 567 cows at the time of calving were enrolled, but for the final analyses only 521 animals were considered. The cows were randomly assigned on a daily basis into 1 of 3 groups: (1) control group (n = 177), (2) application of 20 IU of oxytocin i.m. (OXY; n = 163), and (3) presence of the calf (CA; n = 181) before and during milking. Cows in the control and oxytocin group had no contact with their calves after calving and were milked in a separate milking parlor. Cows in the oxytocin group were injected with 20 IU of oxytocin i.m. 3 min before manual stimulation. For cows in the third group, the calf was placed into a calf cart and located in front of the cow 3 min before manipulation of the cow. Colostrum quantity was determined by a digital hanging scale. The colostrum quality was assessed with digital Brix refractometry and ELISA. To evaluate the effect of 2 different treatment procedures, a generalized linear mixed model was constructed using SPSS (SPSS Inc., IBM, Ehningen, Germany). The mean (±SE) colostrum quantity was 4.17 ± 0.30 kg. The treatment procedures and the harvesting time after calving had no effect on colostrum quantity. Parity, calf birth weight, and calving time affected colostrum quantity. Cows in second parity had the lowest quantity of colostrum (3.74 ± 0.37 kg) compared with cows in parity 1 (4.75 ± 0.34 kg) and cows in parity 3 or greater (4.75 ± 0.38 kg). Cows calving during the night (2200 until 0600 h; 4.93 ± 0.37 kg) had the highest quantity of colostrum compared with cows calving in the morning (0600 until 1400 h; 4.17 ± 0.38 kg) or afternoon (1400 until 2200 h; 4.14 ± 0.34 kg). Regarding colostrum quality, 48% of the colostrum samples contained ≥50 mg of IgG/mL. The mean IgG concentration was 54.6 ± 2.80 mg of IgG/mL. Colostrum quality was affected by the treatment procedures, colostrum quantity, parity, calving time, harvesting time after calving, and the calving day during the week. Both treatment procedures (i.e., OXY with mean IgG concentration results of 57.0 mg of IgG/mL and CA with 56.0 mg of IgG/mL) resulted in higher IgG concentrations in colostrum compared with the control group (50.7 mg of IgG/mL). With increasing colostrum quantity, the colostrum quality decreased in primiparous and multiparous cows. A longer time lag between calving and milking negatively affected the colostrum quality. Concentration of IgG was higher for cows in parity 3 or greater (64.6 ± 2.59 mg of IgG/mL) compared with cows in parity 1 (48.5 ± 2.86 mg of IgG/mL) and cows in parity 2 (50.7 ± 2.89 mg of IgG/mL). Cows calving during the night had greater IgG concentrations (60.4 ± 2.92 mg of IgG/mL) compared with cows calving in the morning (51.9 ± 2.98 mg of IgG/mL) or afternoon (51.3 ± 2.71 mg of IgG/mL). Harvesting colostrum on quieter days, such as Sundays, resulted in higher IgG concentrations (61.4 ± 3.70 mg of IgG/mL). The assessment by Brix refractometry resulted in a mean result of 26.0 ± 0.20% Brix. Treatment procedures and the harvesting time after calving had no effect on colostrum quality. A negative association was observed between colostrum quantity and quality in primiparous and multiparous cows determined by Brix refractometry. Brix readings were greater for cows in parity 3 or higher (27.7 ± 0.26% Brix) compared with cows in parity 1 (25.3 ± 0.30% Brix) and cows in parity 2 (25.0 ± 0.32% Brix). In conclusion, the treatment procedure for the first milking is irrelevant to improve the quantity of colostrum. Both treatment procedures, however, increased IgG concentrations as determined by ELISA.

Short communication: Effect of barn climate and management-related factors on bovine colostrum quality

Several factors have been reported to influence colostrum quality (immunoglobulin concentration). To date, knowledge of the influence of climatic factors in association with other potential influencing factors on colostrum quality is scarce. Associated influential factors are parity, body condition score, length of dry period, ration fed ante partum (AP), β-hydroxybutyrate postpartum (PP), milk yield, milk fat and protein, as well as somatic cell counts from previous and current lactation. The objective of the present study was to examine the effect of barn climate and the aforementioned factors on colostrum quality. Data were collected from 1,381 multiparous Holstein Friesian cows kept on one dairy farm over a period of one year (August 2014 to August 2015). Colostrum was harvested on farm within 1 h PP. The quantity and quality of first colostrum (estimated by Brix refractometry) were recorded for each cow. Additional data recorded were parity, body condition score at drying off, length of dry period, ration fed AP, milk yield data from previous and current lactation, milk somatic cell counts, and β-hydroxybutyrate PP. During the study period, temperature and humidity were recorded in the barn every hour, and temperature-humidity-index (THI) was calculated. Linear regression was performed with colostrum quality as the dependent variable. In the final model, colostrum quantity (L), length of dry period, parity, and climatic factors (specifically, median humidity in the 3rd week AP and hours with THI ≥72 in the last 14 and 21 d AP, respectively) were significant. Colostrum quality improved with parity and length of dry period and decreased with colostrum quantity, humidity, and hours with a THI ≥72. A classification and regression tree analysis revealed that colostrum quantity was the most important factor in this model [normalized importance (NI) 100%]. Parity (NI 42.7%), length of dry period (NI 37.1%), and climatic factors (NI 0.4 to 1.9%) followed with decreasing importance. These results indicate that the most important factors for colostrum quality (i.e., colostrum quantity and parity) may not be influenced by management. The 2 factors that can be influenced by management [i.e., length of dry period and THI (e.g., by cooling)], were quantitatively of minor importance compared with the other 2 factors. Further studies are necessary to determine whether changing these factors can improve colostrum quality significantly.

Rapid Communication: Genome-wide association analyses identify loci associated with colostrum production in Jersey cattle1

Consumption of an adequate volume of high-quality colostrum soon after birth is critical for a calf's health. Few studies have focused on the genetics associated with colostrum production, even though several dairy herds in the United States have reported incidents of low to no colostrum production during the fall and winter seasons. The objectives of this study were to identify loci associated with quantity and quality of colostrum production in a herd of Jersey cattle (n = 345) and to identify potential positional candidate genes and/or transcription factor binding site motifs located near associated loci. Cattle that freshened between the months of October and December of 2016 at a single dairy were enrolled in the study and produced on average 3.03 kg of colostrum at their first milking. This study included 112 cattle genotyped with the GeneSeek GGP50k BeadChip and another 233 cattle previously genotyped with various other arrays. The 233 cattle genotyped at lower densities were imputed to the GGP50k BeadChip density using BEAGLE 4.1.1, and 2 genome-wide association analyses (GWAA) were conducted using an additive efficient mixed-model association expedited method with a genomic relationship matrix (EMMAX-GRM). The first GWAA investigated loci associated with colostrum quantity and identified 7 loci: 6 that were moderately associated (5 × 10-07 > P < 1 × 10-05) and 1 that was strongly associated (P < 5 × 10-07). The second GWAA investigated colostrum quality and identified 1 moderately (5 × 10-07 > P < 1 × 10-05) associated locus. Five loci harbored positional candidate genes which had functional relevance to colostrum production, and 1 locus located on BTA10 contained a transcription factor binding site motif for TFAP2A which has previously been linked to mammary gland development. Pseudoheritability estimates were moderate for colostrum quality (0.19 ± 0.06) and high for colostrum quantity (0.76 ± 0.11), suggesting that genomic selection for these traits would be possible. Diminished colostrum quantity or quality can have a significant impact on herd health and herd economics. The identification of loci, positional candidate genes, and transcription factor binding site motifs associated with colostrum production could be used in genomic selection to allow producers to select for cattle with good colostrum production, improving calf health, and reducing economic losses to the herd.