First Month Of Lactation Research Articles

Blood and milk immune and inflammatory profiles in periparturient dairy cows showing a different liver activity index

This paper reports the results of a study that aimed to assess whether liver functionality defined by liver activity index (LAI) is associated with inflammatory and immune parameters in blood and milk. LAI is an index including the average blood levels of albumin, lipoproteins and retinol-binding protein measured three times in the first month of lactation (at 5, 15 and 30 days in milk). The aim was to assess the relationship of this index with blood and udder immune and inflammatory status as a means of identifying as early as possible cows at risk of disease. The research was carried out using 10 multiparous Italian-Friesian dairy cows of average genetic merit. Cows were retrospectively ranked in three groups according the LAI level. Blood samplings were performed at different intervals before and after calving; quarter milk samples were taken only after calving with the same schedule as blood samples. Leucocytes, oxidative burst, blood lysozyme and N-acetyl-beta-d-glucosaminidase (NAGase) curves showed large overlapping among the three LAI group curves during the follow-up period. Four blood (complement, sialic acid, haptoglobin and reactive oxygen metabolites) and three milk (somatic cell count, lysozyme and NAGase) parameters showed larger and more consistent differences among LAI groups. Complement showed higher values and sialic acid showed lower values in high LAI group when compared with the other two LAI groups. Two other markers of inflammatory status (haptoglobin and reactive oxygen metabolites) showed the lowest values in high LAI cows. A consistent and significant reduction of milk NAGase and milk lysozyme in high LAI group was observed. The results suggest that cows with the highest liver functionality index have also the highest levels of some immune markers and the lowest levels for inflammatory markers at blood (already before calving) and mammary levels. Finally, cows with low LAI index, being more susceptible to metabolic and infectious diseases, should be carefully monitored to identify as early as possible the development of a disease.

Arginase Activity in Human Milk During the First Month of Lactation

Arginase (L-arginine amidinohydrolase, EC 3.5.3.1) is the key enzyme in urea synthesis, hydrolyzing L-arginine into L-ornithine and urea. Arginase modulates levels of nitric oxide, creatine, and creatinine, likely by regulating intracellular L-arginine availability. The objective of the present study was to determine the arginase activity and concentration of urea and creatinine in colostrum and mature human milk obtained from nursing mothers. Our longitudinal biochemical analyses show that arginase activities and urea concentrations were the highest at the first day of lactation (colostrum). The decreasing enzyme activity and urea start at the second day, remaining at this level until the end of the first month of lactation (30th day). The concentration of creatinine in human colostrum and mature milk did not significantly change. The alteration of arginase activity between colostrum and mature milk may be a consequence of the transfer of arginase from the blood of the breast mother mammary glands into the colostrum and mature milk. The concentration of nutrients in colostrum and mature milk undergo alterations, probably to satisfy the requirements of the nursing infant for arginine, essential amino acids for human body growth, and normal physiology.

Impact of a Coagulase-negative Staphylococci or Staphylococcus aureus Intramammary Infection during the First Month of Lactation on Somatic Cell Count, Milk Yield, and Culling in Primiparous Cows

Mastitis in heifers is not uncommon. During the last 20 years, numerous investigations have described the nature of mastitis in heifers (Fox, 2009). Coagulase-negative staphylococci (CNS) are the most prevalent cause of intramammary infections (IMI) in heifers around calving, but Staphylococcus aureus should not be ignored as it is also prevalent, contagious, and more likely to persist into lactation. Some studies have shown a negative impact of an elevated early lactation somatic cell count (SCC) on subsequent test-day SCC, milk production and survival in heifers (De Vleigher et al, 2004-2005). The impact should vary according to the pathogen causing the IMI. The objective of this study was to determine the effect of an IMI caused by CNS or S. aureus diagnosed during the first month of lactation in heifers on SCC, milk production, and culling risk during the first lactation.

Lameness in dairy cattle: A debilitating disease or a disease of debilitated cattle? A cross-sectional study of lameness prevalence and thickness of the digital cushion

Lameness is the most significant challenge for the dairy industry to overcome, given its obvious disruption of animal welfare and severe economic losses. Sole ulcers and white line abscesses are ubiquitous chronic diseases with the highest associated economic losses among all foot lesions. Their underlying causes are still not fully understood. An observational cross-sectional study was carried out to investigate the association between claw horn lesions and the thickness of the digital cushion. The thickness of the digital cushion was evaluated by ultrasonographic examination of the sole at the typical ulcer site. A total of 501 lactating Holstein dairy cows were enrolled in the study. The prevalence of sole ulcers was 4.2 and 27.8% for parity 1 and parity >1, respectively. The prevalence of white line disease was 1.0 and 6.5% for parity 1 and >1, respectively. The prevalence of lameness (visual locomotion score ≥3) was 19.8 and 48.2% for parity 1 and >1, respectively. The prevalence of sole ulcers and white line diseases was significantly associated with thickness of the digital cushion; cows in the upper quartile of digital cushion thickness had an adjusted prevalence of lameness 15 percentage points lower than the lower quartile. Body condition scores were positively associated with digital cushion thickness. The mean gray value of the sonographic image of the digital cushion had a negative linear association with digital cushion thickness (R2=0.14), indicating that the composition of the digital cushion may have changed with its thickness. Furthermore, digital cushion thickness decreased steadily from the first month of lactation and reached a nadir 120 d after parturition. These results support the concept that sole ulcers and white line abscesses are related to contusions within the claw horn capsule and such contusions are a consequence of the lesser capacity of the digital cushion to dampen the pressure exerted by the third phalanx on the soft tissue beneath.

Test-day records as a tool for subclinical ketosis detection

The prevalence, as well as the effect of subclinical ketosis on daily milk yield, was observed using 1.299, 630 test-day records collected from January 2000 to December 2005 on 73, 255 Slovenian Holstein cows. Subclinical ketosis was indicated by the fat to protein ratio (F/P ratio) higher than 1.5 in cows that yielded between 33 to 50 kg of milk per day (Eicher, 2004). The ketosis index was defined in relation to the timing of subclinical ketosis detection to the subsequent measures of test-day milk yields. The effect of subclinical ketosis on test day milk yields were studied separately for each parity using the mixed model analysis. The statistical model included the fixed effect of ketosis index, calving year-month, lactation stage and random effect of animals included in the study. The prevalence peak of subclinical ketosis occurred in the first month of lactation. Subclinical ketosis had a significant negative effect on daily milk yield. Decrease in milk yield in the amount of 4.21 kg/day, 2.73 kg/day ; 2.78 kg/day ; 2.83 kg/day ; and 3.72 kg/day in each parity were determined within 35 days after the detection of subclinical ketosis. The decrease continued in subsequent milk controls. The research results show that test-day records could be a useful tool for early detection of subclinical ketosis.

Effects of feeding dry propylene glycol to early postpartum Holstein dairy cows on production and blood parameters

In all, 18 multiparous and 19 primiparous Holstein dairy cows were used in a completely randomized design with restrictions to evaluate the effects of feeding propylene glycol (PG) as a dry product, via two delivery methods, on production and blood parameters. PG treatments were administered from parturition through 21 days postpartum. Treatments were: (i) control, no PG; (ii) top dress, 162.5 g PG/day by top dressing onto the total mixed ration (TMR) and; (iii) mixing, 162.5 g PG/day as a part of the TMR by incorporating it into the TMR. PG used was a dry product which contained 65% pure PG and 35% silicon dioxide as the dry carrier. Coccygeal blood was sampled on 4, 7, 14 and 21 days in milk (±1.50 pooled s.d.). Supplementation of dry PG by top dressing onto, or incorporating into, the TMR had no effects on average dry matter intake, milk yield and composition, serum insulin, serum and plasma metabolites and milk ketones. Concentrations of urine ketones tended (P = 0.10) to be reduced by PG supplementation from 41.5 to 15.2 mg/dl. Supplementation of PG tended (P = 0.07) to decrease the incidence for subclinical ketosis from 39% to 24% and 13% for cows fed a TMR supplemented with no dry PG, with dry PG as a top dress and dry PG as a part of the TMR, respectively. It is concluded that supplementing PG as a dry product via incorporating into the TMR is as effective as when used as a top dress, based on the efficacies of both delivery methods to numerically reduce urine ketones concentrations and, therefore, the incidence for subclinical ketosis during the first 21 days of lactation. However, it should be noted that the number of cows used in the current study was minimal, and more cows are needed to confirm the efficacy of supplementing PG as a dry product on reducing the prevalence of subclinical ketosis in dairy cows during the first month of lactation.

Lipid Fractions and Fatty Acid Composition of Colostrums, Transitional and Mature She-Camel Milk During the First Month of Lactation

Lipid Fractions and Fatty Acid Composition of Colostrums, Transitional and Mature She-Camel Milk During the First Month of Lactation

Effect of Selenium Supplementation on Blood Status and Milk, Urine, and Fecal Excretion in Pregnant and Lactating Camel

Ten pregnant female camels divided into two groups received, after a 2-week adaptation period, an oral selenium (Se) supplementation (0 and 2 mg, respectively) under sodium selenite form for 6 months from the three last months of gestation up to the three first months of lactation. Feed intake was assessed daily. Blood samples and body weight were taken on a biweekly basis, both in dams and their camel calves after parturition. Feces and urine samples were collected monthly and milk on a biweekly basis. The Se concentration in serum increased significantly in the supplemented group and was threefold higher than the concentration compared to the control group, respectively, 305.9 +/- 103.3 and 109.3 +/- 33.1 ng/mL. The selenium concentration increased in similar proportion in milk (86.4 +/- 39.1 ng/mL in the control group vs 167.1 +/- 97.3 ng/mL in treated group), in urine, and feces. The glutathione peroxidase (GSH-Px) activity varied between 18.1 +/- 8.7 IU/g hemoglobin (Hb) in control group and 47.5 +/- 25.6 IU/g Hb in treated group but decreased after parturition in both groups. Vitamin E did not change significantly and was, on average, 1.17 +/- 0.72 and 1.14 +/- 0.89 ng/mL in the control and treated groups, respectively. Significant correlations were reported between serum Se, milk Se, GSH-Px, and fecal and urinary excretion or concentration. Blood values in camel calves were similar to those of the dams. The results seemed to confirm the sensitivity of camel to Se supplementation with an important increase of selenium in serum and milk.

Relationships among body condition score, milk yield and reproduction in Czech Fleckvieh cows

The objective of this study was to confirm the relationship among body condition score at the time around parturition, milk yield in subsequent lactation, reproductive efficiency and BCS development in Czech Fleckvieh dairy cows. The BCS and milk yield were measured once a month and the cows were divided into groups according to their BCS before and after calving. Next, data from the database of cattle reproduction of the Czech Fleckvieh herd book were used. The dataset was analyzed by multifactorial analysis of variance using procedures COOR and GLM of the statistical program SAS. Cows with lower BCS in the 1<sup>st</sup> month after calving showed an increase in both milk yield and fat and protein corrected milk (FPCM) yield. No significant relationship was found between the BCS level before calving and subsequent milk yield. The body condition level in the last month before parturition influenced its subsequent decrease in the first phase of lactation. The group of cows with the highest BCS level before calving retained a high BCS level in the first five months of lactation. Adequately, the group of cows with the lowest BCS in the first month of lactation had the lowest BCS in the next four months. BCS before calving was not related to reproduction indicators, but the significant effect of BCS in the 1<sup>st</sup> month after calving on the length of calving to the first service interval was confirmed. The group of cows with BCS > 3.5 in the 1<sup>st</sup> month after calving had the most favourable reproduction indicators, also when the milk yield level was taken into account.

Effects of Inflammatory Conditions on Liver Activity in Puerperium Period and Consequences for Performance in Dairy Cows

The relationship between inflammation and general health conditions in dairy cows and the link between inflammation, liver function, and fertility are poorly understood. To clarify these relationships, 120 multiparous dairy cows were followed throughout an entire lactation. Blood samples were collected during the first month of lactation for a metabolic profile, and milk yield, disease occurrence, and fertility parameters were monitored during the entire lactation. Twenty-four cows were culled, and another 19 were excluded because they had serious problems after 30 d in milk (DIM) and before the first insemination. The remaining 77 cows were pregnant at the end of lactation and were retrospectively grouped into quartiles based on liver activity index (LAI), which is based on plasma negative acute phase proteins. Cows in the lower (LO) and intermediate lower (INLO) quartiles of LAI had more severe inflammations with high concentrations of haptoglobin (0.77 and 0.61g/L) and globulin (42.5 and 39.0g/L), respectively, during the first week of lactation compared with cows in the upper (UP) and intermediate upper (INUP) quartiles of LAI (haptoglobin: 0.28 and 0.45g/L, and globulin: 34.2 and 36.9g/L, respectively). At 7 DIM, the cows in LO and INLO had greater bilirubinemia (8.7 and 10.5 vs. 6.3μM/L in UP) and lower blood urea (3.5 and 3.7 vs. 4.1mM in UP). The INLO group exhibited more days open (139 vs. 93) and services per pregnancy (2.68 vs. 1.65), but lower milk yield (38.3 vs. 40.8kg/d at 28 DIM) compared with UP. The LO group did not have a significantly lower fertility status, but presented the lowest milk yield (34.1kg/d at 28 DIM). Our data suggest that cows with lower LAI scores had a more pronounced inflammatory status during the first month of lactation, an impairment of usual hepatic functions (e.g., bilirubin clearance), and a larger negative energy balance. The same cows had poorer performance (lower milk yield and fertility) than cows with higher LAI scores. Overall data suggest that any effort to avoid the acute phase response in the transition period would be useful for optimizing the productive and reproductive performance of high-yielding dairy cows.

Fat content and fatty acids profile of colostrum and milk of primitive Konik horses (Equus caballus gmeliniAnt.) during six months of lactation

The effect of the stage of lactation, the number of foals and age of the mare on changes in the fat content and fatty acid composition of colostrum and milk of primitive Konik horses was investigated. Colostrum and milk samples from 12 lactating mares were collected at the beginning of lactation, on the days 1 and 2 after foaling and then, starting from the first month of lactation, at 4-week intervals up to the sixth month of lactation. Significant differences were observed in fat content as well as the composition of some analysed fatty acids between colostrum and milk of mares of the Konik breed. The number of foalings and the age of mares did not have a statistically significant effect on the fat content in milk and had only a slight effect on the fatty acid composition. Milk produced by mares of the Konik breed is characterized by a considerable content of polyene fatty acids with 18 carbon atoms, a low ratio of n-6 fatty acids to n-3 fatty acids as well as low, highly advantageous values of atherogenic and thrombogenic indices.

Field Trial on Progesterone Cycles, Metabolic Profiles, Body Condition Score and their Relation to Fertility in Estonian Holstein Dairy Cows

Resumption of luteal activity postpartum and fertility were investigated in an Estonian Holstein high milk production and good fertility dairy herd. Body condition was scored after every 10 days in 54 multiparous dairy cows (71 lactations) calving inside from December to March during 4-year period. Blood samples were taken 1-14 days before calving and 1-14, 28-42 and 63-77 days after calving: analytes estimated were serum aspartate aminotransferase (AST), glucose, ketone bodies, total cholesterol, non-esterified fatty acids and triglycerides. The general linear mixed model was used to compare the data for cows with different characteristics in luteal activity postpartum based on their milk progesterone profiles. Forty-five per cent of cases had abnormal profiles; delayed resumption of ovarian cyclicity postpartum (DC) was the most prevalent abnormality. There was no difference in body condition scores between the groups. The DC and prolonged luteal phase groups had higher serum AST activity (p < 0.01) 1-14 days postpartum compared with normal group. The DC group also had higher cholesterol and triglyceride values (p < 0.05) 28-42 days postpartum and higher milk fat/protein ratio (p < 0.01) on the first month of lactation compared with normal profile group. Despite long post-calving anoestrous period (71 +/- 5.0 days; mean +/- SEM) DC group had 64.7% first service pregnancy rate (normal group 48.6% and PLP group 37.5%). This study did not find any detrimental effect of prolonged anovulatory period postpartum on subsequent fertility.

Trace elements in human milk: Correlation with blood levels, inter-element correlations and changes in concentration during the first month of lactation

Using inductively coupled plasma mass spectrometry (ICP-MS) based analytical procedures, the concentration of several trace elements (Mn, As, Pb, Co, Ni, Cu, Zn and Se) was determined in human milk samples collected from a group of healthy lactating Portuguese women ( n=44), both on the 2nd day postpartum (i.e., colostrum; n=34) and at 1 month postpartum (i.e., mature milk; n=19). Blood samples ( n=44), collected on the 2nd day after parturition, were also analyzed for the same trace elements. No major correlations were observed between the levels of the analyzed trace elements in blood and colostrum samples. All the studied elements, except for Co, Pb and Ni, showed a significant trend for a decrease in concentration in milk during the first month of lactation. This trend was more pronounced for Zn and Se, whose levels decreased to approximately 23% and 44% of their initial mean concentration, respectively. With the exception of Co ( r=0.607) and Zn ( r=0.487), no significant correlations were observed when comparing the levels of each trace element between samples of colostrum and mature milk. Several inter-element correlations were found within each type of milk sample. The most significant were: (i) Se vs Cu ( r=0.828) and Se vs Co ( r=0.605) in colostrum samples and (ii) Ni vs Pb ( r=0.756), Ni vs Mn ( r=0.743) and Se vs Co ( r=0.714) in mature milk samples. An inverse correlation between Zn and Se was also found in both types of milk sample; however, it only reached statistical significance for mature milk ( r=−0.624).

The Influence of Cow Factors on the Incidence of Clinical Mastitis in Dairy Cows

Many cow-specific risk factors for clinical mastitis (CM) are known. Other studies have analyzed these risk factors separately or only analyzed a limited number of risk factors simultaneously. The goal of this study was to determine the influence of cow factors on the incidence rate of CM (IRCM) with all cow factors in one multivariate model. Also, using a similar approach, the probability of whether a CM case is caused by gram-positive or gram-negative pathogens was calculated. Data were used from 274 Dutch dairy herds that recorded CM over an 18-mo period. The final dataset contained information on 28,137 lactations of 22,860 cows of different parities. In total 5,363 CM cases were recorded, but only 2,525 CM cases could be classified as gram-positive or gram-negative. The cow factors parity, lactation stage, season of the year, information on SCC from monthly test-day records, and CM history were included in the logistic regression analysis. Separate analyses were performed for heifers and multiparous cows in both the first month of lactation and from the second month of lactation onward. For investigating whether CM was caused by gram-positive or gram-negative pathogens, quarter position was included in the logistic regression analysis as well. The IRCM differed considerably among cows, ranging between 0.0002 and 0.0074 per cow-day at risk for specific cows depending on cow factors. In particular, previous CM cases, SCC in the previous month, and mean SCC in the previous lactation increased the IRCM in the current month of lactation. Results indicate that it is difficult to distinguish between gram-positive and gram-negative CM cases based on cow factors alone.

Chitotriosidase activity in human milk from mothers of premature and full-term infants during the first month of lactation

Objective The objectives of the present study were to measure the activity of chitotriosidase (ChT) in human milk, to record changes in enzyme activity over time and to determine whether there are differences in activity between the milk of mothers of full-term (FT) and premature (PT) infants. Patients and methods Three samples were collected from each of 28 mothers (26.9 ± 4.3 years of age; mean ± SD) of FT infants (gestational age, 39.1 ± 0.9 weeks; birth weight, 3384.8 ± 369.8 g.; median, 3485 g) and 28 mothers (26.6 ± 3.6 years of age) of healthy PT infants (gestational age, 30.5 ± 3.1 weeks; birth weight, 1400 ± 492.9 g.; median, 1285 g). Samples were collected at 3, 7 and 28th days after delivery. ChT activity was estimated using the fluorimetric method. ChT activities were calculated and expressed as nanomoles per milliliter per hour. Results ChT activity was higher in the PT group than in the FT group at day 3 [170.2 (14.0–294.8) vs. 81.7 (6.9–306.3) nmol/mL/h], day 7 [31.6 (0.0–166.7) vs. 17.2 (0.0–214.1) nmol/mL/h] and day 28 [5.5 (0.0–64.9) vs. 3.4 (0.0–51.6) nmol/mL/h]. Conclusion The higher ChT activity in milk of mothers of PT infants than those of FT infants suggests the presence of activated macrophages as its main source. ChT is well known to play a role in defense against fungi and have the ability to degrade both colloidal chitin and chitin in the cell wall of Candida albicans. Thus, our findings may indicate that infants have a natural advantage for protection from fungus infections when they are fed by their mothers' milk.

Limit-Feeding a High-Energy Diet to Meet Energy Requirements in the Dry Period Alters Plasma Metabolite Concentrations but Does Not Affect Intake or Milk Production in Early Lactation

Limit-feeding dry cows a high-energy diet may enable adequate energy intake to be sustained as parturition approaches, thus reducing the extent of negative energy balance after parturition. Our objective was to evaluate the effect of dry period feeding strategy on plasma concentrations of hormones and metabolites that reflect energy status. Multiparous Holstein cows (n=18) were dried off 45 d before expected parturition, paired by expected calving date, parity, and previous lactation milk yield, and randomly assigned to 1 of 2 dry-period diets formulated to meet nutrient requirements at ad libitum or limited intakes. All cows were fed the same diet for ad libitum intake after parturition. Prepartum dry matter intake (DMI) for limit-fed cows was 9.4kg/d vs. 13.7kg/d for cows fed ad libitum. During the dry period, limit-fed cows consumed enough feed to meet calculated energy requirements, and ad libitum-fed cows were in positive calculated net energy for lactation (NEL) balance (0.02 vs. 6.37 Mcal/d, respectively). After parturition, milk yield, milk protein concentration, DMI, body condition score, and body weight were not affected by the prepartum treatments. Cows limit fed during the dry period had a less-negative calculated energy balance during wk 1 postpartum. Milk fat concentration and yield were greater for the ad libitum treatment during wk 1 but were lower in wk 2 and 3 postpartum. Plasma insulin and glucose concentrations decreased after calving. Plasma insulin concentration was greater in ad libitum-fed cows on d −2 relative to calving, but did not differ by dietary treatment at other times. Plasma glucose concentrations were lower before and after parturition for cows limit-fed during the dry period. Plasma nonesterified fatty acid concentrations peaked after parturition on d 1 and 4 for the limit-fed and ad libitum treatments, respectively, and were greater for limit-fed cows on d −18, −9, −5, and −2. Plasma tumor necrosis factor-α concentrations did not differ by treatment in either the pre- or postpartum period, but tended to decrease after parturition. Apart from a reduction in body energy loss in the first week after calving, limit feeding a higher NEL diet during the dry period had little effect on intake and milk production during the first month of lactation.

Buffalo behavioural response to machine milking in early lactation

Buffalo farming in Italy is traditionally oriented towards mozzarella cheese production and over the last decade it has been rapidly increased. As a result, intensive techniques and mechanisation of farm activities have been introduced. Those sudden changes in rearing techniques have aroused a general concern about buffaloes welfare and its possible consequences on products quality.Human-animal interactions are recognized to have an impact on productivity, behaviour and welfare, particularly in dairy farms, where the milking process involves a close interaction with a human handler. Focusing on the first month of lactation, this preliminary study aimed at evidencing buffalo behavioural responses to machine milking. Relationship between behaviour and oxytocin administrations, often performed to allow milk let down, has been also investigated. The experiment included 8 multiparous and 6 primiparous buffaloes, calving in the same period. Starting from the first entrance in the milking parlour, the animals were followed two days/ week during the morning milking for the first 5 weeks of lactation. Behaviour observation was performed following a “focal animal sampling” (continuous recording) technique. Proportional frequencies of the following behaviours were calculated: kicking, stepping, defecating, urinating, vocalizing, pulling the teat cup off the teats. The exogenous oxytocin administration at milking was recorded. Pearson Chi-Square test was used to verify the presence of differences between primiparous and multiparous cows’ behaviour at milking. Cochran’s Q test was used to assess the variability of behaviour over time and a binomial regression was performed in order to verify the correlations between animal behaviours and the need to administer oxytocin. Considering lactation number, every behavioural pattern in primiparous cows, except for stepping, resulted to be more frequently performed (36.67% vs 24.36% for kicking; 5% vs 2.56% for defecating; 11.67% vs 5.13% for pulling the teat cup off the teats).The behaviour of urinating (48.33% vs 11.54%) proved to have a significantly higher mean frequency of occurrence compared to the multiparous one (P<0.001). The frequency of oxytocin administration showed a high variability over time (P<0.001), soon decreasing, while the selected behaviours proved to be more stable in time, except for kicking and urinating (P<0.05). Some correlations between animal behaviour at milking and oxytocin administration were found; particularly kicking, stepping and urinating appeared to be significantly related to the requirement of exogenous molecule (P<0.001). The occurrence of behaviours considered as indicators of acute stress and their correlation with oxytocin administration are a clear proof of the machine milking impact on buffaloes welfare and productivity.

Postcalving factors affecting conception risk in Holstein dairy cows in tropical and sub-tropical conditions

The objective was to identify postpartum risk factors between nutritional imbalance and health disorders affecting first-service conception risk (FSCR) in 21 commercial Holstein herds in Reunion Island. Multivariate logistic-regression models including herd as a random effect were used to analyze the relationship between FSCR and energy status, nitrogen status, hepatic function, mineral deficiencies, and postpartum health disorders. Two models (A and B) were built on two subsets of data ( n = 446 and n = 863) with risk indicators measured during the first month of lactation and around time of first service, respectively, adjusted for season, breed, parity, origin, milk yield, calving to first service interval (CS1), and type of estrus (spontaneous vs. induced). The averaged conception risk was 0.266 ± 0.015 ( n = 913) (mean ± S.E.M.). In both models, FSCR was decreased by CS1 ≤ 60 d and induced estrus. In model A, FSCR was decreased ( p < 0.05) for cows with mean cumulative 100 d daily milk yield ≤23 kg/d and >27 kg/d, with losses of body condition score >1.5, and with retained placenta. In model B, FSCR was decreased ( p < 0.05) for cows inseminated during wet season, previously raised out of the farm as nulliparous, with blood magnesium concentration ≤0.9 mmol/L, and for high-yielding cows (100 d milk yield > 27 kg/d) with glutamate deshydrogenase > 17 UI/L. Hence, high-body-lipid mobilization during the first month of lactation was a strong nutritional predictor of low FSCR together with liver damage in high-yielding cows. Interestingly, our models revealed that infertility is better related to nutritional factors than to postpartum health disorders occurrence.

Glycoprofiling of Bifidobacterial Consumption of Human Milk Oligosaccharides Demonstrates Strain Specific, Preferential Consumption of Small Chain Glycans Secreted in Early Human Lactation

The molecular basis by which human breast milk supports the development of a protective intestinal microbiome in infants is unknown. After lactose and lipids, human milk oligosaccharides (HMOs) are quantitatively the third largest and most diverse component of breast milk. In this work, glycomic profiling of HMO consumption by bifidobacteria using Fourier transform ion cyclotron resonance mass spectrometry reveals that one species, Bifidobacterium longum biovar infantis ATCC 15697, an isolate from the infant gut, preferentially consumes small mass oligosaccharides, representing 63.9% of the total HMOs available. These HMOs were detected in human breast milk at the onset and constantly through the first month of lactation by use of high performance liquid chromatography-chip time-of-flight mass spectrometry. Further characterization revealed that strain ATCC 15697 possesses both fucosidase and sialidase activities not present in the other tested strains. This work provides evidence that these small mass HMOs are selectively metabolized by select bifidobacterial strains and represent a potential new class of bioactive molecules functioning as prebiotics to facilitate a protective gut colonization in breast-fed newborns.

Comparison of Feeding Management and Body Condition of Dairy Cows in Herds with Low and High Mastitis Rates

Feeding practices, ration composition, and body condition scores (BCS) were assessed in an observational case-contrast study of Norwegian dairy herds with low (n = 98) and high (n = 94) mastitis infection rates. Differences between the 2 groups of herds were associated with feeding practices and amount of roughage. More herds in the low-infection group were fed a reduced amount of roughage at drying off, and reduced rations during the dry period resulted in lower BCS at calving. Cows in the low-infection herds had significantly lower BCS in the last month before calving and the first month of lactation than cows in the high-infection herds. The significant associations between mastitis infection rates and BCS, frequency of concentrate feeding, and amount of roughage at drying off and during the dry period indicated that feeding practices may have an important influence on the risk of mastitis in Norwegian dairy cows.