Early Lactation Performance Research Articles

Randomized controlled trial investigating the effect of 2 selective dry-cow therapy protocols on udder health and performance in the subsequent lactation

The objective of this study was to compare culture- and algorithm-guided selective dry-cow therapy (SDCT) programs with blanket dry-cow therapy (BDCT) in a multi-site, randomized, natural exposure clinical trial for the following cow-level outcomes: clinical mastitis, removal from the herd, and Dairy Herd Improvement Association (DHIA) test-day milk yield and SCC measures during the first 120 d in milk (DIM). Two days before planned dry-off, cows in each of 7 herds were randomly allocated to BDCT, culture-guided SDCT (cult-SDCT), or algorithm-guided SDCT (alg-SDCT). At dry-off, BDCT cows received an intramammary antibiotic (500 mg of ceftiofur hydrochloride) in all 4 quarters. Antibiotic treatments were selectively allocated to quarters of cult-SDCT cows by only treating quarters from which aseptically collected milk samples tested positive on a rapid culture system after 30 to 40 h of incubation. For alg-SDCT cows, antibiotic treatments were selectively allocated at the cow level, with all quarters receiving antibiotic treatment if the cow met at least one of the following criteria: (1) any DHIA test with a somatic cell count >200,000 cells/mL during the current lactation, and (2) ≥2 clinical mastitis cases during the current lactation. All quarters of all cows were treated with an internal teat sealant. Clinical mastitis and removal from the herd events (i.e., culling or death) and DHIA test-day data from dry-off to 120 DIM were extracted from herd records. Hazard ratios (HR) for the effect of treatment group on clinical mastitis and removal from the herd during 1 to 120 DIM were determined using Cox proportional hazards regression. The effects of treatment group on test-day loge-transformed SCC and milk yield were determined using linear mixed models. Final models indicated that either SDCT program was unlikely to increase clinical mastitis risk (HRcult-SDCT/BDCT = 0.82, 95% CI: 0.58, 1.15; HRalg-SDCT/BDCT = 0.83, 95% CI: 0.63, 1.09) or test-day logeSCC (cult-SDCT minus BDCT = 0.05, 95% CI: -0.09, 0.18; alg-SDCT minus BDCT = 0.07, 95% CI: -0.07, 0.21). Risk of removal from the herd and test-day milk yield were similar between treatment groups. Findings from this study indicate that culture- or algorithm-guided SDCT can be used at dry-off without negatively affecting cow health and performance in early lactation.

Effects of Zinc Sources on Bioavailability, Production Performance, and Digestibility in Early Lactation of Holstein Dairy Cows

Effects of Zinc Sources on Bioavailability, Production Performance, and Digestibility in Early Lactation of Holstein Dairy Cows

The Effect of Fennel and Black Seed, on Breast milk, Prolactin Levels and Anthropometric Index in Human and Animal Samples: A Review

Background: Breastfeeding is the best food for infants. Prolactin is combined with the corresponding receptors on the alveoli that produce milk, and milk production begins. We aimed to review the effect of fennel and black seed on breast milk, prolactin levels and anthropometric index in human and animal samples. Materials and Methods: After selecting the keywords related to the research question, searching of the online databases (Medline, EMBASE, Scopus, Web of Science, SID and Magiran) were done. After reviewing the retrieved studies based on the title, abstract and full text, and related articles were selected according to the inclusion criteria. Results: Ten studies were included into review. One study indicated the arousal serum levels of prolactin in lactating mothers using fennel. Four studies showed the fennel as alone or embodied in the herbal tea can increase breast milk. In contrast to the above four studies, a combination of fennel, anise, cumin, dill, parsley and fennel flower had no effect on breast milk volume and neonate weight gain.Two studies inspected the effects of fennel in animal studies. Although 140 and 280 μL doses of fennel have significantly increased prolactin in comparison with 35 and 70 μL g doses, this increment is not sufficient to increase breast milk and, subsequently, to elevate neonates weight with fennel to dairy goats have enhancement and reduction effect, respectively on performance and negative energy balance in early lactation. In another study, black seed improved milk production in cows, while it did not change composition of milk and prolactin. Conclusion: Based on the results, fennel is recommended to increase breast milk, prolactin levels in lactating women.

Niacin nutrition and rumen-protected niacin supplementation in dairy cows: an updated review.

As the precursor to NAD+ and NADP+, niacin is important for catabolic and anabolic redox reactions. In addition, niacin is known for its anti-lipolytic action via a hydroxycarboxylic acid-2-receptor-dependent mechanism. The anti-lipolytic effects of traditional free niacin supplementation during transition periods had been studied extensively, but the reported effects are ambiguous. In the past decade, a series of studies were conducted to evaluate the effects of rumen-protected niacin (RPN) on production performance and metabolic status in early lactation and on heat stress in dairy cows. Feeding RPN seems more effective than free niacin regarding increasing circulating niacin concentration. The rebound of plasma NEFA was found after termination of niacin abomasal infusion. Feeding RPN or infusion of niacin via the abomasum could suppress lipolysis and reduce insulin resistance in early lactation. Additionally, RPN supplementation could possibly relieve heat stress through vasodilation during moderate to severe heat stress condition. However, these beneficial effects of niacin supplementation have not always been observed. The inconsistent results across studies may be related to dosages of niacin supplementation, rebound of plasma NEFA concentration, stage of lactation or severity of heat stress. Overall, the current review is to present updated information on niacin nutrition in dairy cows and the recommendations are given for future research.

Early lactation performance in Holstein heifers first calving at 36 months and managed for high or low weight gain during mid- and late gestation.

The effect of weight gain during mid- and late gestation in dairy heifers on performance at the start of first lactation was studied. In this experiment, 47 Holstein heifers with first calving at 36 months of age were used. The plane of nutrition aimed to have a high (900 g/d, H; n = 23) and low (500, L; n = 24) average daily gain (ADG) from the 4th month of gestation until 3 weeks before the expected day of calving, achieved by ad libitum intake of high quality pasture (H) or controlled intake of a total mixed ration (L). Body weight (BW), body condition score (BCS), milking, and reproductive performances were recorded. Concentrations of plasma non-esterified fatty acids (NEFA), glucose, beta-hydroxybutyric acid (BHBA), and urea were characterised at weeks 2, 4, 6 and 8 of lactation. Milk fatty acid composition was determined at weeks 3 and 6. A total of 39 heifers successfully calved and completed first lactation. During feeding treatment the required ADG were achieved. BW and BCS were higher in H heifers at calving compared to L heifers: 707 vs. 640 kg, and 3.91 vs. 3.01 respectively. H heifers lost more weight, BCS and had lower feed intake during the beginning of first lactation (-0.8 kg DM/d/heifer over the first 4 weeks of lactation). Per day of lactation, H heifers produced significantly more milk (29.2 vs. 26.2 kg), fat (1.27 vs. 1.07 kg) and protein (0.84 vs. 0.477 kg) from 0 to 8 weeks of lactation. Concentrations of NEFA, glucose and BHBA were higher in H heifers compared to L heifers, but urea concentration was not affected. Concentration of preformed fatty acids in the milk (C16 and more) was higher. As a result, the calculated daily net energy balance during the first 8 weeks of lactation was -1.53 and -5.95 MJ for L and H heifers, respectively.

The effect of spring grass availability and grazing rotation length on the production and quality of herbage and milk in early spring

AbstractThe importance of spring grass in the diet of early lactation dairy cows has been widely acknowledged. Numerous studies completed on a plot/paddock basis have identified methods of increasing herbage availability in spring, but little focus was placed on how this impacts animal production. The aim of the current study was to investigate the impact of opening farm cover (OFC; grass availability on farm at turnout in spring; 1036 (high), 748 (medium) and 544 (low) kg DM/ha) and spring rotation length (fast – 56 days and normal – 63 days) on animal performance in early lactation and herbage production and quality. Spring rotation length had little effect on animal performance, herbage variables or sward composition. High OFC increased pre-grazing herbage mass, allowing for increased daily herbage allowance (DHA) compared to medium and low OFC. There was a reduced proportion of leaf in the sward of the high OFC compared to the low OFC, resulting in lower organic matter digestibility. Despite the reduction in sward quality observed as a consequence of achieving high OFC in spring, the greater DHA available to animals increased milk production (+1.4 kg milk/cow/day). Additionally, animals grazing a medium or low OFC had a greater requirement for silage supplementation in spring (+1.3 kg DM/cow/day). The benefits of the higher DHA highlighted in the current study suggest that autumn grazing management must be adapted to increase herbage availability in spring. However, the benefits observed in milk production did not persist beyond the first grazing rotation.

Effect of Xylanase and Phytase Supplementation on Goat's Performance in Early Lactation.

Supplementing diets of dairy animals with phytase and xylanase can enhance phosphorus availability and fiber degradation in the rumen and positively affect animal's health and productivity. In vitro and in vivo trials have been conducted to define the optimal addition level of xylanase and phytase to lactating Baldi goat's rations and investigate effects of these enzymes on animal's nutrients digestibility, blood chemistry, milk production and milk composition. In vitro batch culture technique was used to evaluate the effect of phytase and xylanase supplementation at different levels (0, 1, 2 and 3 g kg-1 DM) on rumen fermentation characteristics. Eighteen early lactating Baldi goats were randomly assigned into three groups and fed 4% dry matter according to their body weight. The first group was fed control ration (35% yellow corn, 20% corn stalks, 20% berseem hay, 12.5% soybean meal and 12.5% wheat bran), the second group fed control ration+Penizyme at 2 g kg-1 DM (R1), while the third group fed control ration+Phtase-Plus® at 1 g kg-1 DM (R2). Xylanase and phytase supplementation increased the in vitro DM and OM degradability and ruminal NH3-N and total volatile fatty acids (TVFA) concentrations, with no effect on total gas production (TGP) volume. All nutrients digestibility (except CP), blood serum glucose concentration, milk production and milk components yields were increased for enzymes supplemented goats than control. Inclusion of xylanase and phytase in lactating goat's rations improved their productive performance with no deleterious effects on their health.

Effects of dry period energy intake on insulin resistance, metabolic adaptation, and production responses in transition dairy cows on grass silage–based diets

High energy intake in the dry period has reportedly had adverse effects on mobilization of body reserves, dry matter intake, and productivity of dairy cows. We investigated whether grass silage (GS) fed ad libitum (high energy intake, HEI; 141% of daily metabolizable energy requirements) in an 8-wk dry period affects metabolic adaptation-specifically, peripheral insulin resistance-compared with a total mixed ration consisting of GS, wheat straw, and rapeseed meal (55/40/5%; controlled energy intake, CEI; 108% of metabolizable energy/d) fed ad libitum. Multiparous Ayrshire dairy cows (n = 16) were used in a randomized complete block design until 8 wk after parturition. Commercial concentrates were fed 1 and 2 kg/d during the last 10 to 6 and 5 to 0 d before the expected calving date, respectively. Postpartum, a similar lactation diet with ad libitum access to GS and increasing concentrate allowance (maximum of 16 kg/d) was offered to all. The HEI group gained more body weight and had higher plasma insulin, glucose, and β-hydroxybutyrate concentrations than the CEI group prepartum. Postpartal plasma glucose tended to be higher and milk yield was greater from wk 5 onward for HEI compared with CEI cows. An intravenous glucose tolerance test (IVGTT) was performed at -13 ± 5 d and 9 ± 1 d relative to calving. The HEI cows had greater insulin response to glucose load and smaller area under the response curve for glucose than CEI cows in prepartal IVGTT. Thus, compensatory insulin secretion adapted to changes in insulin sensitivity of the peripheral tissues, preserving glucose tolerance of HEI cows. Higher insulin levels were needed in HEI cows than in CEI cows to elicit a similar decrement of nonesterified fatty acid concentration in prepartal IVGTT, suggesting reduced inhibition of lipolysis by insulin in HEI cows before parturition. In conclusion, high energy intake of moderately digestible GS with low concentrate feeding in the close-up dry period did not have adverse effects on metabolic adaptation, insulin sensitivity, and body mobilization after parturition. Instead, this feeding regimen was more beneficial to early-lactation performance than GS-based total mixed ration diluted with wheat straw.

Body Protein Reserves Sustain Maternal Performance in Early Lactation but Dietary Protein Is Necessary to Maintain Performance and Immune Responses to Nippostrongylus brasiliensis in Lactating Rats

It has been shown that dietary protein supplementation during lactation boosts immunity in Nippostrongylus brasiliensis-infected periparturient rats. It is not known whether body protein reserves accumulated during gestation have a similar effect during lactation. This study aimed to quantify the impact of body protein reserves and dietary protein supplementation on maternal performance and immune responses to N. brasiliensis during lactation. Multiparous female Sprague-Dawley rats were administered a primary infection of N. brasiliensis before mating and were restriction-fed either 60 g [low-protein diet gestation (Lge)] or 210 g [high-protein diet gestation (Hge)] crude protein (CP) per kilogram of dry matter (DM) until parturition. From parturition onward, dams were restriction-fed either 100 g [low-protein diet lactation (Lla)] or 300 g [high-protein diet lactation (Hla)] CP per kilogram of DM, generating 4 different dietary treatments. A subset of rats was sampled before parturition; postparturition, dams were secondarily infected with N. brasiliensis and samples were collected at days 5 and 11 postparturition. Maternal performance until parturition, as measured by pup weight, was better in Hge rats than in Lge rats [Lge: 4.84 g; Hge: 6.15 g; standard error of the difference (SED): 0.19]. On day 11, pup weights of dams with reduced protein reserves fed protein during lactation (Lge-Hla; 20.28 g) were higher than their counterparts from Hge-Lla dams (17.88 g; SED: 0.92). Worm counts were significantly different between Lge-Lla-fed (253; 95% CI: 124, 382) and Hge-Hla-fed (87; 95% CI: 22, 104) dams on day 11 (P=0.024). The expression of splenic interleukin 13 (Il13) and arachidonate 15-lipoxygenase (Alox15) was significantly higher (P<0.05) in Hge-Hla dams compared with Lge-Lla dams on day 5. Although protein reserves were adequate to maintain maternal performance in the early stage of lactation in dams infected with N. brasiliensis, they were not adequate to maintain maternal performance and effective immune responses at later stages. Dietary protein supplementation was required to achieve this.

Association of postpartum hypocalcemia with early-lactation milk yield, reproductive performance, and culling in dairy cows

Periparturient hypocalcemia is frequently observed and considered as a gateway disease that is associated with various health issues. The objective of this study was to evaluate the association of hypocalcemia with early-lactation milk yield, reproductive performance, and culling across a large number of different managerial systems. A prospective cohort study was conducted based on a convenience sample of 125 dairy herds from 8 federal states of Germany between February 2015 and August 2016. A blood sample was drawn from 1,709 animals within 48 h after parturition and analyzed for serum calcium concentration. After discarding cows (n = 283) with missing data, a total of 1,426 cows were considered for final analyses. The median time from calving to sampling was 14.0 h (interquartile range = 5.0-24.9 h). For each herd, a record of the herd management software was requested 150 d after the last cow was sampled. Serum calcium concentration of each cow was associated with early-lactation milk yield (Dairy Herd Improvement Association equivalent test 1 to 3), reproductive performance [days in milk (DIM) at first artificial insemination (AI), pregnancy at first AI, time to pregnancy within 150 DIM], and culling (until 60 DIM) data. Generalized linear mixed models were used to analyze continuous or categorical data. Shared frailty models were used for time to event data. Five different thresholds were used to define hypocalcemia. Thresholds ranged from 1.8 to 2.2 mmol/L using 0.1-mmol/L increments. Clinical hypocalcemia was defined as serum calcium concentration <2.0 mmol/L in combination with clinical signs (e.g., recumbency). The effect of hypocalcemia on milk yield was conditional on parity. In primiparous cows a serum calcium concentration <2.0 mmol/L (6.4% of cows were below this threshold) had no effect on milk production, whereas there was a tendency for multiparous cows with a serum calcium concentration <2.1 mmol/L (63.2% of cows were below this threshold) to produce 0.80 kg/d more milk compared with multiparous cows at or above the threshold. Multiparous cows suffering from clinical hypocalcemia produced 2.19 kg/d less milk compared with normocalcemic cows in early lactation. Calcium status was not associated with days to first insemination. Cows with a serum calcium concentration <1.9 mmol/L (34.6% of cows below this threshold) had decreased odds (odds ratio = 0.56) of pregnancy at first AI. A serum calcium concentration <1.8 mmol/L (24.1% of cows below this threshold) had a significant effect on time to pregnancy. Compared with animals with a serum calcium concentration ≥1.8 mmol/L, the hazard of becoming pregnant within 150 DIM was reduced when cows had a serum calcium concentration <1.8 mmol/L (hazard ratio = 0.68). Cows with a serum calcium concentration <2.0 mmol/L (44.3% of cows were below this threshold) had a 1.69 times greater hazard of being culled within the first 60 DIM compared with normocalcemic animals. The present study shows that the association of hypocalcemia with milk yield was conditional on parity and serum calcium concentration measured once within 48 h after calving. Considering reproductive performance and culling in early lactation, a negative effect of postpartum hypocalcemia was demonstrated.

Periparturient and early lactation performance and metabolism of replacement Holstein‐Friesian heifers out‐wintered on fodder beet or perennial ryegrass compared with winter housing

AbstractThe effect of winter feeding system on the periparturient performance and early milk production and metabolism of pregnant Holstein‐Friesian dairy heifers destined for a high‐output, total mixed ration (TMR)‐based system was examined. Forty‐eight, 23 ± 0.4‐month‐old, in‐calf Holstein‐Friesian heifers were assigned to one of three treatments: out‐wintered on perennial ryegrass and grass silage (G), out‐wintered on fodder beet and grass silage (F) or housed and fed grass silage and concentrate (H). The study commenced in November 2013, with heifers on treatment for 91 days, housed from 6 weeks prior to parturition and fed a dry cow TMR. Postpartum performance and metabolism were monitored for 12 weeks. Prepartum, average daily gain was lower in heifers receiving G at 0.95 kg d−1 cow−1 than F or H (1.24 and 1.11 kg d−1 cow−1 respectively). Body condition score of heifers that received G was also lower compared with treatments F or H both pre‐ and postpartum. Prepartum, plasma β‐hydroxybutyrate concentrations were lowest in animals receiving treatment H, highest in F and intermediate in G, but did not differ between treatment postpartum. Milk yield averaged 30.7 kg d−1 cow−1 and was not affected by treatment, but milk fat content was lowest in animals that received F (35.4, 37.1 and 37.9 g/kg for F, G and H respectively). The results indicate that out‐wintering in‐calf dairy heifers on fodder beet or perennial ryegrass is a viable alternative to winter housing in high‐output TMR‐based milk production systems in a temperate region.

Effect of source of supplemental fat in early lactation on productive performance and milk composition

The objective of this research was to evaluate the effects of diets supplemented with rumen inert fat sources on early-lactation performance of dairy cows. Two studies were conducted that varied in total dietary fat level (3.4% of DM for study 1 and 5.1% of DM for study 2). Calcium salts of fatty acids (CSFA) rich in oleic acid versus SFA rich in palmitic acid diets were supplemented to provide 0.9% (study 1) and 1.2% (study 2) of total dietary fatty acids (DM basis). Compared with cows fed the CSFA diet in study 1, cows fed the SFA diet had 0.06 kg/d greater protein yield (P = 0.01) and 0.02 unit greater protein efficiency (P = 0.01) expressed as milk CP/CP intake. In study 2, cows fed the CSFA diet had 0.2 kg/d greater fat yield (P = 0.04), 0.1 unit greater fat efficiency (P = 0.02) expressed as milk fat/fat intake, 3.6 kg/d greater 3.5% FCM (P = 0.04), and 3.3 kg/d greater energy-corrected milk yield (P < 0.05). In conclusion, when cows started at 45 DIM and with a diet fat level of 5.1% (DM), the CSFA diet rich in oleic acid improved milk fat yield, milk fat efficiency, 3.5% FCM, and energy-corrected milk (P < 0.05). However, when cows started at greater than 70 DIM and with a diet fat level of 3.4% (DM), the SFA diet rich in palmitic acid improved lactation performance by improving milk protein yield and protein efficiency (P < 0.05). This study suggests that dietary fatty acids are potentially absorbed and partitioned differently depending on the level of dietary fat and DIM.

Effect of feeding molasses based multi-nutrient liquid supplement on early lactation performance, intake and nutrient digestibility in crossbred cows

Effect of feeding molasses based multi-nutrient liquid supplement on early lactation performance, intake and nutrient digestibility in crossbred cows

1243 Relationships between early life growth and first lactation performance of Holstein dairy cows

1243 Relationships between early life growth and first lactation performance of Holstein dairy cows

Associations between milk protein concentration, milk yield, and reproductive performance in dairy cows.

Milk protein concentration in dairy cows has been positively associated with a range of measures of reproductive performance. It was possible that these associations were due to confounding by milk volume. A retrospective single cohort study was conducted using data collected from 74 dairy herds with seasonal or split calving patterns. Associations between milk protein concentration and reproductive performance in Holstein dairy cows were assessed using random effects logistic regression. The key finding from this study was that the associations between milk protein concentration in early lactation and reproductive performance were not due to confounding by milk yield. Associations between milk protein concentration and reproductive performance were weaker at higher early lactation milk yields, but positive associations were evident at all milk volumes assessed. The second major finding was that increases in milk yield were associated with improved proportions of cows pregnant by wk 6 and 21 at low to moderate milk protein concentrations but with decreases in these reproductive measures at high milk protein concentrations. Thus, no simple relationship is present between milk yield and reproductive performance; effects of milk yield depend on milk protein concentration. These results indicate that mechanisms causing the associations between milk protein concentration and reproductive performance may be linked to milk yield but these mechanisms operate over a wide range of milk yields (<2,000 to ≥5,000kg in the first 120d of lactation). Further research is required to identify the causes of these associations.

Association between disease occurrence and fertility of dairy cows in three geographic regions of Chile

The objective was to analyze the association between disease occurrence during early lactation and reproductive performance and survival of dairy cows in high-producing herds, under different management practices in three geographic regions of Chile. Data included 30,757 lactation records of cows calving from January 2013 to June 2014 in three different locations: Central (C) area (n = 6198 cows in eight herds), Central-South (CS) area(n = 17,234 cows in 12 herds), and South (S) area (n = 7325 cows in six herds). Data were analyzed using logistic regression and ANOVA, considering cow as the experimental unit. Covariables offered to the models included parity number, season of calving, cow and herd relative milk yield, geographic location, and management system. Average milk yield (305 ME) per cow were 12,091, 11,783, and 6852 kg for C, CS, and S regions, respectively. Time from calving to first service and time to conception were consistently greater for cows with at least one disease event within 50 days in milk (DIM), for cows that were reported lame, or for cows that had mastitis or metritis. The odds (95% confidence interval) of pregnancy at 150 DIM (P150) and the odds of survival until 150 DIM (S150) for cows that had at least one disease event within 50 DIM were 0.84 (0.79–0.91) times the odds of pregnancy and 0.25 (0.22–0.28) times the odds of survival for healthy cows. The odds of P150 for cows located in the C and CS areas were 1.56 (1.36–1.80) and 1.16 (1.04–1.30) times the odds of P150 for cows in the S area. The odds of S150 for cows located in the C and CS areas were 0.48 (0.37–0.62) and 0.54 (0.42–0.67) times the odds of S150 for cows in the S area. These data suggested that cow health status and geographic location are significantly associated with reproductive performance and survival in this population of Chilean dairy cows.

Associations between the degree of early lactation inflammation and performance, metabolism, and immune function in dairy cows

The objective of the current study was to determine associations between the severity of systemic inflammation during the early postpartum period and performance, energy metabolism, and immune function in dairy cows. Cows were assigned to categorical quartiles (Q; Q1=0.18–0.59, Q2=0.60–1.14, Q3=1.15–2.05, and Q4=2.06–2.50g of haptoglobin/L) based on the highest plasma haptoglobin (Hp) concentration measured during wk 1 postpartum. Although cows were assigned to different categories of inflammation during the postpartum period, we detected a quadratic relationship of inflammation on prepartum dry matter intake (DMI) and body weight (BW) such that cows in Q2 had lower prepartum DMI and cows in Q2 and Q3 had lower prepartum BW compared with cows in the other quartiles. We also detected a quadratic association of inflammation with postpartum DMI and BW such that cows in Q2 and Q3 also had generally lower postpartum DMI and BW compared with cows in Q1. There was a tendency for a Q × time interaction for milk yield and Q × time interactions for 3.5% fat-corrected milk and energy-corrected milk yields; quadratic relationships suggested decreased milk yield for Q2 and Q3 cows. We also found Q × parity and Q × time interactions for plasma glucose and insulin concentrations, suggesting alterations with differing degrees of inflammation. There was also a Q × time interaction for plasma nonesterified fatty acids concentration. In addition, alterations in liver triglyceride and glycogen contents for cows with inflammation as well as alterations in [1-14C]propionate oxidation in vitro were observed. Although we observed limited effects of inflammation on neutrophil and monocyte phagocytosis at d 7 postpartum, inflammation appeared to alter neutrophil and monocyte oxidative burst. Overall, cows with any degree of elevated haptoglobin in the first week after calving had alterations in both pre- and postpartum intake and postpartum metabolism.

Relationships between milk fatty acids composition in early lactation and subsequent reproductive performance in Czech Fleckvieh cows

Increase of milk yield after calving causes changes in milk fatty acids (FA) composition and simultaneously corresponds with reproduction performance decrease. The objective of this study was to evaluate the relationships between milk FA group composition (SFA, saturated fatty acids; MUFA, monounsaturated fatty acids; and PUFA, polyunsaturated fatty acids) during the first 5 lactation weeks and subsequent reproductive results (INT, calving to first service interval; NUM, number of services per conception, and DO, days open) in Czech Fleckvieh cows. A total of 1231 individual milk samples from 382 cows were collected and subsequently analyzed. Simultaneously, body condition score (BCS) was weekly evaluated as well. Software SAS 9.1 was used for statistical analysis. Daily milk yields increased whereas BCS, milk fat and protein contents decreased during period observed. The reduction of basic milk components (% of fat, % of protein) was associated with increased SFA and decreased MUFA, respectively PUFA contents. Significant (P<0.01–0.05 days) increase in NUM (+0.15 to +0.29 AI dose) and DO (+8.16 to 15.44 days) were detected in cows with the lowest SFA content. On the contrary, cows with the highest content of MUFA presented significantly (P<0.01–0.05) higher values of NUM (+0.13 to +0.30) and DO (+7.26 to +15.35 days). Milk FA groups composition in early lactation potentially used as NEB indicators, especially SFA and MUFA proportion, affected subsequent reproductive results of Czech Fleckvieh cows. Therefore, its post-partum values could serve as predictors of potential fertility of dairy cows.

Randomized noninferiority clinical trial evaluating 3 commercial dry cow mastitis preparations: II. Cow health and performance in early lactation

The objective of this randomized noninferiority clinical trial was to compare the effect of treatment with 3 different dry cow therapy formulations at dry-off on cow-level health and production parameters in the first 100d in milk (DIM) in the subsequent lactation, including 305-d mature-equivalent (305ME) milk production, linear score (LS), risk for the cow experiencing a clinical mastitis event, risk for culling or death, and risk for pregnancy by 100 DIM. A total of 1,091 cows from 6 commercial dairy herds in 4 states (California, Iowa, Minnesota, and Wisconsin) were randomly assigned at dry-off to receive treatment with 1 of 3 commercial products: Quartermaster (QT; Zoetis Animal Health, Madison, NJ), Spectramast DC (SP; Zoetis Animal Health) or ToMorrow Dry Cow (TM; Boehringer Ingelheim Vetmedica Inc., St Joseph, MO). All clinical mastitis, pregnancy, culling, and death events occurring in the first 100 DIM were recorded by farm staff using an on-farm electronic record-keeping system. Dairy Herd Improvement Association test-day records of milk production and milk component testing were retrieved electronically. Mixed linear regression analysis was used to describe the effect of treatment on 305ME milk production and LS recorded on the last Dairy Herd Improvement Association test day before 100 DIM. Cox proportional hazards regression analysis was used to describe the effect of treatment on risk for experiencing a case of clinical mastitis, risk for leaving the herd, and risk for pregnancy between calving and 100 DIM. Results showed no effect of treatment on adjusted mean 305ME milk production (QT=11,759kg, SP=11,574kg, and TM=11,761kg) or adjusted mean LS (QT=1.8, SP=1.9, and TM=1.6) on the last test day before 100 DIM. Similarly, no effect of treatment was observed on risk for a clinical mastitis event (QT=14.8%, SP=12.7%, and TM=15.0%), risk for leaving the herd (QT=7.5%, SP=9.2%, and TM=10.3%), or risk for pregnancy (QT=31.5%, SP=26.1%, and TM=26.9%) between calving and 100 DIM.

Effect of increasing pasture allowance and grass silage on animal performance, grazing behaviour and rumen fermentation parameters of dairy cows in early lactation during autumn

The aim of the present study was to determine the effect of daily pasture allowance and grass silage supplementation on milk production performance, grazing behaviour, rumen function, and blood and urinary metabolites in early lactation of dairy cows grazing on low herbage mass pastures. The study was conducted with 32 Holstein–Friesian cows over a time period of 63 days. Prior to experimental treatment, milk production, body weight, and days in milk averaged 23.8±0.70kg/day, 537±9.6kg, and 37.1±1.02, respectively. Four dietary treatments resulted from the combination of two pasture allowances above ground level (low 17 vs. high 25kg of dry matter (DM)/cow/day) and grass silage supplementation offered at levels of 4.5 and 9.0kg DM/cow/day. All of the cows received 2.6kg DM of concentrate supplementation. Total DM intake was determined using the controlled-release chromium capsules method and milk composition was analysed weekly using infrared spectroscopy (Foss 4300 Milko-scan). Pasture allowance and grass silage supplementation had no significant effect on milk production (average 23.4kg/day) or on milk composition. Grazing time and ruminating time were not significantly affected by pasture allowance. The rate of intake was significantly reduced (P<0.001) from 32.0 to 19.1g DM/min by increasing grass silage supplementation. Increasing pasture allowance increased (P<0.001) daily live weight change (−0.061 and 0.553kg/day for low and high, respectively). High pasture allowance decreased plasma β-hydroxybutyrate (P<0.05) and increased plasma urea–N (P<0.05) (3.95 and 4.10mmol/L for low and high, respectively). Supplementation with grass silage had no significant effect on blood and urinary metabolites. Rumen ammonia and total volatile fatty acid concentrations were not significantly affected by increasing pasture allowance or increasing grass silage supplementation. This value, the lowest measured, is below the range recommended for optimal microbial growth. Rumen microbial nitrogen efficiency did not appear to be affected by pasture allowance or grass silage supplementation in that the purine derivative/creatinine ratio was similar for the four dietary treatments.