Performance Of Holstein Dairy Cows Research Articles

Genetic relationship between milk urea nitrogen and reproductive performance in Holstein dairy cows

The objective of this study was to describe the genetic and phenotypic relationship between milk urea nitrogen (MUN) and reproductive traits in Iranian Holstein dairy cows. Test-day MUN data obtained from 57 301 dairy cows on 20 large dairy herds in Iran between January 2005 and June 2009. Genetic parameters for MUN and reproductive traits were estimated with a five-trait model using ASREML program. Random regression test-day models were used to estimate heritabilities separately for MUN from first, second and third lactations. Regression curves were modeled using Legendre polynomials of order 3. Herd-year-season along with age at calving was included as fixed effects in all models for reproductive traits. Heritabilities for MUN and reproductive traits were estimated separately for first lactation, second lactation and third lactation. The estimated heritabilities for MUN varied from 0.18 to 0.22. The heritability estimate was low for reproductive traits, which ranged from 0.02 to 0.06 for different traits and across parities. Except for days open, phenotypic and genetic correlations of MUN with reproductive performance traits were close to zero. Genetic correlations between MUN and days open were 0.23, 0.35 and 0.45 in first, second and third lactation, respectively. However, the phenotypic correlation between MUN at different parities was moderate (0.28 to 0.35), but the genetic correlation between MUN at different parities was high and ranged from 0.84 to 0.97. This study shows a limited application of MUN for use in selection programs to improve reproductive performance.

Effects of Different Levels of Effective Fiber in Close-up Cows Diets on Intake and Chewing Activity and Subsequent Lactation Performance in Holstein Dairy Cows

Effects of Different Levels of Effective Fiber in Close-up Cows Diets on Intake and Chewing Activity and Subsequent Lactation Performance in Holstein Dairy Cows

Fenestration des gaines du nerf optique et régression des anomalies vasculaires péripapillaires dans un cas d’hypertension intracrânienne secondaire

The study investigated the effect of chop length of wheat straw in a high-straw dry cow diet on the feeding behavior, health, and performance of Holstein dairy cows across the transition period. Forty cows were enrolled at dry off, approximately 45 d before expected calving, and assigned to 1 of 2 dietary treatments containing (on a dry matter basis) 36% corn silage, 35% dry cow pellet, and 29% wheat straw. Diets were formulated to target an energy consumption of 19 Mcal/d of net energy for lactation per cow. The diets differed in the chop length of wheat straw: (1) long straw chopped with a 10.16-cm screen (LDD; n = 20), or (2) short straw chopped with a 2.54-cm screen (SDD; n = 20). Dietary treatments were fed throughout the dry period. Feeding behavior, rumination time, and reticulorumen pH were monitored electronically, and feed samples were collected to determine feed sorting. Blood samples were taken weekly, and body condition scores and body weights were taken every 2 wk. Postcalving, all cows were fed the same lactating cow total mixed ration for 28 d; the same measurements were recorded with the addition of daily milk yield and twice weekly milk components. During the dry period, cows fed the SDD treatment consumed more dry matter (15.6 vs. 15.0 kg/d), had more consistent dry matter intake in the week leading up to calving, had a faster feeding rate, consumed 0.4 kg/meal more, and had 0.6 fewer meals per day. No differences were observed in rumination time or mean reticulorumen pH between treatments in both the dry and lactating period. Regardless of treatment during the dry period, cows sorted against the long particles (>19 mm) and in favor of the short particles (<8, >4 mm), but cows fed the LDD treatment sorted to a greater extent than cows fed the SDD treatment. Dietary treatment in the dry period did not influence feed sorting behavior postcalving. Cows fed the LDD treatment had a greater daily change (decline) in rumen pH in the first week postcalving and had a greater blood β-hydroxybutyrate concentration in the third week postcalving. Overall, the results from this study indicate that feeding shorter chopped wheat straw in a high-straw dry cow diet improved intake, reduced sorting during the dry period, and resulted in greater metabolic health and rumen stability in early lactation.

Effects of Treating Whole-plant or Chopped Rice Straw Silage with Different Levels of Lactic Acid Bacteria on Silage Fermentation and Nutritive Value for Lactating Holsteins

Two experiments were carried out to investigate i) the effects of four levels of lactic acid bacteria inoculants (LAB; 0, 2×10 5 3×10 5 and 4×10 5 cfu/g fresh forage) and two physical forms of rice straw (whole and chopped rice straw) on silage fermentation quality and nutritive value of rice straw (RS) silage for lactating Holsteins and ii) the effects of the replacement of corn silage (CS) with different inclusion levels (0, 25 and 50%) of LAB treated RS on lactating performance of Holstein dairy cows. Rice straw packed with stretch film was ensiled for 45 d. The results showed that the higher level of LAB inoculants in the silage quadratically decreased pH, NH 3 -N and acetic acid concentrations and increased the contents of lactic acid and total organic acids. The CP content and DM losses in the silage declined linearly as the level of LAB addition was increased. Compared with whole-plant rice straw silage (WRS), chopped rice straw silage (CRS) dramatically reduced pH by 0.83. The concentrations of NH 3 -N were similar in WRS and CRS and both were less than 50 g/kg of total N. Chopping rice straw before ensiling significantly enhanced the lactic acid concentration and total organic acids content whereas the concentration of acetic acid declined. The CP, NDF and ADF content of CRS was 13.4, 5.9 and 10.2% lower than in WRS, respectively. Except for butyric acid concentration, significant interaction effects of inoculation level and physical form of RS were found on all fermentation end-products. Our findings indicated that milk yield and composition were not affected by different level of RS inclusion. However, because of the lower cost of WRS, cows consuming a ration in which WRS was partially substituted for CS had 3.48 Yuan (75% CS+25% WRS) and 4.56 Yuan (50% CS+50% WRS) more economic benefit over those fed a CS-based ration. It was concluded that the chopping process and LAB addition could improve the silage quality, and that substitution of corn silage with RS silage lowered the cost of the dairy cow ration without impairing lactation performance.

Evaluation of the effect of twin births on the perinatal calf mortality and productive performance of Holstein dairy cows

Abstract. Calving records from the Animal Breeding Center of Iran collected from January 1993 to December 2007 and comprising 1 163 594 Holstein calving events from 2 552 herds were used to evaluate reported perinatal calf mortality, 305-d milk yield, 305-d fat yield of milk and 305-d fat percentage of milk in single- and twin-births. A logistic regression model was constructed to analyze calf mortality between singletons and twins. Also statistical analyses of 305-d milk yield, 305-d fat yield of milk and 305-d fat percentage of milk were performed using the general linear models procedure. Greater odds of calf mortality existed for calves born from primiparous cows than from multiparous cows (P&lt;0.001) and for calves born as twins than singletons. The odds of calf mortality increased over years from 4.2 % in calving year Y1 (1993–1997) to 5.1 % in calving year Y3 (2003–2007) (odds ratio [OR] = 1.14; P&lt;0.001). The odds of calf mortality was greater after twin births, with 16.7 % of the twin calving events reporting calves as dead compared to 5.2 % for singleton births (OR=5.62; P&lt;0.001). For same-sex twin pairs, the odds of calf mortality was greater (P&lt;0.01; OR=1.72) for male than for female twin pairs. Also, twin-calved cows had greater 305-d milk production, fat yield and fat percentage of milk than single-calved cows (P&lt;0.05). In general, development of practical management strategies to cope with the negative effects associated with twinning on dairies is critical, especially if the trend toward increased twinning in the dairy cattle population continues.

Reproductive performance of Holstein dairy cows in Iran

The objectives of the present study were to describe the current reproductive parameters of Holstein dairy cows in Iran and to determine factors which have a significant effect on reproductive performance with emphasis on high-producing dairy cows. Five large Holstein dairy herds from the major milk production areas of Iran were selected for this study. Reproduction data including parity of dam, calving date, days to first service, days open, number of services, dry period, and occurrence of diseases for cows that calved from 2004 to 2007 were collected from the herds' databases. To determine the effects of year and season of calving, disease status, level of milk production, and parity of dam on reproductive parameters, the proc-mixed procedure in SAS software was used. Overall, data about 8,204 lactation were collected for the study. Results showed that mean (+/-SD) days open, calving interval, and days to first service for study herds were 134 (+/-89), 403 (+/-86), and 67 (+/-38) days, respectively. Conception rates at the first service and the overall service-conception rate were 41.6% and 41%, respectively. The level of milk production and diseases had significant negative effects on days open and service per conception (P < 0.05); statistical analysis showed that for every 100-kg increase in milk yield, days open will increase by about 0.3 days. However, no significant effect of level of productivity was observed on days to first service. The results of this study indicate that high milk production is a risk factor for decreasing fertility in Iran, like many other parts of the world.

Effects of Polyurethane Coated Urea Supplement on In vitro Ruminal Fermentation, Ammonia Release Dynamics and Lactating Performance of Holstein Dairy Cows Fed a Steam-flaked Corn-based Diet

Three experiments were conducted to investigate the effects of polyurethane coated urea on in vitro ruminal fermentation, ammonia release dynamics and lactating performance of Holstein dairy cows fed a steam-flaked corn-based diet. In Exp. 1, a dual-flow continuous culture was run to investigate the effect of polyurethane coated urea on nutrient digestibility, rumen fermentation parameters and microbial efficiency. Three treatment diets with isonitrogenous contents (13.0% CP) were prepared: i) feed-grade urea (FGU) diet; ii) polyurethane coated urea (PCU) diet; and iii) isolated soy protein (ISP) diet. Each of the diets consisted of 40% steam-flaked corn meal, 58.5% forages and 1.5% different sources of nitrogen. PCU and FGU diets had significantly lower digestibility of NDF and ADF (p<0.01) than the ISP diet. Nitrogen source had no significant effect (p = 0.62) on CP digestibility. The microbial efficiency (expressed as grams of microbial N/kg organic matter truly digested (OMTD)) in vitro of the PCU diet (13.0 g N/kg OMTD) was significantly higher than the FGU diet (11.3 g N/kg OMTD), but comparable with the ISP diet (14.7 g N/kg OMTD). Exp. 2, an in vitro ruminal fermentation experiment, was conducted to determine the ammonia release dynamics during an 8 h ruminal fermentation. Three treatment diets were based on steam-flaked corn diets commonly fed to lactating cows in China, in which FGU, PCU or soybean meal (SBM) was added to provide 10% of total dietary N. In vitro NH 3 -N concentrations were lower (p<0.05) for the PCU diet than the FGU diet, but similar to that for the SBM diet at all time points. In Exp. 3, a lactation trial was performed using 24 lactating Holstein cows to compare the lactating performance and blood urea nitrogen (BUN) concentrations when cows were fed PCU, FGU and SBM diets. Cows consuming the PCU diet had approximately 12.8% more (p = 0.02) dietary dry matter intake than those consuming the FGU diet. Cows fed the PCU diet had higher milk protein content (3.16% vs. 2.94%) and lower milk urea nitrogen (MUN) concentration (13.0 mg/dl vs. 14.4 mg/dl) than those fed the FGU diet. Blood urea nitrogen (BUN) concentration was significantly lower for cows fed the PCU (16.7 mg/dl) and SBM (16.4 mg/dl) diets than the FGU (18.7 mg/dl) diet. Cows fed the PCU diet had less surplus ruminal N than those fed the FGU diet and produced a comparable lactation performance to the SBM diet, suggesting that polyurethane coated urea can partially substitute soybean meal in the dairy cow diet without impairing lactation performance.

Effect of Different Rumen-degradable Carbohydrates on Rumen Fermentation, Nitrogen Metabolism and actation Performance of Holstein Dairy Cows

Four multiparous lactating Holstein cows fitted with rumen cannulae were fed diets varying in the amount and source of rumen-degradable carbohydrates (starch vs. sucrose) to examine their effects on rumen fermentation, nitrogen metabolism and lactation performance. A 4x4 Latin square with four diets and four periods of 28 days each was employed. Corn starch and sucrose were added to diets and corn starch was replaced with sucrose at 0 (0 S), 2.5 (2.5 S), 5.0 (5.0 S) 7.5% (7.5 S) of diet dry matter in a total mixed ration (TMR) containing 60% concentrate and 40% forage (DM basis). Replacing corn starch with sucrose did not affect (p> 0.05) ruminal pH which averaged 6.41, but the ruminal pH for 7.5 S decreased more rapidly at 2 h after morning feeding compared with other treatments. Sucrose reduced (p≤0.05) ruminal NH 3 -N concentration (13.90 vs. 17.09 mg/dl) but did not affect peptide-N concentration. There was no dietary effect on total volatile fatty acids (110.53 rnmol/L) or the acetate to propionate ratio (2.72). No differences (p>0.05) in molar proportion of most of the individual VFA were found among diets, except for the molar proportion of butyrate that was increased (p≤0.05) with the inclusion of sucrose. Total branched chain volatile fatty acids tended to increase (p≥0.051) for the control treatment (0 S) compared with the 7.5 S treatment. Dry matter intake, body weight changes and digestibility of DM, OM, CP, NDF and ADF were not affected by treatments. Sucrose inclusion in the total mixed ration did not affect milk yield, but increased milk fat and total solid percentage (p≤0.05). Sucrose tended (p≥0.063) to increase milk protein percentage (3.28 vs. 3.05) and reduced (p≤0.05) milk urea nitrogen concentration (12.75 vs. 15.48 mg/dl), suggesting a more efficient utilization of the rapidly available nitrogen components in the diet and hence improving nitrogen metabolism in the rumen.

Investigation on the Effect of Supplementing Rumen-Protected Forms of Methionine and Choline on Health Situation and Reproductive Performance of Holstein Dairy Cows

Twenty Holstein dairy cows in their first and second lactation were used from 4-week prepartum through 20-week postpartum. The aim was to investigate the effect of feeding different levels of ruminally protected methionine and choline on health situation and reproductive indices of Holstein dairy cows. Cows were randomly assigned to receive one of the following treatments: 18 g day(-1) of rumen protected methionine (RPM), 60 g day(-1) of rumen protected choline (RPC), 18 g day(-1) of RPM + 60 g day(-1) of RPC and neither supplement (control). The treatments significantly affected services per conception and open days of lactating dairy cows, but did not significantly affect on days to first estrus and number of pregnant cows. RPM + RPC-fed cows had the lowest open days, days to first estrus and services per conception compared with other groups. Although no statistical differences were noted for any given health category, the overall incidence of health-related disorders was numerically lowest for cows fed RPM + RPC. Results indicate that the supplementation of RPM and RPC have been improved reproductive performance and health situation of dairy cows.

Effects of Supplemental Dietary Biotin on Performance of Holstein Dairy Cows

An experiment was conducted to evaluate the effect of different levels of biotin on productive performance of Holstein dairy cow. In this experiment a change-over design with twelve multiparous cows, three rations and three periods was employed. Ingredients of the basal diet were alfalfa hay (24%) corn silage (16%) and concentrate (60%) on dry matter basis. The experimental diets 1 to 3 contained 0, 10 and 20 mg of biotin per day, respectively. The rations were fed to cows as Total Mixed Rations (TMR), but biotin was top-dressed on the a.m. allotment of ration. The cows were individually ad libitum and milked three times per day. Daily milk yielded was recorded and samples of the milk were taken once per week for determination of milk composition. Blood were taken in end of each period. Dry Matter Intake (DMI) and milk yield of cows were not affected by biotin. Also milk compositions were not affected by biotin. The average of Fat Corrected Milk (FCM) yield for 4% fat for rations contain 0, 10 and 20 mg day(-1) biotin, respectively 25.45, 26.2 and 25.9 kg day(-1) were calculated. Blood concentration of were unaffected by different levels of biotin. The differences between averages of the milk cows were not significant.

Effect of Stillbirths on Dam Survival and Reproduction Performance in Holstein Dairy Cows

The objectives of this study were to evaluate the effect of stillbirth on survival and reproductive performance of lactating dairy cows. Data were collected from 2 different regions of the US calving-ease scores (CES) were recorded by farm personnel on a scale of 1 (no problem) to 5 (extreme difficulty). Stillbirths were recorded by farm personnel. The final analysis included 13,608 calvings of which 93.4% were live calves and 6.6% stillbirths. An increasing or decreasing trend in the incidence of stillbirth by parity and by CES was analyzed by Cochran-Armitage trend tests. A significant decreasing trend in the incidence of stillbirth by parity group was detected. The incidence of stillbirth increased as the CES increased. The incidence of stillbirths was 3.6, 11.2, 25.9, and 60.1% for CES score 1, 2, 3, and 4, respectively. Dam survival in the herd and reproductive performance were analyzed by the Cox proportional hazards model. Variables that decreased dam survival time were stillbirths, primiparity, and CES of 3 and 4. The variables that reduced reproductive performance were stillbirths, multiparity, male calves, and CES of 3 and 4. Cows that had stillbirths had significantly increased risk of culling/death throughout the lactation and increased median days open by 88 d compared with cows that had live calves. In conclusion, losses from stillbirths are far greater than just the value of the calf.

Physically effectiveness of beet pulp in dairy cows 2: Intakes, digestibility and chewing activity, and performance of Holstein dairy cows

Many non-forage fibrous sources (NFFS) such as beet pulp (BP) contain more NDF than some forage sources, and have been successfully used in dairy rations to replace a portion of the effective or physical effective fiber (peNDF) that is normally provided by forages. However, BP has limited forage replacement value and effectiveness factor of 0.40 (fraction of NDF) versus 1.0 for forages (Mertens, 1997). In addition, Mertens (1997) suggested that the physically effectiveness factor of ground and pellet were 0.40 and 0.30, respectively. However, the effects of BP when substituted with different feed sources in TMR are variable that depend on chemical composition, types and physical characteristics. The objective of this experiment was to measure the effects of three types of BP on intakes, digestibility, and chewing activity and performance of Holstein dairy cows.

Effects of substitution barley grain with dried citrus pulp on performance of Holstein dairy cows

Dried citrus pulp (DCP) as a by-product from juice extraction of citrus fruit can be used as a feedstuff for ruminant animals (Belbaskis and Tsirgogianni, 1996). The DCP is composed of peel, inside portions, and culled fruits of the citrus family (e.g., orange, lemons, and grapefruit). The DCP is a pectin-rich bulky concentrate that is rich source of energy, fibre and calcium, but poor in CP and phosphorous. There is a different of opinion among researchers about the effect of DCP on milk yield, milk composition and blood metabolites components. The main objective of this experiment was to evaluated effects replacement of dried citrus pulp with barley grain on milk yield, milk composition and blood metabolites of dairy cows.

Effects of Alfalfa Particle Size and Specific Gravity on Chewing Activity, Digestibility, and Performance of Holstein Dairy Cows

Two experiments were carried out to test the effects of alfalfa particle size and functional specific gravity (FSG) on chewing activity, digestibility, rumen kinetics, and production of lactating dairy cows fed corn silage based rations. In experiment 1, water-holding capacity (WHC), insoluble dry matter, hydration rate, and FSG changes were determined in alfalfa hay (varying in particle size) and corn silage. Reduction of particle size increased bulk density, FSG, and the rate of hydration, and decreased WHC of alfalfa. In experiment 2, 9 midlactation Holstein dairy cows fed total mixed rations containing 3 sizes of alfalfa hay (with geometric mean 7.83, 4.04, and 1.14mm) were used in a replicated 3×3 Latin square design. The diets contained 20, 20, 35, 7, 7.5, 10, 0.3, 0.1, and 0.1% of DM alfalfa, corn silage, barley, soybean meal, beet pulp, wheat bran, dicalcium phosphate, vitamin premix, and salt, respectively. The geometric means (GM) of rations were 3.34, 2.47, and 1.66mm in long, medium, and fine alfalfa treatments, respectively. Reduction of particle size increased daily NDF intake (kg), but decreased the proportion of physically effective factor (pef) and physically effective NDF (peNDF) in the ingested rations. Reduction of particle size increased the FSG of rations and intake of DM but reduced digestibility of NDF and ash. Reduction of particle size decreased ruminal mean retention time (RMRT), but increased the ruminal particulate passage rate. Milk and FCM yield were not affected by treatments. The rumen pH, total chewing activity, rumination, eating time, and milk fat were reduced as particle size decreased, but milk protein increased. This study showed that reduction of forage particle size increased bulk density, FSG, and hydration rate of alfalfa and was the most influential factor affecting DMI, milk composition, and chewing behavior. Reduction of forage particle size had minimal impact on digestibility and milk production.

Effect of bST and reproductive management on reproductive performance of Holstein dairy cows.

The objective was to determine the effects of bovine somatotropin (bST) and two artificial insemination (AI) protocols on reproductive performance of Holstein cows. Lactating cows (n = 840) were assigned at 37 d in milk (DIM) to one of four treatments in a 2 x 2 factorial arrangement. Treatments consisted of either bST (500 mg/14 d) starting at 63 +/- 3 DIM or no bST (control), with cows either submitted for timed AI following a synchronized ovulation (Ovsynch) protocol or assigned to receive AI based on estrus detection (ED). Two injections of PGF2, at 37 +/- 3 and 51 +/- 3 DIM were used to presynchronize estrous cycles. Cows then received an injection of GnRH at 63 +/- 3 DIM, followed 7.5 d later by PGF2. Cows assigned to ED treatments were inseminated after observed estrus during a 7-d period. Cows in Ovsynch treatments received a second GnRH injection 48 h after the last PGF2alpha and received timed AI 16 to 18 h later. Pregnancy was diagnosed by ultrasound at 31 d after AI and confirmed 14 d later. Frequency of anovulation (18.5%) at 63 DIM was similar across treatments, but proportions of anovulatory cows decreased quadratically as body condition at 70 DIM increased from 2.25 to 3.75. Estrus detection rate after PGF2alpha tended to be lower in multiparous cows receiving bST, and bST reduced returns to estrus in nonpregnant cows. Conception rates were higher in cows receiving AI after ED and bST improved conception rates to first AI in cyclic cows by reducing embryonic mortality. Pregnancy loss was similar for cows inseminated following ED or the Ovsynch protocol. There was a positive impact of bST on fertility of cyclic cows inseminated at fixed time or at detected estrus, but effective resynchronization protocols are needed to optimize reinsemination of non-pregnant bST-treated cows.

Effect of timing of first clinical mastitis occurrence on lactational and reproductive performance of Holstein dairy cows

Objectives of this study were to determine the influence of timing of first clinical mastitis case occurrence on lactational and reproductive performance in high producing lactating dairy cows during the first 320 days in milk (DIM). Holstein cows, 1001, from two commercial dairy farms in California were retrospectively divided into four treatment groups according to timing of first clinical mastitis case caused by environmental pathogens: control with no recorded clinical cases of mastitis (C; n=501); first clinical mastitis prior to first postpartum AI (MG1; n=250); first clinical mastitis between first postpartum AI and pregnancy diagnosis (MG2; n=147); and first clinical mastitis after diagnosed pregnant (MG3; n=103). Clinical cases of mastitis were identified at every milking by the herd personnel based on abnormal milk or swelling of the mammary gland. A fore sample of milk was aseptically collected from every clinical case for microbiological culture. Mastitis decreased yields of milk, 3.5% fat-corrected milk, and milk components, but the effect was only observed for MG1 and MG2. Cows in the control group had lower linear somatic cell count (SCC) score throughout the lactation. Culling was increased by mastitis, and cows in the mastitis groups left the study earlier than controls. Conception rate at first postpartum AI and pregnancy rate at the end of the study were both decreased by mastitis prior to or after first AI, and MG1 and MG2 cows had extended days open. Furthermore, cows experiencing mastitis during lactation had a higher incidence of abortions. The negative effects of mastitis on reproduction were observed regardless of clinical case being caused by either Gram positive or negative bacteria. Mastitis either prior to or after first postpartum AI impairs lactation performance, increases culling, and decreases reproductive efficiency in high producing Holstein dairy cows.

Effect of the amount of body condition loss from the dry to near calving periods on the subsequent body condition change, occurrence of postpartum diseases, metabolic parameters and reproductive performance in Holstein dairy cows

We investigated the effect of body condition loss from the dry to near calving periods on the subsequent body condition change, the occurrence of postpartum diseases, the serum metabolic parameters total cholesterol, triglyceride, glucose, and urea nitrogen and the number of days to first breeding after calving in Holstein dairy cows. Body condition scoring (using a 5-point scale with quarter-point divisions) was performed on 67 pregnant Holstein dairy cows. Cows were scored once for body condition during the dry period (prepartum day 35±16), near calving (postpartum day 5±4), and subsequently at months 1 (±day 4), 2 (±day 5), 3 (±day 5), and 4 (±day 4) of lactation. At the same time, blood samples were collected to evaluate serum total cholesterol, triglyceride, glucose and urea nitrogen concentrations. Cows were categorized based on body condition loss from the dry to near calving periods into two groups: the moderate condition loss group (0–0.75 points, n=41), or the marked condition loss group (1.0–1.5 points, n=26). Regular reproductive health examination was conducted by the same investigator once a week. The marked condition loss group lost more body condition ( P<0.01) than the moderate condition loss group consistently until month 1 of lactation. The recovery of body condition in the marked condition loss group was more delayed ( P<0.01) than in the moderate condition loss group from months 1 to 4 of lactation. The occurrence of metritis and metabolic diseases (including abomasal displacement, milk fever, ketosis) was greater ( P<0.01) in the marked condition loss group (62 and 23%) than in the moderate condition loss group (27 and 2%), respectively. The total cholesterol concentration was lower ( P<0.05) in the marked condition loss group (167±5.3 mg/dl) than in the moderate condition loss group (183±5.8 mg/dl) at month 1 of lactation, however, the cholesterol levels at the other periods were not different ( P>0.05) between the two groups. The triglyceride, glucose, and urea nitrogen concentrations were not different ( P>0.05) from the dry period to month 4 of lactation between the two groups. The number of days to first breeding after calving was longer ( P<0.05) in the marked condition loss group (103±7.8 day) than in the moderate condition loss group (87±5.3 day). We conclude that marked body condition loss from the dry to near calving periods results in the increased occurrence of postpartum metabolic and reproductive diseases, decreased serum total cholesterol concentrations at month 1 of lactation and a longer interval to first breeding after calving in Holstein dairy cows, probably due to the more severe energy deficit reflected by unfavorable body condition score change during early lactation.

The Effect of Manual Forestripping on Milking Performance of Holstein Dairy Cows

The objective of this study was to evaluate the effects of forestripping as a premilking stimulation technique on milk yield, milking unit attachment time, and milk flow rates in Holstein dairy cattle. Multiparous Holstein cows (n=24) were divided into two groups (HPE, high producing, early lactation; LPL, low producing, late lactation) based on prestudy milk yield and stage of lactation. Within the production group, cows were randomly assigned into treatment (n=6) and control groups (n=6) in a switchback design. Cows were milked twice daily and treatments were switched after 20 milkings. Premilking udder preparation for the treatment group was as follows: forestripping, predipping with 0.5% iodine, and drying with paper towels followed by unit attachment. Udder preparation for the control group was identical except forestripping was not performed. Data were analyzed by using the PROC Means and PROC Mixed models described by SAS. During the study, cows in the HPE group produced significantly more milk and had longer milking unit attachment times compared with cows in the LPL group. The milk flow rate was 0.36 kg/min faster for the HPE cows compared with the LPL cows. There was no significant effect of order of treatment administration on any outcome variable. There were no significant differences in milk yield, milk unit attachment time, or milk flow for animals that were forestripped compared with animals that were not forestripped. In this study, the addition of forestripping to an otherwise acceptable premilking udder preparation routine did not increase milking performance of multiparous Holstein dairy cows.

Comparison of Pre- and Postpartum Performance of Holstein Dairy Cows Having either a Single or Twin Pregnancy

Cows calving with twins are often associated with a myriad of health problems and subsequent poor productive and reproductive performance. Financial losses associated with a twin pregnancy stem from lost replacements, disease costs, reproductive inefficiency, and increased culling. With the twinning rate increasing in many dairy herds, any practice reducing disease prevalence, reproductive problems, or both in cows with twins will help to minimize financial losses during the subsequent lactation. However, minimal comparative data are available to address metabolic or nutritional factors, which may be responsible for the myriad of health problems associated with a twin pregnancy. Data from a previous study were used to determine if animal performance measures over the transition period were different between single- and twin-pregnancy cows.

Milk fat content and production performance of holstein dairy cows fed fish meal

Milk fat content and production performance of holstein dairy cows fed fish meal