Mean Milk Yield Research Articles

29 The effect of fleshing ability on cow and calf performance

Abstract Several factors influence the overall maintenance requirements of a mature beef cow including age, gain, lactation, pregnancy, and fleshing ability. However, limited research is available to distinguish what sets a hard-fleshing cow apart from an easy-fleshing cow. Cows that are hard-fleshing maintain a lower body condition score (BCS) throughout the year compared to easy-fleshing counterparts. The objectives of this experiment are to determine the differences in characteristics and production between cows classified as easy- vs. hard- fleshing. Characteristics of interest include feed intake, milk yield, milk composition, body weight changes, BCS changes, and other body composition measurements, as well as calf weaning weight. In this study, 24 spring-calving, mature Angus beef cows were classified as either hard-fleshing or easy-fleshing based on BCS and ultrasound measurements for back fat and rump fat. The intake study took place during the second trimester, cows were assigned to an easy- or hard-fleshing pen based on treatment where they remained for the entirety of the 45-day intake study. Each treatment was replicated three times in a completely randomized design. Milk data collection began one month after calving with monthly milkings from May-August. There were no differences (P = 0.9) in DMI, although hard-fleshing cows had greater DMI calculated on a metabolic body weight basis (P = 0.05). There was a trend (P = 0.12) for hard-fleshing cows to wean heavier calves, although there was no difference in mean milk yield (P = 0.44). Body condition score was positively correlated with protein and carbohydrate content of milk with easy-fleshing cows having greater contents of both (P = 0.02 and P < 0.01, respectively). Overall, an increase in BCS without an increase in DMI may be beneficial from a reproductive standpoint, though more research in this area is needed.

178 The Effect of Fleshing Ability on Cow and Calf Performance

Abstract Several factors influence the overall maintenance requirements of a mature beef cow including age, gain, lactation, pregnancy, and fleshing ability. However, limited research is available to distinguish what sets a hard-fleshing cow apart from an easy-fleshing cow. Cows that are hard-fleshing maintain a lower body condition score (BCS) throughout the year compared to easy-fleshing counterparts. The objectives of this experiment are to determine the differences in characteristics and production between cows classified as easy- vs. hard- fleshing. Characteristics of interest include feed intake, milk yield, milk composition, body weight changes, BCS changes, and other body composition measurements, as well as calf weaning weight. In this study, 24 spring-calving, mature Angus beef cows were classified as either hard-fleshing or easy-fleshing based on BCS and ultrasound measurements for back fat and rump fat. The intake study took place during the second trimester, cows were assigned to an easy- or hard-fleshing pen based on treatment where they remained for the entirety of the 45-day intake study. Each treatment was replicated three times in a completely randomized design. Milk data collection began one month after calving with monthly milkings from May—August. There were no differences (P = 0.9) in DMI, although hard-fleshing cows had greater DMI calculated on a metabolic body weight basis (P = 0.05). There was a trend (P = 0.12) for hard-fleshing cows to wean heavier calves, although there was no difference in mean milk yield (P = 0.44). Body condition score was positively correlated with protein and carbohydrate content of milk with easy-fleshing cows having greater contents of both (P = 0.02 and P < 0.01, respectively). Overall, an increase in BCS without an increase in DMI may be beneficial from a reproductive standpoint, though more research in this area is needed.

Productive response of crossbred cows grazing Brachiaria decumbens pasture to supplementation of Saccharomyces cerevisiae

The objective of study was to evaluate the productive response of crossbred cows grazing on Brachiaria decumbens pasture to supplementation with an experimental concentrates (CEXP) with or without addition of Saccharomyces cerevisiae (SC). Four milking Brown Swiss × Zebu cows were utilized 4×4 Latin square design. Treatments were T1= 3 kg of CEXP; T2= 2 kg of CEXP; T3= 2 kg of CEXP + 10 g of SC; and T4= 3 kg of commercial concentrate as control treatment. CEXP was 63% ground maize, 25% canola meal, 10% molasses and 2% urea. All cows received 3 kg of maize silage plus free access to grazing Brachiaria decumbens. Experimental periods consisted of 21 days each. Chemical analysis was performed on Brachiaria decumbens grass, maize silage and the concentrate supplements. Variables evaluated were milk yield, protein and fat content in milk, live weight and body condition score (BCS). Mean milk yield was 6.6 kg/cow/day, with no differences among treatments, nor there were differences in live weight or BCS. However, significant differences were found in protein and fat in milk, with lower values for these components in T2 and T3 than in T1 and T4. The addition of different levels of inclusion had no effect on milk yield, live weight and body condition, as well as fat and protein in milk.

Effect of Season, Parity, Exotic Gene Level and Lactation Stage on Milk Yield and Composition of Holstein Friesian Crosses in Central Highlands of Ethiopia

The study used twelve years recorded data’s analysis for milk yield and composition of Holstein Friesian crossbred dairy cows in Holleta agricultural research center dairy farm. Data were summarized and categorized into the season, genotype (exotic blood level), Parity and lactation stages. The summarized data’s were season (219 wet, 1055 dry), genotype (1,117 for 50%, 115 for 62.5% and 42 for >75%), Parity (474 for parity-2, 356 parity-3, 270 for parity-4 and 174 for parity-5), Lactation stage (483 for early, 445 for mid and 346 for late). Analysis of means and standard errors of the mean for the parameter studied was estimated using SAS. The General Linear Model was used for analyses of variance on average monthly milk yield and composition for the effects of season, parity, genotype and stages of lactation. Season significantly affected milk yield, fat, and protein percentage composition. Higher yield and fat% composition record in the dry season and higher protein% during the wet season. Genotype significantly affected milk yield where the yield of 62.5% and >75% crossbred cows were significantly higher than that of 50% crossbred cows. The difference in parity significantly affected milk yield and protein content of milk where higher milk yield and protein content was recorded in parity five. An increasing trend observed in milk yield and protein content as dam parity advances. Mean monthly milk yield, percent of protein and total solid was varied significantly between different lactation stages where protein and Total solid percentage was significantly higher in the late stages of lactation. In overall milk, the yield was significantly affected by season, genotype, parity and stages of lactation but it is negatively correlated with the percentage of fat, protein, and total solids. Season, parity and stages of lactation significantly affected the protein content of milk whereas milk composition strongly correlated with each other.

The Effect of Live Yeast (Saccharomyces cerevisiae) on Milk Yield of Crossbred Dairy Cattle at Khumaltar, Nepal

A study was carried out to assess the effect of live yeast Saccharomyces cerevisiae (Nutriferm™) on milk production at National Cattle Research Program Khumaltar Lalitpur from 19 March 2015 to 15 April 2015. Twenty crossbred cattle were selected randomly and divided into five treatment groups. Each group had four animals arranged in Complete Randomized Design (CRD). Among five treatment groups, treatment (T1) was treated with 0.5 kg/MT of live yeast Saccharomyces cerevisiae (SC) incorporated feed, treatment (T2) with 1 kg/MT SC, treatment (T3) with 1.5 kg/MT SC, treatment (T4) with 2 kg/MT SC and treatment (T5) as control without any live yeast inclusion in feed. Supplementation of the live yeast up to seventh day of the trial had statistically non-significant (P>0.05) effect on average milk yield per cattle between the treatments. Response of the yeast on mean milk yield per cattle between the treatments was found statistically different (P<0.05) on fourteenth day and twenty-eight day of the trial. On fourteenth day mean milk yield of control group (T4) was statistically significant with highest dose rate inclusion T4 only but remained non-significant with the rest of the lower dose rate treatments. With further supplementation of the yeast up to 28th day of the trial results showed the statistically significant effect with lower dose rate T2 as well with respect to control group besides T4. Hence, the result of this experiment indicates that supplementation of live yeast for at least 14 days has role in the enhancement of milk production in crossbred dairy cattle with faster effect by dose rate of T4 treatment.

Milk production and its relationship with milk composition, body and udder morphological traits in Bedouin goat reared under arid conditions

This research aims to assess the performances of lactating Bedouin goat under arid conditions, focusing on the relationship of milk yield with body and udder morphology and growth traits. Fourteen goats and their kids were followed during early lactation (90 days post-partum). Mean daily milk yield was 0.56 kg. Milk fat, proteins, lactose, solids non-fat and minerals were respectively 34.9, 38.9, 48.8, 107 and 6.7 g L-1. Mean kids’ birth weight, adjusted body weight at 90 days of age and average daily gain were respectively 2 kg, 6.6 kg and 51.4 g day-1. Daily milk yield was correlated with goats’ body weight, withers height, rump height, udder width and udder circumference but not with linear udder score and growth performances. These results provide important data about the milk production of Bedouin goat emphasizing its correlation with body and udder morphological traits which can help to elaborate a specific breeding program for this breed.

13 Evaluation of PG-3-G presynchronization in Ovsynch-P programs in lactating dairy cows: Preliminary results

Presynchronization treatments associated with the Ovsynch protocol and its modifications have been used to improve reproductive performance in lactating dairy cows. Use of a PG-3-G protocol is indicated to increase the number of cows in the most ideal stage of the oestrous cycle (Days 5-9) at first gonadotropin-releasing hormone (GnRH) injection of the Ovsynch protocol. The objective of this study was to compare fertility of lactating dairy cows submitted to Ovsynch-P, preceded by PG-3-G protocol or not. A total of 86 Holstein cows [body condition score of 2.6±0.2 (1-to-5 scale), 3 and 10 years old, mean milk yield of 28.1±7.9kg per day, and 118±56 days postpartum period] maintained in a semi-intensive system were blocked by parity and date of calving and randomly assigned to groups: control (n=44) and PG-3-G (n=42). On Day -10 cows in the PG-3-G group received an injection of 500µg of sodium cloprostenol IM (Estron, Agener União, Brazil), and on Day -7 they received 0.05mg of Lecirelin IM (GnRH, Gestran, Agener União). On Day 0, all cows had the first dose of Ovsynch GnRH injection and a 1-g progesterone intravaginal implant (P4, Primer, Agener União). On Day 7, a dose of sodium cloprostenol was administered to induce corpus luteum (CL) luteolysis, and the P4 implant was removed. Forty-eight hours later, cows were injected with the second dose of GnRH and inseminated 12 to 18h later. The presence of CL and ovulatory follicle (OF) diameter were determined by transrectal ultrasonography (Aquila, Pie Medical, Maastricht, the Netherlands) on Days 0, 7, and 9, and gestation diagnosis was done on Day 30 after AI. Statistical analysis was performed using ANOVA, chi-square, Mann-Whitney, and Pearson correlation tests in SPSS 18 (Armonk, NY, USA), considering P=0.05 significant and a tendency when P>0.05 but P=0.10. Incidence of CL on Day 0 tended to be more frequent (P=0.1) in the PG-3-G group (78.6%) compared with the control (59%), but CL presence on Day 7 did not differ (P=0.98) between the groups (35 and 34%, respectively). Based on the odds ratio, PG-3-G cows were 2.16 times more likely to have a CL on Day 0. The mean diameter of OF on Day 9 was smaller (P<0.05) in PG-3-G cows (12.6mm) than in control cows (15.3mm), and a negative correlation was detected (r=−0.29) between the presence of CL on Day 0 and the diameter of OF on Day 9 (P=0.05). Pregnancies per AI tended (P=0.08) to be higher in PG-3-G cows (52%) than in control cows (34%). In summary, cows submitted to presynchronization with the PG-3-G protocol presented higher frequency of CL on Day 0 and tended to have a higher pregnancies per AI compared with control cows.

Identification of polymorphism in the bovine interleukin-17A gene and its association with mastitis in Polish Holstein–Friesian cattle

The main aim of this study was to identify the association between the single nucleotide polymorphism (SNP) in the bovine interleukin-17A (IL-17A) gene and mastitis resistance. Additionally, the connection between the identified polymorphism and the somatic cell score (SCS) was tested. Two hundred and six Polish Holstein?Friesian cows were genotyped using the PCR-RFLP method. One SNP mutation (c.126G>A) was identified within the coding sequence of the analyzed gene. Results of logistic regression analysis displayed no significant association between the IL-17A genotype and clinical mastitis occurrence (Wald chi-square test = 0.74; P = 0.69). The GLM analysis demonstrated that genotype also did not affect the SCS (P = 0.77), while the effects of age at first calving, lactation number, lactation stage, mean milk yield per milking day, and milk yield on the day of milk recording proved to be highly significant (P < 0.01). The present study was one of the first to show an association between polymorphism within the IL-17A gene and selected udder health traits in cattle. An influence of the c.126G>A polymorphism on clinical mastitis and the SCS in the studied set of Polish Holstein?Friesian cows was not found. This suggests that the c.126G>A marker is probably not relevant for genetic selection against mastitis in the analyzed breed.

Effects of feeding wheat or corn and of rumen fistulation on milk production and methane emissions of dairy cows

There has been little research that has quantified methane (CH4) yields when dairy cows consume diets containing wheat grain. Furthermore, although rumen-fistulated animals have been used in many experiments concerned with measuring CH4 emissions, no research has examined the effect of rumen fistulation on in vivo CH4 emissions and yield. This experiment examined the effects of including either wheat or corn grain in the diet and the effects of rumen fistulation on yields of milk and milk components, CH4 emissions, yields, and intensities. Eight rumen-fistulated and six non-fistulated Holstein dairy cows in late lactation were offered a wheat-based diet (WHT) and a corn-based diet (CRN) in a crossover design. For the WHT diet, cows were offered daily, 22.4 kg DM containing 45.5% lucerne hay, 8.9% canola meal, 0.5% mineral mix, 0.5% molasses powder and 44.6% rolled wheat. The CRN diet was similar to the WHT diet except that rolled corn replaced the wheat. There was no difference between the WHT and CRN diets on mean milk yields (27.8 vs 27.9 kg/day), but the WHT diet substantially reduced milk fat concentration (2.76 vs 4.23%) and milk fat yield (0.77 vs 1.18 kg/day). Methane emissions (218 vs 424 g/day), CH4 yield (11.1 vs 19.5 g/kg dry matter intake) and CH4 intensity (7.6 vs 15.7 g/kg milk) were all reduced ~45% by the WHT diet compared with the CRN diet. Rumen fistulation did not affect dry matter intake, milk production, milk composition or CH4 emissions, but decreased CH4 yield and intensity. Including wheat in the diet of dairy cows has the potential to be an effective strategy to reduce their greenhouse gas emissions. In addition, rumen fistulation was associated with a small reduction in CH4 yield and intensity, and this should be considered when using rumen-fistulated cows in research concerned with CH4 emissions.

Effect of milk production on reproductive performance in dairy herds

The objective of the present study was to assess the relationship between individual cow milk yield and fertility, accounting for the contextual effect of the herd. A data set including 657,968 lactations from 677 dairy herds in Argentina from 2001 to 2012 was used. The odds of pregnancy by 100 d in milk (DIM) were assessed by a multilevel logistic model (with cow as the first and herd as the second hierarchical level), and time to pregnancy was assessed by a proportional hazards regression model. Multilevel logistic models included the fixed effects of milk yield by 80 DIM, parity, year, and calving season at cow level and quartiles of herd milk yield by 80 DIM as a contextual effect. The proportional hazards model included the effect of daily cow-level milk yield as time-dependent variable, with milk yield at herd level as the stratification variable. Cows producing 1 standard deviation over the mean milk yield of their herd had 1.3 percentage point lower pregnancy by 100 DIM (from 31.4 to 30.1%; odds ratio = 0.942) when in herds in the top quartile of milk yield, whereas they increased 0.5 percentage points (from 27.9 to 28.4%) when in herds in the lowest quartile of milk yield. Only 4% of the observed variation in pregnancy by 100 DIM was explained by the random effect of the herd. Similarly, cows producing 1 standard deviation (8 kg/d) greater than the herd mean daily milk had 1.3% lower hazard of pregnancy (hazard ratio = 0.987) at 63 DIM in herds in the top quartile of milk yield, whereas they had 14.8% higher hazard (hazard ratio = 1.148) in herds in the lowest quartile of milk yield. The magnitude of the negative association between the cow's daily milk yield and the hazard of pregnancy increased with DIM. In conclusion, the relationship between milk yield and reproductive performance is statistically significant, but the effect size is practically small and is modulated by herd production level.

Effect of paddy straw based complete rations with different levels of neutral detergent fibre on microbial protein synthesis in dairy cows during early and mid lactation

A study was conducted in 18 lactating dairy cows (mean milk yield 10 kg/day) for 6 months by feeding paddy straw based complete rations containing different levels of NDF, in two phases, viz. early and mid lactation, to assess the microbial protein synthesis using purine derivatives (PD) excreted in urine. Isonitrogenous and isocaloric complete rations; T1, T2 and T3 with 25, 30 and 35 per cent NDF, respectively were formulated as per ICAR (1998). Paddy straw was the sole source of roughage NDF and the rest of NDF met by non-forage sources, in 3 diets. PD excreted through urine were comparable between the dietary treatments, in phases 1 and 2. The microbial protein (MBP) synthesis in T1, T2 and T3 were 997.01, 825.91, 842.06 g, respectively, in phase 1 and 1127.93, 1106.74 and 1157.24 g, respectively, in phase 2. The TDN intake calculated from the values of digestibility coefficients of nutrients in T1, T2 and T3 were 5.18, 5.86, 6.10 kg in phase 1 and 8.63, 8.81, 9.00 kg, in phase 2, respectively. The efficiency of MBP production/kg of TDN was 192.47, 140.94, and 138.04 g in phase 1 and 130.70, 125.62 and 128.58 g in phase 2, respectively in T1, T2 and T3. Results suggest that complete diets with 25 per cent are the most ideal NDF level in early lactation while all three NDF levels, viz. 25, 30 and 35% are ideal in mid lactation.

Oat silage for grazing dairy cows in small-scale dairy systems in the highlands of central Mexico

The objective was to evaluate the provision of oat silage (Avena sativa) to supplement grazing dairy cows on pastures of perennial ryegrass (Lolium perenne), festulolium (Lolium multiflorum × Festuca pratense) and white clover (Trifolium repens) during the dry season when pasture growth is limited. The experimental design was a 3 × 3 Latin square replicated three times, with nine milking Holstein cows (mean live weight 496.2 ± 33.6 kg and daily milk yield 14.8 ± 2.8 kg cow−1) under on-farm participatory rural research. Experimental periods were 14 d. Simulated grazing samples of pasture herbage were analysed for chemical composition, sward height recorded and net herbage accumulation determined from exclusion cages. Treatments were the inclusion of oat silage at T0 = 0 kg DM cow−1 d−1 of oat silage, T3 = 3 kg DM cow−1 d−1 of oat silage, and T6 = 6 kg DM cow−1 d−1 of oat silage, plus 5.0 kg fresh weight commercial concentrate and 9 h of continuous grazing. Animal variables were milk yield and composition, live weight and body condition score. Feeding costs were calculated. Mean milk yield was 18.9 ± 0.27 kg cow−1 d−1 with no differences in animal variables (p > 0.05), but feeding costs per kilogram milk increased 25% for T3 and 50% for T6. Oat silage supplementation is only viable under difficult grazing conditions.

Effects of Urea-Molasses Multi-nutrient Blocks (UMMB) supplementation on some production parameters of lactating Horro cows at Horro Guduru Animal Production and Research Center, western Ethiopia

The effects of dietary supplementation of urea-molasses multi nutrient block of lactating Horro cows fed Rhodes grass (chloris gayana) hay as a basal diet on milk yield, milk composition, feed intake and live weight change was studied on-station (at Horro Guduru Animal Production and Research Center of Wollega University). Sixteen cows in similar parity and lactation were randomly assigned to two groups: group A (control) and group B (UMMB-supplemented). The control group received baled Rhodes grass hay as a basal diet and small amount of concentrate; whereas the supplemented group (B) received UMMB in addition to the normal ration offered to the control group. The experiment was conducted for 60 days during the dry months. Mean daily milk yield and feed intake were higher in the cows supplemented with UMMB (P&lt;0.01) compared to the un-supplemented group. The average milk yield for control and supplemented groups are 1.62 and 2.38 respectively. On the other hands no significant differences were observed among the supplemented and control group for milk composition and body weight gain (P&gt;0.05). However the body weight gain is slightly better for the supplemented group. The increased milk production due to UMMB supplementation in this study could be attributed to the increased intakes of energy and nitrogen that was accessed through block supplementation.Keyword: UMMB Rhodes grass Milk yield Feed intake

On-farm deaths of dairy cows are associated with features of freestall barns

On-farm death (OFD) of a dairy cow is always a financial loss for a farmer, and potentially a welfare issue that has to be addressed within the dairy industry. The aim of this study was to explore the associations between OFD of dairy cows, housing, and herd management in freestall barns. To achieve the goal, we followed 10,837 cows calving in 2011 in 82 herds. Data were gathered with observations and a structured interview during farm visits and from a national dairy herd improvement database. The hazard of OFD was modeled with a shared frailty survival model, with SAS 9.3 PHREG procedure (SAS Institute Inc., Cary, NC). The study population was 58% Ayrshire and 42% Holstein cows. The median herd size and mean milk yield in the study herds were 116 cows and 9,151 kg of milk per cow per year. The overall probability of OFD was 6.0%; 1.8% of the cows died unassisted and 4.2% were euthanized. Variation in OFD percentage between individual herds was large, from 0 to 16%, accounting for 0 to 58% of all removals in the herds. Keeping close-up dry cows in their own group was associated with higher hazard of OFD [hazard ratio (HR) = 1.37] compared with keeping them in the same pen with far-off dry cows. Higher hazard on OFD was observed when barns had only one kind of calving pen; single (HR = 2.09) or group pens (HR = 1.72), compared with having both of those types. The hazard of OFD was lower if the whole herd was housed in barns or pens that had only 1 type of feed barrier at the feed bunk, namely post-and-rail (HR = 0.51) or a type with barriers between the cow's heads (HR = 0.49), compared with having 2 types. Lower OFD hazard was observed with wider than 340 cm of walking alley next to the feeding table (HR = 0.75), and with housing a whole herd in pens with only 1 type of walking alley surface, specifically slatted (HR = 0.53) or solid (HR = 0.48), compared with having both types. The hazard of OFD was higher with stalls wider than 120 cm (HR = 1.38) compared with narrower stalls. The hazard of OFD was also associated with breed, parity, and calving season. This study identified many factors that contribute to the incidence of OFD of dairy cows. The solutions for reducing on-farm mortality include housing, management, and breeding choices that are most probably herd specific.

Effect of oral calcium bolus administration on milk production, concentrations of minerals and metabolites in serum, early-lactation health status, and reproductive performance of Holstein dairy cows

AIMS: To determine the effects of oral Ca bolus administration in the early postpartum period of cows on milk yield and composition, blood metabolites, early-lactation health status, and reproductive performance.METHODS: Multiparous Holstein dry cows (n=66) with a mean parity of 3.1 (SD 0.35) were fed a diet with a positive dietary cation–anion difference (DCAD) prior to calving. They were randomly assigned to receive no treatment (Control; n=33) or two oral Ca boluses (n=33, 45 g of Ca per bolus); one was administered immediately after calving (Day 0) and the second 24 hours (±30 minutes) later. Blood samples were collected at calving, and on Days 2 and 7 to determine concentrations in serum of Ca, P, Mg, glucose, non-esterified fatty acids (NEFA), and β-hydroxybutyric acid (BHBA). Milk yield was recorded daily and milk composition was determined weekly from calving until 28 day postpartum. Health and outcomes were determined during the first 30 days postpartum and reproductive outcomes to 180 days postpartum.RESULTS: Mean milk yields and composition over the first month of lactation were similar between cows in the two treatment groups (p>0.1). Mean concentrations of Ca in serum were not different between treatment groups on Day 0, but were higher on Day 2 for cows that received oral Ca boluses (1.77 (SE 0.07)) compared with Control cows (1.54 (SE 0.08)) (p=0.04). Concentrations in serum of P, Mg, glucose, NEFA and ΒHBA did not differ between treatment groups on any day of measurement. Fewer cows that received oral Ca were diagnosed with hypocalcaemia (total concentrations of Ca in serum <1.5 mmol/L) by Day 2 (2/33; 6%) compared with Control cows (12/33; 36%) (p=0.01). There was no difference in the prevalence of other health outcomes between treatment groups. The proportion of cows conceiving to first insemination was greater in cows that received an oral Ca bolus (19/29; 65%) than Control cows (12/29; 41%) (p=0.01).CONCLUSIONS: Oral Ca bolus administration increased concentrations of Ca in serum on Day 2 postpartum, and increased first service conception rates, in cows fed a diet with a positive DCAD prior to calving compared to cows that received no oral Ca bolus supplementation. Because of the small number of cows used in this study, further studies in large-scale dairy farms should be carried out to confirm these findings.

Impact of automatic milking systems on dairy cattle producers’ reports of milking labour management, milk production and milk quality

Automatic milking systems (AMS), or milking robots, are becoming widely accepted as a milking technology that reduces labour and increases milk yield. However, reported amount of labour saved, changes in milk yield, and milk quality when transitioning to AMS vary widely. The purpose of this study was to document the impact of adopting AMS on farms with regards to reported changes in milking labour management, milk production, milk quality, and participation in dairy herd improvement (DHI) programmes. A survey was conducted across Canada over the phone, online, and in-person. In total, 530 AMS farms were contacted between May 2014 and the end of June 2015. A total of 217 AMS producers participated in the General Survey (Part 1), resulting in a 41% response rate, and 69 of the respondents completed the more detailed follow-up questions (Part 2). On average, after adopting AMS, the number of employees (full- and part-time non-family labour combined) decreased from 2.5 to 2.0, whereas time devoted to milking-related activities decreased by 62% (from 5.2 to 2.0 h/day). Median milking frequency was 3.0 milkings/day and robots were occupied on average 77% of the day. Producers went to fetch cows a median of 2 times/day, with a median of 3 fetch cows or 4% of the herd per robot/day. Farms had a median of 2.5 failed or incomplete milkings/robot per day. Producers reported an increase in milk yield, but little effect on milk quality. Mean milk yield on AMS farms was 32.6 kg/cow day. Median bulk tank somatic cell count was 180 000 cells/ml. Median milk fat on AMS farms was 4.0% and median milk protein was 3.3%. At the time of the survey, 67% of producers were current participants of a DHI programme. Half of the producers who were not DHI participants had stopped participation after adopting AMS. Overall, this study characterized impacts of adopting AMS and may be a useful guide for making this transition.

Influence of feeding supplements of almond hulls and ensiled citrus pulp on the milk production, milk composition, and methane emissions of dairy cows

Almond hulls and citrus pulp have been fed to dairy cows with variable responses for milk production, but no information exists on their effect on enteric methane emissions. This experiment examined the effects of dietary supplementation with either almond hulls or ensiled citrus pulp on the milk yield, milk composition, and enteric methane emissions of dairy cows. Thirty-two Holstein dairy cows in mid lactation were offered 1 of 3 diets over a 28-d experiment. Twelve cows received a control (CON) diet, 10 cows a diet containing almond hulls (ALH), and 10 cows a diet containing ensiled citrus pulp (CIT). All cows were offered 6.0 kg of dry matter (DM)/d of crushed corn, 2.0 kg of DM/d of cold-pressed canola, and 0.2 kg of DM/d of a mineral mix. In addition, cows fed the CON diet were offered 14.5 kg of DM/d of alfalfa cubes; cows fed the ALH diet were offered 10.5 kg of DM/d of alfalfa cubes and 4.0 kg of DM/d of almond hulls; and cows on the CIT diet were offered 11.5 kg of DM/d of alfalfa cubes and 3.0 kg of DM/d of ensiled citrus pulp. Milk yield was measured daily and milk composition was measured on 4 d of each week. Individual cow methane emissions were measured by a sulfur hexafluoride tracer technique on d 24 to 28 of the experiment. The mean milk yield of cows fed the CON diet (27.4 kg/d) was greater than the mean milk yield of cows fed the ALH diet (24.6 kg/cow per day), whereas the mean milk yield of cows fed the CIT diet (26.2 kg/cow per day) was not different from the mean milk yield from cows fed the other 2 diets. Dietary treatment did not influence the concentrations of milk fat, protein, and lactose or fat yields, but the mean protein yield from cows fed the CON diet (0.87 kg/d) was greater than that from cows fed the ALH diet (0.78 kg/d) but not different to those fed the CIT diet (0.85 kg/d). In general, we found no differences in the proportion of individual fatty acids in milk. The mean pH of ruminal fluid from cows offered the CON diet was not different to the pH in the ruminal fluids of cows offered the ALH or the CIT diets. The mean methane emissions (g/d) and yields (g/kg of DM intake) were not influenced by dietary treatment. These findings indicate that, although almond hulls and ensiled citrus pulp can be used as a low-cost feed supplement, almond hulls did negatively affect milk production and neither inhibited enteric methane emissions.

Evaluation of milk components as diagnostic indicators for rumen indigestion in dairy cows.

OBJECTIVE To identify milk component alterations that might be useful for detecting cows with rumen indigestion. DESIGN Prospective case-control study. ANIMALS 23 Holstein cows with rumen indigestion (cases) and 33 healthy cohorts (controls) from 1 herd. PROCEDURES Cases were defined as cows between 30 and 300 days postpartum with a > 10% decrease in milk yield for 2 consecutive milkings or > 20% decrease in milk yield from the 10-day rolling mean during any milking, abnormally decreased rumen motility, and no other abnormalities. Each case was matched with 2 healthy cows (controls) on the basis of pen, parity, days postpartum, and mean milk yield. Some cows were controls for multiple cases. All cows underwent a physical examination and collection of a rumen fluid sample for pH measurement at study enrollment. Individual-cow milk yield and milk component data were obtained for the 16 milkings before and after study enrollment. Rumen motility and pH and milk components were compared between cases and controls. RESULTS Rumen motility for cases was decreased from that of controls. Cases had an abrupt increase in milk fat percentage and the milk fat-to-lactose ratio during the 2 milkings immediately before diagnosis of rumen indigestion. Receiver operating characteristic analyses revealed that a 10% increase in the milk fat-to-lactose ratio had the highest combined sensitivity (57%) and specificity (85%) for identifying cows with rumen indigestion. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that a positive deviation in the milk fat-to-lactose ratio might be useful for identifying cows with rumen indigestion.

Effect of paddy straw based complete rations with different levels of neutral detergent fibre on microbial protein synthesis in dairy cows during early and mid lactation

A study was conducted on 18 lactating dairy cows (mean milk yield, 10 kg/day) for 6 months by feeding paddy straw based complete rations containing different levels of NDF, in 2 phases, viz. early and mid lactation, to assess the microbial protein synthesis using purine derivatives (PD) excreted in urine. Isonitrogenous and isocaloric complete rations; T1, T2 and T3 with 25, 30 and 35% NDF, respectively, were formulated as per ICAR (1998). Paddy straw was the sole source of roughage NDF and the rest of was NDF met by non-forage sources, in 3 diets. PD excreted through urine was comparable between the dietary treatments, in phases I and II. The microbial protein (MBP) synthesis in T1, T2 and T3 was 997.01, 825.91 and 842.06 g, respectively, in phase I; and 1127.93, 1106.74 and 1157.24 g, respectively, in phase II. The TDN intake calculated from the values of digestibility coefficients of nutrients in T1, T2 and T3 was 5.18, 5.86 and 6.10 kg in phase I; and 8.63, 8.81 and 9.00 kg, in phase II, respectively. The efficiency of MBP production/kg of TDN was 192.47, 140.94, and 138.04 g in phase I; and 130.70, 125.62 and 128.58 g in phase II, respectively in T1, T2 and T3. Results suggested that complete diets with 25% are the most ideal NDF level in early lactation while all three NDF levels, viz. 25, 30 and 35% are ideal in mid lactation.

Determination of Reproduction and Lactation Parameters in the First Production Year of Brown Swiss and Simmental Cows Imported from Austria

This study was aimed at determining the adaptation levels of pregnant Brown Swiss and Simmental cows, imported from Austria to a dairy cattle enterprise in Manisa, according to their first year performances. Reproduction and milk yield performances of Brown Swiss and Simmental cows was focused in this paper. Insemination, pregnancy and birth parameters for Brown Swiss and Simmental cows were found to be similar. The first insemination interval and gestation length of Simmental cows were shorter than Brown Swiss cows. For Brown Swiss and Simmental cows, real milk yield was 9205.61 L and 8351.05 L; milk yield for 305-days was 8115.71 L and 7693.44 L; the lactation period was 356.0 days and 337.7 days respectively. The differences between breeds according to real and 305-days milk yield were statistically significant. The cows that calved in November and December reached a higher milk yield performance. The effect of calving month on cows’ persistence in first lactation was significant, but the effect of breeds was not significant. Considering that the mean milk yields of Brown Swiss and Simmental cows in first lactation were over eight thousand liters, it can be said that the cows imported from Austria genetically have dairy potential and they can show this dairy potential from the first yield-year onwards.