Short Communication: Effect of subclinical mastitis on reproductive performance of Holstein dairy cows in the Northwest of Spain

Aim of study: To investigate the effect of subclinical mastitis (SCM) before and after first artificial insemination (AI), characterized by a somatic cell count (SCC) higher than 200×103 cell/mL, on reproductive performance including first service conception rate (FSCR) and pregnancy loss (PL) in Holstein dairy cows. Area of study: The central area of Lugo, Galicia, Spain. Material and methods: This retrospective study was conducted on herd database of a population of 80 commercial Holstein dairy cow farms. A total number of 2053 lactations were included in this study. A binary logistic regression was carried out to analyse all data. Main results: The results of this study indicated that cows that registered a SCC lower than 200×103 cell/mL within 30 days after first AI were more likely to conceive pregnancy than cows with a higher SCC (31.2% and 25.1% FSCR, respectively; OR=1.285, 95% CI=1.000-1.653). Additionally, an increased SCC neither 30 days before nor 30 days after first AI had a negative effect on prevalence of PL in dairy cows. Research highlights: These findings revealed that SCM within 30 days after first AI negatively affected FSCR, whilst 30 days before first AI did not affect it. Therefore, it could be suggested that preventing subclinical mastitis after first AI, during a critical period of 30 days, is important to maximize the reproductive performance of dairy cows.

Effect of Milking Time Intervals on Production and Quality of Friesian Holstein

Milking is the act of removing milk from the udder on purpose to get maximum milk production. A reasonable milking interval will affect the amount of milk production. This research aims to know the extent of the milking time interval affecting Friesian Holstein dairy cow milk production and the interval of milking time that produces the best production and quality of Friesian Holstein. The research method was an experiment using a completely rand randomized with four treatments, namely: treatments 1 was 16:8 hours time delivery interval (TDI) dairy cow; treatments 2: time delivery interval (TDI) 15:9 hours; treatment 3: delivery time interval (TDI) 14:10 hours; treatment 4: time delivery interval (TDI) 13:11 hours. The observed variables are milk production and milk quality. The data were analyzed using verbal if any effect of treatment was done Duncan's distance test. Based on the results and discussion, the milking time interval significantly impacts milk production and water content. Still, it has no significant effect on the density, protein content, and milk fat content, 13:11 hours milking interval time produces the most milk and water content.

Milk yield of cows submitted to different levels of olive pomace in the diet

The cultivation of olive trees is expanding in Brazil, mainly in Rio Grande do Sul in order to meet the demand for olive oil, the main product of the industrialization of olives. However, from the extraction, there is a significant generation of waste. This residue has high moisture and an appropriate destination is necessary given its environmental and economic importance. The chemical composition of the residue is similar to other products used in animal feed, such as corn silage or sorghum, in relation to DM, CP and NDF, the differential being high levels of EE and ADL. In order to evaluate the replacement of corn silage by the extraction residue of olive oil (olive pomace), eight Holstein dairy cow, between 90 and 100 days of lactation, were used, making a double Latin square (4x4). Analyzes were made regarding animals, feed and milk product in order to verify the feasibility of the substitution. The inclusion of olive pomace, conserved as silage, to replace corn silage, in the diet of lactating cows up to 15% (dry basis) does not alter milk production, as well as its composition and feed efficiency.

Splenoptosis in a dairy cow and endoscopic correction of left displacement of abomasum

A third lactation Holstein dairy cow was presented with history of acute reduction in milk yield (‘milk drop’). On combined auscultation and percussion of the left costal area and paralumbar fossa, distinct sounds (‘ping’ or ‘slosh’) were identified ventrally. The case was investigated endoscopically, with two portals set-up either side of the 13th left rib. The abomasum was displaced and congested, and ecchymoses were found on its greater curvature. The spleen was not visible on the initial examination. The spleen became visible following abomasocentesis and deflation of the abomasum. Unlike the normal spleen that has a sharp caudal edge, this one’s edge appeared swollen. The swelling was consistent with splenomegaly, due to the compromised blood circulation following the splenoptosis.

PSXIII-32 Effects of rumen-protected niacin on dry mater intake, rumination, and milk production in multiparous Holstein dairy cow during transition period

The dairy cows decrease dry mater intake (DMI) before calving and are frequently in negative energy balance after calving. The objective of this study was to investigate the effect of rumen-protected niacin (NA) on DMI, rumination, and milk production in multiparous Holstein dairy cows during transition period. Eighteen multiparous Holstein dairy cows were allocated into 3 groups: (1) control diet (Con; n = 6), not supplemented with NA, (2) supplemented diet 1 (NA1; supplemented with 20 g NA/cow daily, n = 6), and (3) supplemented diet 2 (NA2; supplemented with 40 g NA/cow daily, n = 6). Experimental stage was from 49 d before calving until 21 d after calving. Daily TMR intake was monitored by Roughage Intake Control System, and daily rumination time was monitored by Hr-Tag rumination monitoring system and milk yield was recorded every day after calving. Blood samples were collected on d -49, -35, -21, -14, -7, 1, 3, 7, 14, 21, and 28 relative to parturition for quantifying concentrations of neuropeptide Y (NPY) and orexin A (OXA). The 20 g/day NA feeding increased DMI during transition period (P < 0.05). The concentrations of NPY and OXA, which are the intake related hormones, were significant higher in NA1 than the other two groups in the first two weeks after calving (P < 0.05). Moreover, the daily rumination time in NA1 was significantly higher than the control group from two weeks before calving to the first week after calving (P < 0.01). The 20 g/day NA feeding significantly increased milk yield (P < 0.05) compared to control group in early lactation. Overall, our study demonstrated that 20 g/day NA feeding could improve DMI and production in fresh cows, while those improvements were not detected with 40 g/day NA feeding.