The aim of the research reported in this paper was to evaluate plasma concentrations of energy, oxidative and inflammatory biomarkers of Simmental (sire) × Holstein (dam) crossbred cows, in comparison with the two parental breeds during the peripartal and early lactation periods and to estimate the effects of heterosis for these traits. Thirty-three animals, managed under the same conditions, 8 Simmental (SI), 9 Holstein (HO) and 16 crossbred (CR) cows were enrolled in this study. Glucose, non-esterified fatty acids (NEFA), β-hydroxybutyrate (BHB), total bilirubin, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), creatine kinase (CK), total protein, albumin, creatinine and urea were determined in blood sampled at six different time points (30 ± 3 and 15 ± 3 d before the expected calving date, at calving and 15, 30 and 60 d after calving). Furthermore, derived reactive oxygen metabolites (d-ROMs), biological antioxidant potential (BAP), interleukin-6 (IL-6), haptoglobin (Hp) and serum amyloid A protein (SAA) were determined to evaluate inflammatory and oxidative status. Results showed that the CR group had significantly lower average values of glucose and NEFA when compared to HO group; signifcantly lower values of urea than SI group and significantly higher values of creatinine than HO. Furthermore, CR cows showed the lowest average value of d-ROMs with respect to SI and HO parental breeds. Finally, the average value of haptoglobin was significantly lower in CR and HO groups, when compared to SI group. As for the heterosis we found the highest (positive) percentage for CK (98%) and BAP (47%) and the lowest (negative) percentage for OSi (−75%) and d-ROMs (−39%). A negative percentage was also found for the glucose (−11%) and NEFA (−20%) toward the Simmental parental breed. Our results suggest a different response among the three genetic groups during the peripartal and early lactation periods. In particular, CR and SI cows seem more adaptable regarding energy metabolism and oxidative status. Heterosis led to a positive effect on those parameters in Simmental (sire) × Holstein (dam) crossbred cows F1 population (50% Simmental and 50% Holstein).

Yield gaps in milk production are here defined as the differentials between the actual yield obtained by the dairy farmer and the potential farm yield (production achieved by the top 10% of farmers: Gap 2) as well as the differential between this potential farm yield and the yield registered in the research stations (Gap 1). Assessment of yield gaps provides valuable information on potential production enhancement and drivers behind yield gaps. Milk production can be increased by narrowing the predominant large yield gaps in resource-poor smallholder farming system. Hence, this study assessed the milk yield gap and factors affecting the yield gap in Ri-Bhoi district of Meghalaya, a state located in the north-eastern Himalayan region of India. This research paper provides a scope for exploring the possibilities for improving dairy production in the state as well as contributing to literature through incorporating crucial determinants responsible for milk yield gap. A sample of 81 respondents was drawn purposely from two blocks of the district. The results indicated that the average number of cattle per household was 9.38 in standard animal units. The total yield gap was estimated at 6.20 l (91.06%) per day, composed of 0.80 l (11.76%) per day of yield gap I and 5.40 l (79.30%) per day of yield gap II. This demonstrates that the top performing farms were achieving a production level not dissimilar to that obtained on the research stations, but many were doing far less well. The size of cattle shed, dairy farming experience, concentrate price and human labour were the important determinants of the yield gap. Hence, encouraging the right stocking density of cattle, training on the preparations of home-made concentrates, access to cheap and quality concentrates, incorporating training and experience sharing on proper dairy management practices and use of technology could benefit the dairy farmers of the region.

An experiment was conducted to evaluate whether a reduction in dietary crude protein (CP) and genotype affects animal performance, feed efficiency and carcass traits of beef cattle at different stages of the feedlot. Twenty-two Nellore and 22 crossbred F1 Angus × Nellore (Nellore: 8 months, initial body weight (iBW) = 212.7 kg; Crossbred: 8 months, iBW = 226.1 kg) were used in this experiment. The experiment was conducted in a complete randomized design with six replicates, in a 2 × 3 factorial design. The factors were two genotypes (Nellore and Crossbred) and three CP concentrations (100, 120 and 140 g/kg dry matter [DM]). The experimental period lasted 224 day, being divided into two stages (Backgrounding = 112 day, and Finishing = 112 day). At the end of the experiment, all animals were slaughtered to evaluate their carcass characteristics. Similar patterns were observed during backgrounding and finishing phases on intake and average daily gain (ADG) regarding genotype. Intakes of DM, organic matter, CP, neutral detergent fibre, non-fibre carbohydrates and total digestible nutrients, ADG (kg/day) and feed efficiency were greater in Crossbred animals than Nellore in both phases. During the backgrounding phase, dietary CP did not influence DM intake. However, a linear effect of CP on ADG was observed in the backgrounding phase. During finishing, Nellore cattle fed 100 g CP/kg DM presented lower ADG than Nellore fed 120 and 140 g CP/kg DM. Crossbred animals were heavier than Nellore at the beginning and end of the trial. Crossbred animals also gained more carcass, retained more CP and fat, and had a greater subcutaneous fat thickness during the experiment compared with Nellore. There was a quadratic effect of dietary CP on retained CP and dressing. The current study found that crossbred animals (F1 Angus × Nellore) not only had greater performance, but also better carcass traits compared with Nellore, representing an option for increasing productivity. Also, it is possible to adjust diets according to phase. During the backgrounding stage, 140 g CP/kg DM should be used, being reduced to 120 g CP/kg DM during the finishing stage of feedlot for Nellore and to 100 g CP/kg DM for Crossbred, without affecting performance adversely.