Evaluation of predictive ability of linear type gonadal traits on reproductive capacity of breeding dairy bulls.

Dimensions of linear type traits facilitate selection of livestock for breeding and rearing. To date, use of linear type traits for selection of breeding bulls is highly concentric to scrotal circumference (SC), with probable overlook to other important traits. Present study reported the importance of various gonadal linear type traits on spermatozoa production, age-related changes in gonadal linear type traits of bulls and predictive ability of these traits on bulls' reproductive potentials. Among all gonadal traits, testicular density (TD), scrotal volume (SV), paired testicular weight (PWT) and SC were found most important predictor variables in order, which can discriminate between good/poor breeding bulls, that is, produced frozen semen doses (FSD) or not. Dimensions of gonadal traits increased significantly up to 36 months age and thereafter, development became slow and negligible. In contrast, TD decreased by 30%, 51%, 64%, 68% and 71% at 12, 24, 36, 48 and >49 months age, respectively, from its base value at 6 months. Bulls of lower TD (≤0.88 g/cm3) had significantly higher ejaculate volume (+9%), sperm motility, sperm concentration (+100 million/mL) and sperm output (+26%)/ejaculate as compared to bulls of higher TD (>0.88 g/cm3). Discriminant function was developed using TD, SV, PWT and SC to identify bulls of superior reproductive potentials. It was concluded that among the investigated traits, TD was the strongest to discriminate between FSD and Non-FSD bulls. Therefore, our findings suggested that TD could be more potential trait than SC for dairy bulls' breeding soundness evaluation and assessment of reproductive ability.

Effect of loose house dairy cattle barn modification on udder health and production performance of Jersey crossbred cows in tropical lower Gangetic plains.

The results reported in this research communication aimed to reduce the housing discomfort and mastitis incidence of lactating Jersey crossbred cows through modifications to the roof and floor of loose housing stalls. The experiment was conducted on twenty Jersey crossbred cows and they were distributed equally into two different types of housing: (i) existing shed/control group (T0) - concrete floor and asbestos roof and (ii) modified shed/treatment group (T1)- sand flooring (4-6 inch deep; 38% of total area) and a thatch ceiling (4″ thick) under an asbestos roof. Under-roof surface temperature differed significantly (P < 0.01) between the two sheds during both the winter season but a greater difference was observed in the summer (modified sheds were 5-9 °C cooler than the control shed during peak hours (10 am to 3 pm) of the day. The milk yield (kg/d) in both seasons was significantly higher in the treatment group than in the control group (P < 0.01). The overall milk fat and total solid percentage were significantly higher in the treatment than the control group (P < 0.01) but solids not fat (SNF) did not show any difference between the groups. The percentage of milk fat did not differ significantly between the seasons, while the SNF and total solids were also significantly higher in the winter than the summer season (P < 0.01). There was a significantly lower subclinical mastitis test score (MCMT grade: P < 0.05) in the treatment group than in the control group. In the treatment group, the somatic cell count (SCC) was numerically but non-significantly less than in the control group. No differences in MCMT and SCC were observed between seasons (P > 0.05). It was concluded that the provision of sand as stall flooring and an under-roof thatch ceiling as a heat insulator was significantly associated with increased milk yield, milk composition and possibly, lower somatic cell count in dairy Jersey crossbred cows. However, since the study was limited to a single replicate of each housing system with analysis done at individual cow level, further work is needed to confirm these conclusions.

Effect of seasons and photoperiods on seminal attributes and sperm morphology in Holstein Friesian × Sahiwal crossbred dairy bulls.

Cattle being non-seasonal breeding species, effects of photoperiods on sperm traits and morphology had been reported inadequately in breeding bulls. To elucidate the plausible existence of effects of photoperiods and seasons, seminal traits of Holstein Friesian × Sahiwal crossbred dairy bulls (N = 557) were analysed using different statistical models. A present study revealed that the biological rhythm of reproduction oscillated almost in parallel to the annual changes of natural photoperiods even in non-seasonal breeding species like cattle bulls. Semen traits diminished to the lowest in winter solstice (WS ± 45 days), progressively increased with the rising day length of spring (vernal equinox ± 45 days), reached a peak in summer solstice (SS ± 45 days), and then gradually reduced with decreasing photoperiod of the autumn equinox (AE ± 45 days). From summer solstice to winter solstice, sperm concentration reduced by 90.53 million/ml (8.85%), total sperm count/ejaculate decreased by 785 million (13.87%), total motile sperm count/ejaculate reduced by 17.59%, and total post-thaw motile sperm counts/ejaculates diminished by 38.64%. In short-duration photoperiods (≤ 12 h), bulls had a significantly (P < 0.01) higher incidence of major, minor, tail abnormality and total aberrant sperm% compared to that of long-duration photoperiods (> 12 h). Solstice equinox-based seasonal classification provided better insight into photoperiodicity on bulls' semen quality and sperm traits as compared to conventional meteorological classification of seasons. It was concluded that photoperiods affect sperm productivity, semen quality, and sperm morphology in non-seasonal breeding species like dairy bulls, maintained at transitional latitude (29° N) tropical climate. Bulls' reproductive ability was more influenced by the phases of increasing/decreasing day length duly primed by climax/trough of photoperiods, compared to mere long/short duration of photoperiods.

Association of linear type pelvic traits with testicular characteristics and reproductive capability of breeding dairy bulls.

Associations of pelvic linear type traits (PLT) on production and reproduction of cows were widely documented; in contrast, importance of PLT on bulls' reproductive ability, semen quality, semen cryo-preservability, frozen semen doses (FSD) production etc. was inadequately reported. The present study was conducted on Frieswal bulls (N = 378, age: 6-91 months, m) to assess age-wise growth dynamics of pelvic dimensions, classifying age into 6 groups (6 m, 7-12 m, 13-24 m, 25-36 m, 37-48 m, >48 m). Iso-age group bulls' (N = 100; 25-36 m) records were analysed after classifying seasons (summer/rainy/winter) of semen collection, if pelvic morphometric traits had any practical associations with testicular traits, semen quality and FSD production or not. A discriminant function was developed based on PLT, which showed poor predictive ability to distinguish FSD/non-FSD category bulls. Age significantly influenced growth and dimensions of gonadal and external pelvic morphometry traits. The dimensions of PLT increased at higher rate up to 36 m age and thereafter enhancement became insignificant. Pelvic linear type traits were positively (p < .01) associated with testicular/scrotal traits. Among PLT studied, pelvic triangle area (PTA) was the strongest discriminating variable to distinguish between good and poor breeding bulls. Bulls of larger PTA (≥1000 cm2 ), at average 30 m age, produced relatively inferior-quality semen, viz. lower volume (-3%), sperm concentration (-48 × 106 /mL), motility, semen quality index, total sperm counts/ejaculate (-601 × 106 ), motile sperm counts/ejaculate (-474 × 106 ) and total post-thaw motile sperm counts (-226 106 ), than bulls of lesser PTA (<1000 cm2 ). It was concluded that external PTA could be a useful addition to the bulls' breeding soundness evaluation.

Effect of supplementation of phytogenic feed additives on intake, in vitro fermentation, growth performance and carcass traits in weaned Barbari kids reared under intensive feeding.

Twenty-four weaned male Barbari kids (age 144.67 days; weight 11.99 ± 0.49 kg) were divided equally into three groups (T1, T2, and T3) in order to investigate the effect of supplementation of phytogenic feed additives (herbal mixture) in the complete pelleted feed on growth performance, in vitro rumen fermentation and carcass quality in kids reared under stall-fed condition. Treatment groups were as follows: T1, concentrate mixture (40%) plus arhar (Cajanus cajan) straw (60%) in total mixed ration (TMR) form fed ad libitum; T2, T1 diet in complete feed pellets form fed ad libitum; and T3, T1 diet in complete feed pellets form supplemented with herbal mixture (Tulsi/Haldi/Amla/Arni; ratio 1:1:1:1 on DM basis) at 0.5% in complete feed fed ad libitum. The experimental kids in each group were allowed for feeding for 8 months by following the respective feeding schedule. Rumen fermentation pattern under in vitro system was also studied using the same three diets as substrates. After 240 days of feeding, all goats were slaughtered following standard protocol. Total body weight gain (kg) and average daily gain (ADG, g/day/kid) were 18.57, 22.26, and 23.06 kg, and 79.91, 101.49, and 100.18 g in T1, T2, and T3 treatments, respectively. Pelleting of TMR (T2) and supplementation of herbal mixture in pelleted feed (T3) increased (P < 0.001) average daily weight gain in Barbari kids compared to T1 (TMR). Average dry matter intake (DMI, g/day/kid) during growth trial was greater (P < 0.05) in T3 (1079.17) than T1 (849.76) and T2 (968.76). Feed conversion efficiency was 8.92, 9.48, and 8.68% in T1, T2, and T3, respectively. The difference was statistically non-significant among the treatments. Supplementation of herbal mixture in the complete pelleted substrate had adjunct effect on improvement of TCA-precipitable-N and total VFAs in the incubation medium under in vitro system. Carcass weight (kg) tended to increase in finisher kids under T2 (16.58) and T3 (16.70) than T1 (14.61), but the variation was non-significant. The dressing percentage was similar among three treatments. Similarly, the muscle protein, fat, and cholesterol contents remained unaffected by different dietary treatments. Therefore, it may be concluded that densification of feeds in the form of complete pelleted feed and further supplementation with potential phytogenic feed additives increased total DMI and ADG and tended to enhance meat production potential in finisher Barbari kids without changing the meat chemical composition.

Non-gonadal linear type traits can discriminate reproductive ability of breeding dairy bulls.

Linear type traits are easily measurable phenotypic characteristics that help breed characterization, selection of animals for breeding and found to be associated with animals' performance. Unlike cows, there have been limited studies linking body linear traits with male reproductive ability and semen cryo-preservability of breeding bulls. Present study reported the age-related changes in body linear type traits in Frieswal (N = 378) dairy bulls and its relevance with reproductive potentials of breeding bulls. Our results indicated that body frame size traits were significantly and positively correlated with gonadal linear traits. Among the selected body mophometric parameters body length, chest girth and head circumference were the important body linear type traits having capability to discriminate between bulls of frozen semen doses (FSD) and non-FSD categories. Discriminant function has been developed based on body linear traits of crossbred dairy bulls to find out males of superior reproductive potentials. Our finding provided evidence that body length (humerous tuberosity to tuber ischii) was the most powerful linear body trait associated with breeding bulls' reproductive ability and semen quality.

Impact of environmental factors on physiological adaptability, thermo-tolerance indices, and productivity in Jersey crossbred cows.

Environmental stressors such as temperature, humidity, rainfall, photoperiod, etc. under tropical conditions are some of the important limiting factors for optimum expression of production and reproduction in dairy cows. The present study evaluated changes in cardinal physiological responses, heat tolerance indices, and milk yield in Jersey crossbred cows due to abiotic stress. Climograph was developed using daily maximum and minimum temperatures, humidity, and rainfall at livestock farm over a period of 15 years. Seasons significantly (P < 0.01) influenced cardinal physiological responses and thermal adaptability of Jersey crossbred cows. Diurnal environmental variations between morning and afternoon of the shed caused increase in body temperature, pulse, and respiration rate by 0.59-0.91%, 4.95-7.18%, and 9.73-32.37%, respectively. Thermal adaptability of cows showed significant (P < 0.01) higher deviations from perfect state of adaptability during summer, monsoon, and post-monsoon as compared to winter and spring seasons. The responsiveness and ranking of cows were dissimilar among 3 heat tolerance indices, viz., Iberia heat tolerance index, Benezara's coefficient of adaptability, and Dairy Search Index (DSI). Enhanced respiration rate was the most important observable bio-indicator to poor thermal adaptability. Good thermo-tolerant cows had 8.86% higher (P < 0.05) monthly milk yield per cow than poorly adapted ones. Findings of this study suggest that deviations in cardinal physiological responses across the seasons are very reliable and simple estimates for evaluating levels of thermo-tolerance in crossbred cows.

Effect of heat stress amelioration through open-ridge ventilated thatched roof housing on production and reproduction performance of crossbred Jersey cows.

The present study was conducted to assess the impacts of loose house roofing designs and materials on modulation of micro-climate of the cow shed and its influences on production and reproduction performance of lactating crossbred Jersey cows. The control group (T0) was kept in a traditional single-slope asbestos roof shed and treatment group (T1) at a specially designed open-ridge ventilated, double-slope thatch roof shed. Lactation stage, average daily milk yield, and average parity at the beginning of the experiment were kept similar between T0 and T1 cows. The specifically designed T1 shed had significantly (P < 0.05) lower temperature, humidity, and thermal humidity index as compared to the traditional shed (T0). The T1 shed was cooler and more comfortable than T0. Housing significantly (P < 0.05) influenced cardinal physiological parameters of resident cows. Body temperature, pulse rate, respiration rate, and discomfort index were significantly (P < 0.05) higher in T0 as compared to those in T1 cows. Improved housing significantly (P < 0.01) influenced milk yield, composition, quality, and udder health of cows. Daily milk yield depending on parity, monthly milk yield, milk fat, SNF, and protein were significantly (P < 0.01) higher in T1 than those in T0 cows. The milk somatic cell count, modified California mastitis test score, electrical conductivity, and pH of milk samples of T0 cows were significantly (P < 0.0) higher than those of T1. Effect of housing type, parity, and interaction of housing × parity did not cause any significant (P > 0.05) differences in reproductive traits such as service period, break period, calving interval, pregnancy rate, and other cow fertility parameters. Post-partum body condition score and body weight loss did not differ significantly (P > 0.05) between the two groups; however, more loss occurred in T0 than T1. The estimated net profit from housing of cows (N = 20) in a comfortable shed was 2200 kg milk per annum, i.e., 110 kg/cow/annum. The study concluded that a central open-ridge ventilated, double-slope thatched roof design created a favorable micro-environment and it significantly affected cows' comfort index; thermo-comfortable housing significantly reduced the heat stress-oriented drop in milk yield and decline in milk composition, and improved udder health and other milk production traits; however, its impact was non-significant on reproduction and fertility traits in Jersey crossbred cows.

Influence of pre and postpartum alpha-tocopherol supplementation on milk yield, milk quality, and udder health of Jersey crossbred cows at tropical lower Gangetic region.

BACKGROUND AND AIM: Alpha-tocopherol supplementation influences milk yield, milk quality, and udder health of dairy cows, which needs to be investigated for Jersey crossbred cows at hot-humid climate. Therefore, the present study was framed with an objective to study the effect of pre and postpartum Alpha-tocopherol supplementation on milk yield, milk quality, and udder health status of Jersey crossbred cows at tropical climate. MATERIALS AND METHODS: For this study, 19 similar parity, body condition score, and production level dairy animals were separated randomly into three groups, namely, Control, T1 and T2. Control group (no supplementation) was compared with two treatment groups, namely, T1 and T2. Supplementation of Alpha-tocopherol was done in concentrate fed to the animals (at 1 g/cow/day) 30 days prepartum to 30 days postpartum in T1 and 30 days prepartum to 60 days postpartum in T2 groups. Observations were taken for different parameters up to 5 months of lactation. RESULTS: Statistically analyzed data revealed that overall significantly (p<0.01) more milk production was found in T2, followed by T1 than the control group. Overall significantly (p<0.01) lower somatic cell counts and modified California mastitis tests were recorded in T2, followed by T1 than the control group. Overall significantly (p<0.01), better milk quality in terms of methylene blue reduction test was found in T2, followed by T1 than control groups. Differences in the milk composition of all three groups were non-significant (p>0.05). CONCLUSION: Supplementation of Alpha-tocopherol during prepartum to initial lactation period may enhance milk yield, milk quality, and udder health status of Jersey crossbred cows at the tropical lower Gangetic region.