Accuracy of pregnancy/non pregnancy diagnosis in zebu and crossbred cattle and Murrah buffaloes by milk progesterone determination post insemination

Tropical Animal Health and Production - Milk samples collected on days 0, 6, 20, 22 and 24 post insemination from Sahiwal and Tharparkar (zebu) cows, Karan Swiss (Sahiwal × Brown Swiss) and...     

Divergent development of testosterone secretion in male zebu (Bos indicus) and crossbred cattle (Bos indicus x Bos taurus) and buffaloes (Bubalus bubalis) during growth

Delayed pubertal development and low fertility of Bos indicus x Bos taurus crossbred male cattle and domestic buffaloes is hardly understood hence, a sensitive enzymeimmunoassay (EIA) was developed using the second antibody-coating technique and testosterone-3-O-carboxymethyloxime-horseradish peroxidase conjugate as a label for determination of testosterone in blood plasma. The EIA was validated by standard criteria. Blood samples were collected by venipuncture from growing male cattle (Karan Fries and Sahiwal) and buffalo (Murrah) and testosterone was estimated using the EIA procedure. Plasma testosterone concentrations increased significantly (P < 0.05) with advancing age. Testosterone concentrations were significantly (P < 0.01) higher in Sahiwal males in comparison to Karan Fries males. The low testosterone levels in crossbred than Sahiwal could imply that crossbred males have either not stabilized genetically or not adapted well in Indian climatic conditions resulting in poor libido and poor semen quality. The low testosterone levels in Murrah buffalo males may be the possible reason for delayed maturity in this species. The direct, sensitive EIA validated for estimating the plasma testosterone concentration was reliable for studying the testosterone profile in blood plasma of males. The results suggest that there could be a requirement for higher testosterone secretion by males during early stages of growth for attaining early sexual maturity.     

Additive and heterosis effects on preweaning traits, maternal ability and reproduction from crossing of the Angus and brown Swiss breeds in Florida

Angus (A), Brown Swiss (S) and A X S reciprocal F1 (AS) dams were mated to A, S and AS (also reciprocal F1) sires resulting in nine breed groups of progeny with varying proportions of Angus and Brown Swiss breeding. Breed group of dam and of sire significantly influenced birth weight, preweaning daily gain, weaning weight, 205-d weight, condition score and frame size. The means for birth weight and weaning weight were 33 and 213 kg, respectively. Brown Swiss bulls sired calves with the heaviest birth and weaning weights. Calves produced by S dams likewise were heavier at birth and weaning. Pregnancy rates were influenced significantly by year, age and breed of dam and averaged 79, 95 and 92% for S, AS and A cows, respectively. Survival rate averaged 97% and was not influenced significantly by any of the effects examined. Because survival rates were similar for all breed groups, the results for weaning rate paralleled those for pregnancy rate. Genetic influences on preweaning growth traits and survival rate were partitioned into additive breed differences (B) and heterosis (H) effects for direct (d) and maternal (m) components. Pregnancy and weaning rates were examined using similar analyses except that genotype of service sire of dam replaced that of the offspring for the direct additive breed and direct heterosis components. The Bd values indicated that the Angus breed was inferior (P less than .01) to the Brown Swiss breed for all preweaning growth traits except for condition score, in which the Angus breed surpassed (P less than .01) the Brown Swiss. The Bm values also showed an advantage for the Brown Swiss breed for all preweaning growth traits. The additive maternal effect (the genotype of the females exposed), Bm, was important for pregnancy rate and weaning rate (P less than .001 and P less than .05) but not for survival rate (P greater than .10). The direct additive breed effect was not important for any reproductive trait. Direct heterosis did not affect any of the preweaning or reproduction traits; however, maternal heterosis (Hm) significantly affected all traits except birth weight, frame score and survival rate. The Hm estimates were 12.0 and 8.4 kg for weaning weight and 205-d weight, respectively. The Hm estimates for pregnancy rate, survival rate and weaning rate were 10, 2 and 13%, respectively.     

Breed comparisons of Angus,Brahman, Hereford,Pinzgauer, Sahiwal,and Tarentaise for weight,weight adjusted for condition score,height, and body condition score

Data from topcross cows (n = 468) from six breeds of sire (Angus, Brahman, Hereford, Pinzgauer, Sahiwal, Tarentaise) and two breeds of dam (Angus and Hereford) of Cycle III of the Germplasm Evaluation (GPE) program at the U.S. Meat Animal Research Center (MARC) comprising cow weight (CW, n = 9,012), height (CH, n = 9,010), and condition score (CS, n = 8,991) recorded in four seasons per year from 2 to 6 yr of age were used to estimate breed-group differences. The mixed models included cow age, season of measurement and their interactions, year of birth, pregnancy-lactation code (PL), and breed group as fixed effects for CW and CS. Analyses of weight adjusted for condition score included CS as a linear covariate. Model for CH excluded PL. Random effects were additive genetic and permanent environmental effects. Differences among breed-groups were significant for all traits for different ages and were maintained across ages, with few interchanges in ranking through maturity. Cows with Sahiwal sires were lightest (392 to 479 kg), whereas Hereford-Angus (HA) reciprocal-cross cows were shortest (119 to 123 cm) at each age. Cows with Brahman sires were heaviest and tallest among breed groups at all ages, exceeding HA cows by 19 to 24 kg and 9 to 10 cm, respectively. Cows with Pinzgauer and Tarentaise sires were intermediate for weight and height and interchanged ranking across ages. Differences in weight due to differences in condition seemed to be of small magnitude because adjustment for condition score did not affect rankings of breed groups across ages. Important changes for mature size of cows can be achieved by breed substitution with the breeds of sires used in this study.     

Inhibition of NF-κB signaling pathway by astaxanthin supplementation for prevention of heat stress–induced inflammatory changes and apoptosis in Karan Fries heifers

Present study was conducted on 12 Karan Fries (Holstein Friesian X Tharparkar) heifers (10–12 months) to assess the effect of astaxanthin supplementation on heat stress amelioration and inhibition of NF-κB signaling pathway for prevention of heat stress–induced inflammatory changes and apoptosis in the cell during the summer season. The heifers were randomly and equally divided into two groups, i.e., control (fed as per ICAR 2013) and treatment groups (additionally supplemented astaxanthin at a dose rate of 0.25 mg/kg BW/day/animal). Temperature humidity index used to assess the levels of summer stress during the experimental period. Blood samples were collected at the fortnightly interval for quantification of plasma cortisol and IL-12 from both the groups of the heifers and from collected blood samples, RNA was isolated and transcribed into cDNA for real time PCR, for genes expression of NF-κB, IL-2, caspase-3, and Bcl-2. Plasma cortisol, IL-12 levels, and expression pattern of NF-κB, IL-2, and caspase-3 were significantly (P ≤ 0.05) lower in treatment group of Karan Fries heifers than control group, whereas, Bcl-2 was higher (P ≤ 0.05) in astaxanthin supplemented group. The temperature humidity index had a positive correlation (P ≤ 0.05) with plasma cortisol and IL-12 and expression pattern of NF-κB, IL-2, and caspase-3. However, it was negatively correlated with Bcl-2. The supplementation of astaxanthin can ameliorate the impact of summer stress through NF-κB downregulation, might be due to the quenching of free radicals, which regulates the expression of pro-inflammatory mediators and apoptotic genes.

     

Production characters of the Sahiwal and Ayrshire breeds and their crosses in Kenya

Summary Data were analysed for lactation characters of Ayrshire, Ayrshire×Sahiwal, Sahiwal×Ayrshire and Sahiwal females and on survival and growth characters of progeny of Ayrshire, Sahiwal, Simmental and Mixed breed sires mated to these females in the temperate highlands ecological zone of Kenya. The Ayrshire females had significiantly higher total lactation yield than the other breeding groups; however, the Ayrshire females received preferential treatment. Despite this the Sahiwal-Ayrshire crosses were superior (3.8%) to the Ayrshire females in productivity index per cow per year because of a shorter calving interval and a higher level of calf survival. Sahiwal females had significantly lower total lactation yield than Ayrshire and Sahiwal×Ayrshire cross females. At 2 years of age female progeny of Sahiwal and Simmental sires were significantly heavier than the female progeny of Ayrshire sires but not of Mixed breed sires,viz. Sahiwal×Ayrshire and calves with sires not known. The Ayrshire breed was shown to be superior to the Sahiwal breed in transmitted effects for milk production and the Sahiwal breed was superior to the Ayrshire breed in transmitted effects for growth rate. It is concluded that the Sahiwal breed has potential to contribute to both milk and beef production programmes when combined in crosses withBos taurus breeds of cattle in ecological zones similar to the lower to mid-potential areas of the temperate highlands of Kenya.

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Caracteres De Produccion De Las Razas Sahiwal Y Ayrshire Y Sus Cruces En Kenia

Resumen Se analizaron datos de los caracteres de lactación de Ayrshire, Ayrshire×Sahiwal, Sahiwal×Ayrshire y hembras Sahiwal como tambien caracteres de supervivencia y crecimiento de la progénie de Ayrshire, Sahiwal, Simmental y toros mestizos cruzados con ellas, en las tierras altas de Kenia. Las hembras Ayrshire tuvieron el más alto indice de lactancia; sinembargo éstas recibieron tratamiento preferencial. A pesar de esto, los cruces Sahiwal-Ayrshire fueron superiores (3.8%) a las hembras Ayrshire en indices de productividad vaca/año de bido a losintervalos de parición más cortos y niveles más altos de supervivencia neonatal. Las hembras Sahiwal tuvieron significativamente las producciones de leche más bajas. A los 2 años de edad, las hembras progenie de toros Sahiwal y Simmental pesaron significativamente más que las hembras progénie de toros Ayrshire pero nó de toros mestizos.La raza Ayrshire fué superior a la Sahiwal en transmitir los caracteres de crecimiento. Se concluye que la raza Sahiwal tiene potencial para contribuir a la producción de leche y carne cuando se combinan los cruces conBos taurus en zonas ecológicas similares a las más bajas y medias de las zonas montañosas frias de Kenia.

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Productivite, Au Kenya, Des Races Sahiwal Et Ayrshire, Et Des Produits De Leurs Croisements

Résumé Des documents ont été analysés concernant la lactation des femelles Ayrshire, Ayrshire × Sahiwal, Sahiwal×Ayrshire et femelles Sahiwal, le taux de survie, la croissance des produits Ayrshire, Sahiwal, Simmental et des produits métissés issus de croisement de taureaux avec ces femelles, dans la zone des hauts plateaux tempérés du Kenya.Les vaches Ayrshire ont une production lactée totale significativement supérieure à celle des autres races; il est vrai que ces femelles ont été l'objet de traitements préférentiels. Malgré cela, les produits Ayrshire×Sahiwal ont un taux de productivité par vache et par an supérieur (3,8 p. 100) à celui des femelles Ayrshire à cause d'intervalles plus courts entre les vêlages et un taux plus élevé en ce qui concerne la survivance des veaux. Les femelles Sahiwal ont une lactation totale significativement plus basse que celles des vaches Ayrshire et Sahiwal×Ayrshire. A l'âge de 2 ans, les femelles issues des taureaux Sahiwal et Simmental sont significativement plus lourdes que les femelles de taureaux Ayrshire mais pas plus lourdes que celles issues de taureaux métis (par exemple métis Sahiwal×Ayrshire et veaux dont le géniteur est inconnu).Le bétail Ayshire a été reconnu comme étant supérieur au bétail Sahiwal dans la transmission des caractères de production laitière et le bétail Sahiwal supérieur au Ayrshire en ce qui concerne le taux de croissance. En conclusion, le bétail Sahiwal peut potentiellement contribuer à la fois aux programmes visant à la production de lait et de viande lorsque croisé avec du bétail taurin (Bos taurus) dans les zones écologiquement semblables aux régions à faible et moyen potentiel des hautes terres tempérées du Kenya.

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Roman L. Hruska US Meat Animal Research center, Agricultural Research, Science and Education Administration, US Department of Agriculture, Clay Center, NE 68933 USA.     

Effect of micronutrient supplementation around calving on the plasma cortisol levels of Murrah buffaloes and Sahiwal and Karan Fries cows

Micronutrients when fed around peripartum may reduce the stress induced by cortisol. With this objective, 24 Sahiwal (SW) and 24 Karan Fries (KF) cows and 24 Murrah (Mu) buffaloes were taken and divided into four groups of six each. Vitamin E (VE), zinc (Zn) and copper were supplemented from 30 days pre- to 30 days postcalving in groups 1, 2 and 3. Animals without supplementation served as control. Blood sampling was done on days 30, 15, 7 and 3 precalving; at calving; and on days 3, 7, 15 and 30 postcalving. Plasma cortisol levels were measured by ELISA. Supplementation of VE and Zn significantly (P?<?0.05) reduced plasma cortisol levels at calving and at 30 days postcalving. KF cows exhibited best results with VE, whereas SW cows and Mu buffaloes responded best to Zn. Copper increased the peripartum cortisol levels. Reduction in cortisol levels may help in keeping the animal healthy and stronger to fight immuno-suppression generally observed around the period of peripartum.     

Evaluation of between- and within-breed variation in measures of weight-age relationships

Variation between- and within-breeds was evaluated for accretion of weight from birth to 7 yr of age and hip height at 7 yr for 1,577 cows sired by Angus, Brahman, Brown Swiss, Charolais, Chianina, Gelbvieh, Hereford, Jersey, Limousin, Maine Anjou, Pinzgauer, Sahiwal, Simmental, South Devon, and Tarentaise and from either Angus or Hereford dams. Parameters from Wt = A (1 - Be-kt) were estimated by nonlinear regressions and provided estimates of mature body weight (A) and rate of weight accretion relative to change in age (k) for each cow. Actual weight at birth, linear adjusted weights at 200, 365, and 500 d of age, ratios of these weights to mature weight, and height at the hip at 7 yr were analyzed. Beyond 20 mo, weights were adjusted to a constant condition score within breed of sire. Variance and covariance components were derived for breed (sigma 2 b), sires within breed (sigma 2 s), and progeny within sire (sigma 2 w). For all traits, the sigma 2 b estimate of genetic variance ranged from two to four times greater than the variance component for sigma 2 s. Between-breed heritabilities were .91 +/- .27 and .54 +/- .17 for A and k, respectively. Estimates of within-breed heritability for these two traits were .61 +/- .11 and .27 +/- .09. Estimates, both between- and within-breed, of the genetic correlation between A and k were moderate to large and negative; those between A and weights at 200, 365, and 500 d and height at maturity were large and positive. Selection for immediate change in measures of growth would be most effective among breeds. Sufficient direct genetic variation exists between breeds to enhance breed improvement of growth characters through breed substitution. Greater opportunity to alter the shape of the growth curve exists through selection for within-breed selection than through breed substitution.     

Expression of skin color genes in lymphocytes of Karan Fries cattle and seasonal relationship with tyrosinase and cortisol

To evaluate difference in the expression of skin color genes (melanocortin 1 receptor (MC1R) and premelanosome (PMEL)) in lymphocytes during winter and summer season and their correlation with tyrosinase enzyme and cortisol, ten Karan-Fries heifers were selected from National Dairy Research Institute (NDRI) cattle farm. Blood samples were collected from the animals during winter (THI?=?60) and summer (THI?=?83) season at weekly intervals. Relative MC1R and PMEL messenger RNA (mRNA) expression of Karan Fries cattle was found to be significantly (P?P?P?相似文献   

Growth and Survival of Holstein and Brown Swiss Calves Reared Outdoors in Individual Hutches

The effects of outdoor raising of Brown Swiss and Holstein replacement calves in individual hutches were studied on a farm having northern Mediterranean climatic conditions. A total of 240 female calves was used with 30 calves of each breed and born in each of the four seasons. The animals were kept for 3 months in individual hutches and then in groups of 10 until 6 months of age. The birth weights of the Brown Swiss and Holstein calves were 37.2±0.21 and 37.9±0.22, respectively. The average birth weights were highest in spring and lowest in winter. Breed and seasonal effects were evident at 6 months. The live weights for the two breeds at 6 months were 114.1±1.3 and 126.3±1.5 kg, respectively. The numbers of health disorders were significantly higher in the first month of life. Mortalities occurred in the following months, being 2.5% in Holsteins and 5% in Brown Swiss by 6 months of age. The results indicated that calves can be reared outdoors successfully.     

A longitudinal study of disease incidence and case-fatality risks on small-holder dairy farms in coastal Kenya

A longitudinal study was carried out in the coastal lowlands coconut-cassava agro-ecological zone of Kaloleni Division, Coast Province, Kenya between June 1990 and December 1991 to estimate disease incidence and cause-specific case-fatality risk in an average of 120 cattle in 26 small-holder dairy herds kept in two grazing-management systems. East Coast fever (ECF) was the predominant disease diagnosed; the mean monthly incidence rate was 2.5 and 6.9% in animals < or = 18 months of age under stall-fed and herded-grazing systems, respectively. In cattle > 18 months of age, the monthly incidence rate was < 1%. The 6-month ECF incidence rate was 20+/-8% (S.E.) in the stall-feeding system compared with 39+/-7% in the herded-grazing systems. There was a gradual increase in antibody prevalence with age to over 90% in cattle over 18 months of age in herded-grazing systems, whilst less than a third of cattle in the stall-feeding systems were sero-positive at any age. Overall accumulated mortality to 18 months of age was estimated to be 56%. Annual mortality in cattle > 18 months averaged 9%. Cattle managed in the herded-grazing system had a 60% higher mortality, although not significantly so, than those fed in stalls. Deaths due to ECF accounted for over two-thirds of the deaths. ECF was then the major disease constraint to small-holder dairy production in the coconut zone of coastal Kenya. Clinical cases occur the whole year round (especially in young stock)--despite apparent tick control, and in both herded-grazing and stall-feeding system.     

Effect of ovsynch versus prostaglandin F2α protocol on estrus response,ovulation rate,timing of ovulation and pregnancy per artificial insemination in Sahiwal cows

Sahiwal cow is Bos indicus which is an important dairy breed of tropical and sub‐tropical region. Research on reproduction is rare in this breed. The objectives of the present study were to determine the effect of Ovsynch (OVS) versus prostaglandin F_2α (PG) protocol on estrus response and its intensity, ovulation rate, timing of ovulation and pregnancy per artificial insemination (AI) in Sahiwal cows. Experimental cows (n = 80) were of mixed parity, lactating, suckled, ≥120 days postpartum with body condition score 3.08 ± 0.34 and 375‐475 kg of body weight which were randomly assigned to receive either OVS (n = 46) or PG (n =34) protocol. Cows were inseminated twice at 12 and 24 h after second gonadotropin releasing hormone in the OVS group, and 72 and 84 h after administration of prostaglandin F_2α in PG group, respectively. The results revealed that estrus response did not differ (P > 0.05) and was 87% in OVS and 78% in PG cows. Ovulation rate did not differ (P > 0.05) and was 50% in both, OVS and PG cows. The pregnancy per AI did not differ (P > 0.05) and was 43% in OVS compared to 31% in PG cows. It is concluded that estrus response, ovulation rate and pregnancy per AI of OVS protocol is the same as PG in Sahiwal cows.     

Comparative evaluation of raw and roasted soybean in lactating crossbred cows

An experiment was conducted to evaluate the effect of roasting whole soybean in the local level on their chemical composition, nitrogen fractions, in situ degradability, and feeding performance in crossbred (Karan Swiss and Karan Fries) dairy cows. Twelve lactating crossbred cattle (369.08 ± 17.53 kg body weight) were randomly divided into two groups on the basis of milk yield (10.18 kg/day) and day of calving (89 days) in a randomized block design. Cows were fed green maize fodder and concentrate mixtures with 1 kg raw soybean as fed basis (7.6% of total diet) in the control group, where as roasted soybean replaced raw soybean in the treatment group to make both diets isonitrogenous and isocaloric. The roughage to concentrate ratio was around 55:45 in both diets. The cows were housed in individual byres and fed experimental diet for 90 days. The total dry matter intake per animal in both groups was similar. The digestibility of dry matter, organic matter, crude protein, ether extract, and neutral detergent fiber was comparable in both groups. The average milk production and fat-corrected milk yield per day was similar during the trial. Milk fat, milk protein, and solids not fat content remained unaffected and similar in both groups. All the animals maintained their body weight in both groups. Thus, rumen bypassing of protein fractions at the present method of bypassing did not have the desired level of beneficial effect in medium producing crossbred cows.     

Occurrence of concurrent trypanosomosis,theileriosis, anaplasmosis and helminthosis in Friesian,Zebu and Sahiwal cattle in Uganda

An epidemiological investigation was conducted on farms in Tororo and Soroti districts of Uganda from January to February 2000 to determine the cause of reported persistent mortality of cattle. Blood and faecal material of 98 cattle comprising of 33 Friesians, 58 Zebu and 7 Sahiwal were examined. Results revealed that seven (7.1 %) cattle had trypanosome infection, mainly due to Trypanosoma vivax and T. brucei, 17 (17.3%) Fasciola infection, 28 (28.6%) gastrointestinal nematode infection, 33 (33.7%) Theileria sp. infection and 13 (13.3%) Anaplasma marginale infection. Mixed infections were detected in 30%, 20.6% and 43 % of the Friesian, Zebu and Sahiwal cattle respectively. Anaemia (PCV < 25) was detected in 24%, 19% and 14% of the Friesian, Zebu and Sahiwal cattle respectively. Persistent mortality of cattle on these farms could have been due to either single or mixed parasitic infections probably exacerbated by malnutrition.     

Nutritional evaluation of transgenic cottonseed in the ration of lactating dairy cows

The effects of feeding transgenic (Bt) whole cottonseed (WCS) were studied in lactating cows. Twenty multiparous crossbred cows (Karan Swiss × Karan Fries) in early lactation were given a concentrate mixture containing 40% crushed delinted non-transgenic (non-Bt) WCS, 2 kg wheat straw and green fodder ad lib for a 15-day adaptation period. Thereafter, the cows were divided in two similar groups of 10 each on the basis of milk yield, body weight (BW) and date of calving. The non-Bt control group continued on same ration, while for the Bt group the non-Bt WCS was replaced by transgenic WCS, in a feeding trial of four weeks. The diets provided a minimum of 2 kg cottonseed/cow/d. Mean DMI/100 kg BW and milk yield of non-Bt and Bt groups was 3.48 and 3.45 kg and 11.4 and 12.0 kg/d, respectively. Intake of nutrients, digestibility, milk production and body condition score (BCS) did not differ between the groups (P > 0.05), but BW gain was higher (P < 0.05) in the Bt group than the non-Bt group, probably as a result of hoof problem in two cows of non-Bt group, which when compared excluding two animals from each group did not differ significantly (P > 0.05). Transgenic protein (Cry1C) was not detected in the weekly milk samples or in blood plasma at the end of the experiment, showing that delinted WCS containing Cry1C protein can safely be fed to lactating cows.     

Tolerance of New Zealand White and Californian doe rabbits at first parity to the sub-tropical environment of Egypt

Tolerance of New Zealand White (NZW) and Californian (Cal) doe rabbits at the first parity to the sub-tropical environmental conditions of Egypt was evaluated. The study included 1090 parturitions: 601 NZW and 489 Cal. The does used were 5 months of age and 3.1 ± 0.10 kg mean body weight. The study was carried out during the different seasons of the year. The results showed that the effects of breed on the traits studied were not significant except on the doe kindling weight. However, the traits studied were, in general, higher in NZW than in Cal. The estimated temperature–humidity index (THI) average values were 19.8, 18.0, 23.7 and 25.7 during autumn, winter, spring and summer, respectively, indicating absence of heat stress during autumn and winter (less than 22.2) and exposure to severe (more than 23.3) and very severe heat stress (more than 25.6), during spring and summer, respectively. The effects of season of kindling were highly significant (P < 0.001 or 0.01) on conception rate, gestation period, kindling weight, litter weight at birth (live and total), 21 days of age and at weaning and kit weight at birth. The values were, in general, the lowest (P < 0.05) during the very severe heat stress in summer, while the kindling interval and pre-weaning mortality were the highest in summer. Adaptability was estimated (during the four seasons of the year) to be 93.3% and 95.1% for NZW and Cal, respectively. No interactions were observed in the analysis.     

Genetic and non-genetic factors affecting semen production traits in Karan Fries crossbred bulls

The objective of the study was to evaluate the effects of genetic and non-genetic factors on production of breeding bulls and semen quality parameters in Karan Fries crossbred male by fitting least squares analysis. Genetically, the animals were divided into three subclasses. The non-genetic factors were season of birth, period of birth, and age group with three subclasses each for season of birth and period of birth. Age group was classified into four subclasses. The traits generated in the study were number of males reaching semen donation stage (AFSC) and first freezing (AFSF), age at last semen collection (ALSC) and last freezing (ALSF), age at disposal (AD), and lifetime semen production traits (up to 1 year after first freezing). The effect of period of birth was significant for AFSC, AFSF, ALSC, and AD. It was also significant for total ejaculates produced in a year. The age group had significant effect on AFSF. Effect of genetic group was significant for freezable ejaculates produced in a year, for frozen semen doses produced in a year, and for number of ejaculates cryoprocessed in a year. Season had no statistically significant effect on any of the traits studied. The influence of period revealed that the most of the traits of breeding bulls improved after intermediate period, which could be due to better care, training, feeding, and other management practices in the latter years. However, no consistent trend could be established for the effects of genetic groups and other non-genetic causes on the traits considered.     

Variations in the Length of the Y Chromosome and the Seminal Attributes of Karan Fries Bulls

Fresh semen and blood samples from 20 Karan Fries bulls (4–6 years of age), maintained at the Artificial Breeding Complex of the National Dairy Research Institute, Karnal, were collected for one year. All the bulls had 60 chromosomes, comprising 58 acrocentric autosomes and 2 sex chromosomes, with X as the larger and Y as the smaller submetacentric. The mean lengths of Y_p and Y_q; the total length of the Y chromosome and the length ratio were 1.10±0.01 m, 1.83±0.02 m, 2.92±0.02 m and 62.46%±0.18%, respectively. Analysis of the length measurements of the the Y chromosomes in Karan Fries bulls showed that all the measurements, viz., the short arm of the Y chromosome, the long arm of the Y chromosome, the total length of the Y chromosome and the variation in length of Y chromosome, varied significantly among bulls. All the seminal parameters, the volume of semen, mass activity, initial motility, concentration, live sperm count and the total abnormal sperm count, were significantly affected by bulls, whereas season had a significant effect on all the seminal parameters except the total abnormal sperm count. No significant relationship between the ratio of the long arm to the total length of the Y chromosome and seminal attributes was observed.     

Estimated breeding values for meat characteristics of crossbred cattle with an animal model.

Longissimus muscle area, shear force measure, and sensory panel scores for flavor, juiciness, and tenderness, and marbling score were obtained from 682 steer carcasses, resulting from crosses among five Bos taurus and Bos indicus breeds. The single-trait model used included birth year and as covariates breed fractions, weaning age, and days on feed. The numerator relationship matrix was for 1,350 animals (682 steers, 74 pure breed and 52 F1-cross sires and 542 dams). The coefficient matrix was inverted to examine standard errors of prediction. Estimated breeding value is the sum of the estimate of genetic deviation and the weighted (fractions) sum of estimates of breed effects. Heritabilities used in estimating breeding values were .62, .06, .05, .11, .05, and .43 for longissimus muscle area, shear force, flavor, juiciness, tenderness, and marbling score. Sires within a breed or crossbred group tended to rank similarly due to large differences among breed effects (e.g., the six Sahiwal sires ranked in the highest six places for shear force). These results illustrate that for traits with large breed differences, selection of the proper breed should be done before selection within that breed.     

Production objectives and breeding goals of Sahiwal cattle keepers in Kenya and implications for a breeding programme

The Sahiwal breed has been used for upgrading the East African Zebu (EAZ) for improved milk production and growth performance in the southern rangelands of Kenya. Main users of this breed are Maasai pastoralists. Until now, there has been no deliberate effort to understand why these pastoralists specifically prefer to keep Sahiwal genetic resources as well as which traits are considered important by them and what is the underlying reason for this. However, this information is regarded vital for further development of the breed. A survey was conducted between May and October 2009 among Maasai pastoralists in Kajiado and Narok counties in the Southern part of Kenya, and private ranches and government farms to identify production objectives and breeding goals of Sahiwal cattle producers. Sahiwal genetic resources were mainly kept for domestic milk production and for revenue generation through milk sales and live animals. To a limited extent, they were kept for breeding and also for multiple objectives that included insurance against risks and social functions. Production aims were influenced to varying extents by various household and farmer characteristics. Sahiwal cattle and their crosses were generally perceived to be better with respect to productive traits and fertility traits when compared to the EAZ. However, the EAZ was rated higher with respect to adaptation traits. The breeding objective traits of primary importance were high milk yield and big body size, good reproductive efficiency and relatively good adaptation to local production conditions. Performance and functional traits are important breeding goals that play a major role in fulfilling the multiple production objectives. This forms the basis for the optimisation of a breeding programme for sustainable utilisation to meet the needs of Sahiwal cattle producers.