Growth performances of F1 angus plus calves grazing on pasture in Hawaii’s tropical climate

Angus Plus cattle offer advantages for heat tolerance and forage utilization by introduction of Brangus and Brahman to Angus. To evaluate its adaptability in Hawaii Islands, we reported the growth performances of 213 F1 Angus Plus calve grazing on pasture. Least-square means of pre-weaning ADG ranged from 1,087 to 1,167 g in bull calves and from 1,030 to 1,048 g in heifer calves. The 205 d-adjusted weaning weight were 226 to 285 kg in bulls and 214 to 252 kg in heifers. The birth weight and hip height at birth were significantly correlated with weaning weight, 205 d-adjusted weaning weight, hip height at weaning and pre-weaning ADG (P < 0.01). Sire group significantly influenced pre-weaning growth performances through interaction with sex of calf. Bull calves from sire group of high growth were 1.0–3.8 kg heavier in birth weight than the bull calves from other sires (P < 0.001). Sire group x sex interaction was significant (P < 0.05) for calf birth weight, 205-d adjusted weaning weight and pre-weaning ADG. Sire group also played a significant role in hip height at birth (P < 0.05). Selections of the sires preferable for growth significantly improved calf pre-weaning growth performances.     

Estimates of (co)variance components and genetic parameters for growth traits of Avikalin sheep

(Co)variance components and genetic parameters for various growth traits of Avikalin sheep maintained at Central Sheep and Wool Research Institute, Avikanagar, Rajasthan, India, were estimated by Restricted Maximum Likelihood, fitting six animal models with various combinations of direct and maternal effects. Records of 3,840 animals descended from 257 sires and 1,194 dams were taken for this study over a period of 32 years (1977–2008). Direct heritability estimates (from best model as per likelihood ratio test) for weight at birth, weaning, 6 and 12 months of age, and average daily gain from birth to weaning, weaning to 6 months, and 6 to 12 months were 0.28 ± 0.03, 0.20 ± 0.03, 0.28 ± 0.07, 0.15 ± 0.04, 0.21 ± 0.03, 0.16 and 0.03 ± 0.03, respectively. Maternal heritability for traits declined as animal grows older and it was not at all evident at adult age and for post-weaning daily gain. Maternal permanent environmental effect (c ²) declined significantly with advancement of age of animal. A small effect of c ² on post-weaning weights was probably a carryover effect of pre-weaning maternal influence. A significant large negative genetic correlation was observed between direct and maternal genetic effects for all the traits, indicating antagonistic pleiotropy, which needs special care while formulating breeding plans. A fair rate of genetic progress seems possible in the flock by selection for all traits, but direct and maternal genetic correlation needs to be taken in to consideration.     

Effects of genetic and environmental factors on pre-weaning and post-weaning growth in West African crossbred sheep

Effects of genetic and environmental factors on pre-weaning and post-weaning growth were studied in West African crossbred sheep. Effects of lamb genotype (7/8 Sahelian–1/8 Djallonké, 3/4 Sahelian–1/4 Djallonké and 1/2 Sahelian–1/2 Djallonké; hereafter denoted 7/8Sa, 3/4Sa and 1/2Sa, respectively), parity, type of birth, sex of lamb and year-season of lambing on birth weight, weaning weight, 8-month weight and pre- and post-weaning growth rates were determined. At birth 7/8Sa and 3/4Sa lambs were heavier (p<0.01) than 1/2Sa lambs. Lambs born to first-parity ewes were lighter (p<0.01) at birth than lambs of older ewes. At weaning and 8 months of age, lambs born to fourth-parity ewes were heavier (p<0.05) than those born to ewes of the other parities. Parity did not have any significant effects on pre-weaning growth rate. Lambs born in the rainy season of 2001 were significantly heavier at birth and at 8 months of age than those born in the dry season of 2001/02, but there was no difference between the two groups at weaning. Pre-weaning growth rate was significantly faster in lambs born in the dry season of 2001/02 but the reverse was true for post-weaning growth rate.     

Estimates of (co)variance components and genetic parameters for growth traits in Sirohi goat

Data were collected over a period of 21 years (1988–2008) to estimate (co)variance components for birth weight (BWT), weaning weight (WWT), 6-month weight (6WT), 9-month weight (9WT), 12-month weight (12WT), average daily gain from birth to weaning (ADG1), weaning to 6WT (ADG2), and from 6WT to 12WT (ADG3) in Sirohi goats maintained at the Central Sheep and Wool Research Institute, Avikanagar, Rajasthan, India. Analyses were carried out by restricted maximum likelihood, fitting six animal models with various combinations of direct and maternal effects. The best model was chosen after testing the improvement of the log-likelihood values. Heritability estimates for BWT, WWT, 6WT, 9WT, 12WT, ADG1, ADG2, and ADG3 were 0.39 ± 0.05, 0.09 ± 0.03, 0.06 ± 0.02, 0.09 ± 0.03, 0.11 ± 0.03, 0.10 ± 0.3, 0.04 ± 0.02, and 0.01 ± 0.01, respectively. For BWT and ADG1, only direct effects were significant. Estimate of maternal permanent environmental effect were important for body weights from weaning to 12WT and also for ADG2 and ADG3. However, direct maternal effects were not significant throughout. Estimate of c ² were 0.06 ± 0.02, 0.03 ± 0.02, 0.06 ± 0.02, 0.05 ± 0.02, 0.02 ± 0.02, and 0.02 ± 0.02 for 3WT, 6WT, 9WT, 12WT, ADG2, and ADG3, respectively. The estimated repeatabilities across years of ewe effects on kid body weights were 0.10, 0.08, 0.05, 0.08, and 0.08 at birth, weaning, 6, 9, and 12 months of age, respectively. Results suggest possibility of modest rate of genetic progress for body weight traits and ADG1 through selection, whereas only slow progress will be possible for post-weaning gain. Genetic and phenotypic correlations between body weight traits were high and positive. High genetic correlation between 6WT and 9WT suggests that selection of animals at 6 months can be carried out instead of present practice of selection at 9 months.     

Genetic analysis for growth traits of prolific Garole × Malpura (GM) sheep

The FecB gene of Garole sheep was introgressed into non-prolific Malpura sheep to evolve a new prolific sheep strain Garole × Malpura (GM), suitable for semi-arid conditions. The present study was conducted to evaluate the impact of breeding program on production profile of GM sheep and to estimate the genetic parameters for growth traits of GM sheep. Overall prolificacy increased significantly in the new strain as compared to the native Malpura sheep. In the GM flock of F2 and F2 onwards generation 35.31% single, 55.83% twins, 8.16% triplet and 0.70% quadruplets were obtained during lambing. Over the years, prolificacy in the flock has increased significantly. Over all least squares means for birth weight, 3, 6, 9, 12 month weight, pre-weaning gain (ADG1) and post-weaning gain (ADG2) were 1.82 ± 0.03, 9.44 ± 0.18, 14.00 ± 0.24, 16.56 ± 0.33, and 19.32 ± 0.35 kg, and 84.08 ± 1.84 and 35.19 ± 0.99 g, respectively. Majority of the fixed effects had significant influence on the performance traits. The heritability estimates for birth, 3, 6, 9, 12 month weight, ADG1 and ADG2 were 0.30 ± 0.11, 0.22 ± 0.09, 0.23 ± 0.10, 0.27 ± 0.10, 0.30 ± 0.11, 0.17 ± 0.08, and 0.17 ± 0.10, respectively. Modest rate of genetic progress seems possible for these traits under selection. The genetic and phenotypic correlations among different body weights were moderate to high and positive. The genetic correlation of pre and post-weaning daily gains with body weight traits were also high and positive.     

Growth and carcass traits of Creole goats under different pre-weaning,fattening and slaughter conditions

Data of 198 male Creole kids were analysed to assess the main non-genetic sources of variation of their meat abilities. Basal diet was composed of tropical pasture (28 days): in FD (forage diet), kids received no supplement; in group MD (mixed diet) they were offered 360 g/day pellet, while in group PD (pasture diet) kids were reared at pasture without supplementation. Given a regular four-month interval of weaning within the flock, fixed ages at slaughter (AS) were 7, 11 and 15 months. Three slaughter weights (SW) were compared 17–18, 21–22 and 25–26 kg. The growth levels before weaning and the season of birth effects were added in the statistical analysis. The use of MD has a significant (P < 0.05) effect on almost all the body and carcass traits: 85% more ADG and carcass weight. The weights of fat tissues increased but represented only 4% of empty body weight. As expected, there were significant (P < 0.05) differences within the SW and AS classes that are discussed. Range of variations allow for suggesting further experiments or practical recommendations. The initial results: carcass yield (55%), conformation score (more than 3), fat cover score (less than 3), proportion of primal cuts (63%) or muscle/bone ratio (3–4 points) are a good incentive for the local sector.     

Estimating non-genetic and genetic parameters of pre-weaning growth traits in Raini Cashmere goat

Data and pedigree information used in the present study were 3,022 records of kids obtained from the breeding station of Raini goat. The studied traits were birth weight (BW), weaning weight (WW), average daily gain from birth to weaning (ADG) and Kleiber ratio at weaning (KR). The model included the fixed effects of sex of kid, type of birth, age of dam, year of birth, month of birth, and age of kid (days) as covariate that had significant effects, and random effects direct additive genetic, maternal additive genetic, maternal permanent environmental effects and residual. (Co) variance components were estimated using univariate and multivariate analysis by WOMBAT software applying four animal models including and ignoring maternal effects. Likelihood ratio test used to determine the most appropriate models. Heritability ( \texth_\texta² ) \left( {{\text{h}}_{\text{a}}^2} \right) estimates for BW, WW, ADG, and KR according to suitable model were 0.12 ± 0.05, 0.08 ± 0.06, 0.10 ± 0.06, and 0.06 ± 0.05, respectively. Estimates of the proportion of maternal permanent environmental effect to phenotypic variance (c ²) were 0.17 ± 0.03, 0.07 ± 0.03, and 0.07 ± 0.03 for BW, WW, and ADG, respectively. Genetic correlations among traits were positive and ranged from 0.53 (BW-ADG) to 1.00 (WW-ADG, WW-KR, and ADG-KR). The maternal permanent environmental correlations between BW-WW, BW-ADG, and WW-ADG were 0.54, 0.48, and 0.99, respectively. Results indicated that maternal effects, especially maternal permanent environmental effects are an important source of variation in pre-weaning growth trait and ignoring those in the model redound incorrect genetic evaluation of kids.     

Effect of pre-weaning selection on estimates of genetic parameters and breeding values for post-weaning growth rate of beef bulls on test

Data on South African Angus cattle consisting of 45 259 records on weaning weight (WWT), 4 360 records on average daily gain from on-farm test (ADG-D) and 1 118 from centralized test (ADG-C) were analyzed to evaluate the effect of pre-weaning selection on estimates of genetic parameters and subsequent estimated breeding values (EBV) for post-weaning average daily gain. (Co)variance components and genetic parameters for weaning weight (WWT), ADG-C and ADG-D were estimated by REML procedures fitting three different animal models. Model 1 was a univariate model of WWT, ADG-C or ADG-D and did not account for the effect of pre-weaning selection on post-weaning ADG. Model 2 was a two-trait model of WWT and either ADG-C or ADG-D. Model 3 was a multi-trait animal model including WWT, ADG-C and ADG-D. Estimates of heritability for ADG-C were 0.39 ± 0.080, 0.42 ± 0.060 and 0.44 ± 0.010 from Model 1, 2 and 3 respectively. Corresponding estimates for ADG-D were 0.18 ± 0.020, 0.19 ± 0.020 and 0.21 ± 0.020 respectively. Rank correlations based on EBVs for ADG-C for all bulls were 0.92, 0.83 and 0.94 for Model 1 vs. Model 2, Model 1 vs. Model 3, and Model 2 vs. Model 3, respectively and they indicated a possible re-ranking of bulls when including or excluding a correlated pre-weaning trait. Rank correlations for ADG-D also followed a similar trend. Inclusion of pre-weaning information in genetic analysis for post-weaning average daily gain is necessary to account for selection at weaning.     

Growth performances of Washera sheep under smallholder management systems in Yilmanadensa and Quarit districts,Ethiopia

A study was conducted to evaluate growth performances of Washera sheep under smallholder production systems in the Yilmanadensa and Quarit districts of the Amhara National Regional State, Ethiopia. Data were collected and analysed on the growth of 690 lambs owned by 110 households from October 2004 to September 2007. Weight (kilograms) of Washera lambs at birth, 1, 3, 6, 9 and 12 months of age was 2.69 ± 0.02, 7.10 ± 0.16, 12.42 ± 0.11, 16.12 ± 0.91, 20.05 ± 0.55 and 23.47 ± 0.68, respectively. Birth weight was significantly (P < 0.05) affected by district, year of birth, parity of the dam, birth type and sex of lamb and by the interaction effect of parity by birth type and parity by sex of lamb. Weaning weight was also affected by year of birth, type of birth and sex of lamb. Yearling weight was affected by only year of birth and sex of birth. The average daily weight gain (ADG; grams) from birth to 30 days, birth to 90 days, 90 to 180 days and birth to 1 year of age was 143.37 ± 13.46, 107.09 ± 2.67, 39.78 ± 9.73 and 60.13 ± 1.89, respectively. Growth rates from birth to 30 and 90 days of age were significantly (P < 0.05) affected by birth year, birth type and sex. ADG from birth to 1 year of age was affected by lamb sex and district. The indigenous Washera sheep had faster growth rate than those sheep breeds of Ethiopia extensively studied thus far. Integrated efforts combining improved nutrition, health and participatory community-based breeding would help the smallholder farmers to utilise and conserve this immense sheep genetic resource of Ethiopia.     

Effect of doe milking and supplementation using <Emphasis Type="Italic">Dichrostachys cinerea</Emphasis> pods on kid and doe performance in grazing goats during the dry season

Effects of supplementation and milking of Matebele does four weeks pre-partum to weaning, on milk yield, kid birth weight and growth rate were studied. Forty does were divided into four treatments: supplemented and milked (SM), supplemented and not milked (SNM), not supplemented and milked (NSM); and not supplemented and not milked (NSNM). Supplemented goats were given 200 g/doe/day of Dichrostachys cinerea pods containing 19% CP. The study was carried out in September during time of feed unavailability and animals were grazed on rangelands for seven hours before being given the supplement. Fifty-six kids were born from all the experimental animals and 24 were singles whereas 32 were twins. Milk yield was higher (P < 0.05) in supplemented than non-supplemented does. Although supplementation had no effect on kid birth weights, growth rates were higher (P < 0.05) in the SNM group (103 ± 10.1 g/day) than in the SM group (74 ± 10.8 g/day). Among the non-supplemented groups, kids from milked does had higher (P < 0.05) daily gains (85 ± 10.9 g/day) than those from non-milked does (67 ± 10.7 g/day). Weaning weights were higher (P < 0.05) in SNM does (12.8 ± 1.30 g/day) than in the SM does (10.2 ± 1.17 g/day). Among kids from the non-supplemented does, those from milked does had superior (P < 0.05) weaning weights (11.2 ± 1.23 g/day) than those from non - milked does (9.2 ± 1.27 g/day). Mortalities were also lowest in kids born from SNM does. It is concluded that pre-partum to weaning supplementation generally increases milk production which then increases kids growth rates and weaning weights, as well as reduce kid mortalities.     

Effect of ruminally protected Methionine on the productive and reproductive performance of grazing <Emphasis Type="Italic">Bos indicus</Emphasis> heifers raised in the humid tropics of Costa Rica

With the objective of evaluating the effect of methionine supplementation prior to a breeding program, thirty one heifers (Bos taurus x Bos indicus) were used averaging 386  ±  29 days of age and a mean body weight of 402.6  ±  28 kg. Fifteen of the animals received a supplement (SG) during 45 days with molasses-urea mixture (2 kg molasses + 407 g urea/head/day), plus 10 g of ruminally protected methionine. The other sixteen heifers did not receive supplement (CG). Fecal and pastures samples were collected to assess dry herbage intake and digestibility. Serial ultrasound measurements from the ovary were performed in both groups to evaluate follicular dynamics. The heifers were categorized according to their follicular size and presence of a CL. Forage intake and dry matter digestibility were reduced (P  <  0.05) and body condition tended to improve (P  =  0.07) in the supplemented heifers, however, total intake, final weight, daily gain and dorsal back fat were not affected. After the supplementation period, the percentage of females in the categories < 3 mm and 3 to < 6 mm, was greater (P  <  0.05) in CG (25% and 43.7%) that in SG (0% and 26.6%) but in the follicle category of ≥  9 mm, the percentage of animals was 60% in SG and 18.8% in CG (P  <  0.05). The percentage of ovulation for the SG and CG was 86.7% and 62.5%, respectively (P  <  0.05). The combination of supplementation with methionine-urea and molasses at the end of the dry season and the anticipated onset of the rainy season favored the establishment of ovarian activity and follicular dynamics.     

Comparative studies on growth traits of Sanga and Friesian-Sanga crossbred calves raised on natural pasture on the Accra Plains of Ghana

Data collected from 1993 to 2006 at the Animal Research Institute of Ghana was used to compare the performance of Sanga and Friesian-Sanga crossbred calves on natural pasture. Performance traits analyzed were birth weight (BWT), weaning weight adjusted to 210 days (WW7), preweaning average daily gain to 210 days (ADG 1), weight at 12 months adjusted to 365 days (W12), weight at 18 months adjusted to 540 days (W18) and postweaning average daily gain (ADG 2, from weaning to 540 days). Effects in the model describing these traits were breed, season, sex and first-order interactions between these effects. With the exception of heavier birth weight of Friesian-Sanga crossbred calves (19.98 kg vs. 19.18 kg), body weights of Sangas at weaning, 12 months and 18 months exceeded those of the Friesian-Sanga crossbred calves by 3.76 kg, 35.06 kg and 46.24 kg respectively. The Sangas were also superior in preweaning average daily gain (0.35 kg/day vs. 0.26 kg/day) and postweaning average daily gain (0.28 kg/day vs. 0.21 kg/day). There was a tendency of increasing weight difference between the two breeds with advancing age. It was suggested that improved nutrition such as supplementary feeding would be necessary for crossbreds to express their potential for growth.     

Determinants of bone mass,density and growth in growing dogs with normal and osteopenic bones

Survey radiographs of all the growing dogs aged up to 6 months, which were presented to the IVRI polyclinics during the 10 year period were screened to study the determinants of bone mass, density and growth. On the basis of clinical history and radiographic evaluation of long bones, the cases were categorized as normal or osteopenic. The relative cortical density (RCD), cortical index (CI), diameter of bone at the distal metaphysis (DDFM) and the width of the growth plate (WFGP) were determined by taking the femur as a model bone in German shepherd, Doberman and Spitz breeds of dogs at different age groups. The results showed that the RCD was the least in 0–2 month old normal growing dogs in all the breeds. As the age advanced up to 6 months the RCD increased 20–25%, and at 6 months, Spitz and Doberman showed significant increase (P < 0.05) in the RCD. In osteopenic bones, RCD remained less (25–50%) than that of normal animals at all age groups, and at 2–6 months of age, RCD in osteopenic bones was significantly lesser than in normal animals in GSD and Spitz breeds. The CI was also the least at 0–2 months of age in normal dogs. The CI increased about 50% at 4–6 months of age in GSD and Spitz. Whereas in Dob., there was no appreciable change in the CI at different age groups, and at 2–6 months it was significantly (P < 0.05) lesser than that of Spitz. In osteopenic bones, the CI was 25–75% lesser than that of normal animals at different age groups, and at 4–6 months there was significant difference (P < 0.05) between the normal and osteopenic bones in GSD and Spitz. The DDFM was the least in 0–2 month old normal growing dogs, and as the age advanced, it increased 10–20% up to 6 months. However, no significant difference in the DDFM was seen between breeds and also between the normal and osteopenic bones at different age groups. In normal animals, the WFGP was highest in the early age, subsequently it reduced 50–75% and at 4–6 months there was significant decrease (P < 0.05) in all the breeds of dogs. And at 4–6 months, there was significant (P < 0.05) difference in the WFGP between breeds, it was the least in Spitz and maximum in Dob., suggesting faster growth plate closure in Spitz than in GSD and Dob. breeds. In osteopenic bones, WFGP was generally more than in normal animals, and at 4–6 months (about 3–5 times more) there was significant difference (P < 0.05) between the normal and osteopenic bones in all breeds, indicating that physeal closure may be delayed in osteopenic bones. The results indicate that among different breeds Doberman breed has the least bone mass and may be more prone to osteopenia; whereas Spitz has the strongest bone.     

Effect of feeding calcium salts on performance of nursing Awassi ewes

Twenty nursing Awassi ewes (BW = 50 ± 2.35 kg, age = 4.5 ± 1.2 years) with their lambs were used to evaluate the effects of feeding calcium salts in lactation diets on performance and pre-weaning growth of their lambs. Treatments were 0% calcium salts (CON) or 5% calcium salts (FAT). At the end of the study, a digestibility experiment was performed. Milk yield was greater (P < 0.05) for ewes fed the FAT diet than the CON diet. Milk composition was similar (P > 0.05) between diets. However, milk energy value (kcal/day) tended to be greater (P = 0.07) for the FAT diet than the CON diet. Concentrations of milk C18:1c9 and C20:0 were greater (P < 0.05) in ewes fed the FAT diet than the CON diet. However, concentration of trans-10, cis-12 CLA was lower (P = 0.05) in the FAT diet than in the CON diet. No differences in feed intake and body weight change were detected between diets. Digestibility of dry matter, organic matter, crude protein, ether extract, neutral detergent fiber, and acid detergent fiber were similar (P > 0.05) for diets. For lambs, weaning weight was not affected by treatments. However, average daily gain and total gain were greater (P = 0.053) for the FAT diet than the CON diet. Results suggest that supplementing lactating ewes with calcium salts at the beginning of lactation phase improves daily milk yield of ewes and pre-weaning growth of their lambs with no major negative impact on feed intake and digestibility.     

Relationship of age to body weight,scrotal circumference,testicular ultrasonograms,and semen quality in Sahiwal bulls

The objective of the present study was to determine the relationship of age to body weight (BW), scrotal circumference (SC), number of pixels of testicular ultrasonograms (NP), and semen quality in Sahiwal bulls. The study was based on 128 Sahiwal bulls of different age groups (from 0 to >100 months of age). Bulls were evaluated for SC, BW, and NP. Semen was evaluated once a week for five consecutive weeks from regularly collected donor bulls (n = 86) ranging in age from 25–30 to >100 months. Ejaculate volume, sperm motility, sperm concentration, sperm morphology, percent live sperms, sperm plasma membrane integrity, and normal acrosome were compared among different age groups. Mean SC and BW increased (P < 0.05) in a curvilinear manner from birth to >100 months of age. Mean NP of testicular ultrasonograms increased (P < 0.05) from 0 to 24 months and then plateaued until >100 months of age. Body weight, SC, and NP were positively correlated with age from birth until >100 months (r = 0.91, 0.87, and 0.40, respectively). Ejaculate volume (5.7 ± 0.2 vs. 4.6 ± 0.09 ml) and sperm concentration (1,281.6 ± 17.7 vs. 1,115.8 ± 55.9 × 10⁶/ml) increased (P < 0.05) in mature bulls compared to younger ones. However, motility (68.6 ± 0.3%), plasma membrane integrity (50.8 ± 1.0%), and normal acrosome (74.8 ± 0.5%) remained insignificant due to age. In six of eight age groups studied, morphological abnormalities were well within the range (18.1 ± 0.3%). In conclusion, the BW, SC, and NP of testicular ultrasonograms, ejaculate volume, and concentration increased with age. Moreover, semen quality is fairly independent of age except volume and concentration in Sahiwal bulls.     

Risk Factors for Kid Mortality in West African Dwarf Goats Under an Intensive Management System in Ghana

Breeding records from 1997 to 2000 for West African Dwarf goats kept under an intensive management system on the National Breeding Station at Kintampo in Ghana were analysed for the effect on mortality of sex, season and type of birth, and birth weight. The pre-weaning and post-weaning mortalities were 10% (n = 390) and 23.1% (n = 351), respectively, while the overall mortality from birth up to 12 months of age was 30.8% (n = 390). The post-weaning period recorded significantly higher proportions of deaths in males, females, single-born and twins, during the rainy and dry seasons, and for kids with low or high birth weight, compared to the pre-weaning period. There was significantly higher mortality in male kids than in female kids. The odds and risks of death for male kids were about twice those for females at post-weaning and up to 1 year of age. At pre-weaning and up to 1 year of age, a higher proportion of the dead were twins. Twins had approximately 2.5 the risk of death at pre-weaning, compared to singles. Also, kids born in the rainy season had significantly higher mortality than those born in the dry season. Kids that died by the time of weaning were significantly lighter in weight at birth than those that survived. Male kids had significantly higher mean weights at birth and at weaning, but not at 12 months of age. The significance of these findings is discussed.     

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.     

Genetic parameters for birth weight,weaning weight and age at first calving in Brown Swiss cattle in Mexico

Heritabilities and genetic correlations between birth weight (n = 13,741), adjusted 240-day weaning weight (WW, n = 8,806) and age at first calving (AFC, n = 3,955) of Brown Swiss cattle in Mexico were estimated. Data from 91 herds located in 19 of 32 states of Mexico from 1982 to 2006 were provided by the Mexican Brown cattle Breeder Association. Components of (co)variance, direct and maternal heritabilities were estimated for birth weight, WW and AFC using bivariate animal models. Direct and maternal heritabilities were 0.21 and 0.05 for birth weight, 0.40 and 0.05 for WW, whereas direct heritability for AFC was 0.08. The correlations between direct and maternal effects for birth weight and WW were −0.49 and −0.64, respectively. The genetic correlations between birth weight–WW and WW–AFC were 0.36 and −0.02, respectively. Under the conditions of this study, selection for increasing birth weight would increase WW, but increasing WW will not change AFC.     

Risk Factors for Lamb Mortality in Sahelian Sheep on a Breeding Station in Ghana

A retrospective cohort study was designed to examine the effect of sex, season of birth, type and year of birth, and birth weight on lamb mortality. The method used involved analysis of breeding records for Sahelian sheep kept on a breeding station at Pong-Tamale in northern Ghana from 1994 to 2000. The pre-weaning and post-weaning mortalities were 10% (n = 505) and 19% (n = 453), respectively, while the overall mortality from birth up to 12 months of age was 28% (n = 505). Compared to the pre-weaning period, the post-weaning period recorded significantly higher proportions of deaths in male, single-born, lambs born in the rainy or dry seasons, and in lambs with low (<3 kg) or high (> or =3 kg) birth weight. The odds and risks of death for male lambs were about one and a half times those for females at post-weaning. Lambs born in the dry season had significantly higher mortality than those born in the rainy season. Lambs that died by the time of weaning were not significantly different in weight at birth from those that survived. The mean birth and weaning weights of single-born lambs were significantly higher than those for twins. The mean pre-weaning ADG was significantly higher in lambs born as singles compared to that for twins. The season of birth had influence on mean birth weight, with those born in the rainy season having significantly higher weights than those born in the dry season. The year of birth significantly affected birth weight, weaning weight, weight at 12 months and ADG at all stages of the lambs' life. The study concluded that the most significant risk factors for lamb mortality included sex of the lamb, season of birth and birth weight. The last two could be manipulated, to some extent, to reduce lamb mortality.     

Effectiveness of strategic anthelmintic treatments in the control of gastrointestinal nematodes and <Emphasis Type="Italic">Fasciola gigantica</Emphasis> in cattle in Iringa region,Tanzania

A longitudinal field trial was conducted to determine the effectiveness of strategic anthelmintic treatments in the control of gastrointestinal (GI) nematodes and Fasciola gigantica in cattle. A total of 167 cattle (6–18 months) from three large-scale dairy farms, four traditional farms and nine small-scale dairy farms were randomly selected. The selected animals on each farm were ear tagged and allocated into three groups based on live weight and treated as follows: Group T4 was treated with albendazole 10% drench at 10 mg/kg four times a year (mid rainy, end of the rain, mid dry and late dry/early rainy season). Group T2 was treated with albendazole 10% drench at 10 mg/kg two times a year (mid rainy and late dry/early rainy season). Group UT remained as untreated control. Faecal, blood and pasture samples were taken every month for 13 months. In addition, individual body weight (BWT) was measured on every sampling date. Results showed that two and four strategic treatments significantly reduced faecal egg counts (FEC) by 49.5% and 62.3% respectively compared to untreated control animals (P < 0.001). Two and four strategic treatments per year significantly reduced the proportion of animals passing Fasciola eggs in faeces by 30.6% and 51.7% (P < 0.001), respectively. Animals treated two and four times a year significantly outgained untreated animals by 14.8 kg and 17.7 kg respectively at the end of the trial (P < 0.05). The management system had a significant effect on packed cell volume and the proportion of animals passing Fasciola eggs in faeces (P < 0.05). The programme of two strategic treatments per year was only effective in controlling GI nematodes. It is concluded that a programme of four strategic treatments per year was effective in controlling GI nematodes and F. gigantica and improved weight gain.