An investigation on the different environmental and genetic causes of variation in the birth weight of Black Bengal goats was conducted at the Central Livestock Research-cum-Breeding Station, Haringhata, India. The data consisted of 1375 birth weight records of kids from 284 does and 20 bucks during the period from 1955 to 1961. The goats were maintained under standard farm management throughout the period.

Year had significant effect on birth weight, while the effect of season was insignificant. The interaction was, however, significant. Male kids were significantly heavier at birth than the females. Age of dam and litter size also caused significant variation in birth weight of kids.

From paternal half-sib analysis the heritability of birth weight was estimated to be 0·01. Full sib and maternal half sib analyses estimated the maternal environment common to litter mates to account for 60 % of the variance, out of which 25 % were due to permanent differences between dams. The remaining 39 % were attributed to individual environment, including most of the non-additive genetic variance. The heritability of maternal environment was estimated to be 0·2.

The partial correlation coefficient between birth weight of kids and post-kidding body weight of their dam, independent of litter size and age of dam, was 0·175. Thus, body size of dam, as indicated by post kidding body weight, did not reveal much information about maternal environment.

Thirty-six Border Leicester x Scottish Blackface ewes were separated from their lambs after approximately 12 weeks lactation and brought indoors. They were allocated at random to nine dietary treatments comprising three dietary ratios of chopped roughage to concentrate, each offered at three levels of feeding. During the course of the experiment digestibility and nitrogen balance trials were carried out using three ewes from each dietary treatment.

The daily nitrogen intakes required for nitrogen equilibrium were calculated from the regressions of nitrogen intake on nitrogen retained for each of the three ratios. The intakes increased from 0·47 g/kg W0·75 on the diet containing the lowest proportion of roughage to 0·59 g/kg W0·75 on the diet containing the highest proportion of roughage. The corresponding digestible organic matter intakes did not differ significantly from the pooled value of 18·8 g/kg W0·75.

The daily digestible organic matter intakes required for the maintenance of live weight on the three ratios did not differ significantly from the pooled estimate of 26·9 g/kg W0·75 which is in close agreement with other published results. The nitrogen intakes required for the maintenance of live weight increased from 0·70 on the diet containing the lowest proportion of roughage to 0·84 g/kg W0·75/day on the diet containing the highest proportion of roughage.

The coefficients for live-weight change in the regression equations relating digestible organic matter to live weight and live-weight change for each ratio did not differ significantly from the pooled estimate of 2·0 g DOMI/g live-weight change.

The significance of the results are discussed in relation, to the nutritional status of the ewe and other research findings.

Statistical analyses were carried out on the data obtained, under strictly controlled conditions in metabolism stalls, from 219 adult non-pregnant dry cows fed on seventyone different rations. The authors have calculated and studied the correlations between total water intake, faecal and urinary water losses, absorbed and available water, and the seventy-five other factors which were analysed in each of the seventy-one rations. Total water intake closely correlated with the dry-matter intake and also with the dry-matter content of the diet; forages with high moisture content enhance the total water intake which is also significantly correlated to the intake of nitrogen, fat and some mineral elements.

Total water intake closely correlated with the dry-matter intake and also with the dry-matter content of the diet; forages with high moisture content enhance the total water intake which is also significantly correlated to the intake of nitrogen, fat and some mineral elements.

Faecal water losses are strongly correlated with the dry-matter intake and on the faecal dry matter. Moisture content of the diet has no significant effect but increasing pentosans and crude-fibre intake enhance the losses.

Urinary water excretion is closely related to the amount of absorbed water and to the dry-matter content of the diet; a highly significant correlation also exists between urinary water and urinary nitrogen and potassium. The amount of water excreted in the urine may affect the utilization of digestible nitrogen and potassium.

Available water is increased logarithmically when total water intake rises arithmetically. Feeds with high moisture content thus enhance the amount of available water.

A breeding programme initiated at Oak Park, Carlow, in September 1965, in which perennial ryegrass plants, instead of being widely spaced as traditionally used in grassbreeding, were planted 9 x 9 in apart, is described. At this density, plants were individually distinguishable throughout three growing seasons yet gave a complete ground cover of herbage on which was imposed two contrasting systems of defoliation. Data on ear emergence, dry-matter yields, persistence and some quality components agreed with data obtained from swards by other workers.

The in vitro cellulose digestibility of thirteen cuts of perennial ryegrass, cocksfoot and two varieties of Rhodes grass was determined under different conditions. Cellulose digestibility was increased by increasing the length of the incubation period (1,2 and 6 days), the fineness of grinding of the samples and by addition of a supplement. The effects of fineness of grinding and of supplement were greatest after incubation for 1 day and least after 6 days. Between-run variation in cellulose digestibility was reduced by the supplement and by increasing the length of the incubation period.

In a comparison of different methods of predicting in vivo organic matter digestibility the lowest residual standard deviation ( ± 2·29) was with in vitro organic matter digestibility (1 mm screen and incubated with supplement for 2 days). Other residual errors were: in vitro cellulose digestibility ± 2·40, pepsin-soluble organic matter ± 4·93, total available carbohydrate ± 6·39, cellulose ± 6·40 and nitrogen ± 6·46.

Higher pH values had been established under grass than under clover pastures during a prior pasture phase. The differential effect of pasture species on the pH of the subsequently cultivated soil was reduced in time, but continued to be significant after 4 years.

There was greater cation exchange capacity and lower percentage base saturation after clovers than after grasses. The cation exchange capacity of the inorganic fraction of the soil was not affected by the type of pasture and did not change with time. The difference in cation exchange capacity for the cultivated soil was, therefore, due to the difference in the cation exchange capacity of organic matter residual from the clover and grass pastures.

‘Nitro-chalk” was applied to established swards of ryegrass S. 24 and cocksfoot S. 37 at the rate of 24 and 96 lb N/acre (27 and 107 kg N/ha) before growth commenced and after each cutting. The cuts were taken each time the grass reached a length of 10–11 in (8–9 in of cut herbage). The main effect was that the higher rate of fertilization allowed the grass to be harvested more frequently and this grass had lower pectin, cellulose and hemicellulose contents and a higher level of digestibility. A secondary effect was that the proportion of hemicellulose to cellulose was less in the more heavily fertilized grasses. The cocksfoot grasses at both levels of fertilizer were cut more frequently than the corresponding ryegrasses and were only slightly less digestible. There was some decline in the digestibility of the grasses from May to September which was associated with lengthening growth intervals and generally higher percentages of the structural constituents.

This study is the first comprehensive estimation of breed parameters for the Jamaica Hope breed of dairy cattle. It has shown that the breed has considerable potential for milk production undser good husbendry in a tropical environment. Improvements in reproductive performance may be achieved, without prejudice to production performance, by using milk yield per day of calving interval (which has a moderatoly high repestability) as a criterion for selection.

Using data (1950–64) from the government-owned herd of Jamaica Hope cattle at Bodles, Jamaica, it was estimated that the fraction of cows called on the basis of their milk production in any given lactation was of the order 0·00 to 0·05. Using data (1967–68) from ten high–and ten low-producing farmer herds of the same breed, it was found that the level of calling was low and that cows proceeding from one lactation to the next had a yield superiority over the total population of only + 4 gallons. It is suggested that one of the principal reasons for the apparent lack of response to selection in dairy herds in the tropics may be that little or no selection for production is in fact practised.

The contemporary comparison method of evaluating the progeny test of sires has been employed in estimating the breeding values of bulls used in the development of the Jamaica Hope breed. The need to test a larger number of bulls by combining the programme at the national level is stressed.

Nine Merino wethers were used in a cross-over experiment to compare the voluntary intake of three diets after a 4-week period in which the intake of the same diets was restricted, either to a level which maintained the live weight and energy status of the sheep, or to one which resulted in losses of 18% and 26% in their live weight and total energy content respectively. The diets were prepared from lucerne hay; chaffed (L), ground and pelleted (P) and pelleted after mixing with ground wheat (W).

The voluntary intake of food increased only slowly during the 4 weeks after restrictions were removed; the total intake of digestible organic matter from diets W, L and P was in the ratio 100:122:146. Differences between diets L and P, but not W, were associated with their rates of disappearance from the rumen. Sheep which had been severely restricted ate less food during the first fortnight and no more during the second fortnight than those which had previously maintained their energy status. The difference in the first fortnight was less for diet P than for diet L. The process of adaptation by the sheep to unrestricted feeding was associated with an increase in the net rate of disappearance of volatile fatty acids from the rumen.

Sheep offered food ad lib. after a period of submaintenance feeding gained more weight than sheep which had previously been fed to maintain weight and this increase was greater with diet P than with diet L. However, the differences in live-weight change consisted largely of water in the gut and did not result from a relative increase in the voluntary intake of food or in the efficiency of energy utilization.

Changes in yield and quality of an Andropogon gayanus sward were traced throughout the 1964 wet season and part of the following dry season.

Quality, in terms of crude-protein content, was highest at the beginning of the wet season, but yield increased to a maximum at the beginning of the dry season. Once flowering was completed in October, herbage quality fell to a very low level. It was concluded that the best time to cut for hay was in early October, at which time the crude-protein content showed a small but significant increase. Regrowth measurements taken in mid-November indicated the benefit of taking an early hay cut in July as a means of producing better quality hay at the end of the rains.

During the early vegetative phase of growth leaf production was greater than stem production. Quality was high because the leaves contained a higher content of crudeprotein, calcium, phosphorus and carotene than the stems. During the reproductive stage of growth, comprising stem elongation in September culminating in anthesis in early October, quality was lower due to the high fibre content of the stems. The increase in crude-protein in early October, coincided with the expansion of new leaves on the flowering stems.

It was concluded that throughout most of the latter part of the growing season A. gayanus did not provide adequate supplies of crude-protein, calcium and particularly phosphorus for normal cattle growth, especially after flowering was completed in late October.

Potatoes (var. Pentland Dell) were grown in pots containing soils from the Bothamsted ley–arable experiments. When about half the initially available K was used, the tops were harvested and the potential limiting K uptake, inferred from K uptakes, was – 4150 cals/equiv. The plants grew on until they exhausted the available K and died, having set tubers. The potential then limiting K uptake, inferred from total K uptakes, was – 4900 cals/equiv., similar to the mean potential in the exhausted soils, – 4710 ± 61 cals/equiv. The significance of these measurements is discussed.

Total K uptake was closely related to the amount of K that had to be removed from each soil to lower the potential to – 4900 cals/equiv. and the relationship suggested that the potatoes did not use any K from initially non-available reserves.

Dry-matter yields of tubers and of tops + roots, and the ratio of the two, were well related to quantity and potential of K in the soil; tuber yield was also well related to K in tops. The K potential needed for maximum yield of tubers exceeded – 2430 cals/equiv.

Experiments with Sitka spruce (Picea sitchensis) seedlings grown on an acid sandy podzol at Wareham, Dorset, England showed that sulphur fertilizers improved the colour but not the height of the crop and increased sulphur concentrations in the needles above those considered by Ingestad (1962) to indicate sulphur deficiency for Norway spruce (Picea abies). Spruce seedlings grown on other soils (Oxford and Woburn) contained more sulphur than those grown at Wareham. Sulphur concentrations in transplants of both species were generally less when S-free basal fertilizers were used.

Radish (Raphanus sativus) experiments confirmed that Wareham soil was low in available sulphur. Increased yields were obtained from elemental sulphur treatments during the springs of 1968 and 1969, but not the summer months, when more sulphur may have been mineralized in the warmer soil. Wareham is in an area with less sulphur in the rain and atmosphere than most other parts of England.

The application of 2,4-D in combination with certain mineral nutrients was shown to produce a wide range of results on yield of the potato crop. Several variables were studied for their effects on the response of the crop to a commercially available compound of the above constituents (NCL).

While no environmental factors were shown to influence the response of the crop to NCL, the following factors did: time of application, potato variety, time of harvest, plant population and the presence or absence of the parent tuber. NCL was shown to modify the growth pattern of the crop and to increase the efficiency of the leaf canopy.

In 1964 spring wheat and kale each were grown with 0·0, 0·5, 1·0 or 1·5 cwt N/acre. In 1965 barley measured residues. Without N and with 0·33 cwt N/acre the barley yielded more after wheat than after kale, but, with 0·66 or 1·0 cwt N/acre, more after kale. The residues of the N given for the wheat and kale increased barley yields.

In 1965 spring wheat, kale and Italian ryegrass each were grown with 0·0, 1·0 or 2·0 cwt N/acre. In 1966 and 1967 barley tested 0·0, 0·5 or 1·0 ewt N/acre in all combinations with previous treatments. In 1966 yields were largest after kale and smallest after ryegrass. Differences from the three crops were diminished by the N applied for them, and these N residues consistently increased yields. N given to the barley greatly increased yields, most after ryegrass and least after kale, and equally with or without fertilizer residues, but did not change differences from the crops. In 1967 yields were largest after ryegrass, but no larger after kale than after wheat. The residues of the N given for ryegrass increased yields. N given to the barley increased yields greatly, but most after kale.

In 1966 spring wheat, kale and Italian ryegrass each were grown without N and with 1·0 or 2·0 cwt N/acre, but on a more fertile field. In 1967 and 1968 barley tested 0·0, 0·5 or 1·0 cwt N/acre in all combinations with previous treatments. In 1967 yields were largest after kale and smallest after ryegrass. The residues of the N given in 1966 consistently increased yields when the barley was not given N, and after ryegrass when it was; but they decreased yields when N was given after wheat and kale. The barley needed 1·0 cwt N/acre after ryegrass, but less than 0·5 cwt N/acre after wheat or kale. In 1968 barley yielded most when it was not given N and then the largest yields were after ryegrass. The N given for the barley greatly decreased yields and the N residues decreased them further.

The amounts of N removed in the barley grain were well correlated with yields.

The dry weight contributed to the grain yield of sorghum by different parts of the plant was measured by removing laminae and by shading the head. A Nigerian tall variety formed more dry weight after heading and had a larger leaf area duration than a short-season, hybrid sorghum, but its grain yield was smaller. Laminae contributed more than 80% of the dry weight formed after heading in the Nigerian sorghum but less than half of this went into the grain. The remainder went into the stem, mainly to replace respiratory losses, or accumulated in the rachis and branches of the head. Top, middle and bottom groups of laminae contributed 42, 22 and 12% respectively to the dry weight of the grain; the remaining 24% was contributed by the sheaths. In the short-season hybrid sorghum over 70% of the dry matter formed after heading was stored in the grain. Only about half of this came from the laminae; assimilation in the head and in the sheaths contributed about equally to the remainder.

The effect of different spacings between and within rows on the pod yield of Ashford (semi-spreading, alternately branched type) and Barberton (upright, sequentially branched type) were studied.

The largest yield of Ashford was obtained at 60 cm x 15 cm spacing, while in Barberton the largest yield was obtained at 40 cm x 15 cm. It is suggested that the optimum spacing for these varieties varied because of differences in their growth habits.

Differences in yield were generally associated with differences in the number of pods and weight of pods per plant. An inverse relation between number of pods per plant and number of seeds per pod suggested internal competition between alternative sinks.

The number of flowers per plant decreased with closer spacing. The percentage of flowers which set pods ranged from 14 to 21%. Wider spacing increased the number of branches, total number of pods and the proportion of pods which matured, but did not affect the mean individual kernel weight.

Seventy-two (thirty-six hogs and thirty-six gilts) Large White type weaner pigs were individually and restrictedly fed four diets (as wet mashes) containing high levels (85% in the starter diets and 90% in the finisher diets) of either maize, sorghum, wheat or barley. Thirty-six pigs (nine per treatment) were slaughtered at 120 lb (54 kg approximately) live weight at the end of the period in which the starter diets were fed and the remaining thirty-six at 200 lb (90 kg approximately) live weight at the end of the period in which the finisher diets were fed.

In the starter period the growth rates and food conversion efficiencies of the pigs fed the barley- and wheat-based diets were similar but taken together were slightly superior to those of the pigs fed the maize- and sorghum-based diets. Based on determined digestible energy values the caloric efficiency of live-weight growth was significantly better for the barley-based diet than for all other diets. At a slaughter weight of 120 lb the killing out percentage of the pigs fed the maize diet was significantly higher than that of the pigs fed the barley and wheat diets. Iodine numbers of inner and outer backfats were significantly higher in pigs fed maize than in those fed sorghum and wheat and in those fed barley compared with those fed wheat. There were no other differences in carcass measurements or in the percentages of lean, fat and bone dissected from the carcasses. However, the pigs fed barley had (1) significantly smaller middle regions and (2) as percentages of the total tissue within the body, significantly less fat in the middle region but significantly more fat in the shoulder region, than did any of the other pigs.

In the finisher period the pigs fed the barley- and wheat-based diets grew significantly faster and converted their food and digestible energy of that food significantly more efficiently than did the pigs fed maize and sorghum. The caloric efficiency of live-weight gain was also significantly greater for the barley-fed pigs compared with those fed wheat. When slaughtered at 200 lb live weight, with the exception of backfat iodine numbers, where identical differences to those recorded at 120 lb were found, there were no significant differences in carcass measurements. On dissection the barley-fed pigs had significantly more lean and significantly less fat in the carcass than did any of the other pigs.

Sections of muzzle skin were studied from twelve Murrah buffaloes including seven females and five males ranging from 1½ years to mature animals up to 7 years old. The 130–1350 μ thick epidermis of muzzle rested on a PAS positive, argyrophilic basement membrane. The stratum lucidum was lacking. The stratum granulosum could not be identified in some animals. In such animals, a wavy, deeply eosinophilic layer was seen in the area of stratum granulosum and stratum lucidum.

Lamellated nerve endings, 40–45 μ in diameter, and arteriovenous anastomoses, frequently appeared in the reticular layer of the muzzle dermis.

The muzzle glands were lobulated, compound tubuloacinar and resembled the salivary glands morphologically. Their acini were strongly PAS reactive and acidic mucopolysaccharide positive. While intercellular secretory canaliculi were present, myoepithelial cells could not be observed. It is suggested that fine bundles of striated muscle fibres which run perpendicular to the skin surface might function to expel gland secretions. Most gland-cell nuclei were intensely Feulgen reactive and the cells revealed a moderate alkaline phosphatase activity. The intralobular duct system of the muzzle glands consisted of PAS negative intercalated ducts and mildly PAS reactive striated tubules. The simple cuboidal to columnar epithelium of the striated tubule changed to pseudostratified columnar type toward the larger interlobular ducts which were lined by stratified columnar epithelium. Toward their opening, the excretory ducts had stratified squamous epithelium. The lumina of the ducts frequently contained PAS positive and colloidal iron reactive secretory mass.